Sulphones having a 1,5-dimethyl-hexa-1,5-dienylene group

Sulphones useful for preparing polyenes have the formula: ##STR1## where the sulphonyl group replaces a hydrogen atom on carbon atom (a) or (b), R represents alkyl, aralkyl or aryl, optionally substituted, A and Q represent an optionally substituted hydrocarbon of 5n+1 carbon atoms (n is 1-5), methyl, optionally substituted by halogen, sulphide or sulphone, CH.sub.2 OH (or an ether or ester thereof), CHO (optionally protected), COOH (or an acid chloride, ester or nitrile thereof), with the proviso that when A represents a 2-(2,6,6-trimethylcyclohex-1-enyl) ethenyl radical, Q cannot represent --COOH or an ester thereof.

This invention relates to sulphones having a 1,5-dimethylhexa-1,5-dienylene 
group and their applications as intermediates in organic synthesis. 
The present invention provides a sulphone corresponding to the general 
formula: 
##STR2## 
in which the sulphonyl group --SO.sub.2 R replaces a hydrogen atom on 
carbon atom (a) or (b), R represents an alkyl, e.g., of 1 to 4 carbon 
atoms, aralkyl or aryl radical, each of which is substituted or 
unsubstituted, each of A and Q, which may be the same or different, 
represents 
(a) a hydrocarbon radical containing 5n+1 carbon atoms (n being an integer 
of 1-5) which is substituted or unsubstituted. 
(b) a methyl radical, which is unsubstituted or substituted by a halogen 
e.g. chlorine or bromine or by a --SR' or --SO.sub.2 R' group in which R' 
represents an alkyl, aralkyl or aryl radical, which is substituted or 
unsubstituted, 
(c) a primary alcohol group --CH.sub.2 OH, an ether group thereof or an 
ester which it forms with an inorganic or organic acid, 
(d) a free or protected aldehyde group, 
(e) an acid group --COOH, its acid chloride group, an ester thereof or a 
nitrile group with the proviso that, when A represents a 
2-(2,6,6-trimethyl-cyclohex-1-enyl)ethenyl radical, Q cannot represent 
--COOH or an ester thereof. 
When A or Q represents a hydrocarbon radical containing 5n+1 carbon atoms, 
this radical can be saturated or unsaturated and with conjugated and/or 
unconjugated ethylenic unsaturation, this radical can possess functional 
groups or it can be substituted by alkyl groups; when n is 2 to 5, this 
radical can contain a ring to which alkyl groups and/or functional groups 
such as O.dbd. or --OH may be attached, the functional groups being free 
or protected. 
R and R' preferably represent aryl radicals, e.g. aromatic hydrocarbon 
radicals (such as phenyl or naphthyl radicals) which may optionally be 
substituted by one or two radicals such as halogen, e.g. fluorine, 
chlorine or bromine, alkyl of preferably 1 to 4 carbon atoms, e.g., methy, 
or alkoxy of 1 to 4 carbon atoms, e.g. methoxy. 
The hydrocarbon radical represented by A or Q preferably is a group having 
a carbon skeleton of formula: 
##STR3## 
wherein n is 1-5, each C.sub.5 unit containing 0-2 ethylenic double bonds, 
the remaining valencies being satisfied by hydrogen atoms, or two adjacent 
C.sub.5 units are joined to form a structure containing a ring of 6 ring 
carbon atoms, which can be substituted by a hydroxy or oxo groups, by a 
methyl group additional to the methyl substituents forming part of the 
carbon skeleton of C.sub.5 units, and the chain of C.sub.5 units can have 
one substituent of formula SO.sub.2 R, wherein R is as defined above, in a 
grouping 
##STR4## 
The ring is usually a 2,6,6-trimethylcyclohex-1-enyl ring. 
A preferably represents a 2-(2,6,6-trimethylcyclohex-1-enyl)-ethenyl, a 
6-(2,6,6-trimethylcyclohex-1-enyl)-4-methylhexa-1,3,5-trienyl, 
4-methylpent-3-enyl, 4,8-dimethylnona-3,7-dienyl, methyl or t-butoxymethyl 
radical. A can also preferably represent a saturated or unsaturated linear 
or branched chain alkyl radical (within the broad definition given for A 
above) or a 2-(2,6,6-trimethyl-3-oxo-cyclohex-1-enyl)-ethenyl group. 
Q represents a COOH or CN group carboxylic acid alkyl ester group of 2 to 7 
carbon atoms, a CH.sub.2 OH group or an alkyl ether group thereof 
containing a total of 2 to 7 carbon atoms or an ester group thereof with 
an alkanoic acid of 1 to 6 carbon atoms, a CHO group or dialkyl acetal 
with 1 to 6 carbon atoms in each alkyl group, or a sulphone group of 
formula CH.sub.2 SO.sub.2 R' or a polyene radical containing a 
2,6,6-trimethylcyclohex-1-ene ring. Preferred radicals for Q are an 
acetoxymethyl, hydroxymethyl, methoxymethyl, t-butoxymethyl, 
diethoxymethyl, phenylsulphonylmethyl, 
6-(2,6,6-trimethylcyclohex-1-enyl)-4-methyl-1 or 
2-phenylsulphonylhexa-3,5-dienyl radical or a 
10-(2,6,6-trimethylcyclohex-1-enyl)-4,8-dimethyl-2-phenylsulphonyl 
deca-3,5,7,9-tetraenyl radical. 
A may also represent any of the radicals listed above for Q and vice versa, 
subject to the proviso clause above. 
The present invention also provides a process for preparing a sulphone of 
formula I which comprises reacting a compound of the formula 
A--C(CH.sub.3).dbd.CH--CH.sub.2 X with a compound of the formula 
Q--CH.dbd.C(CH.sub.3)--CH.sub.2 Y one of X and Y representing a halogen 
and the other SO.sub.2 R, in the presence of a basic agent capable of 
converting the compound, in which X or Y represents a SO.sub.2 R group, 
into an anion, A, Q and R being as defined above. This process has two 
embodiments. In this first embodiment for the preparation of the sulphones 
of formula I, in which the sulphonyl group replaces a hydrogen atom on 
carbon atom (a) the process comprises reacting a sulphone of the formula 
A--C(CH.sub.3).dbd.CH--CH.sub.2 SO.sub.2 R (XVII) with a halide of the 
formula Q--CH.dbd.C(CH.sub.3)--CH.sub.2 X, in the presence of a basic 
agent, capable of converting the sulphone XVII into its anion, A, Q and R 
being as defined above and X representing a halogen atom, and in 
particular chlorine or bromine. An equation for the reaction can be given 
as follows. 
##STR5## 
In the second embodiment, a halide of the formula 
A--C(CH.sub.3).dbd.CH--CH.sub.2 X and a sulphone 
Q--CH.dbd.C(CH.sub.3)--CH.sub.2 SO.sub.2 R are reacted together in the 
presence of the basic agent to obtain a compound in which the --SO.sub.2 R 
group replaces a hydrogen atom on carbon atom (b), as shown below: 
##STR6## 
The reaction is carried out in the presence of a basic agent which 
possesses sufficient activity to convert the sulphone employed into an 
anion. The basic agents which are suitable are inorganic or organic 
compounds, examples of which are alkali metal alcoholates, alkali metal 
hydrides or amides and organometallic compounds such as organo-zinc, 
organo-lithium and organo-magnesium compounds. They can be used alone or 
in conjunction with another basic agent intended to neutralise the 
hydrohalic acid formed. When the basic agent is used alone, the amount 
employed must be sufficient to achieve this neutralisation. The amount 
used also depends on how the reaction is carried out and on the reactivity 
of the products of the reaction with respect to this basic agent. For 
these various reasons, it can be advantageous to employ a smaller amount 
of basic agent in the reaction and to add another basic agent, with 
respect to which the products of the reaction are less sensitive in an 
amount sufficient to neutralise the hydrohalic acid formed. 
