Radicicol derivatives, their preparation and their anti-tumour activity

Abstract: Radicicol derivatives in which one or both hydroxy groups are acylated have valuable anti-tumor activity or may be used as chemical intermediates.

Description: The present invention relates to a series of new derivatives of the compound "radicicol", which is also known by the name "monorden", and provides methods and compositions using these derivatives as well as processes for their preparation Radicicol (see, for example, Merck Index, 11th Edition, monograph No 6163, "Monorden") was first isolated in 1953, and its structure was elucidated in 1964 by Mirrington et al . [Tetrahedron Letters, 7 , 365 (1964)], who also disclosed the diacetyl derivative of radicicol. At that time, radicicol was known to have an activity which can be broadly described as "antibiotic" (as it is described in the Merck Index), although, in fact, its activity is strictly anti-fungal. It is also known to have a relatively strong tranquilizing activity without having any effect on the central nervous system. Subsequently, it was disclosed in US Patent No. 3 428 526 that radicicol has a strong inhibitory effect in vitro on the growth of tumour cells of the mouse mastocytoma P-815. However, to date, no commercial use for the compound has been found. DE-A-2903997 discloses dialkoxy derivatives of radicicol. Despite the strong in vitro activity, we have found that radicicol itself can exert little anti-tumour activity against various types of tumour in vivo , and have also surprisingly found that certain acylated derivatives of radicicol demonstrate a superior anti-tumour activity. It is believed that the relative inactivity of radicicol itself in vivo compared to the good activity in vitro may be a result of an instability of the compound to a component of the mammalian metabolism. We have, however, found that the acylated derivatives of radicicol of the present invention have greater stability in the mammalian body and can, therefore, be of practical use in the treatment of tumours. The compounds of the present invention are those radicicol derivatives of formula (I): in which: R 1 and R 2 are the same or different and each represents a hydrogen atom or a group of formula R 3 -CO-, where R 3 represents: a hydrogen atom; an alkyl group having from 1 to 50 carbon atoms; a substituted alkyl group which has from 1 to 50 carbon atoms and which is substituted by at least one of substituents (a), defined below; an alkoxy group which has from 1 to 20 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkenyl group which has from 2 to 30 carbon atoms and which has at least one carbon-carbon double bond; a substituted alkenyl group which has from 2 to 30 carbon atoms, which has at least one carbon-carbon double bond and which is substituted by at least one of substituents (a), defined below; an alkenyloxy group which has from 2 to 30 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkynyl group which has from 2 to 10 carbon atoms; a substituted alkynyl group which has from 2 to 10 carbon atoms and which is substituted by at least one of substituents (a), defined below; or a methoxyethoxymethoxy-substituted nonyl, undecanyl or pentadecanyl group and, where there are two groups R 3 , these may be the same or different; substituents (a) alkoxy groups which have from 1 to 20 carbon atoms and which are unsubstituted or are substituted by at least one alkoxy group having from 1 to 4 carbon atoms and/or alkylthio group having from 1 to 4 carbon atoms; and aliphatic carboxylic acylthio groups having from 1 to 20 carbon atoms; PROVIDED THAT R 1 and R 2 do not both represent hydrogen atoms AND THAT R 1 and R 2 do not both represent acetyl groups; and pharmaceutically acceptable salts thereof. The invention also provides a pharmaceutical composition for the treatment or prophylaxis of tumours, which comprises an effective amount of an active compound in admixture with a pharmaceutically acceptable carrier or diluent, wherein said active compound is selected from compounds of formula (I) and salts thereof, as defined above. The invention also provides the use of compounds of formula (I) and salts thereof for the manufacture of a medicament for the treatment or prophylaxis of tumours. The invention still further provides compounds of formula (I) and salts thereof for use in therapy. The invention also provides various processes for preparing the compounds of the present invention, which are described in greater detail hereafter. In the compounds of the present invention, where R 3 represents an alkyl group, this has from 1 to 50 carbon atoms, and may be a straight or branched chain group. Examples of such groups include the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, t-butyl, pentyl, 3-methylbutyl, 2,2-dimethylpropyl, 1,1-dimethylpropyl, hexyl, 1-methylpentyl, 4-methylpentyl, heptyl, 1-methylhexyl, 2-methylhexyl, 5-methylhexyl, 3-ethylpentyl, octyl, 2-methylheptyl, 6-methylheptyl, 2-ethylhexyl, 2-ethyl-3-methylpentyl, 3-ethyl-2-methylpentyl, nonyl, 2-methyloctyl, 7-methyloctyl, 4-ethylheptyl, 3-ethyl-2-methylhexyl, 2-ethyl-1-methylhexyl, decyl, 2-methylnonyl, 8-methylnonyl, 5-ethyloctyl, 3-ethyl-2-methylheptyl, 3,3-diethyihexyl, undecyl, 2-methyldecyl, 9-methyldecyl, 4-ethylnonyl, 3,5-dimethylnonyl, 3-propyloctyl, 5-ethyl-4-methyloctyl, 1-pentylhexyl, dodecyl, 1-methylundecyl, 10-methylundecyl, 3-ethyldecyl, 5-propylnonyl, 3,5-diethyloctyl, tridecyl, 11-methyldodecyl, 7-ethylundecyl, 4-propyldecyl, 5-ethyl-3-methyldecyl, 3-pentyloctyl, tetradecyl, 12-methyltridecyl, 8-ethyldodecyl, 6-propylundecyl, 4-butyldecyl, 2-pentylnonyl, pentadecyl, 13-methyltetradecyl, 10-ethyltridecyl, 7-propyldodecyl, 5-ethyl-3-methyldodecyl, 4-pentyldecyl, 1-hexylnonyl, hexadecyl, 14-methylpentadecyl, 6-ethyltetradecyl, 4-propyltridecyl, 2-butyldodecyl, heptadecyl, 15-methylhexadecyl, 7-ethylpentadecyl, 3-propyltetradecyl, 5-pentyldodecyl, octadecyl, 16-methylheptadecyl, 5-propylpentadecyl, nonadecyl, 17-methyloctadecyl, 4-ethylheptadecyl, icosyl, 18-methylnonadecyl, 3-ethyloctadecyl, henicosyl, docosinyl, tricosinyl, tetracosinyl and pentacosinyl groups. Certain of the acylated radicicol derivatives of the present invention may not be easily soluble in the most common physiologically acceptable solvents, and in such cases (which most notably include the derivatives of the longer chain aliphatic acids), a special solvent system may be employed to solubilize the compound, as is well known in the art; Such a system can readily be determined by the man skilled in the art. However, to avoid the need for this, shorter chain alkyl groups among those represented by R 3 are preferred, for example those alkyl groups having from 1 to 25 carbon atoms, more preferably from 8 to 20 carbon atoms, and most preferably from 12 to 17 carbon atoms (i.e. the alkanoyl group represented by R 1 or R 2 would have from 2 to 26, more preferably from 9 to 21 and most preferably from 13 to 18, carbon atoms). Where R 3 represents a substituted alkyl group, this may be any of those groups listed above, which is substituted by at least one of substituents (a), defined above and exemplified below. In relation to these, and all substituted groups where a specific number of substituents is not given herein, there is no particular restriction on the number of such groups, except such as may be required by the number of substitutable atoms in the group being substituted, or possibly by steric constraints. In general, however, we prefer (provided that there are sufficient subtitutable atoms) from 1 to 5 substituents, more preferably from 1 to 3 substituents. Where R 3 represents an alkoxy group, this has from 1 to 20 carbon atoms, and may be a straight or branched chain group. Examples of such groups include the methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t-butoxy, pentoxy, 3-methylbutoxy, 2,2-dimethylpropoxy, 1,1-dimethylpropoxy, hexyloxy, 1-methylpentyloxy, 4-methylpentyloxy, heptyloxy, 1-methylhexyloxy, 2-methylhexyloxy, 5-methylhexyloxy, 3-ethylpentyloxy, octyloxy, 2-methylheptyloxy, 6-methylheptyloxy, 2-ethylhexyloxy, 2-ethyl-3-methylpentyloxy, 3-ethyl-2-methylpentyloxy, nonyloxy, 2-methyloctyloxy, 7-methyloctyloxy, 4-ethylheptyloxy, 3-ethyl-2-methylhexyloxy, 2-ethyl-1-methylhexyloxy, decyloxy, 2-methylnonyloxy, 8-methylnonyloxy, 5-ethyloctyloxy, 3-ethyl-2-methylheptyloxy, 3,3-diethylhexyloxy, undecyloxy, 2-methyldecyloxy, 9-methyldecyloxy, 4-ethylnonyloxy, 3,5-dimethylnonyloxy, 3-propyloctyloxy, 5-ethyl-4-methyloctyloxy, 1-pentylhexyloxy, dodecyloxy, 1-methylundecyloxy, 10-methylundecyloxy, 3-ethyldecyloxy, 5-propylnonyloxy, 3,5-diethyloctyloxy, tridecyloxy, 11-methyldodecyloxy, 7-ethylundecyloxy, 4-propyldecyloxy, 5-ethyl-3-methyldecyloxy, 3-pentyloctyloxy, tetradecyloxy, 12-methyltridecyloxy, 8-ethyldodecyloxy, 6-propylundecyloxy, 4-butyldecyloxy, 2-pentylnonyloxy, pentadecyloxy, 13-methyltetradecyloxy, 10-ethyltridecyloxy, 7-propyldodecyloxy, 5-ethyl-3-methyldodecyloxy, 4-pentyldecyloxy, 1-hexylnonyloxy, hexadecyloxy, 14-methylpentadecyloxy, 6-ethyltetradecyloxy, 4-propyltridecyloxy, 2-butyldodecyloxy, heptadecyloxy, 15-methyihexadecyloxy, 7-ethylpentadecyloxy, 3-propyltetradecyloxy, 5-pentyldodecyloxy, octadecyloxy, 16-methylheptadecyloxy, 5-propylpentadecyloxy, nonadecyloxy, 17-methyloctadecyloxy, 4-ethylheptadecyloxy, icosyloxy and 18-methylnonadecyloxy, 3-ethyloctadecyloxy groups. Where R 3 represents a substituted alkoxy group, this may be any of those groups listed above, which is substituted by at least one of substituents (a), defined above and exemplified below. Where R 3 represents an alkenyl group, this has from 2 to 30 carbon atoms, and may be a straight or branched chain group. It may have 1 or more, preferably from 1 to 4, double bonds. Examples of such groups include the vinyl, allyl, 1-propenyl, isopropenyl, 2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, 5-hexenyl, 1-heptenyl, 2-heptenyl, 3-heptenyl, 1-octenyl, 8-nonenyl, 1-nonenyl, 1-decenyl, 9-decenyl, 8-tridecenyl, cis -8-pentadecenyl, trans -8-pentadecenyl, 8-heptadecenyl, 8-heptadecenyl, 8,11-heptadecadienyl, 8,11,14-heptadecatrienyl, 4,7,11,14-nonadecatetraenyl and 2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1,3,5,7-nonatetraen-1-yl groups. Where R 3 represents a substituted alkenyl group, this may be any of those groups listed above, which is substituted by at least one of substituents (a), defined above and exemplified below. Where R 3 represents an alkynyl group, this has from 2 to 10 carbon atoms, and may be a straight or branched chain group. Examples of such groups include the ethynyl, 1-propynyl, propargyl, 1-heptynyl, 1-octynyl and 1-decynyl groups. Where R 3 represents a substituted alkynyl group, this may be any of those groups listed above, which is substituted by at least one of substituents (a), defined above and exemplified below. Examples of groups and atoms which may be included in substituents (a) include: 1. alkoxy groups which have from 1 to 20 carbon atoms and which are unsubstituted or are substituted by at least one alkoxy group having from 1 to 4 carbon atoms and/or alkylthio group having from 1 to 4 carbon atoms, such as the methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, t-butoxy, pentyloxy, methoxymethoxy, 1-methoxyethoxy, 2-methoxyethoxy, butoxymethoxy, 2-butoxyethoxy, 3-ethoxypropoxy, 3-methylbutoxy, 2,2-dimethylpropoxy, 1,1-dimethylpropoxy, hexyloxy, 1-methylpentyloxy, 4-methylpentyloxy, heptyloxy, 1-methylhexyloxy, 2-methylhexyloxy, 5-methylhexyloxy, 3-ethylpentyloxy, octyloxy, 2-methylheptyloxy, 6-methylheptyloxy, 2-ethylhexyloxy, 2-ethyl-3-methylpentyloxy, 3-ethyl-2-methylpentyloxy, nonyloxy, 2-methyloctyloxy, 7-methyloctyloxy, 4-ethylheptyloxy, 3-ethyl-2-methylhexyloxy, 2-ethyl-1-methylhexyloxy, decyloxy, 2-methylnonyloxy, 8-methylnonyloxy, 5-ethyloctyloxy, 3-ethyl-2-methylheptyloxy, 3,3-diethylhexyloxy, undecyloxy, 2-methyldecyloxy, 9-methyldecyloxy, 4-ethylnonyloxy, 3,5-dimethylnonyloxy, 3-propyloctyloxy, 5-ethyl-4-methyloctyloxy, 1-pentylhexyloxy, dodecyloxy, 1-methylundecyloxy, 10-methylundecyloxy, 3-ethyldecyloxy, 5-propylnonyloxy, 3,5-diethyloctyloxy, tridecyloxy, 11-methyldodecyloxy, 7-ethylundecyloxy, 4-propyldecyloxy, 5-ethyl-3-methyldecyloxy, 3-pentyloctyloxy, tetradecyloxy, 12-methyltridecyloxy, 8-ethyldodecyloxy, 6-propylundecyloxy, 4-butyldecyloxy, 2-pentylnonyloxy, pentadecyloxy, 13-methyltetradecyloxy, 10-ethyltridecyloxy, 7-propyldodecyloxy, 5-ethyl-3-methyldodecyloxy, 4-pentyldecyloxy, 1-hexylnonyloxy, hexadecyloxy, 14-methylpentadecyloxy, 6-ethyltetradecyloxy, 4-propyltridecyloxy, 2-butyldodecyloxy, heptadecyloxy, 15-methylhexadecyloxy, 7-ethylpentadecyloxy, 3-propyltetradecyloxy, 5-pentyldodecyloxy, octadecyloxy, 16-methylheptadecyloxy, 5-propylpentadecyloxy, nonadecyloxy, 17-methyloctadecyloxy, 4-ethylheptadecyloxy, icosyloxy, 18-methylnonadecyloxy, 3-ethyloctadecyloxy and methylthiomethoxy groups; and 2. aliphatic carboxylic acylthio groups having from 1 to 22, preferably from 1 to 20, carbon atoms, such as the formylthio, acetylthio, propionylthio, butyrylthio, isobutyrylthio, valerylthio, isovalerylthio, pivaloylthio, hexanoylthio, 2-methylpentanoylthio, 2-ethylbutyrylthio, heptanoylthio, 2-methylhexanoylthio, 4-methylhexanoylthio, 2-ethylpentanoylthio, octanoylthio, 2-methylheptanoylthio, 4-methylheptanoylthio, 2-ethylhexanoylthio, nonanoylthio, 2-methyloctanoylthio, 5-methyloctanoylthio, 2-ethylheptanoylthio, nonylcarbonylthio, decylcarbonylthio, 3-methylnonylcarbonylthio, 8-methylnonylcarbonylthio, 3-ethyloctylcarbonylthio, 3,7-dimethyloctylcarbonylthio, undecylcarbonylthio, dodecylcarbonylthio, tridecylcarbonylthio, tetradecylcarbonylthio, pentadecylcarbonylthio, hexadecylcarbonylthio, 1-methylpentadecylcarbonylthio, 14-methylpentadecylcarbonylthio, 13,13-dimethyltetradecylcarbonylthio, heptadecylcarbonylthio, 15-methylhexadecylcarbonylthio, octadecylcarbonylthio, 1-methylheptadecylcarbonylthio, nonadecylcarbonylthio, icosylcarbonylthio and henicosylcarbonylthio groups; such groups may be substituted or unsubstituted, and, if substituted, the substituents are selected from substituents (a), provided that any such substituent is not further