The reaction can be carried out at temperatures which can range from 
-100.degree. C. to +150.degree. C., depending on the nature of the 
products employed and produced. 
In order that the reaction can take place satisfactorily, it is 
advantageous to carry it out in an organic solvent which can be a 
hydrocarbon such as hexane, benzene or toluene, a protic solvent, e.g. 
methanol, ethanol or ethylene glycol, or a linear or cyclic ether of a 
monoalcohol or a diol such as diethyl ether, dioxane or tetrahydrofuran. 
Other solvents such as dimethylformamide, dimethylacetamide, 
dimethylsulphoxide, N-methylpyrrolidone and hexamethylphosphotriamide are 
also suitable. 
In certain cases, e.g. when A or Q represents a CH.sub.2 SO.sub.2 R' group, 
wherein R' is as defined above, the halogenated derivative reacting with 
the sulphone can be replaced by a compound which possesses a terminal 
conjugated diene chain, for example a compound of the formula 
Q'.dbd.CH--C(CH.sub.3).dbd.CH.sub.2 in which Q' represents a divalent 
radical such that Q'H corresponds to Q as defined above. The reaction is 
then represented by the equation: 
##STR7## 
and it gives rise to the formation of a product with the sulphone group 
replacing a hydrogen atom on carbon atom (a), which is identical to that 
obtained by reacting the same sulphone with a halogenated derivative 
Q--CH.dbd.C(CH.sub.3)--CH.sub.2 X. 
If a sulphone of the formula Q--CH.dbd.C(CH.sub.3)--CH.sub.2 SO.sub.2 R is 
reacted with a diene compound of the formula 
A'.dbd.C(CH.sub.3)--CH.dbd.CH.sub.2, in which A' represents a divalent 
radical such that A'H corresponds to A, a compound of formula I is 
obtained in which the sulphone group replaces a hydrogen atom on carbon 
atom (b), the reaction being represented by the following equation: 
##STR8## 
This condensation of diene compounds with a sulphone is carried out in the 
presence of an inorganic or organic alkaline agent such as an alkali metal 
hydroxide or alcoholate, an amine such as diethylamine, diisopropylamine, 
pyridine, triethylamine and tributylamine, or a quaternary ammonium 
hydroxide. The reaction can be carried out with or without a solvent, but 
it is however preferable to choose a solvent so that the reaction takes 
place in a homogeneous phase. This solvent can be an alcohol such as 
methanol, ethanol and tertiary butyl alcohol or an ether such as diethyl 
ether, dioxane and tetrahydrofuran or any other inert solvent such as 
benzene, toluene, dimethylformamide, or acetonitrile. 
The reaction takes place at ambient temperature and when the reaction 
products are not affected by heating, the reaction can be accelerated by 
carrying it out at a higher temperature. If the reaction products are 
sensitive to heat, the reaction can be carried out at temperatures below 
ambient temperature. A description of all the working conditions relating 
to the Michael Reaction, of which this variant is an application, will be 
found in "Organic Reactions, vol. 10, p. 264-266--The Michael Reaction". 
The sulphones used to prepare the products of the general formula I are 
known products or new products. They are generally obtained by reacting an 
alkali metal sulphinate of the formula RSO.sub.2 M, wherein M represents 
an alkali metal, with a halogenated compound in accordance with a usual 
method for preparing sulphones. In the case of those which are employed in 
the following Examples, their preparation will be given in these examples. 
Compounds of formula A--C(CH.sub.3).dbd.CH--CH.sub.2 SO.sub.2 R and wherein 
A represents a 2-(2,6,6-trimethylcyclohex-1-enyl)ethylene group are 
described and claimed in U.S. Ser. No. 218,838 filed Jan. 18, 1972, now 
U.S. Pat. No. 3,781,313 by Marc Julia. 
They may be prepared by reacting an alkali metal sulphinate of formula 
RSO.sub.2 M, wherein R and M are as defined above with either a compound 
of formula A--C(CH.sub.3).dbd.CH--CH.sub.2 X, wherein X represents 
chlorine, bromine or iodine, obtained by halogenation of 
vinyl-.beta.-ionol with a phosphorus trihalide, or with vinyl-.beta.-ionol 
itself. 
Compounds of formula A--C(CH.sub.3).dbd.CH--CH.sub.2 SO.sub.2 R wherein A 
represents a group --CH.sub.2 X or CH.sub.2 SO.sub.2 R, where X represents 
a halogen, are described and claimed in U.S. Ser. No. 328,600 filed Feb. 
1, 1973, now abandoned by Albert Menet. They may be prepared by reacting 
an akali metal sulphinate of formula RSO.sub.2 M with a 
1,4-dihalogeno-2-methylbut-2-ene, or, when A represents a group CH.sub.2 
SO.sub.2 R with a compound of formula X--C(CH.sub.3).dbd.CH--CH.sub.2 
SO.sub.2 R, where X represents a halogen. 
Compounds of formula A--C(CH.sub.3).dbd.CH--CH.sub.2 SO.sub.2 R and 
Q--CH.dbd.C(CH.sub.3)--CH.sub.2 SO.sub.2 R, wherein A and Q represent a 
group CH.sub.2 OR.sub.1 where R.sub.1 represents an alkyl or aryl group 
which may be substituted, are described and claimed in U.S. Ser. No. 
328,611 filed Feb. 1, 1973, now U.S. Pat. No. 3,835,195 by Albert Menet. 
They may be prepared by reacting an alkali metal compound of formula 
R.sub.1 OM with a 4-alkyl- (or aryl) sulphonyl- 2- or 3-methylbut-2-enyl 
halide. 
Compounds of formula A--C(CH.sub.3).dbd.CH--CH.sub.2 --SO.sub.2 R in which 
A represents a 6-(2,6,6-trimethylcyclohex-1-enyl) 
4-methylhexa-1,3,5-trienyl radical are described and claimed in U.S. Ser. 
No. 254,103 filed May 17, 1972, now U.S. Pat. No. 3,803,252 in the name of 
Pierre Chabardes and Marc Julia. They may be prepared by reacting an 
alkali metal sulphinate with retinol or a retinol ester of an inorganic or 
organic acid, e.g. retinyl chloride, or with 3-retinol. 
Retinyl halides, which are known compounds are preferably prepared by a 
process comprising reacting 1-(or 3)-retinol with a halogenating reagent 
(e.g. phosphorus trichloride or tribromide) at a low temperature and in an 
inert solvent. This process is described and claimed in U.S. Ser. No. 
254,102 filed May 17, 1972, now abandoned in the name of Pierre Chabardes. 
The diene compounds employed in the variant of the process can be obtained, 
for example, by dehydrochlorination of a chlorinated compound by means of 
an inorganic or organic alkaline agent. The halides are products the 
majority of which are well known and their preparation will also be given 
in the Examples. 
The sulphones of the formula I are used to prepare polyene compounds 
belonging to the series of terpenes, geraniolenes, sesquiterpenes and 
carotenes, and more generally they can be used to prepare any compound 
containing a polyisoprene chain with various degrees of saturation. By 
means of them, it is possible to synthesise these compounds from molecules 
which possess fewer carbon atoms, by adding to the latter one or more 
isoprene chains, which carry the functional group characteristic of the 
desired compounds. The addition of several isoprene units can be carried 
out in a single stage if a product containing the desired number of 
isoprene units is used, or in successive stages giving rise to the 
formation of several sulphone groups on the same molecule. Whatever the 
method of synthesis chosen, desulphonation of the product obtained can be 
carried out by a suitable reduction treatment e.g. with lithium and 
ethylamine and compounds containing one or more diene chains 
##STR9## 
are then obtained. It can also be carried out by treatment with an 
inorganic or organic basic agent such as, an alkali metal hydroxide, an 
alkali metal carbonate or an alkali metal alcoholate, and compounds 
containing one or more conjugated triene chains 
##STR10## 
characteristic of polyisoprene compounds are obtained. Desulphonation of 
any 
##STR11## 
in the rest of the sulphone of formula I usually occurs with the reduction 
or elimination at carbon atoms (a) and (b). 