substituted by a group which is or contains such an aliphatic carboxylic acyl group. Many of the compounds of the present invention have the anti-tumour activity referred to above. Others may be of value as intermediates in the preparation of other compounds of the present invention, which may have a greater activity. Preferred classes of compounds of the present invention include those compounds of formula (I) in which R 1 and R 2 each represents a group of formula R 3 -CO- and the groups represented by R 3 are the same or different and each is selected from: unsubstituted alkyl groups having from 9 to 20 carbon atoms; substituted alkyl groups having from 10 to 20 carbon atoms and substituted by at least one of substituents (d), defined below; unsubstituted alkenyl groups having from 9 to 20 carbon atoms; substituted alkenyl groups having from 10 to 20 carbon atoms and substituted by at least one of substituents (d), defined below; unsubstituted alkynyl groups having from 8 to 10 carbon atoms; and substituted alkynyl groups having from 8 to 10 carbon atoms and substituted by at least one of substituents (d), defined below; substituents (d): alkoxy groups having from 1 to 8 carbon atoms. More preferred classes of compounds of the present invention include those compounds of formula (I) in which R 1 and R 2 each represents a group of formula R 3 -CO- and the groups represented by R 3 are the same or different and each is selected from: unsubstituted alkyl groups having from 9 to 20 carbon atoms; substituted alkyl groups having from 10 to 20 carbon atoms and substituted by at least one of substituents (e), defined below; unsubstituted alkenyl groups having from 9 to 20 carbon atoms; substituted alkenyl groups having from 10 to 20 carbon atoms and substituted by at least one of substituents (e), defined below; unsubstituted alkynyl groups having from 8 to 10 carbon atoms; and substituted alkynyl groups having from 8 to 10 carbon atoms and substituted by at least one of substituents (e), defined below; substituents (e): alkoxy groups having from 1 to 8 carbon atoms. The most preferred classes of compounds of the present invention include those compounds of formula (I) in which R 1 and R 2 each represents a group of formula R 3 -CO- and the groups represented by R 3 are the same or different and each is selected from: unsubstituted alkyl groups having from 9 to 20 carbon atoms; and unsubstituted alkenyl groups having from 9 to 20 carbon atoms. In any of the compounds of the present invention which contains a hydroxy group, said hydroxy group may be protected by a suitable protecting group. Where the protecting group is on a compound intended for use merely as a chemical intermediate, its nature is not critical to the invention and any of the well known protecting groups may be employed. Where the resulting compound is intended for therapeutic use, the protecting group should be pharmaceutically acceptable. Examples of hydroxy-protecting groups include: 1. aliphatic acyl groups, e.g.: alkylcarbonyl groups preferably having from 1 to 20 carbon atoms, such as the formyl, acetyl, propionyl, butyryl, isobutyryl, pentanoyl, pivaloyl, valeryl, isovaleryl, octanoyl, lauroyl, myristoyl, tridecanoyl, palmitoyl and stearoyl groups; haloalkylcarbonyl groups, especially the haloacetyl groups, such as the chloroacetyl, dichloroacetyl, trichloroacetyl and trifluoroacetyl groups; lower alkoxyalkylcarbonyl groups, especially those having from 3 to 7 carbon atoms, such as the methoxyacetyl group; and unsaturated alkylcarbonyl groups, such as the ( E )-2-methyl-2-butenoyl group; 2. aromatic acyl groups, especially: the unsubstituted arylcarbonyl groups, such as the benzoyl, α-naphthoyl and β-naphthoyl groups; haloarylcarbonyl groups, such as the 2-bromobenzoyl and 4-chlorobenzoyl groups; lower alkylarylcarbonyl groups, especially those in which the alkyl part has from 1 to 4 carbon atoms and the aryl part is a phenyl group, such as the 2,4,6-trimethylbenzoyl and 4-toluoyl groups; lower alkoxyarylcarbonyl groups, especially those in which the alkoxy part has from 1 to 4 carbon atoms and the aryl part is a phenyl group, such as the 4-anisoyl group; nitroarylcarbonyl groups, especially those in which the aryl part is a phenyl group, such as the 4-nitrobenzoyl and 2-nitrobenzoyl groups; lower alkoxycarbonylarylcarbonyl groups, especially those in which the alkoxy part has from 1 to 4 carbon atoms and the aryl part is a phenyl group, such as the 2-(methoxycarbonyl)benzoyl group; and arylarylcarbonyl groups, especially those in which each aryl part is an optionally substituted phenyl group, such as the 4-phenylbenzoyl group; 3. tetrahydropyranyl and tetrahydrothiopyranyl groups, such as the tetrahydropyran-2-yl, 3-bromotetrahydropyran-2-yl, 4-methoxytetrahydropyran-4-yl, tetrahydrothiopyran-2-yl and 4-methoxytetrahydrothiopyran-4-yl groups; 4. tetrahydrofuranyl and tetrahydrothienyl groups, such as the tetrahydrofuran-2-yl and tetrahydrothien-2-yl groups; 5. silyl groups, especially: tri(lower alkyl)silyl groups, such as the trimethylsilyl, triethylsilyl, isopropyldimethylsilyl, t-butyldimethylsilyl, methyldiisopropylsilyl, methyldi-t-butylsilyl and triisopropylsilyl groups; and tri(lower alkyl)silyl groups in which 1 or 2 of the alkyl groups has been replaced by an aryl group, such as the diphenylmethylsilyl, diphenylbutylsilyl, diphenylisopropylsilyl and phenyldiisopropylsilyl groups; 6. alkoxymethyl groups, especially lower alkoxymethyl groups, such as the methoxymethyl, 1,1-dimethyl-1-methoxymethyl, ethoxymethyl, propoxymethyl, isopropoxymethyl, butoxymethyl and t-butoxymethyl groups; lower alkoxy-lower-alkoxymethyl groups, especially such groups in which each of the alkoxy parts has from 1 to 4 carbon atoms, such as the 2-methoxyethoxymethyl group; halogen-substituted lower-alkoxymethyl groups, such as the 2,2,2-trichloroethoxymethyl and bis(2-chloroethoxy)methyl groups; 7. substituted ethyl groups, especially the lower alkoxyethyl groups, such as the 1-ethoxyethyl and 1-(isopropoxy)ethyl groups; haloethyl groups, such as the 2,2,2-trichloroethyl group; arylselenylethyl groups, such as the 2-(phenylselenyl)ethyl group; 8. aralkyl groups, and especially lower (e.g. having from 1 to 4 carbon atoms) alkyl groups which are substituted by from 1 to 3 aryl groups (especially having from 6 to 10 ring atoms), such as the benzyl, α-naphthylmethyl, β-naphthylmethyl, diphenylmethyl, triphenylmethyl, α-naphthyldiphenylmethyl and 9-anthrylmethyl groups; and such groups in which the aryl part is substituted with such substituent(s) as lower alkyl, lower alkoxy, nitro, halogen or cyano group(s), such as the 4-methylbenzyl, 2,4,6-trimethylbenzyl, 3,4,5-trimethylbenzyl, 4-methoxybenzyl, 4-methoxyphenyldiphenylmethyl, 4,4'-dimethoxytriphenylmethyl, 2-nitrobenzyl, 4-nitrobenzyl, 4-chlorobenzyl, 4-bromobenzyl, 4-cyanobenzyl, 4-cyanobenzyldiphenylmethyl, bis(2-nitrophenyl)methyl and piperonyl groups; 9. alkoxycarbonyl groups, including: lower alkoxycarbonyl groups, such as the methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl and isobutoxycarbonyl groups; lower alkoxycarbonyl group substituted by at least one halogen atom or tri(lower alkyl)silyl group, such as the 2,2,2-trichloroethoxycarbonyl and 2-trimethylsilylethoxycarbonyl groups; 10. alkenyloxycarbonyl groups, such as the vinyloxycarbonyl and allyloxycarbonyl groups; 11. aralkyloxycarbonyl groups in which the alkyl part preferably has from 1 to 4 carbon atoms and the aryl part or parts preferably has from 6 to 10 ring carbon atoms and which may optionally have 1 or 2 such substituents as lower alkoxy and/or nitro groups on its aryl ring, such as the benzyloxycarbonyl, 4-methoxybenzyloxycarbonyl, 3,4-dimethoxybenzyloxycarbonyl, 2-nitrobenzyloxycarbonyl and 4-nitrobenzyloxycarbonyl groups. The hydroxy-protecting groups mentioned above are for protection of the hydroxy group during a reaction. In addition to these, there may be mentioned protecting groups which can easily be hydrolyzed in vivo when administered to living body and which may be used for making a pro-drug, such as the pivaloyloxymethoxycarbonyl group. In the above groups, where reference is made to "lower" groups and the number of carbon atoms is not otherwise qualified, "lower alkyl" and "lower alkoxy" groups preferably have from 1 to 4 carbon atoms, and other "lower" groups are to be construed accordingly. The compounds of the invention may contain asymmetric carbon atoms and/or carbon-carbon double bonds and can, therefore, form optical and/or cis / trans isomers. Although these are all referred to herein by a single formula, the present invention envisages both mixtures of the isomers (whether as obtained in the course of synthesis or by mixing) as well as the individual isolated isomers (which may be prepared by stereo-specific synthesis techniques or by separation of a synthesised mixture using conventional methods). Examples of specific compounds of the present invention are those compounds of formula (I), given above, in which R 1 and R 2 are as defined in the following Table 1. In the Table, the following abbreviations are used to refer to certain substituent groups: Ac acetyl Bu butyl Dco decanoyl Ddc dodecyl Et ethyl Hpo heptanoyl Hx hexyl Me methyl Mem methoxyethoxymethyl Mom methoxymethyl Oc octyl Pn pentyl Pr propyl Of the compounds listed above, the following are preferred, that is to say Compounds No. 13, 15, 17, 19, 21, 23, 25, 28, 31, 34, 36, 38, 64, 66, 68, 70, 72, 74, 76, 78, 79, 80, 99, 100, 101, 102, 248, 249, 250, 251, 252, 253, 262, 263, 264, 284, 286, 288, 289, 290, 291, 292, 323, 324 and 325, of which Compounds No. 13, 15, 17, 19, 21, 23, 25, 28, 31, 34, 36, 38, 64, 66, 68, 70, 72, 74, 76, 78, 79, 80, 99, 100, 101, 102, 248, 249, 250, 251, 252, 253, 262, 263, 264, 284, 286, 288, 289, 290, 291, 292, 323, 324 and 325 are more preferred, and Compounds No. 13, 15, 17, 19, 21, 23, 25, 28, 31, 34, 36, 38, 64, 66, 68, 70, 72, 74, 76, 78, 79, 80, 284, 286, 288, 289, 290, 291, 292, 323, 324 and 325 are still more preferred. The most preferred individual compounds are Compounds No.: 15. 14,16-diundecanoylradicicol; 17. 14,16-dilauroylradicicol; 19. 14,16-ditridecanoylradicicol; 21. 14,16-dimyristoylradicicol; 23. 14,16-dipentadecanoylradicicol; 25. 14,16-dipalmitoylradicicol; 28. 14,16-diheptadecanoylradicicol; 31. 14,16-distearoylradicicol; 70. 14,16-dipalmitoleoylradicicol; 72. 14,16-dioleoylradicicol, and its isomeric 14,16-dielaidoylradicicol; 76. 14,16-dilinolenoylradicicol; 288. 16-palmitoyl-14-stearoylradicicol; 323. 14-elaidoyl-16-palmitoylradicicol; and 325. 16-palmitoyl-14-(10-undecenoyl)radicicol. The compounds of the present invention may be prepared by a variety of methods well known for preparing acylated compounds from the corresponding hydroxy compound. For example, compounds of formula (I) may be prepared by reacting a compound of formula (II): [in which either both of R 8 and R 9 represents a hydrogen atom or one of R 8 and R 9 represents a hydrogen atom and the other represents a hydroxy-protecting group, which may be one of the groups defined for R 1 and R 2 (other than a hydrogen atom) or any of the hydroxy-protecting groups exemplified above] with a compound of formula (III): R 3' -COOH (in which R 3' represents any of the groups or atoms represented by R 3 or any such group in which any active group or atom is protected, and R 3 is as defined above) or with a reactive derivative thereof, and, if required, removing any protecting group, to give said compound of formula (I). Radicicol itself is the compound of formula (II) in which both R 8 and R 9 represent hydrogen atoms. The compound of formula (II) in which one of R 8 and R 9 represents a hydrogen atom and the other represents a hydroxy-protecting group may itself be one of the compounds of the invention, depending on the nature of the protecting group. The reaction of the compound of formula (II) with a carboxylic acid of formula (III): R 3' COOH (in which R 3' is as defined above) or with a reactive derivative thereof can be conducted using any acylation reaction known this field. If a carboxylic acid of formula (III) is used in the form of the free acid, the reaction is preferably effected in the presence of a suitable condensation agent, for example 1,1'-oxalyldiimidazole, 2,2'-dipyridyl disulphide, N , N '-dicyclohexylcarbodiimide (DCC), N , N '-disuccinimidyl carbonate, N , N '-bis(2-oxo-3-oxazolidinyl)phosphinic chloride, N , N '-carbodiimidazole, N , N '-disuccinimidyl oxalate (DSO), N , N '-diphthalimide oxalate (DPO), N , N '-bis(norbornenylsuccinimidyl) oxalate (BBTO), 1,1'-bis(benzotriazolyl)oxalate (BBTO), 1,1'-bis(6-chlorobenzotriazolyl) oxalate (BCTO) or 1,1'-bis(6-trifluoromethylbenzotriazolyl) oxalate (BTBO). When a condensation agent is employed, the reaction is preferably conducted in the presence of an inert solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aliphatic hydrocarbons, such as hexane, heptane, ligroin and petroleum ether; aromatic hydrocarbons, such as benzene, toluene and xylene; halogenated hydrocarbons, especially aromatic and aliphatic hydrocarbons, such as methylene chloride, chloroform, carbon tetrachloride, dichloroethane, chlorobenzene and the dichlorobenzenes; esters, such as ethyl formate, ethyl acetate, propyl acetate, butyl acetate and diethyl carbonate; ethers, such as diethyl ether, diisopropyl ether, tetrahydrofuran, dioxane. dimethoxyethane and diethyleneglycol dimethyl ether; ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone and cyclohexanone; nitro compounds, which may be nitroalkanes or nitroaranes, such as nitroethane and nitrobenzene; nitriles, such as acetonitrile and isobutyronitrile; amides, which may be fatty acid amides, such as formamide, dimethylformamide, dimethylacetamide and hexamethylphosphoric triamide; and sulphoxides, such as dimethyl sulphoxide and sulpholane. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from -10°C to 130°C. If R 1 and R 2 are the same in the compound of formula (I), the compound of the present invention can be obtained by reaction of a compound of formula (II) as defined above with 2 and more equivalents of a carboxylic acid and a condensation agent or of a reactive derivative of the carboxylic acid. If a compound in which one of R 1 and R 2 represents a hydrogen atom is desired, it can be obtained by using less than 2 equivalents, preferably from 1 to 1.5 equivalents, of the carboxylic acid and a condensation agent or of a reactive derivative of the carboxylic acid. In such a case, if the two possible isomers of the mono-acylated compound are produced, these may be separated from each other and identified by known methods. If R 1 and R 2 both represent acyl groups which are different from each other in the compound of formula (I), the desired compound can be obtained by reaction of a compound of formula (II) in which one of R 8 and R 9 represents a hydrogen atom with 1 or more equivalents of the carboxylic acid and a condensation agent or of a reactive derivative of the carboxylic acid. Examples of reactive derivatives of the carboxylic acid of formula (III) include: acid halides, such as the acid chloride and the acid bromide; and acid anhydrides. When an acid halide is employed, the reaction is preferably conducted in an inert organic solvent in the presence of an acid binding agent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aromatic hydrocarbons, such as benzene, toluene and xylene; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as chloroform, methylene chloride and trichloroethane; ethers, such as diethyl ether, tetrahydrofuran and dioxane; aliphatic dialkylamides, which may be fatty acid amides, such as dimethylformamide and dimethylacetamide; nitriles, such as acetonitrile; ketones, such as acetone; dimethyl sulphoxide; and pyridine. The acid binding agent may be any such compound which binds to an acid and does not interfere with the reaction, and examples include: alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; alkali metal carbonates, such as sodium carbonate and potassium carbonate; and organic bases, such as triethylamine, pyridine, 4-dimethylaminopyridine and 1-methylimidazole. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from -10°C to 130°C. When an acid anhydride is employed, the reaction is preferably carried out in the presence of an inert organic solvent, or in the absence of an inert organic solvent by using an excess of the acid anhydride. There is no particular restriction on the nature of the solvent which may be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aromatic hydrocarbons, such as benzene, toluene and xylene; and ethers, such as dioxane, tetrahydrofuran and diethylene glycol dimethyl ether. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from room temperature to 160°C. The desired compound thus obtained can be collected, separated and purified by any suitable technique. For example, one suitable recovery procedure comprises: pouring the reaction solution into water; extracting the resulting mixture with a water-immiscible solvent, such as benzene, ether or ethyl acetate; and finally removing the solvent e.g. by distillation, to obtain the desired compound. The desired compound may, if necessary, be further purified by various methods, including: adsorption chromatography or ion exchange chromatography using various carriers, such as active carbon or silica gel; by gel filtration by using a Sephadex (trade mark) column; or by recrystallization from an ether (e.g. diethyl ether), ethyl acetate or chloroform. When the compound of formula (II) contains a protecting group, the desired compound of formula (I) can be obtained by its removal, if necessary. When the removal of a protecting group is required, the reaction employed will, as is well known in the art, vary depending upon the nature of the protecting group, and may be carried out using conventional procedures known in the technology of this field, for example as follows. If a silyl group is employed as the hydroxy-protecting group, it can generally be removed by treatment with a compound capable of forming fluorine anions, such as tetrabutylammonium fluoride. The reaction is preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include ethers, such as tetrahydrofuran and dioxane. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of about room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 to 18 hours will usually suffice. If the hydroxy group is protected by an aralkyl or aralkyloxycarbonyl group, it can be removed by contact with a reducing agent. The removal is preferably performed by means of a catalytic reduction, which may take place at room temperature, by using a catalyst, such as palladium-carbon, platinum or Raney nickel. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; aliphatic acids, such as acetic acid; and a mixtures of any one or more of these organic solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 5 minutes to 12 hours will usually suffice. Such groups can be also removed by treating the protected compound with lithium or sodium in a liquid ammonia or in an alcohol, such as methanol or ethanol at a relatively low temperature, for example from -78°C to -20°C. Such groups can also be removed by treating the protected compound with aluminium chloride-sodium iodide or an alkylsilyl halide, such as trimethylsilyl iodide. The reaction is normally and preferably carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: nitriles, such as acetonitile; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride and chloroform; and mixtures of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C. When the reaction substrate contains a sulphur atom, aluminium chloride-sodium iodide is preferably employed. If the hydroxy-protecting group is an aliphatic acyl, aromatic acyl or alkoxycarbonyl group, it can be removed by treatment with a base in the presence of a solvent. The base employed is not particularly limited provided that it does not affect other parts of the compounds. The reaction is preferably performed using one of the following bases: metal alcoholates, such as sodium methoxide; aqueous ammonia; alkali metal carbonates, such as sodium carbonate and potassium carbonate; alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; and concentrated ammonia-methanol. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent, and any solvent commonly used for hydrolysis reactions can equally be used here. Examples of suitable solvents include: alcohols, such as methanol, ethanol and propanol; ethers, such as tetrahydrofuran and dioxane; and mixtures of any one or more of these organic solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 150°C in order to inhibit any side reaction. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 1 to 10 hours will usually suffice. When the hydroxy-protecting group is an alkoxymethyl, tetrahydropyranyl, tetrahydrothiopyranyl, tetrahydrofuranyl, tetrahydrothiofuranyl or substituted ethyl group, it can generally be removed by treatment with an acid in a solvent. Examples of suitable acids include: hydrochloric acid, acetic acid-sulphuric acid, p -toluenesulphonic acid and acetic acid. A strong acidic cation exchange resin, such as Dowex 50W can be employed instead. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 18 hours will usually suffice. When the hydroxy-protecting group is an alkenyloxycarbonyl group, it can be removed by treatment with a base under similar conditions to those mentioned above for the case when the hydroxy-protecting group is an aliphatic acyl, aromatic acyl or alkoxycarbonyl group. When the hydroxy-protecting group is an aryloxycarbonyl group, it can easily be removed using palladium together with triphenyiphosphine or nickeltetracarbonyl with few side reactions. When the amino-protecting group is a trialkylsilyl group, it can be removed by treating the compound with a compound capable of forming fluorine anions, for example tetrabutylammonium fluoride. The reaction is normally and preferably effected in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include ethers, such as tetrahydrofuran and dioxane. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of about room temperature. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 to 18 hours will usually suffice. When the amino-protecting group is an aliphatic acyl, aromatic acyl or alkoxycarbonyl group or a substituted methylene group capable of forming a Schiff base, it can be removed by treatment with an acid or a base in the presence of an aqueous solvent. Suitable acids include hydrochloric acid, sulphuric acid, phosphoric acid and hydrobromic acid. Suitable bases may be selected from any commonly known bases, provided that they do not affect the other parts of the compound, and examples include: alkali metal carbonates, such as sodium carbonate and potassium carbonate; alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; and concentrated ammonia-methanol. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent, and any solvent commonly used for hydrolysis reactions may equally be employed here. Examples of suitable solvents include: water; mixtures of one or more alcohols, such as methanol, ethanol or propanol, with water; and mixtures of one or more ethers, such as tetrahydrofuran or dioxane, with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 150°C, in order to inhibit any side reaction. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 1 to 10 hours will usually suffice. When the amino-protecting group is an aralkyl or aralkyloxycarbonyl group, it can preferably be removed by catalytic reduction at room temperature using, for example, platinum or palladium-on-carbon; or by using an oxidizing agent. For the reductive removal, there is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol, ethanol and isopropanol; ethers, such as diethyl ether, tetrahydrofuran and dioxane; aromatic hydrocarbons, such as toluene, benzene and xylene; aliphatic hydrocarbons, such as hexane and cyclohexane; esters, such as ethyl acetate and propyl acetate; aliphatic acids, such as acetic acid; and mixtures of any one or more of these solvents with water. Preferred catalysts which may be used in this reaction are not particularly limited, provided that they are capable of use in catalytic reduction; and examples include: palladium-on-carbon, Raney nickel, platinum oxide, platinum black, rhodium-on-aluminium oxide, triphenylphosphine-on-rhodium chloride and palladium-on-barium sulphate. Although there is no particular restriction on the pressure employed, the reaction is usually carried out at from 1 to 10 atmospheres. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention, although the preferred temperature will vary, as is known in the art, depending upon the starting materials and the catalyst. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 100°C. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 5 minutes to 24 hours will usually suffice. For the oxidative removal, there is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: aqueous organic solvents; preferred organic solvents which may be used include: ketones, such as acetone; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride, chloroform and carbon tetrachloride; nitriles, such as acetonitrile; ethers, such as diethyl ether, tetrahydrofuran and dioxane; amides, which may be fatty acid amides, such as dimethylformamide, dimethylacetamide and hexamethylphosphoric triamide; and sulphoxides, such as dimethyl sulphoxide. There is no particular restriction on the nature of the oxidizing agent employed, provided that it is capable of use for oxidation, and preferred examples include: potassium persulphate, sodium persulphate, ammonium cerium nitrate (CAN) and 2,3-dichloro-5,6-dicyano- p -benzoquinone (DDQ). The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 150°C, depending on the starting materials and the catalyst employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 24 hours will usually suffice. When the amino-protecting group is an alkenyloxycarbonyl group, it can be removed by treatment with a base under similar conditions to those employed when the protecting group is an aliphatic acyl, aromatic acyl or lower alkoxycarbonyl group. In particular, when the amino-protecting group is an allyloxycarbonyl group, it can be removed conveniently and with few side reactions by using palladium and triphenylphosphine or nickeltetracarbonyl. When the mercapto-protecting group is an aralkyl or aralkyloxycarbonyl group, it can generally be removed by contact with a reducing agent. For example, the removal may be performed by catalytic reduction at room temperature using palladium-on-carbon, platinum or Raney nickel as the catalyst. The reaction is conducted in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; aliphatic acids, such as acetic acid; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to room temperature, depending on the starting materials and the reducing agent employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 5 minutes to 12 hours will usually suffice. Such groups can alternatively be removed by treatment with lithium or sodium in liquid ammonia or an alcohol, such as methanol or ethanol, at a relatively low temperature, e.g. from -78°C to -20°C. Alternatively, such groups can be removed by treatment with aluminium chloride-sodium iodide or an alkylsilyl halide, such as trimethylsilyl iodide. The reaction is carried out in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: nitriles, such as acetonitrile; halogenated hydrocarbons, especially halogenated aliphatic hydrocarbons, such as methylene chloride and chloroform; and mixtures of any two or more of these solvents. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C, depending on the starting materials. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. When the mercapto-protecting group is an alkoxycarbonyl group, such as a t-butoxycarbonyl group or an arylmethyl group, it can be removed by treatment with an acid in the presence of a solvent. Preferred acids include, for example, trifluoroacetic acid and acetic acid-hydrobromic acid. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C, depending on the starting materials and the acid employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 18 hours will usually suffice. When the mercapto-protecting group is an aliphatic acyl, aromatic acyl or alkoxycarbonyl group, it can be removed by treatment with a base in the presence of a solvent. There is no particular restriction on the nature of the base employed, provided that it does not affect the other parts of the compound, and examples include: metal alcoholates, such as sodium methoxide; aqueous ammonia; alkali metal carbonates, such as sodium carbonate and potassium carbonate; alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide; and concentrated ammonia-methanol. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent, and any solvent commonly employed for hydrolysis reactions may equally be employed here. Examples of suitable solvents include: water; alcohols, such as methanol, ethanol and propanol; ethers, such as tetrahydrofuran and dioxane; and mixture of any one or more of these organic solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 150°C, depending on the starting materials and the base employed, in order to inhibit any side reaction. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 1 to 10 hours will usually suffice. When the mercapto-protecting group is a tetrahydropyranyl group, it can generally be removed by treatment with an acid in a solvent. Preferred acids which may be used in this reaction include hydrochloric acid, acetic acid-sulphuric acid, p -toluenesulphonic acid and acetic acid. A strong acidic cation exchange resin, such as Dowex 50W may be employed instead. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C, depending on the starting materials and the acid employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 18 hours will usually suffice. When the mercapto-protecting group is an alkenyloxycarbonyl group, it can be removed by treatment with a base under similar conditions to those employed when the protecting group is an aliphatic acyl, aromatic acyl or alkoxycarbonyl group. In particular, when the mercapto-protecting group is an allyloxycarbonyl group, it can be removed conveniently and with few side reactions by using palladium and triphenyiphosphine or nickeltetracarbonyl. When the mercapto-protecting group is an S-2-pyridinesulphenyl or S-3-nitro-2-pyridinesulphenyl group, it can be removed by reaction with a secondary amine, such as triphenyiphosphine, pyrrolidine, piperidine or morpholine. When the carboxy-protecting group is a lower alkyl group or an aryl group, it can be removed by treatment with an acid or a base. Suitable acids include hydrochloric acid, sulphuric acid, phosphoric acid and hydrobromic acid. Suitable bases are those which do not affect other parts of the compound, and examples include alkali metal carbonates, such as sodium carbonate and potassium carbonate, alkali metal hydroxides, such as sodium hydroxide and potassium hydroxide, and concentrated ammonia-methanol. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent, and any solvent commonly used for hydrolysis reactions may equally be used here. Examples of suitable solvents include: water; and mixtures of water with an alcohol, such as methanol, ethanol or propanol, or with an ether, such as tetrahydrofuran or dioxane. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 150°C, depending on the starting materials and the base employed, in order to inhibit any side reaction. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 1 to 10 hours will usually suffice. When the carboxy-protecting group is a di-aryl-substituted methyl group, such as a diphenylmethyl (or "benzhydryl") group, it can generally be removed under acidic conditions. The reaction is normally and preferably effected in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include aromatic hydrocarbons, such as anisole. Suitable acids include fluoro-organic acids, such as trifluoroacetic acid. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of about room temperature, depending on the starting materials. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 30 minutes to 10 hours will usually suffice. When the carboxy-protecting group is an aralkyl or halogenated lower alkyl group, it can be removed in general by contact with a reducing agent. When the carboxy-protecting group is a halogenated lower alkyl group, zinc/acetic acid is preferably employed as the reducing agent. When the carboxy-protecting group is an aralkyl group, it can be removed by catalytic reduction by using palladium-on-carbon or platinum as the catalyst, or by using an alkali metal sulphide, such as potassium sulphide or sodium sulphide. These reactions may be conducted in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; aliphatic acids, such as acetic acid; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to near room temperature, depending on the starting materials and the reducing agent employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 5 minutes to 12 hours will usually suffice. When the carboxy-protecting group is an alkoxymethyl group, it can generally be removed by treatment with an acid. Preferred acids include hydrochloric acid, acetic acid/sulphuric acid and p -toluenesulphonic acid/acetic acid. The reaction is conducted in the presence of a solvent. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include: alcohols, such as methanol and ethanol; ethers, such as tetrahydrofuran and dioxane; and mixtures of any one or more of these solvents with water. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 50°C, depending on the starting materials and the acid employed,. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 10 minutes to 18 hours will usually suffice. In addition, where the compound thus obtained is a carboxylic acid compound, if desired, its corresponding alkali metal salt can be prepared by various conventional procedures, for example as follows: The carboxylic acid compound is dissolved in a mixture of water with a water-immiscible organic solvent, such as ethyl acetate, and then an aqueous solution of an alkali metal carbonate or an alkali metal bicarbonate, such as sodium bicarbonate or potassium carbonate, is added to the solution, preferably at a temperature from 0°C to room temperature; the pH of the solution is then adjusted to a value of near 7, and the resulting separated precipitate is collected by filtration. Furthermore, the salt or the carboxylic acid compound can be converted to its corresponding ester in which the carboxylic acid is protected by a protecting group which can easily be hydrolyzed in vivo by the procedures below: The salt or the acid is dissolved in an ether, such as tetrahydrofuran, or a polar solvent, such as N , N -dimethylformamide, dimethyl sulphoxide, hexamethylphosphoric triamide or triethyl phosphate, and allowed to react with two equivalents of an organic base, such as triethylamine or dicyclohexylamine, an alkali metal hydride, such as sodium hydride, or an alkali metal carbonate or bicarbonate, such as sodium bicarbonate, sodium carbonate or potassium carbonate, to prepare its salt; and then the salt is allowed to react with an aliphatic acyloxymethyl halide, such as acetoxymethyl chloride or propionyloxymethyl bromide, a 1-(lower alkoxy)carbonyloxyethyl halide, such as 1-methoxycarbonyloxyethyl chloride or 1-ethoxycarbonyloxyethyl iodide, a phthalidyl halide, or a (2-oxo-5-methyl-1,3-dioxolen-4-yl)methyl halide. There is no particular restriction on the nature of the solvent to be employed, provided that it has no adverse effect on the reaction or on the reagents involved and that it can dissolve the reagents, at least to some extent. Examples of suitable solvents include any of the polar solvents mentioned above. The reaction can take place over a wide range of temperatures, and the precise reaction temperature is not critical to the invention. In general, we find it convenient to carry out the reaction at a temperature of from 0°C to 100°C, depending on the starting materials, solvent and reagents employed. The time required for the reaction may also vary widely, depending on many factors, notably the reaction temperature and the nature of the reagents. However, provided that the reaction is effected under the preferred conditions outlined above, a period of from 0.5 to 10 hours will usually suffice. y be preferably employed. Many of the radicicol derivatives of the present invention show a strong anti-tumour effect against transplanted M5076 cells in mice, and are therefore expected to demonstrate activity against solid type tumours in general. Accordingly, the radicicol derivatives of the present invention can be used in warm-blooded animals, including humans, as an anti-tumour agent against these kinds of tumoral diseases. The compounds may be administered by any convenient route, for example by parenteral administration methods, such as intravenous injection, subcutaneous injection, intramuscular injection or by suppositories; or oral administration by using, for example, capsules, powders or granules. The dosage to an adult human may vary depending on the nature of the disease, the route of administration and the administration frequency and period. However, a daily dosage of from 1 to 100 mg in a single dose or in divided doses may be given. The radicicol derivatives of the present invention may be administered in combination with other anti-tumour agents, for example, nitrosourea agents such as ACNU or BCNU, cisplatin, 5-FU, Daunomycin, adriamycin, mitomycin C and etoposide. In addition, preparations of the radicicol derivative can be provided for administration according to any conventional method. Therefore, the present invention covers any pharmaceutical preparations and compositions containing the radicicol derivatives of the present invention. The form will, of course, vary depending upon the route of administration. For example, compositions for injection can be provided in the form of ampoules, each containing a unit dose amount, or in the form of a container containing multiple doses. The composition may sometimes contain additives such as emulsifiers, stabilizers and/or dispersants, and may often be in the form of a powder which is intended to be dissolved by the pharmacist in a suitable solvent, such as a pyrogen-free sterilized aqueous solvent, just before use. Such a preparation can be prepared, for example, as follows: The radicicol derivative is dissolved in acetone, and the acetone solution is poured into vials, water is added, and then the mixture is lyophilized. On the other hand, compositions for oral administration can be provided by means of capsules, powders, granules or syrups each containing a suitable amount of one or more of the radicicol derivatives of the present invention. BIOLOGICAL ACTIVITY The test animals used were female mice, 8 weeks old, of the BDF 1 strain, weighing 20 - 25g. The mice were purchased from Charles River Japan Inc., Kanagawa, Japan. The mice were divided into experimental groups, each group containing 6 mice, and all mice within each group were treated identically. Each mouse was inoculated subcutaneouly with 1 X 10 6 viable cells (the number of cells was measured by a dye exclusion method under microscopy ) of the mouse fibrosarcoma M5076. The test compounds (80mg) listed in the following Table, except radicicol, were dissolved in 0.2 ml of N , N -dimethylacetamide (DMA) and to the solution was added 0.2 ml of 40°C-warmed HCO60 (polyoxyethylene hydrogenated caster oil 60). Immediately thereafter 3.6 ml of 40°C-warmed physiological saline was added to form a colloidal solution or a suspension. The final concentration of DMA and HCO60 was 5% v/v, each. Radicicol was dissolved in 0.25 mg/ml of DMA and the solution was dispersed slowly into 3.75 ml of 10 % Emulphor(trade mark)-physiological saline stirred well with a stirring rod. The final concentration of DMA was 6.25 %. The solution was administered intravenously (in the case of a suspension it was administered intraperitoneally) on the first, fifth and ninth days following inoculation of the fibrosarcoma cells. The period for which the mice survived and the % inhibition of tumour growth were determined. A control group was treated identically, except that no active compound was administered. The anti-tumour effect is shown in the following Table as the increase in life span [ILS (%)] and the growth inhibition [GI (%)], calculated from the following equations [R. I. Geran et al., Cancer Chemother. Rept., 3 (1972)]: ILS (%) + ( Dt/Dc - 1 ) X 100 where Dt = median survival time (days) of mice in the treated group; and Dc = median survival time (days) of mice in the control group. In this experiment, Dc was 40 - 47 days. GI (%) = ( 1 - TDt/TDc ) X 100 where TDt = average value of tumour sizes on the fourteenth day in the treated group; and TDc = average value of tumour sizes on the fourteenth day in the control group tumour size = (tumour length + tumour width )/2. The compounds of the invention are identified in the following Table by the numbers assigned to them in the foregoing list. Cpd No. dose ( mg/kg ) route growth Inhibition (%) ILS (%) 17 200 iv 89 24 19 200 iv 89 9 21 200 iv 91 35 23 200 iv 95 35 25 200 iv 100 43 28 200 iv 95 27 31 200 ip 66 -4 70 200 iv 65 31 72(cis) 200 iv 80 4 72(trans) 200 iv 86 9 76 200 iv 74 11 radicicol 150 iv 5 -29 As is shown in the above Table, all of the compounds tested exhibited higher anti-tumour activitives than radicicol in the solid type tumour model (M5076 fibrosarcome sc implanted) in terms of both of tumour growth inhibition and increase in life span. The invention is further illustrated by the following non-limiting Examples. Example 12 is outside the scope of the present invention but illustrates a general synthetic method used in later examples. EXAMPLE 1 14,16-Dipalmitoylradicicol 1.6 g of radicicol was dissolved in 37 ml of dry benzene, and the solution was placed on an ice bath. While the solution was still on the ice bath, 2.2 ml of pyridine and a catalytic amount of dimethylaminopyridine were added to it, after which 20 ml of benzene containing 1.32 g of palmitoyl chloride was added dropwise. The reaction solution was then stirred for 1 hour on an ice bath, and ice water was added; it was then extracted with ethyl acetate. The organic layer was washed with an aqueous solution of sodium bicarbonate, with water and with a saturated solution of sodium chloride, in that order, after which it was dried over anhydrous magnesium sulphate. The magnesium sulphate was removed by filtration, and the solvent was then removed from the filtrate by distillation under reduced pressure. 