Depending on the method of desulphonation chosen, it is possible to prepare 
compounds having the above diene or triene chains, for example, acyclic or 
cyclic, terpene products such as ocimene, geraniol, citronnellol, citral 
all of which are used in perfumes, geranic acid and its esters, farnesal, 
farnesol and its esters, farnesic acid and its derivatives, axerophthene 
and its lower or higher isoprene homologues and the functional derivatives 
of this same series, particularly retinal and its acetals, vitamin A, its 
ethers and its esters, vitamin-A-acid, its esters, its nitrile, other 
functional derivatives of retinene such as 4-oxo-retinal, apocarotenals 
and the corresponding alcohols as well as their ethers and their esters, 
apocarotenic acids and their derivatives. Carotenoid compounds containing 
40 or more than 40 atoms can also be prepared, examples of which are the 
various carotenes such as .beta.-carotene, a naturally occurring colorant, 
.gamma.-carotene, lycopene, squalene, canthaxanthine, zeaxanthine, 
isozeaxanthine and more generally xanthophyllic compounds corresponding to 
these various carotenes. Such methods of synthesis employing sulphones of 
formula I can also be used to prepare compounds in which the molecule 
contains a saturated or unsaturated polyisoprene chain as in vitamin E or 
vitamines K.sub.1 and K.sub.2. 
The desulphonation can be carried out on the sulphone isolated from the 
reaction medium or within this medium. Whatever the method chosen, it 
results in the liberation of an alkali metal sulphinate or a sulphinic 
acid which can be reused in the preparation of the starting sulphone, so 
that, since the synthesis of the polyisoprene compounds proceeds via these 
sulphones as intermediates, practically no alkali metal sulphinate is 
consumed.

The following Examples illustrate the preparation of sulphones according to 
the invention and their application in organic synthesis. 
EXAMPLE 1 
(a) 16.8 g. of potassium t-butylate (15.times.10.sup.-2 mol) and 90 
cm.sup.3 of tetrahydrofuran are introduced into a 500 cm.sup.3 
three-necked flask equipped with a magnetic stirrer, a condenser and a 
dropping funnel. The mixture is cooled to -30.degree. C. and 25.7 g 
(7.5.times.10.sup.-2 mol) of 
phenyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-penta-2,4-dienyl-sulph 
one diluted in 65 cm.sup.3 of tetrahydrofuran are run in, with stirring. 
The reaction mixture is left for 30 minutes at this temperature and then 
14.5 g (8.9.times.10.sup.-2 mol) of 1-chloro-2-methyl-4-acetoxy-2-butene 
in 25 cm.sup.3 of tetrahydrofuran are run in (duration of addition 
approximately 40 minutes). The reaction mixture is kept at -30.degree. C. 
and at the end of 5 hours it is poured rapidly into 2 liters of a 50/50 
water/diethyl ether mixture. After washing with water and drying the ether 
layer followed by evaporation in vacuo, 35.3 g of a red viscous mass are 
obtained, in which the products of the reaction are measured by thin layer 
chromatography (silica, hexane/diethyl ether in a volume ratio of 70/30). 
This determination indicates that 95% of the starting sulphone has been 
converted into the desired sulphone-ester (yield 65-70%) and into the 
corresponding sulphone-alcohol (20-25%) as a result of saponification of 
the ester. 
Recrystallization of the crude product from methanol yields a white solid, 
of melting point 90.degree. C., identified by elementary analysis, 
infra-red spectrography and nuclear magnetic resonance. When dissolved in 
ethanol, it gives an absorption maximum at 273 nm (E.sub.1 cm.sup.1% =408) 
and at 248 nm (E.sub.1 cm.sup.1% =360) in UV spectrography. It corresponds 
to the formula: 
##STR12## 
1-Chloro-2-methyl-4-acetoxy-2-butene was prepared in accordance with the 
process described in J. Am. Chem. Soc. 72 4610 (1950) by reacting t-butyl 
hypochlorite with isoprene in an acetic acid medium. 
The starting sulphone is obtained by reacting an alkali metal 
phenylsulphinate with a halide of the same carbon structure. This sulphone 
and its preparation are described and claimed in our aforesaid Ser. No. 
218,838. 
(b) 611 mg of the sulphone-ester prepared above (1.3.times.10.sup.-3 mol) 
are run slowly into a solution of 436.8 mg of potassium t-butylate 
(3.9.times.10.sup.-3 mol) in 10.2 cm.sup.3 of tetrahydrofuran. The 
reaction mixture is kept for 17 hours at 20.degree. C. in the absence of 
light and under an argon atmosphere and then it is poured rapidly into 200 
cm.sup.3 of a 50/50 water/diethyl ether mixture. The ether portion is 
washed with 4 times 50 cm.sup.3 of water and then evaporated in vacuo. 436 
mg of an orange-red oil are thus obtained, which, when dissolved in 
ethanol, gives an absorption maximum at 324 nm (E.sub.1 cm.sup.1% =890) in 
UV spectrography, characteristic of vitamin A. 
EXAMPLE 2 
(a) 1.9 g of the sulphone-ester of the formula II prepared above, 893 mg of 
potassium hydroxide, 2 cm.sup.3 of water and 15 cm.sup.3 of absolute 
alcohol are introduced into a 30 cm.sup.3 flask. The reaction mixture is 
stirred for 15 hours at ambient temperature and then poured into 200 
cm.sup.3 of water; it is extracted with 3 times 100 cm.sup.3 of diethyl 
ether. The product is washed with water, dried and then evaporated to 
remove the ether. 1.5 g. of a viscous red oil are thus obtained in which 
the desired sulphone-alcohol is measured by thin layer chromatography. The 
degree of conversion is 100% and the yield is 80%. Recrystallisation from 
methanol yields a white solid, of melting point 50.degree.-51.degree. C., 
which, from elementary analysis, infra-red spectrography and nuclear 
magnetic resonance, corresponds to the formula: 
##STR13## 
(b) 535 mg of the sulphone-alcohol obtained are run slowly into 436.8 mg of 
potassium t-butylate and 5 cm.sup.3 of pyridine. This mixture is treated 
under the conditions of the preceding Example under part (b) and 450 mg of 
an orange-red oil are thus obtained which, when dissolved in ethanol, 
gives an absorption maximum at 325 nm (E.sub.1 cm.sup.1% =739) in UV 
spectrography, indicating the presence of vitamin A. 
EXAMPLE 3 
Following the procedure of Example 1, 23.9 g of 
phenyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methylpenta-2,4-dienyl-sulpho 
ne (6.9.times.10.sup.=2 mol) are dissolved in 60 cm.sup.3 of 
tetrahydrofuran and this solution is run into a suspension of 15.6 g. of 
potassium t-butylate in 83 cm.sup.3 of tetrahydrofuran. The reaction 
mixture is left for 30 minutes at -30.degree. C. and then 11.2 g of 
1-chloro-2-methyl-4-methoxy-2-butene (8.4.times.10.sup.-2 mol) dissolved 
in 20 cm.sup.3 of tetrahydrofuran are run in. The mixture is left for 2 
hours at -30.degree. C. and then the temperature is allowed to rise slowly 
to 23.degree. C. The tetrahydrofuran is removed from the reaction mixture, 
which has become dark brown, by means of the vacuum provided by a water 
pump, 300 cm.sup.3 of water are added and the product is then extracted 
with 3 times 200 cm.sup.3 of diethyl ether. After washing with water, 
drying and concentration in vacuo, 32 g of an orange-yellow viscous oil 
are obtained. Analysis of this oil by thin layer chromatography indicates 
a degree of conversion of 100% of the starting sulphone and a yield of 85% 
of the desired product. Recrystallization of this oil from methanol yields 
a white solid product, of melting point 94.degree. C., corresponding to 
the formula: 
##STR14## 
When dissolved in ethanol, this product gives an absorption maximum at 271 
nm (E.sub.1 cm.sup.1% =484) in UV spectrography. 