2.70 g of an oily residue were thus obtained, and this was subjected to silica gel column chromatography using a 1 : 1 by volume mixture of hexane and ethyl acetate as the eluent, to obtain a crystalline substance having an Rf value of 0.64 (developing solvent, hexane : ethyl acetate = 3 : 1 by volume). Recrystallization of this from hexane afforded 1.47 g of the title compound. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.88 (6H, triplet, J = 6.3 Hz); 1.21 - 1.42 (5OH, multiplet); 1.53 (3H, doublet, J = 4.8 Hz); 1.63 - 1.79 (3H, multiplet); 2.37 - 2.45 (1H, multiplet); 2.49 (2H, triplet, J = 6.8 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.99 - 3.02 (1H, multiplet); 3.52 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.1 Hz); 5.39 - 5.41 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 3.9 & 10.7 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.14 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.0 & 10.3 Hz). Infrared Absorption Spectrum (Nujol - trade mark) ν max cm -1 : 1759, 1722. EXAMPLE 2 14-Palmitoylradicicol After the silica gel column chromatography of the mixture obtained as described in Example 1, 866 mg of the title compound having an Rf value of 0.31 (developing solvent, hexane : ethyl acetate = 1 : 1 by volume) were obtained. Recrystallization from hexane afforded 731 mg of the title compound as white crystals. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.88 (3H, triplet, J = 6.3 Hz); 1.20 - 1.50 (24H, multiplet); 1.54 (3H, doublet, J = 6.3 Hz); 1.72 - 1.80 (2H, multiplet); 1.85 - 1.96 (1H, multiplet); 2.34 - 2.42 (1H, multiplet); 2.59 (2H, triplet, J = 7.3 Hz); 2.92 - 2.97 (1H, multiplet); 3.17 (1H, multiplet); 3.97, 4.69 (2H, AB-quartet, J = 16.0 Hz); 5.53 - 5.58 (1H, multiplet); 5.83 (1H, doublet of doublets, J = 10.7 & 3.0 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.14 (1H, doublet of doublets, J = 10.7 & 9.2Hz); 6.84 (1H, singlet); 7.42 (1H, doublet of doublets, J = 17.0 & 9.2 Hz); 10.78 (1H, singlet). Infrared Absorption Spectrum (Nujol) ν max cm -1 : 1772, 1717. Elemental analysis: Calculated for C 34 H 47 O 7 Cℓ: C, 67.70%; H, 7.85%; Cℓ, 5.88%. Found: C, 67.43%; H, 7.77%; Cℓ, 6.15%. EXAMPLE 3 14,16-Di(octanoyl)radicicol A procedure similar to that described in Example 1 was repeated, except that a mixture of 320 mg of radicicol, 7.4 ml of dry benzene, 880 µℓ of pyridine, a catalytic amount of dimethylaminopyridine and 338 mg (2.4 times the equimolar amount) of octanoyl chloride were used, to give 1.514 mg (yield 95%) of the title compound as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.84 - 0.96 (6H, multiplet); 1.22 - 1.45 (17H, multiplet); 1.53 (3H, doublet, J = 6.8 Hz); 1.51 - 1.62 (1H, multiplet); 1.64 - 1.80 (4H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.50 (2H, triplet, J = 7.4 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.96 - 3.04 (1H, multiplet); 3.52 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.1 Hz); 5.34 - 5.45 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.4 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.2 & 10.7 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.0 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1765, 1735 EXAMPLE 4 14,16-Di(behenoyl)radicicol A methylene chloride solution containing 2.24 g of behenoyl chloride was added dropwise to a mixed solution of 1.459 g of radicicol, 37 ml of dry methylene chloride, 1.9 ml of pyridine and a catalytic amount of dimethylaminopyridine on an ice bath. The mixture was then reacted and treated as described in Example 1, to give a crystalline product having an Rf value of 0.80 (developing solvent, benzene : ethyl acetate = 9 : 1 by volume). Recrystallization of this from hexane afforded 1.63 g of the title compound. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.88 (6H, doublet, J = 6.4 Hz); 1.24 - 1.45 (72H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.48 - 1.81 (5H, multiplet); 2.37 - 2.46 (1H, multiplet); 2.49 (2H, triplet, J = 7.3 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.99 - 3.02 (1H, multiplet); 3.52 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.36 - 5.45 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 11.0 & 3.9 Hz); 6.06 (1H, doublet, J = 16.2 Hz); 6.14 (1H, doublet of doublets, J = 11.0 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 11.0 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1738. Elemental analysis: Calculated for C 62 H 101 O 8 Cℓ: C, 73.74%; H, 10.08%; Cℓ, 3.51%. Found: C, 73.71%; H, 9.84%; Cℓ, 3.52%. EXAMPLE 5 14-Behenoylradicicol After the silica gel column chromatography of the mixture obtained as described in Example 4, a crystalline product having an Rf value of 0.64 (developing solvent, benzene : ethyl acetate = 9 : 1 by volume) was obtained. Recrystallization of this from hexane afforded 463 mg of the title compound. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.85 (3H, triplet, J = 7.3 Hz); 1.22 - 1.45 (37H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.72 - 1.83 (2H, multiplet); 1.85 - 1.97 (1H, multiplet); 2.33 - 2.42 (1H, multiplet); 2.53 (2H, triplet, J = 7.4 Hz); 2.93 - 2.97 (1H, multiplet); 3.16 (1H, multiplet); 3.96, 4.69 (2H, AB-quartet, J = 16.6 Hz); 5.52 - 5.63 (1H, multiplet); 5.83 (1H, doublet of doublets, J = 11.0 & 2.4 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 16.0 & 11.0 Hz); 6.84 (1H, singlet); 7.42 (1H, doublet of doublets, J = 16.0 & 9.3 Hz); 10.78 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1725. Elemental analysis: Calculated for C 40 H 59 O 7 Cℓ: C, 69.90%; H, 8.65%; Cℓ, 5.16%. Found: C, 69.87%; H, 8.56%; Cℓ, 5.18%. EXAMPLE 6 14,16-Di(stearoyl)radicicol A procedure similar to that described in Example 4 was repeated, except that a mixed solution containing 1.459 g of radicicol, 37 ml of dry methylene chloride, 1.9 ml of pyridine, a catalytic amount of dimethylaminopyridine and 1.454 g of stearoyl chloride were reacted and treated, to give 923 mg of the title compound as crystals. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 ) δ ppm: 0.88 (6H, triplet, J = 6.4 Hz); 1.21 - 1.42 (56H, multiplet); 1.53 (3H, doublet, J = 6.8 Hz); 1.50 - 1.62 (1H, multiplet); 1.65 - 1.80 (4H, multiplet); 2.37 - 2.46 (1H, multiplet); 2.49 (2H, triplet, J = 6.8 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.99 - 3.05 (1H, multiplet); 3.52 (1H, multiplet); 3.91, 4.63 (2H, AB-quartet, J = 16.6 Hz); 5.35 - 5.46 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.2 Hz); 6.14 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.0 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1772, 1740. Elemental analysis: Calculated for C 54 H 85 O 8 Cℓ: C, 72.25%; H, 9.54%; Cℓ, 3.95%. Found: C, 72.29%; H, 9.30%; Cℓ, 3.92%. EXAMPLE 7 14-Stearoylradicicol After the silica gel column chromatography of the mixture obtained as described in Example 6, a reaction product having an Rf value of 0.35 (developing solvent, hexane : ethyl acetate = 2 : 1 by volume) was obtained. Recrystallization of this from hexane afforded 1.09 g of the title compound. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (3H, triplet, J = 6.4 Hz); 1.19 - 1.42 (29H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.72 - 1.80 (1H, multiplet); 1.86 - 1.96 (1H, multiplet); 2.33 - 2.42 (1H, multiplet); 2.59 (2H, triplet, J = 7.4 Hz); 2.92 - 2.97 (1H, multiplet); 3.16 (1H, multiplet); 3.97, 4.69 (2H, AB-quartet, J = 16.6 Hz); 5.53 - 5.62 (1H, multiplet); 5.83 (1H, doublet of doublets, J = 10.7 & 2.4 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.7 & 9.3 Hz); 6.84 (1H, singlet); 7.42 (1H, doublet of doublets, J = 16.0 & 9,3 Hz); 10.78 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1772, 1730 Elemental analysis: Calculated for C 36 H 51 O 7 Cℓ: C, 68.50%; H, 8.14%; Cℓ, 5.62%. Found: C, 68.59%; H, 8.17%; Cℓ, 5.38%. EXAMPLE 8 14,16-Di(oleoyl)radicicol A procedure similar to that described in Example 4 was repeated, except that a mixed solution of 1.641 g of radicicol, 40 ml of dry methylene chloride, 2.14 ml of pyridine, a catalytic amount of dimethylaminopyridine and 1.49 g of oleoyl chloride were reacted and treated, to give 1.736 g of the title compound having an Rf value of 0.83 (developing solvent, hexane : ethyl acetate = 2 : 1 by volume) as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.4 Hz); 1.22 - 1.42 (42H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 1.63 - 1.80 (4H, multiplet); 1.93 - 2.08 (7H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.49 (2H, triplet, J = 7.8 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.98 - 3.03 (1H, multiplet); 3.52 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.28 - 5.46 (5H, multiplet); 5.78 (1H, doublet of doublets, J = 10.8 & 3.9 Hz); 6.06 (1H, doublet, J = 16.2 Hz); 6.14 (1H, doublet of doublets, J = 10.8 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.4 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1742. EXAMPLE 9 14-Oleoylradicicol After the silica gel column chromatography of the mixture obtained as described in Example 8, 872 mg of the title compound having an Rf value of 0.43 (developing solvent, hexane : ethyl acetate, 2 : 1 by volume) were obtained as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.87 (3H, triplet, J = 6.4 Hz); 1.26 - 1.46 (22H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.72 - 1.80 (1H, multiplet); 1.86 - 2.00 (4H, multiplet); 2.33 - 2.43 (1H, multiplet); 2.59 (2H, triplet, J = 7.4 Hz); 2.96 - 2.98 (1H, multiplet); 3.16 (1H, multiplet); 3.98, 4.68 (2H, AB-quartet, J = 16.6 Hz); 5.32 - 5.41 (2H, multiplet); 5.52 - 5.61 (1H, multiplet); 5.83 (1H, doublet of doublets, J = 10.0 & 2.9 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.0 & 8.8 Hz); 6.84 (1H, singlet); 7.42 (1H, doublet of doublets, J = 16.1 & 8.8 Hz); 10.7 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1775, 1732. EXAMPLE 10 14,16-Di(elaidoyl)radicicol A procedure similar to that described in Example 4 was repeated, except that a mixed solution containing 1.641 g of radicicol, 40 ml of dry methylene chloride, 2.14 ml of pyridine, a catalytic amount of dimethylaminopyridine and 1.49 g of elaidoyl chloride was reacted and treated, to give 1.24 g of the title compound having an Rf value of 0.84 (developing solvent, hexane : ethyl acetate = 2 : 1 by volume) as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.87 (6H, triplet, J = 6.3 Hz); 1.26 - 1.48 (42H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 1.62 - 1.79 (4H, multiplet); 1.95 - 2.05 (7H, multiplet); 2.37 - 2.42 (1H, multiplet); 2.49 (2H, triplet, J = 7.3 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.98 - 3.03 (1H, multiplet); 3.51 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.30 - 5.46 (5H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.14 (1H, doublet of doublets, J = 10.7 & 10.7 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.0 & 10.7 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1772, 1740. EXAMPLE 11 14-Elaidoylradicicol After the silica gel column chromatography of the mixture obtained as described in Example 10, a product having an Rf value of 0.40 (developing solvent, hexane : ethyl acetate = 2 : 1 by volume) was obtained. Recrystallization of this product from hexane afforded 1.22 g of the title compound as white crystals. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.87 (3H, triplet, J = 6.3 Hz); 1.26 - 1.42 (21H, multiplet); 1.54 (3H, doublet, J = 6.3 Hz); 1.72 - 1.80 (2H, multiplet); 1.86 - 1.96 (5H, multiplet); 2.33 - 2.43 (1H, multiplet); 2.59 (2H, triplet, J = 7.3 Hz); 2.92 - 2.97 (1H, multiplet); 3.16 (1H, multiplet); 3.97, 4.69 (2H, AB-quartet, J = 16.6 Hz); 5.51 - 5.59 (1H, multiplet); 5.83 (1H, doublet of doublets, J = 10.7 & 2.9 Hz); 6.09 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.7 & 8.7 Hz); 6.84 (1H, singlet); 7.42 (1H, doublet of doublets, J = 16.0 & 8.7 Hz); 10.78 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1772, 1730. EXAMPLE 12 14,16-Bis(2,2,2-trichloroethoxycarbonylaminohexanoyl)radicicol 182 mg of radicicol were dissolved in 6 ml of dry tetrahydrofuran, and 383 mg of 2,2,2-trichloroethoxycarbonylaminohexanoic acid, 363 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine were added at room temperature to the resulting solution; it was then stirred at the same temperature for 2 hours. At the end of this time, the dicyclohexylurea which was produced by a side reaction was filtered off. Water was added to the filtrate and the resulting mixture was extracted with ethyl acetate. The ethyl acetate solution was washed with an aqueous solution of sodium bicarbonate and then with water, after which it was dried over anhydrous magnesium sulphate. The solvent was then removed by distillation under reduced pressure. The resulting residue was purified by silica gel column chromatography, using a 1 : 1 by volume mixture of hexane and ethyl acetate as the eluent. After condensation of the eluate having an Rf value of 0.75 (developing solvent, ethyl acetate : hexane = 2 : 1 by volume), 191 mg of the title compound was obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.15 - 1.98 (13H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 2.40 - 2.46 (1H, multiplet); 2.50 - 2.56 (2H, multiplet); 2.61 (2H, triplet, J = 7.3 Hz); 3.00 - 3.04 (1H, multiplet); 3.24 (2H, triplet, J = 6.8 Hz); 3.29 (2H, triplet, J = 6.9 Hz); 3.52 (1H, multiplet); 3.93, 4.01 (2H, AB-quartet, J = 16.1 Hz); 4.72 (4H, singlet); 4.95 - 5.04 (1H, multiplet); 5.06 - 5.17 (1H, multiplet); 5.40 - 5.45 (1H, multiplet); 5.80 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.2 & 10.7 Hz); 7.03 (1H, singlet); 7.53 (1H, doublet of doublets, J = 10.7 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. EXAMPLE 14 14,16-Di(methoxyacetyl)radicicol 182 mg of radicicol, 4 ml of dry methylene chloride, 255 µℓ of pyridine, a catalytic amount of dimethylaminopyridine and 412 mg of methoxyacetyl chloride were reacted together, and then the product was treated, in each case in a similar manner to that described in Example 4, to give a mixture. This mixture was purified by silica gel short column chromatography using a 3 : 1 by volume mixture of ethyl acetate and hexane as the eluent, to give 255 mg of the title compound as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.54 (3H, doublet, J = 6.3 Hz); 1.53 - 1.68 (1H, multiplet); 2.37 - 2.43 (1H, multiplet); 2.98 - 3.05 (1H, multiplet); 3.50 (3H, singlet); 3.52 (1H, multiplet); 3.53 (3H, singlet); 3.95, 4.07 (2H, AB-quartet, J = 16.1 Hz); 4.23 (2H, singlet); 4.33 (2H, singlet); 5.36 - 5.46 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 11.2 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 11.2 & 10.8 Hz); 7.26 (1H, singlet); 7.49 (1H, doublet of doublets, J = 16.0 & 10.8 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1792, 1740. EXAMPLE 15 14-Methoxyacetylradicicol 1.54 g of 14,16-di(methoxyacetyl)radicicol (prepared as described in Example 14) was dissolved in 20 ml of ethyl acetate, and 15 g of silica gel were added to the resulting solution; the mixture was then stirred for 23 hours at room temperature. At the end of this time, the silica gel was removed by filtration, and the solution was washed well with ethyl acetate. The filtrate and the washings were combined and condensed by evaporation under reduced pressure, and the resulting residue was purified by silica gel column chromatography using a 2 : 1 by volume mixture of ethyl acetate and hexane as the eluent. The eluate having an Rf value of 0.50 (developing solvent, ethyl acetate : hexane = 2 : 1 by volume) was collected and condensed, to give 340 mg of the title compound as an oily substance. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.53 (3H, doublet, J = 6.8 Hz); 1.86 - 1.97 (1H, multiplet); 2.34 - 2.42 (1H, multiplet); 2.92 - 2.97 (1H, multiplet); 3.17 (1H, multiplet); 3.53 (3H, singlet); 3.98, 4.70 (2H, AB-quartet, J = 16.6 Hz); 5.51 - 5.60 (1H, multiplet); 5.84 (1H, doublet of doublets, J = 10.7 & 2.9 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.7 & 9.2 Hz); 6.89 (1H, singlet); 7.42 (1H, doublet of doublets, J = 17.0 & 9.2 Hz); 10.79 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1790, 1725. EXAMPLE 16 16-Methoxyacetylradicicol The eluate having an Rf value of 0.42 (developing solvent, ethyl acetate : hexane = 2 : 1 by volume) obtained in the course of the silica gel column chromatography described in Example 15 was collected and condensed, to give 357 mg of the title compound. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.51 (3H, doublet, J = 6.9 Hz); 1.58 - 1.67 (1H, multiplet); 2.34 - 2.42 (1H, multiplet); 2.98 - 3.04 (1H, multiplet); 3.51 (3H, singlet); 3.52 (1H, multiplet); 4.00, 4.13 (2H, AB-quartet, J = 16.1 Hz); 4.24 (2H, singlet); 5.32 - 5.42 (1H, multiplet); 5.77 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 5.99 (1H, singlet); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.2 Hz); 6.82 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.0 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1782, 1730. EXAMPLE 25 14-Stearoyl-16-palmitoylradicicol Following a procedure similar to that described in Example 4, but using 442 mg of 14-stearoylradicicol (prepared as described in Example 7), 20 ml of dry methylene chloride, 186 µℓ of pyridine, a catalytic amount of dimethylaminopyridine and 202 mg of palmitoyl chloride, and then purifying the reaction mixture by silica gel column chromatography using a 2 : 1 by volume mixture of hexane and ethyl acetate, 581 mg of the title compound were obtained as crystals. Recrystallization of this product from pentane afforded 302 mg of white crystals. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.3 Hz); 1.22 - 1.42 (52H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.48 - 1.62 (1H, multiplet); 1.64 - 1.81 (4H, multiplet); 2.35 - 2.44 (1H, multiplet); 2.49 (2H, triplet, J = 6.8 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.97 - 3.04 (1H, multiplet); 3.54 (1H, multiplet); 3.91, 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.36 - 5.45 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.2 Hz); 6.14 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. EXAMPLE 26 14,16-Di(10-undecenoyl)radicicol Following a procedure similar to that described in Example 1, but using 1459 mg of radicicol, 973 mg of 10-undecenoyl chloride, 37 ml of dry methylene chloride, 1.9 ml of pyridine and a catalytic amount of dimethylaminopyridine, 840 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.25 - 1.80 (24H, multiplet); 1.48 - 1.58 (1H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 1.99 - 2.10 (4H, multiplet); 2.35 - 2.47 (1H, multiplet); 2.49 (2H, triplet, J = 7.7 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.93 - 3.04 (1H, multiplet); 3.51 (1H, multiplet); 3.91 & 4.03 (2H, AB-quartet, J = 16.1 Hz); 4.90 - 5.04 (2H x 2, multiplet); 5.35 - 5.46 (1H, multiplet); 5.74 - 5.90 (3H, multiplet); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.2 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Mass spectrum (m/e): 696 (M + ) Elemental analysis: Calculated for C 40 H 53 0 8 Cℓ: C, 68.90%; H, 7.66%; Cℓ, 5.08%. Found: C, 68.02%; H, 7.53%, Cℓ, 5.41%. EXAMPLE 27 14-(10-Undecenoyl)radicicol The reaction mixture obtained in the final product treatment employed in Example 26 was fractionated and purified by chromatography through silica gel using a 2 : 1 by volume mixture of hexane and ethyl acetate as the eluent, to give 360 mg of the title compound having an Rf value of 0.3 (developing solvent, a 2 : 1 by volume mixture of hexane and ethyl acetate). Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.25 - 1.48 (12H, multiplet); 1.55 (3H, doublet, J = 6.8 Hz); 1.70 - 1.82 (2H, multiplet); 1.86 - 1.98 (1H, multiplet); 2.02 - 2.10 (2H, multiplet); 2.33 - 2.43 (1H, multiplet); 2.59 (2H, triplet, J = 7.3 Hz); 2.93 - 2.98 (1H, multiplet); 3.17 (1H, multiplet); 3.97 and 4.69 (2H, AB-quartet, J = 16.6 Hz); 4.92 - 5.03 (2H, multiplet); 5.51 - 5.62 (1H, multiplet); 5.73 - 5.90 (2H, multiplet); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.2, 9.28 Hz); 6.84 (1H, singlet); 7.43 (1H, doublet of doublets, J = 16 1, 9.2 Hz); 10.78 (1H, singlet). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1730. Mass spectrum (m/e): 530 (M + ), 364. EXAMPLE 30 14-Elaidoyl-16-palmitoylradicicol Following a procedure similar to that described in Example 25, but using 500 mg of 14-elaidoylradicicol, 303 mg of palmitoyl chloride, 20 ml of dry methylene chloride, 0.2 ml of pyridine and a catalytic amount of dimethylaminopyridine, 484 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.87 (6H, triplet, J = 6.8 Hz); 1.2 - 18 (48H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 1.92 - 2.00 (4H, multiplet); 2.35 - 2.45 (1H, multiplet); 2.49 (2H, triplet, J = 7.8 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.96 - 3.05 (1H, multiplet); 3.52 (1H, multiplet); 3.91 & 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.36 - 5.47 (3H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.4 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.14 (1H, doublet of doublets, J = 18.7 & 10.2 Hz); 7.01 (1H, singlet); 7.51 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis Calculated for C 52 H 79 O 8 Cℓ: C, 71.98%; H, 9.18%; Cℓ, 4.09%. Found: C, 71.26%; H, 9.45%; Cℓ, 3.93%. EXAMPLE 31 14,16-Dimyristoylradicicol Following a procedure similar to that described in Example 1, but using 1.28 g of radicicol, 1.04 g of myristoyl chloride, 35 ml of dry methylene chloride, 1.76 ml of pyridine and a catalytic amount of dimethylaminopyridine, 0.80 g of the title compound was obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.5 (40H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.45 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 2.35 - 2.45 (1H, multiplet); 2.50 (2H, triplet, J = 6.8 Hz); 2.59 (2H, triplet, J = 7.5 Hz); 2.98 - 3.04 (1H, multiplet); 3.50 - 3.53 (1H, multiplet); 3.92 (1H, doublet, J = 16.4 Hz); 4.03 (1H, doublet, J = 16.4 Hz); 5.3 - 5.5 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 46 H 69 O 8 Cℓ: C, 70.34%; H, 8.85%; Cℓ, 4.51%. Found: C, 70.43%; H, 8.68%; Cℓ, 4.46%. EXAMPLE 32 14-Myristoylradicicol The reaction mixture obtained in the final product treatment employed in Example 31 was fractionated and purified by chromatography through silica gel, using a 2 : 1 by volume mixture of hexane and ethyl acetate as the eluent, to give 543 mg of the title compound having an Rf value of 0.7 (developing solvent, a 1 : 1 by volume mixture of hexane and ethyl acetate). Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.26 (3H, triplet, J = 6.9 Hz); 1.2 - 1.5 (20H, multiplet); 1.55 (3H, doublet, J = 6.8 Hz); 1.7 - 1.8 (2H, multiplet); 1.85 - 2.0 (1H, multiplet); 2.38 (1H, doublet of triplets, J = 15.6 & 3.4 Hz); 2.59 (2H, triplet, J = 7.5 Hz); 2.95 (1H, doublet of triplets, J = 8.8 & 2.4 Hz); 3.16 (1H, multiplet); 3.98 (1H, doublet, J = 16.6 Hz); 4.69 (1H, doublet, J = 16.6 Hz); 5.52 - 5.59 (1H, multiplet); 5.84 (1H, doublet of doublets, J = 10.7 & 2.4 Hz); 6.10 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 6.84 (1H, singlet); 7.43 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770. Elemental analysis: Calculated for C 32 H 43 O 7 Cℓ: C, 66.83%; H, 7.54%; Cℓ, 6.16%. Found: C, 66.83%; H, 7.60%; Cℓ, 6.01%. EXAMPLE 33 14-Myristoyl-16-palmitoylradicicol Following a procedure similar to that described in Example 25, but using 539 mg of 14-myristoylradicicol, 509 mg of palmitoyl chloride, 15 ml of dry methylene chloride, 0.47 ml of pyridine and a catalytic amount of dimethylaminopyridine, 742 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.5 (44H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.5 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 2.3 - 2.45 (1H, multiplet); 2.50 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.98 - 3.04 (1H, multiplet); 3.51 - 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.1 Hz); 4.03 (1H, doublet, J = 16.1 Hz); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. Elemental analysis: Calculated for C 48 H 73 O 8 Cℓ: C, 70.87%; H, 9.04%; Cℓ, 4.36%. Found: C, 70.21%; H, 9.32%; Cℓ, 3.95%. EXAMPLE 34 14,16-Dilinoleoylradicicol Following a procedure similar to that described in Example 1, but using 814 mg of radicicol, 800 mg of linoleoyl chloride, 22 ml of dry methylene chloride, 1.09 ml of pyridine and a catalytic amount of dimethylaminopyridine, 761 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.89 (6H, triplet, J = 6.8 Hz); 1.2 - 1.4 (28H, multiplet); 1.54 (3H, doublet, J = 7.8 Hz); 1.49 - 1.61 (1H, multiplet); 1.63 - 1.80 (4H, multiplet); 2.0 - 2.1 (8H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.50 (2H, triplet, J = 7.8 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.78 (4H, doublet of doublets, J = 5.9 & 5.4 Hz); 2.98 - 3.03 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.3 Hz); 4.03 (1H, doublet, J = 16.3 Hz); 5.25 - 5.45 (9H, multiplet); 5.79 (1H, doublet of doublets, J = 10.3 & 3.7 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. Elemental analysis: Calculated for C 54 H 76 O 8 Cℓ: C, 72.99%; H, 8.62%; Cℓ, 3.99%. Found: C, 72.89%; H, 8.79%; Cℓ, 3.94%. EXAMPLE 35 14-Linoleoylradicicol The reaction mixture obtained in the final product treatment employed in Example 34 was fractionated and purified by chromatography through silica gel, using a 2 : 1 by volume mixture of hexane and ethyl acetate as the eluent, to give 662 mg of the title compound having an Rf value of 0.72 (developing solvent, a 1 : 1 by volume mixture of hexane and ethyl acetate). Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.89 (3H, triplet, J = 6.3 Hz); 1.2 - 1.5 (14H, multiplet); 1.55 (3H, doublet, J = 6.8 Hz); 1.5 - 1.8 (3H, multiplet); 1.8 - 2.3 (4H, multiplet); 2.38 (1H, doublet of triplets, J = 15.1 & 3.4 Hz); 2.60 (3H, triplet, J = 7.2 Hz); 2.78 (1H, triplet, J = 5.9 Hz); 2.9 - 3.0 (1H, multiplet); 3.17 (1H, broad singlet); 3.98 (1H, doublet, J = 16.9 Hz); 4.38 (1H, doublet, J = 16.9 Hz); 5.25 - 5.45 (2H, multiplet); 5.5 - 5.7 (3H, multiplet); 5.86 (1H, doublet of doublets, J = 10.2 & 5.8 Hz); 6.11 (1H, doublet, J = 16.1 Hz); 6.18 (1H, triplet, J = 9.3 Hz); 6.84 (1H, singlet); 7.43 (1H, doublet of doublets, J = 16.1 & 9.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1730. EXAMPLE 37 14-(10-Undecenoyl)-16-palmitoylradicicol Following a procedure similar to that described in Example 1, but using 400 mg of 14-(10-undecenoyl)radicicol (prepared as described in Example 27), 329 mg of palmitoyl chloride, 15 ml of dry methylene chloride, 0.19 ml of pyridine and a catalytic amount of dimethylaminopyridine, 477 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (3H, triplet, J = 6.8 Hz); 1.2 - 1.8 (39H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 2.00 - 2.10 (2H, multiplet); 2.36 - 2.45 (1H, multiplet); 2.49 (2H, triplet, J = 6.3 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.97 - 3.05 (1H, multiplet); 3.52 (1H, multiplet); 3.91 & 4.03 (2H, AB-quartet, J = 16.1 Hz); 4.90 - 5.03 (2H, multiplet); 5.35 - 5.47 (1H, multiplet); 5.75 - 5.90 (2H, multiplet); 6.06 (1H, doublet, J = 16.6 Hz); 6.14 (1H, doublet of doublets, J = 11.2 & 10.2 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1766, 1735. Mass spectrum (m/e): 768 (M + ), 602, 364. EXAMPLE 38 14,16-Bis(3-methylthiopropionyl)radicicol Following a procedure similar to that described in Example 1, but using 1.56 g of radicicol, 0.71 g of 3-methylthiopropionyl chloride, 40 ml of dry methylene chloride, 2.15 ml of pyridine and a catalytic amount of dimethylaminopyridine, 447 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.54 (3H, triplet, J = 6.4 Hz); 2.16 (3H, singlet); 2.17 (3H, singlet); 2.41 (1H, doublet of triplets, J = 14.7 & 3.4 Hz); 2.83 (4H, singlet); 2.83 - 2.95 (4H, multiplet); 3.01 (1H, doublet of triplets, J = 11.3 & 2.9 Hz); 3.51 (1H, multiplet); 3.93 (1H, doublet, J = 16.4 Hz); 4.03 (1H, doublet, J = 16.4 Hz); 5.42 - 5.47 (1H, multiplet); 5.80 (1H, doublet of doublets, J = 10.7 & 3.4 Hz); 6.07 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.10 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1775, 1740. Elemental analysis: Calculated for C 26 H 29 O 8 S 2 Cℓ: C, 54.87%; H, 5.14; Cℓ, 6.23, S: 11.27%. Found: C, 55.26%; H, 5.37; Cℓ, 6.14, S: 11.01%. EXAMPLE 39 14,16-Dipalmitoleoylradicicol Following a procedure similar to that described in Example 12, but using 365 mg of radicicol, 636 mg of palmitoleic acid, 20 ml of dry methylene chloride, 716 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 654 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.4 (32H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.5 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 1.9 - 2.1 (8H, multiplet); 2.35 - 2.45 (1H, multiplet); 2.50 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.98 - 3.04 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.4 Hz); 4.03 (1H, doublet, J = 16.4 Hz); 5.3 - 5.5 (5H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. Elemental analysis: Calculated for C 50 H 73 O 8 Cℓ: C, 71.70%; H, 8.79%; Cℓ, 4.23%. Found: C, 72.09%; H, 8.89%; Cℓ, 3.56%. EXAMPLE 40 14,16-Diisopalmitoylradicicol Following a procedure similar to that described in Example 12, but using 500 mg of radicicol, 878 mg of isopalmitic acid, 20 ml of dry tetrahydrofuran, 848 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 1.12 g of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.85 - 0.9 (12H, multiplet); 1.2 - 1.5 (40H, multiplet); 1.55 (3H, doublet, J = 6.4 Hz); 1.4 - 1.9 (9H, multiplet); 2.40 (1H, doublet of doublets, J = 14.6 & 2.6 Hz); 2.45 - 2.65 (2H, multiplet); 3.01 (1H, doublet of triplets, J = 8.8 & 2.6 Hz); 3.53 (1H, multiplet); 3.89 (1H, doublet, J = 16.4 Hz); 3.96 (1H, doublet, J = 16.4 Hz); 5.4 - 5.5 (1H, multiplet); 5.84 (1H, doublet of doublets, J = 10.7 & 3.4 Hz); 6.07 (1H, doublet, J = 16.1 Hz); 6.15 (1H, triplet, J = 10.7 Hz); 6.92 (1H, singlet); 7.62 (1H, doublet of doublets, J = 16.1 & 10.7 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. Elemental analysis: Calculated for C 50 H 77 O 8 Cℓ: C, 71.36%; H, 9.22%; Cℓ, 4.21%. Found: C, 71.31%; H, 9.32%; Cℓ, 3.96%. EXAMPLE 41 16-Palmitoylradicicol Following a procedure similar to that described in Example 12, but using 364 mg of radicicol, 384 mg of palmitic acid, 15 ml of dry tetrahydrofuran, 309 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 62 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (3H, triplet, J = 6.3 Hz); 1.51 (3H, doublet, J = 6.3 Hz); 1.20 - 1.76 (27H, multiplet); 2.34 - 2.43 (1H, multiplet); 2.50 (2H, triplet, J = 7.8 Hz); 2.96 - 3.04 (1H, multiplet); 3.56 (1H, multiplet); 3.96 & 4.06 (2H, AB-quartet, J = 16.6 Hz); 5.34 - .5.45 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.04 (1H, singlet); 6.06 (1H, doublet, J = 16.6 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.2 Hz); 6.77 (1H, singlet); 7.56 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1765, 1730. Mass spectrum (m/e): 602 (M + ). Elemental analysis: Calculated for C 34 H 47 O 7 Cℓ: C, 67.70%; H, 7.85%; Cℓ, 5.88%. Found: C, 67.10%; H, 7.62%; Cℓ, 5.72%. EXAMPLE 42 14,16-Di(2-octynoyl)radicicol Following a procedure similar to that described in Example 12, but using 730 mg of radicicol, 701 mg of 2-octynoic acid, 15 ml of dry tetrahydrofuran, 1.03 g of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 611 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.91 (3H, triplet, J = 6.8 Hz); 0.92 (3H, triplet, J = 7.3 Hz); 1.2 - 1.6 (8H, multiplet); 1.56 (3H, doublet, J = 6.8 Hz); 1.5 - 1.7 (4H, multiplet); 1.7 - 1.8 (1H, multiplet); 2.35 - 2.47 (5H, multiplet); 3.0 - 3.1 (1H, multiplet); 3.5 - 3.55 (1H, multiplet); 3.93 (1H, doublet, J = 16.1 Hz); 4.26 (1H, doublet, J = 16.1 Hz); 5.2 - 5.35 (1H, multiplet); 5.69 (1H, doublet of doublets, J = 10.7 & 5.1 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 9.8 Hz); 7.11 (1H, singlet); 7.34 (1H, doublet of doublets, J = 16.1 & 9.8 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 2250, 1745. Elemental analysis: Calculated for C 34 H 37 O 8 Cℓ: C, 67.04%; H, 6.12%%; Cℓ, 5.82%. Found: C, 66.76%; H, 6.21%%; Cℓ, 5.76%. EXAMPLE 44 14,16-Dipentadecanoylradicicol Following a procedure similar to that described in Example 12, but using 500 mg of radicicol, 830 mg of pentadecanoic acid, 15 ml of dry tetrahydrofuran, 707 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 782 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.5 (44H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.5 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 2.40 (1H, triplet, J = 13.7 & 3.1 Hz); 2.49 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.99 - 3.04 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.1 Hz); 4.03 (1H, doublet, J = 16.1 Hz); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.53 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 48 H 73 O 8 Cℓ: C, 70.87%; H, 9.04%; Cℓ, 4.36%. Found: C, 71.11%; H, 9.16%; Cℓ, 3.97%. EXAMPLE 45 14,16-Diheptadecanoylradicicol Following a procedure similar to that described in Example 1, but using 730 mg of radicicol, 693 mg of heptadecanoyl chloride, 25 ml of dry methylene chloride, 1 ml of pyridine and a catalytic amount of dimethylaminopyridine, 539 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.5 (52H, multiplet); 1.54 (3H, doublet, J = 7.8 Hz); 1.5 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 2.40 (1H, doublet of triplets, J = 14.7 & 3.4 Hz); 2.49 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.98 - 3.04 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.1 Hz); 4.03 (1H, doublet, J = 16.1 Hz); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 52 H 81 O 8 Cℓ: C, 71.82%; H, 8.39%; Cℓ, 4.08%. Found: C, 71.98%; H, 9.42%; Cℓ, 3.93%. EXAMPLE 46 14-Heptadecanoylradicicol The reaction mixture obtained in the final product treatment employed in Example 45 was fractionated and purified by chromatography through silica gel, using a 3 : 1 by volume mixture of hexane and ethyl acetate as the eluent, to give 640 mg of the title compound having an Rf value of 0.5 (developing solvent, a 2 : 1 by volume mixture of hexane and ethyl acetate). Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (3H, triplet, J = 6.6 Hz); 1.2 - 1.5 (26H, multiplet); 1.55 (3H, doublet, J = 6.8 Hz); 1.7 - 1.85 (2H, multiplet); 1.85 - 2.0 (1H, multiplet); 2.38 (1H, doublet of triplets, J = 16.1 & 2.4 Hz); 2.60 (2H, triplet, J = 7.3 Hz); 2.92 - 2.97 (1H, multiplet); 3.17 (1H, multiplet); 3.98 (1H, doublet, J = 16.6 Hz); 4.69 (1H, doublet, J = 16.6 Hz); 5.52 - 5.60 (1H, multiplet); 5.84 (1H, doublet of doublets, J = 10.7 & 2.9 Hz); 6.11 (1H, doublet, J = 16.1 Hz); 6.18 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 6.84 (1H, singlet); 7.43 (1H, doublet of doublets, J = 16.1 & 10.3 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1730. Elemental analysis: Calculated for C 35 H 49 O 7 Cℓ: C, 68.11%; H, 8.00%; Cℓ, 5.74%. Found: C, 68.55%; H, 8.39%; Cℓ, 5.27%. EXAMPLE 54 14,16-Dilinolenoylradicicol Following a procedure similar to that described in Example 1, but using 280 mg of radicicol, 600 mg of linolenoyl chloride, 11 ml of dry methylene chloride, 0.37 ml of pyridine and a catalytic amount of dimethylaminopyridine, 552 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (hexadeuterated dimethyl sulphoxide, 270 MHz) δ ppm: 0.84 (3H, triplet, J = 5.4 Hz); 0.85 (3H, triplet, J = 6.4 Hz); 1.1 - 1.8 (24H, multiplet); 1.47 (3H, doublet, J = 6.3 Hz); 1.5 - 1.8 (1H, multiplet); 1.9 - 2.2 (8H, multiplet); 2.4 - 2.5 (1H, multiplet); 2.5 - 2.7 (5H, multiplet); 2.7 - 2.8 (6H, multiplet); 3.05 - 3.15 (1H, multiplet); 3.40 (1H, multiplet); 3.84 (1H, doublet, J = 16.1 Hz); 4.00 (1H, doublet, J = 16.1 Hz); 5.2 - 5.5 (13H, multiplet); 5.78 (1H, doublet of doublets, J = 10.8 & 3.9 Hz); 6.08 (1H, doublet, J = 16.1 Hz); 6.25 (1H, doublet of doublets, J = 10.8 & 10.2 Hz); 7.38 (1H, singlet); 7.38 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 54 H 73 O 8 Cℓ: C, 73.24%; H, 8.31%; Cℓ, 4.00%. Found: C, 73.35%; H, 8.60%; Cℓ, 3.91%. EXAMPLE 55 14,16-Bistridecanoylradicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 588 mg of tridecanoic acid, 6 ml of dry tetrahydrofuran, 566 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 688 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.5 Hz); 1.1 - 1.5 (36H, multiplet); 1.54 (3H, doublet, J = 6.3 Hz); 1.6 - 1.8 (5H, multiplet); 2.35 - 2.45 (1H, multiplet); 2.50 (2H, triplet, J = 7.5 Hz); 2.59 (2H, triplet, J = 7.5 Hz); 3.02 (1H, multiplet); 3.51 (1H, multiplet); 3.86 & 3.97 (2H, AB-quartet, J = 13.6 Hz); 5.40 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 11.3 & 10.3 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 44 H 65 O 8 Cℓ: C, 69.77%; H, 8.65%; Cℓ, 4.68%. Found: C, 69.54%; H, 8.69%; Cℓ, 4.66%. EXAMPLE 56 14,16-Dilauroylradicicol Following a procedure similar to that described in Example 1, but using 730 mg of radicicol, 656 mg of lauroyl chloride, 14 ml of dry methylene chloride, 0.97 ml of pyridine and a catalytic amount of dimethylaminopyridine, 644 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.6 Hz); 1.2 - 1.5 (32H, multiplet); 1.54 (3H, doublet, J = 6.3 Hz); 1.48 - 1.5 (1H, multiplet); 1.5 - 1.8 (4H, multiplet); 2.40 (1H, doubled doublet of doublets, J = 4.9 Hz); 2.49 (2H, triplet, J = 6.6 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 3.01 (1H, multiplet); 3.51 (1H, multiplet); 3.92 & 4.03 (2H, AB-quartet, J = 16.6 Hz); 5.40 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 9.7 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.2 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1735. Elemental analysis: Calculated for C 42 H 61 O 8 Cℓ: C, 69.16%; H, 8.43%; Cℓ, 4.86%. Found: C, 69.11%; H, 8.65%; Cℓ, 4.89%. EXAMPLE 57 14,16-Bis(16-acetylthiohexadecanoyl)radicicol Following a procedure similar to that described in Example 12, but using 120 mg of radicicol, 206 mg of 16-acetylthiohexadecanoic acid, 5 ml of dry tetrahydrofuran, 330 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 235 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.2 - 1.8 (52H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 2.31 (6H, singlet); 2.34 - 2.45 (1H, multiplet); 2.50 (2H, triplet, J = 7.3 Hz); 2.58 (2H, triplet, J = 7.3 Hz); 2.86 (2H x 2, triplet, J = 7.31 Hz); 2.97 - 3.05 (1H, multiplet); 3.53 (1H, multiplet); 3.91 & 4.03 (2H, AB-quartet, J = 16.1 Hz); 5.37 - 5.45 (1H, multiplet); 5.78 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.7 Hz); 7.01 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.7 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770. EXAMPLE 61 14,16-Dicaproylradicicol Following a procedure similar to that described in Example 1, but using 365 mg of radicicol, 460 mg of caproyl chloride, 7 ml of dry methylene chloride, 0.49 ml of pyridine and a catalytic amount of dimethylaminopyridine, 575 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.89 (6H, triplet, J = 6.3 Hz); 1.2 - 1.5 (24H, multiplet); 1.45 - 1.6 (1H, multiplet); 1.54 (3H, doublet, J = 6.6 Hz); 1.6 - 1.8 (4H, multiplet); 2.41 (1H, dm, J = 14.5 Hz); 2.50 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 3.01 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.5 Hz); 4.03 (1H, doublet, J = 16.5 Hz); 5.42 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.6 & 3.9 Hz); 6.11 (1H, doublet, J = 15.9 Hz); 6.17 (1H, triplet, J = 5.9 Hz); 7.02 (1H, singlet); 7.53 (1H, doublet of doublets, J = 16.5 & 10.6 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1730. Elemental analysis: Calculated for C 38 H 53 O 8 Cℓ: C, 67.79%; H, 7.93%; Cℓ, 5.27%. Found: C, 67.76%; H, 7.80%; Cℓ, 5.02%. EXAMPLE 62 14,16-Diundecanoylradicicol Following a procedure similar to that described in Example 1, but using 365 mg of radicicol, 450 mg of undecanoyl chloride, 7 ml of dry methylene chloride, 0.49 ml of pyridine and a catalytic amount of dimethylaminopyridine, 586 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.89 (6H, triplet, J = 6.4 Hz); 1.2 - 1.5 (28H, multiplet); 1.45 - 1.6 (1H, multiplet); 1.54 (3H, doublet, J = 6.6 Hz); 1.6 - 1.8 (4H, multiplet); 2.40 (1H, dm, J = 15.2 Hz); 2.50 (2H, triplet, J = 7.9 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 3.0 (1H, multiplet); 3.5 (1H, multiplet); 3.92 (1H, doublet, J = 16.2 Hz); 4.03 (1H, doublet, J = 16.2 Hz); 5.42 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.5 Hz); 6.15 (1H, triplet, J = 10.7 Hz); 7.02 (1H, singlet); 7.53 (1H, doublet of doublets, J = 16.5 & 10.5 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1730. Elemental analysis: Calculated for C 40 H 57 O 8 Cℓ: C, 68.50%; H, 8.19%; Cℓ, 5.06%. Found: C, 68.56%; H, 8.04%; Cℓ, 4.86%. EXAMPLE 63 14,16-Dieicosanoylradicicol Following a procedure similar to that described in Example 1, but using 300 mg of radicicol, eicosanoyl chloride (prepared from 1.2 g of eicosanoic acid), 5 ml of dry methylene chloride, 0.4 ml of pyridine and a catalytic amount of dimethylaminopyridine, 646 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.88 (6H, triplet, J = 6.3 Hz); 1.2 - 1.5 (44H, multiplet); 1.45 - 1.6 (1H, multiplet); 1.54 (3H, doublet, J = 7.3 Hz); 1.6 - 1.8 (4H, multiplet); 2.40 (1H, dm, J = 14.5 Hz); 2.50 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 3.02 (1H, multiplet); 3.52 (1H, multiplet); 3.92 (1H, doublet, J = 16.1 Hz); 4.03 (1H, doublet, J = 16.1 Hz); 5.40 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.5 & 3.3 Hz); 6.07 (1H, doublet, J = 16.5 Hz); 6.15 (1H, triplet, J = 10.5 Hz); 7.02 (1H, singlet); 7.53 (1H, doublet of doublets, J = 16.5 & 10.5 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. Elemental analysis: Calculated for C 58 H 93 O 8 Cℓ: C, 73.04%; H, 9.83%; Cℓ, 3.72%. Found: C, 72.99%; H, 9.93%; Cℓ, 3.77%. EXAMPLE 67 14,16-Dimyristoleoylradicicol Following a procedure similar to that described in Example 1, but using 365 mg of radicicol, myristoleoyl chloride prepared from 900 mg of myristoleic acid, 7 ml of dry methylene chloride, 0.97 ml of pyridine and a catalytic amount of dimethylaminopyridine, 510 mg of the title compound were obtained. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 0.89 (6H, triplet, J = 6.2 Hz); 1.2 - 1.5 (24H, multiplet); 1.53 (3H, doublet, J = 6.3 Hz); 1.45 - 1.6 (1H, multiplet); 1.6 - 1.8 (4H, multiplet); 2.02 (8H, doublet, J = 5.9 Hz); 2.40 (1H, doubled doublet of doublets, J = 14.7 Hz); 2.49 (2H, doublet of doublets, J = 7.8 & 6.8 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 3.01 (1H, multiplet); 3.51 (1H, multiplet); 3.92 (1H, doublet, J = 16.6 Hz); 4.03 (1H, doublet, J = 16.6 Hz); 5.27 - 5.45 (5H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.4 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 11.7 & 10.7 Hz); 7.02 (1H, singlet); 7.51 (1H, doublet of doublets, J = 16.6 & 10.7 Hz). Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1740. EXAMPLE 69 14,16-Di[10-(methoxyethoxymethoxy)decanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 758 mg of 10-(methoxyethoxymethoxy)decanoic acid, 6 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 829 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1775, 1735. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.2 - 1.5 (24H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.5 - 1.8 (5H, multiplet); 2.40 (1H, doubled doublet of doublets, J = 15.1 Hz); 2.50 (2H, doublet of doublets, J = 6.6 & 8.0 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 3.01 (1H, multiplet); 3.40 (6H, singlet); 3.47 - 3.52 (9H, multiplet); 3.55 - 3.65 (4H, multiplet); 3.92 (1H, doublet, J = 16.1 Hz); 4.03 (1H, doublet, J = 16.1 Hz); 4.72 (4H, singlet); 5.41 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, triplet, J = 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.7 Hz). EXAMPLE 70 14,16-Di[10-(methoxymethoxy)decanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 595 mg of 10-(methoxymethoxy)decanoic acid, 6 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 739 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1775, 1735. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.25 - 1.5 (24H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.5 - 1.8 (5H, multiplet); 2.40 (1H, doubled doublet of doublets, J = 14.7 Hz); 2.50 (2H, doublet of doublets, J = 7.8 & 6.8 Hz); 2.57 (2H, triplet, J = 7.5 Hz); 3.00 (1H, multiplet); 3.36 (6H, singlet); 3.51 (4H, triplet, J = 6.1 Hz); 3.5 (1H, multiplet); 3.92 (1H, doublet, J = 16.6 Hz); 4.03 (1H, doublet, J = 16.6 Hz); 4.62 (4H, singlet); 5.41 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 6.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 9.7 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.6 & 10.3 Hz). EXAMPLE 71 14,16-Di[12-(methoxyethoxymethoxy)dodecanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 856 mg of 12-(methoxyethoxymethoxy)dodecanoic acid, 6 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 893 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1770, 1738. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.24 - 1.45 (32H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.45 - 1.6 (1H, multiplet); 1.65 - 1.77 (4H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.50 (2H, doublet of doublets, J = 7.8 & 6.8 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 2.98 - 3.04 (1H, multiplet); 3.40 (6H, singlet); 3.51 - 3.58 (9H, multiplet); 3.68 - 3.71 (4H, multiplet); 3.97 (2H, AB-quartet, J = 16.1 Hz); 4.72 (4H, singlet); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz) EXAMPLE 72 14,16-Di[12-(methoxymethoxy)dodecanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 716 mg of 12-(methoxymethoxy)dodecanoic acid, 7 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 756 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1767, 1730. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.23 - 1.47 (32H, multiplet); 1.5 - 1.6 (1H, multiplet); 1.54 (3H, doublet, J = 6.8 Hz); 1.6 - 1.8 (4H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.50 (2H, triplet, J = 7.8 Hz); 2.59 (2H, triplet, J = 7.6 Hz); 2.98 - 3.04 (1H, multiplet); 3.36 (6H, singlet); 3.52 (4H, triplet, J = 6.6 Hz); 3.45 - 3.55 (1H, multiplet); 3.97 (2H, AB-quartet, J = 16.1 Hz); 4.62 (4H, singlet); 5.16 - 5.23 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz) EXAMPLE 73 14,16-Di[16-(methoxyethoxymethoxy)hexadecanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 996 mg of 16-(methoxyethoxymethoxy)hexadecanoic acid, 6 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 946 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1765, 1734. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.2 - 1.46 (48H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.47 - 1.62 (1H, multiplet); 1.65 - 1.80 (4H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.49 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 2.98 - 3.04 (1H, multiplet); 3.40 (6H, singlet); 3.5 - 3.6 (9H, multiplet); 3.67 - 3.72 (4H, multiplet); 3.97 (2H, AB-quartet, J = 16.1 Hz); 4.71 (4H, singlet); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.52 (1H, doublet of doublets, J = 16.1 & 10.3 Hz) EXAMPLE 74 14,16-Di[16-(methoxymethoxy)hexadecanoyl]radicicol Following a procedure similar to that described in Example 12, but using 400 mg of radicicol, 865 mg of 10-(methoxymethoxy)decanoic acid, 7 ml of dry tetrahydrofuran, 567 mg of dicyclohexylcarbodiimide and a catalytic amount of dimethylaminopyridine, 543 mg of the title compound were obtained. Infrared Absorption Spectrum (CHCℓ 3 ) ν max cm -1 : 1737, 1768. Nuclear Magnetic Resonance Spectrum (CDCℓ 3 , 270 MHz) δ ppm: 1.2 - 1.46 (48H, multiplet); 1.54 (3H, doublet, J = 6.4 Hz); 1.5 - 1.6 (1H, multiplet); 1.6 - 1.77 (4H, multiplet); 2.36 - 2.44 (1H, multiplet); 2.50 (2H, triplet, J = 7.3 Hz); 2.59 (2H, triplet, J = 7.3 Hz); 2.98 - 3.04 (1H, multiplet); 3.36 (6H, singlet); 3.52 (4H, triplet, J = 6.6 Hz); 3.48 - 3.58 (1H, multiplet); 3.97 (2H, AB-quartet, J = 16.1 Hz); 4.62 (4H, singlet); 5.38 - 5.43 (1H, multiplet); 5.79 (1H, doublet of doublets, J = 10.7 & 3.9 Hz); 6.06 (1H, doublet, J = 16.1 Hz); 6.15 (1H, doublet of doublets, J = 10.7 & 10.3 Hz); 7.02 (1H, singlet); 7.51 (1H, doublet of doublets, J = 16.6 & 10.3 Hz).

Claims: Claims for the following Contracting States : GB, DE, FR, IT, CH, LI, DK, BE, NL, SE, LU, AT Compounds of formula (I): in which: R 1 and R 2 are the same or different and each represents a hydrogen atom or a group of formula R 3 -CO-, where R 3 represents: a hydrogen atom; an alkyl group having from 1 to 50 carbon atoms; an alkyl group which has from 1 to 50 carbon atoms and which is substituted by at least one of substituents (a), defined below; an alkoxy group which has from 1 to 20 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkenyl group which has from 2 to 30 carbon atoms and which has at least one carbon-carbon double bond; an alkenyl group which has from 2 to 30 carbon atoms, which has at least one carbon-carbon double bond and which is substituted by at least one of substituents (a), defined below; an alkenyloxy group which has from 2 to 30 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkynyl group which has from 2 to 10 carbon atoms; or an alkynyl group which has from 2 to 10 carbon atoms and which is substituted by at least one of substituents (a), defined below; or a methoxyethoxymethoxy-substituted nonyl, undecanyl or pentadecanyl group and, where there are two groups represented by R 3 , these are the same or different; substituents (a) alkoxy groups which have from 1 to 20 carbon atoms and which are unsubstituted or are substituted by at least one alkoxy group having from 1 to 4 carbon atoms and/or alkylthio group having from 1 to 4 carbon atoms; and aliphatic carboxylic acylthio groups having from 1 to 20 carbon atoms; PROVIDED THAT R 1 and R 2 do not both represent hydrogen atoms AND THAT R 1 and R 2 do not both represent acetyl groups; and pharmaceutically acceptable salts thereof. Compounds according to Claim 1, in which R 3 represents: an unsubstituted alkyl group having from 9 to 20 carbon atoms; or an unsubstituted alkenyl group having from 9 to 20 carbon atoms. Compounds according to any one of the preceding Claims, in which R 1 and R 2 both represent said group of formula R 3 -CO-. A compound according to Claim 1, selected from the group consisting of: 14,16-diundecanoylradicicol; 14,16-dilauroylradicicol; 14,16-ditridecanoylradicicol; 14,16-dimyristoylradicicol; 14,16-dipentadecanoylradicicol; 14,16-dipalmitoylradicicol; 14,16-diheptadecanoylradicicol; 14,16-distearoylradicicol; 14,16-dipalmitoleoylradicicol; 14,16-dioleoylradicicol; 14,16-dielaidoylradicicol; 14,16-dilinolenoylradicicol; 16-palmitoyl-14-stearoylradicicol; 14-elaidoyl-16-palmitoylradicicol; and 16-palmitoyl-14-(10-undecenoyl)radicicol. A pharmaceutical composition for the treatment or prophylaxis of tumors, which comprises an active compound in admixture with a pharmaceutically acceptable carrier or diluent, in which said active compound is at least one compound according to any one of Claims 1 to 4. A compound according to any one of Claims 1 to 4 for use in therapy. The use of a compound according to any one of Claims 1 to 4 for the manufacture of a medicament for the treatment or prophylaxis of tumorous conditions. The use according to Claim 7, in which the tumors are solid tumors. A process for preparing a compound according to any one of Claims 1 to 4, which comprises reacting a compound of formula (II): [in which either both of R 8 and R 9 represents a hydrogen atom or one of R 8 and R 9 represents a hydrogen atom and the other represents a hydroxy-protecting group] with a compound of formula (III): R 3' -COOH (in which R 3' represents any of the groups or atoms represented by R 3 or any such group in which any active group or atom is protected, and R 3 is as defined in Claim 1) or with a reactive derivative thereof, and, if required, removing any protecting group, to give said compound of formula (I). A process according to Claim 9, in which said compound of formula (III) has the formula: R 3 -COOH (in which R 3 is as defined in Claim 1). Claims for the following Contracting States : ES, GR A process for preparing a compound of formula (I): [in which: R 1 and R 2 are the same or different and each represents a hydrogen atom or a group of formula R 3 -CO-, where R 3 represents: a hydrogen atom; an alkyl group having from 1 to 50 carbon atoms; an alkyl group which has from 1 to 50 carbon atoms and which is substituted by at least one of substituents (a), defined below; an alkoxy group which has from 1 to 20 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkenyl group which has from 2 to 30 carbon atoms and which has at least one carbon-carbon double bond; an alkenyl group which has from 2 to 30 carbon atoms, which has at least one carbon-carbon double bond and which is substituted by at least one of substituents (a), defined below; an alkenyloxy group which has from 2 to 30 carbon atoms and which is unsubstituted or is substituted by at least one of substituents (a), defined below; an alkynyl group which has from 2 to 10 carbon atoms; an alkynyl group which has from 2 to 10 carbon atoms and which is substituted by at least one of substituents (a), defined below; or a methoxyethoxymethoxy-substituted nonyl, undecanyl or pentadecanyl group and, where there are two groups represented by R 3 , these are the same or different; substituents (a) alkoxy groups which have from 1 to 20 carbon atoms and which are unsubstituted or are substituted by at least one alkoxy group having from 1 to 4 carbon atoms and/or alkylthio group having from 1 to 4 carbon atoms; aliphatic carboxylic acylthio groups having from 1 to 20 carbon atoms, PROVIDED THAT R 1 and R 2 do not both represent hydrogen atoms AND THAT R 1 and R 2 do not both represent acetyl groups]; or a pharmaceutically acceptable salt thereof, which process comprises reacting a compound of formula (II): [in which either both of R 8 and R 9 represents a hydrogen atom or one of R 8 and R 9 represents a hydrogen atom and the other represents a hydroxy-protecting group] with a compound of formula (III): R 3' -COOH (in which R 3' represents any of the groups or atoms represented by R 3 or any such group in which any active group or atom is protected, and R 3 is as defined above) or with a reactive derivative thereof, and, if required, removing any protecting group, to give said compound of formula (I). A process according to Claim 1, in which the reagents and reaction conditions are so chosen as to prepare a compound of formula (I) or a salt thereof, in which R 3 represents: an unsubstituted alkyl group having from 9 to 20 carbon atoms; or an unsubstituted alkenyl group having from 9 to 20 carbon atoms. A process according to any one of the preceding Claims, in which the reagents and reaction conditions are so chosen as to prepare a compound of formula (I) or a salt thereof, in which R 1 and R 2 both represent said group of formula R 3 -CO-. A process according to Claim 1, in which the reagents and reaction conditions are so chosen as to prepare: 14,16-diundecanoylradicicol; 14,16-dilaurcyiradicicol; 14,16-ditridecanoylradicicol; 14,16-dimyristoylradicicol; 14,16-dipentadecanoylradicicol; 14,16-dipalmitoylradicicol; 14,16-diheptadecanoylradicicol; 14,16-distearoylradicicol; 14,16-dipalmitoleoylradicicol; 14,16-dioleoylradicicol; 14,16-dielaidoylradicicol; 14,16-dilinolenoylradicicol; 16-palmitoyl-14-stearoylradicicol; 14-elaidoyl-16-palmitoylradicicol; or 16-palmitoyl-14-(10-undecenoyl)radicicol. A process according to any one of the preceding Claims, in which said compound of formula (III) has the formula: R 3 -COOH (in which R 3 is as defined in Claim 1). A method of making a pharmaceutical composition for the treatment or prophylaxis of tumors, which comprises mixing an active compound with a pharmaceutically acceptable carrier or diluent, in which said active compound is at least one compound according to any one of Claims 1 to 4.

Inventors: IINO KIMIO, KAGASAKI TAKESHI, KOBAYASHI TOMOWO, SHIMADA YOKO, SUGIMURA YUKIO, TSUJITA YOSHIO, IINO, KIMIO, KAGASAKI, TAKESHI, KOBAYASHI, TOMOWO, SHIMADA, YOKO, SUGIMURA, YUKIO, TSUJITA, YOSHIO, Iino, Kimio, c/o Sankyo Company Ltd., Kagasaki, Takeshi, c/o Sankyo Company Ltd., Kobayashi, Tomowo, c/o Sankyo Company Ltd., Shimada, Yoko, c/o Sankyo Company Ltd., Sugimura, Yukio, c/o Sankyo Company Ltd., Tsujita, Yoshio, c/o Sankyo Company Ltd.
Applicants: SANKYO CO, SANKYO COMPANY LIMITED
Application year: 1991
Main classification: C07D493
IPC codes: C07D493