1-Chloro-2-methyl-4-methoxy-2-butene was prepared by reacting t-butyl 
hypochlorite with isoprene dissolved in methanol according to the process 
described in J. Am. Chem. Soc. 72, p. 4610 (1950). 
By treating the sulphone-ether (IV) under the conditions of Example 2 under 
part (b) the methyl ether of vitamin A is obtained on desulphonation and 
is identified by its UV spectrum which, when dissolved in ethanol, gives 
an absorption maximum E.sub.1 cm.sup.1% =648 at 325 m.mu.. 
EXAMPLE 4 
A solution of 3.44 g (1.times.10.sup.-2 mol) of 
phenyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-penta-2,4-dienyl-sulph 
one in 7 cm.sup.3 of tetrahydrofuran is run into a suspension prepared from 
4.6 g of potassium t-butylate and 10 cm.sup.3 of tetrahydrofuran which has 
been cooled to -50.degree. C. A solution of 4.12 g of 
1-bromo-2-methyl-4,4-diethoxy-2-butene in 10 cm.sup.3 of diethyl ether is 
then added. The mixture is kept at -50.degree. C. for 30 minutes and then 
at -20.degree. C. for 2 hours and thereafter at 0.degree. for 3 hours. The 
reaction mixture is then poured into 50 cm.sup.3 of a 50/50 mixture of 
iced water and diethyl ether. It is extracted with 4 times 20 cm.sup.3 of 
diethyl ether and the ether layer is washed with an aqueous solution of 
potassium chloride, dried over magnesium sulphate and filtered and the 
ether is evaporated in vacuo. 6 g of a red oil are thus obtained in which 
3.6 g of a sulphone, identified by infra-red spectrography and nuclear 
magnetic resonance, of the formula: 
##STR15## 
are measured by thin layer chromatography. The yield is 72%. 
1-Bromo-2-methyl-4,4-diethoxy-2-butene was prepared by bromoethoxylation of 
1-ethoxy-3-methylbutadiene in accordance with the process described in 
Journal General Chemistry USSR 32 No. 4, 1091 (1962). 
EXAMPLE 5 
A solution of 3.44 g of 
phenyl-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-dienyl-sulpho 
ne in 5 cm.sup.3 of anhydrous tetrahydrofuran is run into a suspension of 2 
g of potassium t-butylate in 5 cm.sup.3 of tetrahydrofuran which has been 
cooled to -30.degree. C. The mixture is stirred for 10 minutes at 
-30.degree. C. and then a solution of 2.44 g of 
phenyl-4-chloro-3-methyl-but-2-enyl-sulphone in 15 cm.sup.3 of 
tetrahydrofuran is run in over the course of 7 minutes. The reaction 
mixture is left to react for 3 hours 30 minutes at -30.degree. C. and is 
then poured into 50 cm.sup.3 of iced water. The mixture is extracted with 
3 times 40 cm.sup.3 of diethyl ether and the combind ether layers are 
washed with 3 times 30 cm.sup.3 of water, dried over magnesium sulphate 
and filtered and the ether is evaporated from the filtrate. 5.8 g of a 
crude solid product, which contains 4.95 g of a disulphone, are thus 
obtained. The disulphone is recrystallized from a 50/50 diisopropyl 
ether/methanol mixture in the form of white crystals of melting point, 
(KOFLER) 123.degree. C. It gives an absorption maximum at 236 nm (E.sub.1 
cm.sup.1% =295) and at 268 nm (E.sub.1 cm.sup.1% =260) in hexane in UV 
spectrography and corresponds to the formula: 
##STR16## 
The yield relative to the sulphone employed is 89.5%. 
Phenyl-4-chloro-3-methyl-2-butene-sulphone was prepared by reacting sodium 
phenylsulphinate with 1,4-dichloro-2-methyl-2-butene in equimolecular 
amounts, in anhydrous ethanol, at a temperature of 38.degree. C. for 15 
hours. The heterogeneous mixture which is obtained is filtered and the 
filtrate is placed in the refrigerator overnight. A white crystalline 
precipitate is thus obtained, of melting point 88.degree. C., which is 
phenyl-4-chloro-3-methyl-but-2-enylsulphone. 
EXAMPLE 6 
A solution of 2.05 g of phenyl-retinyl-sulphone in 6 cm.sup.3 of 
tetrahydrofuran is run, over the course of 6 minutes, into a suspension of 
1.9 g of potassium t-butylate in 3 cm.sup.3 of tetrahydrofuran which has 
been cooled to 0.degree. C. A solution of 0.980 g of 
1-chloro-2-methyl-4-acetoxy-2-butene in 6 cm.sup.3 of anhydrous 
tetrahydrofuran is then run in over the course of 15 minutes and the 
mixture is stirred for 15 minutes at ambient temperature (18.degree. C.) 
The reaction mixture is left for 3 hours at this temperature and then it 
is poured into a mixture of 80 cm.sup.3 of iced water and 40 cm.sup.3 of 
diethyl ether. The mixture is then decanted, the aqueous layer is 
extracted with 3 times 40 cm.sup.3 of diethyl ether and the ether layer is 
washed with water. By treating the ether layers as above, 1.8 g of a 
C.sub.25 sulphone, of the formula: 
##STR17## 
are obtained. Yield 67.1% relative to the sulphone employed. 
Preparation of phenyl-retinyl-sulphone: 1.43 g. of 
9-(2,6,6-trimethyl-cyclohex-1-enyl)-3,7-dimethyl-nona-1,4,6,8-tetraen-3-ol 
or 3-retinol dissolved in 3 cm.sup.3 of ether are added to a solution of 
1.06 g of sodium phenylsulphinate in 100 cm.sup.3 of acetic acid. The 
reaction mixture is left to stand for several hours and is then poured 
into 60 cm.sup.3 of water. The aqueous layer is extracted with 4 times 10 
cm.sup.3 of diethyl ether. The ether layers are washed with an aqueous 
solution of sodium bicarbonate and then dried over magnesium sulphate. On 
evaporating the ether, phenyl-retinyl-sulphone is obtained. 
EXAMPLE 7 
Following the conditions of Example 5, 2.05 g of phenyl-retinyl-sulphone 
dissolved in 6 cm.sup.3 of tetrahydrofurane are reacted with 1.22 g of 
phenyl-4-chloro-3-methyl-but-2-enyl-sulphone dissolved in 6 cm.sup.3 of 
tetrahydrofurane, in the presence of 1.9 g of potassium t-butylate. 
The reaction mixture is then poured into 80 cm.sup.3 of a 50/50 iced 
water/diethyl ether mixture. After decanting, washing the aqueous layer 
with ether and treating the combined ether layers, (drying, filtration, 
evaporation of the ether), 3.7 g of a yellow solid product, which contains 
2.6 g of a disulphone identified by N.M.R. and I.R. and corresponding to 
the formula: 
##STR18## 
are obtained. The yield is 83.8% relative to the sulphone employed. 
EXAMPLE 8 
Following the same procedure as in the preceding Examples, 1.8 g of a 
sulphone corresponding to the formula: 
##STR19## 
dissolved in 15 cm.sup.3 of tetrahydrofuran are reacted with 
5-(2,6,6-trimethyl-cyclohex-1'-enyl)-3-methyl-1-chloropenta-2,4-diene 
dissolved in 20 cm.sup.3 of diethyl ether, in the presence of 3.75 g of 
potassium t-butylate. The reaction mixture is left for 3 hours at 
-30.degree. C. and then for 16 hours at 0.degree. C. and is then poured 
into a mixture of 100 cm.sup.3 of iced water and 50 cm.sup.3 of diethyl 
ether. The mixture is decanted and the aqueous layer is extracted with 3 
times 50 cm.sup.3 of diethyl ether. The combined ether layers are washed 
with water, dried over magnesium sulphate and then concentrated in vacuo. 
3.85 g of an orange product are thus obtained in which 1.35 g of a 
disulphone corresponding to the formula: 
##STR20## 
are identified and measured. 
When this disulphone of the formula (IX) is desulphonated by an alkaline 
agent it is converted into .beta.-carotene. 
5-(2,6,6-Trimethyl-cyclohex-1-enyl)-3-methyl-1-chloro-penta-2,4-diene is 
obtained by reacting phosphorus trichloride with vinyl .beta.-ionol, 
according to a known process. 
The starting C.sub.25 disulphone is described and claimed in U.S. Ser. No. 
328,624 filed Feb. 1, 1973, in the name of the applicants. It was prepared 
in the following manner: 2.05 g of phenyl-retinyl-sulphone (the 
preparation of which is given in Example 6) in 6 cm.sup.3 of 
tetrahydrofuran, followed by 1.22 g of 
phenyl-4-chloro-2-methyl-but-2-enyl-sulphone in 5 cm.sup.3 of the same 
solvent, are added to a solution of 1.88 g of potassium t-butylate in 3 
cm.sup.3 of tetrahydrofuran which has been cooled to -25.degree. C. The 
temperature is then kept at -15.degree. C. for 7 hours 30 minutes. After 
having kept the reaction mixture at -70.degree. C. for 16 hours, it is 
poured into a mixture of 80 cm.sup.3 of water and 50 cm.sup.3 of diethyl 
ether. The C.sub.25 disulphone is isolated from the ether layers by 
evaporating the solvent. 
Phenyl-4-chloro-2-methyl-but-2-enyl-sulphone was prepared by reacting 
phenylsulphonyl chloride with isoprene in accordance with the process 
described in French Pat. No. 1,409,516. 
EXAMPLE 9 
3.36 g of potassium t-butylate and 25 cm.sup.3 of tetrahydrofuran are 
introduced into a flask and are cooled, under argon, to -20.degree. C. A 
solution of 2.1 g of prenyl-phenylsulphone in 7 cm.sup.3 of 
tetrahydrofuran is then run in, whilst maintaining the same temperature. A 
solution of 1.95 g of 1-chloro-2-methyl-4-acetoxy-2-butene in 5 cm.sup.3 
of tetrahydrofuran is then also run in over the course of 15 minutes. The 
mixture is kept at -20.degree. C., with stirring, for 2 hours 20 minutes 
and then the temperature is allowed to rise to +20.degree. C. over the 
course of 45 minutes. After removing the solvent by applying a vacuum 0.56 
g of potassium hydroxide dissolved in 15 cm.sup.3 of ethanol and 2 
cm.sup.3 of water is added. The reaction mixture is stirred for 1 hour at 
35.degree. C. and is then poured into a mixture of 300 cm.sup.3 of water 
and 150 cm.sup.3 of diethyl ether. The combined ether layers are dried 
over magnesium sulphate and then concentrated, and from them 2.9 grams of 
an orange-yellow oil are isolated which is identified by nuclear magnetic 
resonance and I.R. spectrography, as being a compound corresponding to the 
formula: 
##STR21## 
The yield is 78% relative to the prenyl-phenyl-sulphone. 
The sulphone of the formula X can be converted into geraniol: to do this, 
1.48 g of this sulphone and 50 cm.sup.3 of ethylamine are introduced into 
a 100 cm.sup.3 flask and the temperature is adjusted to approximately 
5.degree. to 10.degree. C. 0.347 g of lithium is added in small portions 
and the reaction mixture is stirred for 2 hours 15 minutes. 1.5 g. of 
ammonium chloride are then added and the ethylamine is then driven off by 
heating at 30.degree. C. under a stream of argon and 50 cm.sup.3 of water 
and 30 cm.sup.3 of diethyl ether are added. The aqueous layer is decanted 
and extracted with 3 times 50 cm.sup.3 of diethyl ether; the combined 
ether layers are washed with water, dried over magnesium sulphate and then 
concentrated in vacuo. 640 mg of a pale yellow oil are thus isolated in 
which geraniol is characterised and measured by infra-red spectography and 
nuclear magnetic resonance. The yield of geraniol is 85% relative to the 
starting sulphone. 
Prenyl-phenyl-sulphone, used to prepare the sulphone of the formula IX, was 
prepared from prenyl chloride and sodium phenylsulphinate in accordance 
with the usual method for preparing sulphones employing an alkali 
sulphinate. 
EXAMPLE 10 
2.24 g of potassium t-butylate in 20 cm.sup.3 of tetrahydrofuran are added 
to a solution of 2.3 g of geranyl bromide in 15 cm.sup.3 of 
tetrahydrofuran, keeping the temperature at -50.degree. C. A solution of 
3.12 g of phenyl-4-methoxy-2-methyl-but-2-enyl-sulphone in 15 cm.sup.3 of 
tetrahydrofuran is then run in over the course of 30 minutes. 
The reaction mixture is kept under these conditions for 2 hours 15 minutes 
and is then poured into a mixture of 250 cm.sup.3 of water and 100 
cm.sup.3 of diethyl ether. After decanting and extracting the aqueous 
layer with 3 times 50 cm.sup.3 of diethyl ether, the combined ether layers 
are washed with water, dried over magnesium sulphate and concentrated by 
evaporation. 4.53 g of an orange-brown oil are thus obtained in which the 
compound of the formula: 
##STR22## 
is identified and measured by thin layer chromatography and nuclear 
magnetic resonance. 
The degree of conversion of the sulphone employed is 60% and the yield of 
the compound of the formula XI is 84%. 
Phenyl-4-methoxy-2-methyl-but-2-enyl-sulphone was prepared by reacting 
sodium phenylsulphinate with 4-methoxy-2-methyl-but-2-enyl bromide, in a 
solvent medium such as ethylene glycol, by heating at 100.degree. C. for 2 
hours. 
EXAMPLE 11 
(a) 3.68 g of potassium t-butylate and 5 cm.sup.3 of tetrahydrofuran are 
introduced into a flask which is cooled to -40.degree. C., and then 3.1 g 
of 
phenyl-5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-penta-2.4-dienyl-sulph 
one dissolved in 4 cm.sup.3 of tetrahydrofuran are run in over the course 
of 5 minutes. 3 cm.sup.3 of tetrahydrofuran containing 3.1 g of 
13-(2,6,6-trimethyl-cyclohex-1-enyl)-5-phenylsulphonyl-2,7,11-trimethyl-1- 
chloro-trideca-2,6,8,10,12-pentaene (a chlorinated C.sub.25 sulphone) are 
then run in over the course of 10 minutes. The temperature is kept between 
-40.degree. C. and -50.degree. C. for 5 hours. The reaction mixture is 
then poured into a mixture of 25 cm.sup.3 of iced water and 25 cm.sup.3 of 
diethyl ether and then treated as in the preceding examples. 9.8 g of a 
yellow solid product are obtained in which 2.87 g of a compound 
corresponding to the formula: 
##STR23## 
are identified and measured. 
Yield 49% relative to the chlorinated sulphone. 
The chlorinated C.sub.25 sulphone was prepared by reacting 
phenyl-retinyl-sulphone dissolved in tetrahydrofurane with 
1,4-dichloro-2-methyl-2-butene in this same solvent, in the presence of 
potassium t-butylate in tetrahydrofurane. The temperature is kept at 
-70.degree. C. for 7 hours. 
(b) Preparation of .beta.-carotene: 1.43 g of the compound of the formula 
XII, 4.5 g of potassium t-butylate and 25 cm.sup.3 of anhydrous pyridine 
are introduced into a flask. The mixture is heated for 3 hours at 
50.degree.-55.degree. C. and then left to stand overnight at a temperature 
of 20.degree.-21.degree. C. 
The mixture is acidified to pH 5 by means of a normal aqueous solution of 
sulphuric acid and then concentrated by evaporation without exceeding 
40.degree. C. in the mixture. The residue is taken up in a mixture of 50 
cm.sup.3 of water and 50 cm.sup.3 of diethyl ether and the aqueous layer 
is decanted and then extracted with diethyl ether. The combined ether 
layers are treated as in the preceding examples. A dark red solid product 
which contains 0.61 g of .beta.-carotene is isolated. Yield 65.5% relative 
to the product of the formula XII. 
EXAMPLE 12 
4.1 g of 75% pure farnesyl bromide are dissolved in 15 cm.sup.3 of 
tetrahydrofuran; the solution is cooled to -50.degree. C. and 2.24 g of 
potassium t-butylate in 20 cm.sup.3 of tetrahydrofuran are added. A 
solution of 3.12 g of 4-methoxy-2-methyl-but-2-enyl-phenyl-sulphone in 15 
cm.sup.3 of tetrahydrofuran is then added. The reaction mixture is kept at 
-50.degree. C. for 2 hours 15 minutes and is then poured into a mixture of 
250 cm.sup.3 of water+100 cm.sup.3 of diethyl ether. The ether layers are 
washed with water, dried, filtered and concentrated. 6.35 g of an 
orange-yellow oil are thus obtained in which a compound corresponding to 
the formula: 
##STR24## 
is identified and measured by thin layer chromatography and nuclear 
magnetic resonance. 
The degree of conversion of the C.sub.5 sulphone is 60%. The yield of the 
compound XIII relative to this sulphone is 86%. 
EXAMPLE 13 
A solution of 3.47 g of phenyl-farnesyl-sulphone in 15 cm.sup.3 of 
tetrahydrofuran is run into 20 cm.sup.3 of this same solvent which 
contains 2.24 g of potassium t-butylate and which is cooled to -30.degree. 
C. A solution of 1.93 g of methyl bromo-senecioate in 15 cm.sup.3 of 
tetrahydrofuran is then run in over the course of 40 minutes. The compound 
corresponding to the formula: 
##STR25## 
is identified by thin layer chromatography of the reaction mixture, 10 
minutes after the addition of the bromo-senecioate is complete. 
The mixture is kept at -30.degree. C. and is stirred for 2 hours and is 
then poured into a mixture of 200 cm.sup.3 of water and 100 cm.sup.3 of 
diethyl ether. The ether layer is decanted and treated as in the preceding 
examples to yield 4.17 g of an orange oil in which methyl 
2,6,10,14-tetramethyl-pentadeca-1,3,5,9,13-pentaene-carboxylate is 
characterised and measured by nuclear magnetic resonance. 
Degree of conversion of the starting sulphone: 100%. Yield: 28%. 
EXAMPLE 14 
3.44 g of the C.sub.15 phenyl-sulphone used in Example 1 are dissolved in 
10 cm.sup.3 of tetrahydrofuran and the solution is run into 12 cm.sup.3 of 
tetrahydrofuran which contains 2.24 g of potassium t-butylate and which 
has been cooled to -30.degree. C. A solution of 0.347 g of 
1,4-dichloro-2-methyl-2-butene in 5 cm.sup.3 of tetrahydrofuran is then 
run in over the course of 15 minutes. By a treatment identical to that of 
the preceding Examples, 3.9 g of a product which contains 1.4 g of the 
compound of the formula: 
##STR26## 
are isolated. 
Yield 73% relative to the dichlorinated product. 
EXAMPLE 15 
A mixture of 1.88 g of potassium t-butylate and 3 cm.sup.3 of 
tetrahydrofuran is cooled to -70.degree. under an atmosphere of nitrogen. 
A solution of 3.1 g of the disulphone of the formula: 
##STR27## 
in 15 cm.sup.3 of tetrahydrofuran is run in first over the course of 10 
minutes, followed by a solution of 1.94 g of 
1-chloro-3-methyl-4-t-butoxy-2-butene in 3 cm.sup.3 of tetrahydrofuran. 
Stirring is continued at this temperature for 19 hours. The reaction 
mixture is poured into a water/diethyl ether mixture and treated according 
to the preceding examples. An orange-red oil, which contains 2.4 g of a 
compound of the formula 
##STR28## 
is thus obtained. 
Yield of 72% relative to the disulphone employed. 
The disulphone employed was prepared by reacting phenyl-retinyl-sulphone 
with phenyl-4-chloro-2-methyl-but-2-enyl-sulphone in tetrahydrofuran and 
in the presence of potassium t-butylate at -15.degree. C. or as described 
in Example 8. 
EXAMPLE 16 
7.5 cm.sup.3 of a solution of butyl-lithium in hexane (obtained by 
dissolving 17 g of this product in 100 cm.sup.3 of hexane) which has been 
cooled to -70.degree. C., are added to 4 g of 
phenyl-3-methyl-but-2-enyl-sulphone and the mixture is stirred for 1 hour. 
3.86 g of methyl bromo-senecioate dissolved in 20 cm.sup.3 of 
tetrahydrofuran cooled to -70.degree. C. are then added and stirring is 
continued for 1 hour whilst allowing the mixture to return to ambient 
temperature. It is poured into 100 cm.sup.3 of a saturated aqueous 
solution of sodium chloride mixed with 100 cm.sup.3 of an aqueous solution 
of sodium bicarbonate. It is then extracted with 3 times 100 cm.sup.3 of 
diethyl ether. A residue which crystallises on adding pentane and has a 
melting point of 42.degree.-43.degree. C. is isolated from the ether 
layers, treated as above. This product is identified by elementary 
analysis, infra-red spectrography and nuclear magnetic resonance and 
corresponds to the formula: 
##STR29## 
Yield 83% relative to the sulphone employed. 
EXAMPLE 17 
Following the procedure of the preceding example, 4.4 g of 
phenyl-3-methyl-but-2-enyl-sulphone are reacted with 4.55 g of 
1-chloro-2-methyl-4-acetoxy-2-butene. At the end of the treatment, a 
product is isolated which is identified by elementary analysis, infra-red 
spectrography and nuclear magnetic resonance and corresponds to the 
formula: 
##STR30## 
The yield is 73% relative to the sulphone employed. 
EXAMPLE 18 
1.3 g of potassium methylate, 10 cm.sup.3 of hexamethylphosphotriamide and 
10 cm.sup.3 of diethyl ether are introduced into a 50 cm.sup.3 flask. The 
mixture is cooled to -20.degree. C. and then a solution of 2.05 g of 
phenyl-retinyl-sulphone in a mixture of 5 cm.sup.3 of 
hexamethyl-phosphotriamide and 5 cm.sup.3 of anhydrous diethyl ether is 
added slowly. A solution of 1.93 g of methyl bromo-senecioate in 3 
cm.sup.3 of anhydrous diethyl ether is then run in over the course of 10 
minutes and stirring is continued for 2 hours 30 minutes at -20.degree. C. 
The reaction mixture is poured into a mixture of 50 cm.sup.3 of iced water 
and 50 cm.sup.3 of diethyl ether and then the ether layers are treated as 
in the preceding examples. An orange viscous product is obtained in which 
1.85 g of a product of the formula: 
##STR31## 
are measured. 
Yield: 71% relative to the sulphone employed. 
EXAMPLE 19 
A solution of 4.31 g of 
5-(2,6,6-trimethyl-3-oxocyclohex-1-enyl)-3-methyl-1-phenylsulphonyl-penta- 
2,4-diene in 20 cm.sup.3 of acetonitrile, followed by 0.2 g of 
trimethyl-benzyl-ammonium hydroxide (TRITON B) dissolved in 3 cm.sup.3 of 
acetonitrile, are introduced into a 50 cm.sup.3 three-necked flask 
equipped with a dropping funnel, a condenser and a nitrogen inlet. A 
solution of 2.1 g of 1-phenylsulphonyl-3-methyl-butadiene in 10 cm.sup.3 
of acetonitrile is then run into the flask, over the course of 10 minutes. 
The reaction mixture is stirred for several hours at ambient temperature 
and is then poured into a mixture of 200 cm.sup.3 of water and 100 
cm.sup.3 of diethyl ether. The aqueous layer is decanted and extracted 
with 3 times 100 cm.sup.3 of diethyl ether; the combined ether layers are 
washed with 3 times 100 cm.sup.3 of water, dried over magnesium sulphate 
and concentrated. 6.1 g of an oil are thus obtained in which a product of 
the formula: 
##STR32## 
is identified and measured by infra-red spectrography, nuclear magnetic 
resonance and thin layer chromatography. 
Degree of conversion: 61%. Yield: 54%. 
5-(2,6,6-trimethyl-3-oxo-cyclohex-1-enyl)-3-methyl-1-phenylsulphonyl-penta- 
2,4-diene was prepared by oxidation of 
5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-1-phenyl-sulphonyl-penta-2,4- 
diene by means of sodium meta-periodate in accordance with the process 
described in French Pat. No. 2,071,508. The product oxidised in this way 
was itself obtained by reacting sodium phenylsulphinate with 
5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-1-chloro-penta-2,4-diene as 
described in Example 1. 
1-Phenylsulphonyl-3-methyl-butadiene was prepared by reacting 
phenyl-4-chloro-3-methyl-but-2-enylsulphone with triethylamine in benzene. 
The chlorosulphone which was dehydrochlorinated in this way was itself 
prepared by reacting sodium phenylsulphinate with 
1,4-dichloro-2-methyl-2-butene in equimolecular amounts in anhydrous 
ethanol. 
EXAMPLE 20 
A solution of 2.257 g of 
tolyl-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-dienyl 
sulphone in 3.5 cm.sup.3 of N-methylpyrrolidone is added with agitation 
and over a period of 5 minutes to a solution of 0.886 g of sodium 
t-butylate in 3 cm.sup.3 of N-methylpyrrolidone maintained under argon and 
cooled to -20.degree. C. The reaction mixture turns red. After 5 minutes 
agitation, a solution of 1.4105 g of 
1-chloro-2-methyl-4,4-dimethoxy-2-butene in 1.7 cm.sup.3 of 
N-methyl-pyrrolidone is added over 5 minutes. The reaction is followed by 
thin layer chromatography using as eluent a mixture of hexane, diethyl 
ether and ethanol (70/25/5 by volume). After 42 minutes the sulphone 
starting material has entirely reacted. 6 cm.sup.3 of N-methylpyrrolidone 
are added and the pH of the mixture is adjusted to about 6 by addition of 
0.74 cm.sup.3 of 4 N-sulphuric acid. A further 0.16 cm.sup.3 of 4 
N-sulphuric acid is then added, and the mixture is then allowed to warm up 
slowly to about 20.degree. C. while the hydrolysis of the acetal group is 
followed by thin layer chromatography using the same eluent as before. 
After 65 minutes, the reaction mixture is diluted with 25 cm.sup.3 of 
diethyl ether and 10 cm.sup.3 of distilled water. The aqueous phase is 
separated and extracted with more ether. The ethereal extracts are united 
and washed with distilled water until the pH of the washing water is about 
6. The extract is then dried over anhydrous sodium sulphate and 
concentrated. 3.00 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-tolylsulphonyl-3,7-dimethyl-2,6,8-non 
a-trienone melting at 97.degree. C. are thus obtained after 
recrystallisation from a mixture of hexane and ethyl acetate (80/20 by 
volume). This compound shows by ultra-violet spectroscopy in solution in 
ethanol an absorption maximum at 233 nm and a shoulder at 272 nm. It has 
the formula: 
##STR33## 
EXAMPLE 21 
A solution of 3.501 g of 
(4-methoxyphenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-di 
enyl sulphone in 3.6 cm.sup.3 of N-methylpyrrolidone is added with 
agitation and over a period of 10 minutes to a solution of 1.165 g of 
sodium t-butylate in 3 cm.sup.3 of N-methylpyrrolidone maintained under 
argon and cooled to -20.degree. C. The addition causes the reaction 
mixture to turn red. After 5 minutes agitation, a solution of 1.664 g of 
1-chloro-2-methyl-4,4-dimethoxy-2-butene in 1.7 cm.sup.3 of 
N-methylpyrrolidone are added over a period of 5 minutes. The reaction is 
followed by thin layer chromatography using the same eluent as in Example 
20. After 90 minutes, the sulphone starting material has entirely reacted. 
6 cm.sup.3 of N-methylpyrrolidone are added, and the pH of the mixture is 
adjusted to about 6 by addition of 0.74 cm.sup.3 of 4 N-sulphuric acid. A 
further 0.23 cm.sup.3 of 4 N-sulphuric acid is then added and the 
temperature of the mixture is allowed to rise progressively to about 
20.degree. C., while the hydrolysis of the acetal group is followed by 
thin layer chromatography using the same eluent as before. After 2 hours, 
25 cm.sup.3 of diethyl ether and 10 cm.sup.3 of distilled water are added 
to the reaction mixture, and the aqueous phase is separated and extracted 
with more ether. The ethereal extracts are combined and washed with 
distilled water until the pH of the washing water is about 6. The extract 
is then dried over anhydrous sodium sulphate and concentrated. 3.4 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-(4-methoxyphenylsulphonyl)-3,7-dimeth 
yl-2,6,8-nona-trienone are thus obtained, which shows by ultraviolet 
spectroscopy in solution in ethanol an absorption maximum at 242 nm and a 
shoulder at 272 nm. 
EXAMPLE 22 
A solution of 3.501 g of 
(4-chlorophenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-die 
nyl sulphone in 5 cm.sup.3 of N-methylpyrrolidone is added with agitation 
and over 5 minutes to a solution of 1.169 g of sodium t-butylate in 4 
cm.sup.3 of N-methylpyrrolidone kept under nitrogen and cooled to 
-20.degree. C. The addition causes the reaction mixture to turn red. After 
5 minutes agitation, a solution of 1.664 g of 
1-chloro-2-methyl-4,4-dimethoxy-2-butene in 2.25 cm.sup.3 of 
N-methyl-pyrrolidone is added over 5 minutes. The reaction is followed by 
thin layer chromatography using the same eluent as in Example 20. After 1 
hour and 47 minutes the sulphone starting material has entirely reacted. 8 
cm.sup.3 of N-methylpyrrolidone are added, and the pH of the mixture is 
adjusted to about 6 by addition of 0.77 cm.sup.3 of 4 N-sulphuric acid. A 
further 0.22 cm.sup.3 of 4 N-sulphuric acid is then added, and the 
temperature of the mixture is allowed to rise progressively to about 
20.degree. C. while the hydrolysis of the acetal group is followed by thin 
layer chromatography using the same eluent as before. After 2 hours, 25 
cm.sup.3 of diethyl ether and 10 cm.sup.3 of distilled water are added to 
the reaction mixture. The aqueous phase is separated and extracted with 
more ether. The ethereal extracts are combined and washed with distilled 
water until the pH of the washing water is about 6. The extract is then 
dried with anhydrous sodium sulphate and concentrated. 4.4 g of 
9-(2,6,6-trimethyl-cyclohex-1-enyl)-5-(4-chlorophenylsulphonyl)-3,7-dimeth 
yl-2,6,8-nona-trienone, melting at 125.degree. C. after recrystallisation 
from a mixture of hexane and ethyl acetate (80/20 by volume), are thus 
obtained showing, on ultraviolet spectroscopy in solution in ethanol, an 
absorption maximum at 232 nm and a shoulder at 272 nm. 
EXAMPLE 23 
A solution of 2.786 g of 
(2,5-dichlorophenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4 
-dienylsulphone in 3.6 cm.sup.3 of N-methylpyrrolidone is added with 
agitation and over a period of 5 minutes to a solution of 0.834 g of 
sodium t-butylate in 2.9 cm.sup.3 of N-methylpyrrolidone kept under argon 
and cooled to -20.degree. C. The addition causes the reaction mixture to 
turn red. After 5 minutes agitation, a solution of 1.1909 g of 
1-chloro-2-methyl-4,4-dimethoxy-2-butene in 1.3 cm.sup.3 of 
N-methylpyrrolidone is added over 5 minutes. The reaction is followed by 
thin layer chromatography using the same eluent as in Example 20. After 1 
hour and a half the sulphone starting material has entirely reacted. 6 
cm.sup.3 of N-methylpyrrolidone are added, and the pH of the mixture is 
adjusted to about 6 by addition of 0.52 cm.sup.3 of 4 N-sulphuric acid. A 
further 0.26 cm.sup.3 of 4 N-sulphuric acid is added and the temperature 
of the mixture is allowed to rise progressively to about 20.degree. C. 
while the hydrolysis of the acetal group is followed by thin layer 
chromatography using the same eluent as before. After 2 hours, 25 cm.sup.3 
of diethyl ether and 10 cm.sup.3 of distilled water are added to the 
reaction mixture, and the aqueous phase is separated and extracted with 
more ether. The ethereal extracts are combined, washed with water until 
the washings have a pH of about 6, and then dried over anhydrous sodium 
sulphate and concentrated. 3 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-(2,-5-dichlorophenylsulphonyl)-3,7-di 
methyl-2,6,8-nona-trienone, melting at 122.degree. C. after 
recrystallisation from a mixture of hexane and ethyl acetate (80/20 by 
volume) are thus obtained, showing on ultraviolet spectroscopy in solution 
in ethanol absorption maxima at 233 nm and 283 nm. 
EXAMPLE 24 
A solution of 7.98 g of 
(2-naphthyl)-5-(2,6,6-trimethyl-cyclohex-1-enyl)-3-methyl-penta-2,4-dienyl 
sulphone in 16 cm.sup.3 of N-methylpyrrolidone is added with agitation and 
over a period of 5 minutes to a solution of 2.54 g of sodium t-butylate in 
8.5 cm.sup.3 of N-methylpyrrolidone kept under argon and cooled to 
-20.degree. C. The addition causes the reaction mixture to turn 
maroon-coloured. After 5 minutes agitation, a solution of 3.9 g of 
1-chloro-2-methyl-4,4-dimethoxy-2-butene in 5 cm.sup.3 of 
N-methylpyrrolidone is added over 5 minutes. The reaction is followed by 
thin layer chromatography using the same eluent as in Example 20. After 1 
hour and a half, the sulphone starting material has entirely reacted. 11.5 
cm.sup.3 of N-methylpyrrolidone are added, and the pH of the mixture is 
adjusted to about 7 by addition of 1.6 cm.sup.3 of 4 N-sulphuric acid. A 
further 0.5 cm.sup.3 of 4 N-sulphuric acid is then added, and the 
temperature of the mixture is allowed to rise progressively to about 
20.degree. C. while the hydrolysis of the acetal group is followed by thin 
layer chromatography using the same eluent as before. After 2 hours, 25 
cm.sup.3 of diethyl ether and 5 cm.sup.3 of distilled water are added to 
the reaction mixture. The aqueous phase is separated, and extracted with 
ether. The ethereal extracts are combined, washed with distilled water 
until the pH of the washings is about 6, dried over anhydrous sodium 
sulphate, and concentrated. 9.72 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-(2-naphthylsulphonyl)-3,7-dimethyl-2, 
6,8-nona-trienone melting at 124.degree. C. after recrystallisation from a 
mixture of hexane and ethyl acetate (80/20 by volume) are thus obtained 
showing, on ultraviolet spectroscopy in solution in ethanol, an absorption 
maximum at 230 nm and a shoulder between 270 and 280 nm. 
EXAMPLE 25 
A solution of 8.51 g of 
(4-bromophenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-dien 
yl sulphone in 16 cm.sup.3 of N-methylpyrrolidone is added with stirring 
over a period of 5 minutes to a solution of 2.54 g of sodium t-butylate in 
8.5 cm.sup.3 of N-methylpyrrolidone kept under argon and cooled to 
-20.degree. C. The reaction mixture turns red. After 10 minutes stirring, 
a solution of 3.9 g of 1-chloro-2-methyl-4,4-dimethoxy-2-butene in 4 
cm.sup.3 of N-methylpyrrolidone is added over a period of 10 minutes. The 
reaction is followed by thin layer chromatography using as eluent a 
mixture of hexane, diethyl ether and ethanol (70:25:5 by volume). After 30 
minutes, the sulphone starting material has entirely reacted. 11.5 
cm.sup.3 of N-methylpyrrolidone are added, the pH of the mixture is 
adusted to about 6 by addition of 1.6 cm.sup.3 of 4 N-sulphuric acid, and 
a further 0.5 cm.sup.3 of 4 N-sulphuric acid is added. The temperature is 
allowed to rise progressively to about 20.degree. C., while the hydrolysis 
of the acetal group is followed by thin layer chromatography using the 
same eluent as before. After 50 minutes, the reaction mixture is mixed 
with 25 cm.sup.3 of diethyl ether and 40 cm.sup.3 of distilled water. The 
aqueous phase is separated and extracted with more ether. the ethereal 
extracts are combined, washed with distilled water until the pH of the 
washing water is about 6, dried over anhydrous sodium sulphate, and 
concentrated. 11.5 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-(4-bromophenylsulphonyl)-3,7-dimethyl 
-2,6,8-nona-trienone are thus obtained, m.p. 128.degree. C. after 
recrystallisation from a mixture of hexane and ethyl acetate (80:20 by 
volume) and showing by ultra-violet spectrography in solution in ethanol 
an absorption maximum at 238 nm and a shoulder at 274 nm. 
EXAMPLE 26 
A solution of 7.24 g of 
(4-fluorophenyl)-5-(2,6,6-trimethylcyclohex-1-enyl)-3-methyl-penta-2,4-die 
nyl sulphone in 16 cm.sup.3 of N-methylpyrrolidone is added with stirring 
and over 20 minutes to a solution of 2.54 g of sodium t-butylate in 8.5 
cm.sup.3 of N-methylpyrrolidone kept under argon and cooled to -20.degree. 
C. The reaction mixture turns a maroon colour. After 10 minutes stirring, 
a solution of 3.9 g of 1-chloro-2-methyl-4,4-dimethoxy-2-butene in 5 
cm.sup.3 of N-methylpyrrlidone is added over a period of 10 minutes. The 
reaction is followed by thin layer chromatography using an eluent a 
mixture of hexane, diethyl ether and ethanol (70:25:5 by volume). After 35 
minutes, the sulphone starting material has entirely reacted. 11.5 
cm.sup.3 of N-methylpyrrolidone are added, the pH of the mixture is 
adjusted to about 6 by addition of 1.6 cm.sup.3 of 4 N-sulphuric acid, and 
a further 0.5 cm.sup.3 of 4 N-sulphuric acid is added. The temperature is 
allowed to rise progressively to about 20.degree. C., while the hydrolysis 
of the acetal group is followed by thin layer chromatography using the 
same eluent as before. After 1 hour 40 minutes the reaction mixture is 
mixed with 25 cm.sup.3 of diethyl ether and 40 cm.sup.3 distilled water. 
The aqueous phase is separated and extracted with ether. The ethereal 
extracts are combined, washed with distilled water until the pH of the 
washing water is about 6, dried over anhydrous sodium sulphate, and 
concentrated. 7.14 g of 
9-(2,6,6-trimethylcyclohex-1-enyl)-5-(4-fluorophenylsulphonyl)-3,7-dimethy 
l-2,6,8-nona-trienone are thus obtained, m.p. 114.degree. C. after 
recrystallisation from a mixture of hexane and ethyl acetate (80:20 by 
volume) and showing by ultra-violet spectrography in solution in ethanol 
an absorption maximum at 236 nm and a shoulder at 276 nm.