# 1911 Encyclopædia Britannica/Polymethylenes

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​POLYMETHYLENES, in chemistry, cyclic compounds, the simplest members of which are saturated hydrocarbons of general formula C, .H2, ., where n may be 1 to 9, and known as tri-, tetra-, penta-, hexa-, and hepta-methylene, &c., or cyclopropane, -butane, -pentane, -hexane, -heptane, &c.:- CH1, CH, -CH, CH2'CH2
CH2< | 1 | CH2< | | CH2< >CH2, &c.
CH CH C H CH CH CH CH
2v 2 ' 2 2° 21' 2° 2
Cyclo-propane, -butane, -pentane, - -h€Xan6-The unsaturated members of the series are named on the Geneva system in which the termination -one is replaced by-ene, -diene, -triene, according to the number of double linkages in the compound, the position of such double linkages being shown by a numeral immediately following the suliix -ene; for example I. is methyl-cyclo-hexadiene-1. 3. An alternative method employs A. v. Baeyer's symbol A. Thus A 2-4 indicates the presence of two double bonds in the molecule situated immediately after the carbon atoms 2 and 4; for example II. is A 2-4 dihydrophthalic acid. 8% été? éito H) til
(1)CH CCH2.CH2/CH(4), (1)HOC CHCH2 CH%CH(4). <6>I<5> <6> H <5>
As to the stability of these compounds, most trim ethylene derivatives are comparatively unstable, the ring being broken fairly readily; the tetra methylene derivatives are rather more stable and the penta- and hexa-methylene compounds are very stable, showing little tendency to form open chain compounds under ordinary conditions (see CHEMISTRY: Organic). Isomerism.-No isomerism can occur in the mono substitution derivatives but ordinary position isomerism exists in the diand poly-substitution compounds. Stereo-isomerism may occur: the simplest examples are the dibasic acids, where a cis(maleinoid) form and a trans- (fumaroid) form have been observed. These isomers may frequently be distinguished by the facts that the cis-acids yield anhydrides more readily than the trans-acids, and are generally converted into the trans-acids on heating with hydrochloric acid. O. Aschan (Ber., 1902, 35, p. 3389) depicts these cases by representing the plane of the carbon atoms of the ring as a straight line and denoting the substituted hydrogen atoms by the letters X, Y, Z. Thus for dicarboxylic acids (CO2H= X) the possibilities are represented by 1 (cis), Q (trans), (1).
The trans compound is perfectly asymmetric and so its mirror image (I) should exist, and, as all the trans compounds synthetically prepared are optically inactive, they are presumably racemic compounds (see O. Aschan, Chemie der alicyklischen Verbinflungen, p. 346 seq.).
General Methods of Formation.—Hydrocarbons may be obtained from the dihalogen paratiins by the action of sodium or zinc dust, provided that the halogen atoms are not attached to the same or to adjacent carbon atoms (A. Freund, M onats., 1882, 3, p. 625; W. H. Perkin, jun., Journ. Chem. Soc., 1888, 53, p. 213):-
CH -CH -Br CH -CH
CH;-CH;-Bf+2N“=2NaBf+cH§ -cH§ ¢
by the action of hydriodic acid and phosphorus or of phosphonium iodide on benzene hydrocarbons (F. Wreden, Ann., 1877, 187, p. 153; A. v. Baeyer, ibid., 1870, 155, p. 266), benzene giving methylpentamethylene; by passing the vapour of benzene hydrocarbons over finely divided nickelat I8O*2 50° C. (P. Sabatier and ]'. B. Senderens, Comptes rendns, 1901, 132, p. 210 seq.); and from hydra zines of the type C, .H2, ,, ~NH-NH, by oxidation with alkaline potassium ferricyanide (N. Kijner, Journ. prak. Chem., 1901, 64, p. 113). Unsaturated hydrocarbons of the series may be prepared from the corresponding alcohols by the elimination of a molecule of water, using either the xanthogenic ester methodof L. Tschugaelf (Ben 1899, 32: p~ 3332): CnH2n 1ON&*>CnH2n-1O'vCS'SN3'(R) ->CnH2n 2+COS-I-R-SH; or simply by dehydrating with anhydrous oxalic acid (N. Zelinsky, Ber., 1901, 34, p. 3249); and by eliminating the halogen acid from mono- or di-halogen poly methylene compounds by heating them with quinoline. Alcohols are obtained from the corresponding halogen compounds by the action of moist silver oxide, or by warming them with silver acetate and acetic acid; by the reduction of ketones with metallic sodium; by passing the vapours of monohydric phenols and hydrogen over finely divided nickel (P. Sabatier and ]. B. Senderens, loc. cit.); by the reduction of cyclic esters with ​ sodium and alcohol (L. Bouveault and G. Blanc, Comptes rendus, 1903, 136, p. 1676; 137, p. 60); and by the addition of the elements of water to the unsaturated cyclic hydrocarbons on boiling with dilute acids.
Aldehydes and Ketones.—The aldehydes are prepared in the usual manner from primary alcohols and acids. The ketones are obtained by the dry distillation of the calcium salts of dibasic saturated aliphatic acids (J. Wislicenus, Ann., 1893, 275, p. 309): [CH$_2$·CH$_2$·CO$_2$]$_2$Ca→[CH$_2$·CH$_2$]2CO; by the action of sodium on the esters of acids of the adipic and pimelic acid series (W. Dieckmann, Ber., 1894, 27, pp. 103, 2475):—
| CH$_2$·CH$_2$·CH$_2$·CO$_2$R | | CH$_2$CH$_2$·CH$_2$·CH$_2$ |
| ĊH$_2$·CH$_2$·CO$_2$R | | ĊH$_2$·CH$_2$Ċ·O |
by the action of sodium ethylate on δ-ketonic acids (D. Vorländer, Ber., 1895, 28, p. 2348):—
CH -CH CH -CH
CH2< 2 2c0.H- > CH 2 2>co;
CO-CH;, CO-CH2
from sodio-malonic ester and aB-unsaturated ketones or ketonic esters:-
CH - co
(RO2C)2CH2-l-Ph-CH:CH-CO-CH3->PhCH/ ” cucH<co2R)-co 2
from aceto-acetic ester and esters of aB-unsaturated acids, followed by elimination of the carboxyl group:- /CH2-CR'g
CH3-CO~CH2-CO2R-I-R'2C: CH-COQR->CO /CHCOZR; CH, -CO
by the condensation of two molecules of aceto-acetic ester with aldehydes followed by saponification (E. Knoevenagel, Arm., 1894, 281, p. 25; 1896, 288, p. 321; Ber., 1904, 37, p. 4461):—
CH2-CHR'
2CH3-CO-CH2-CO2R+OHC»R'->CH;, -C /CHQ; CH—CO
from 1·5-dike tones which contain a methyl group next the keto-group (W. Kerp, Ann., 1896, 290, p. 123):—
CH2~C(CH;,)
3CH3-CO-CH3->(CH3)2C CH
(CH2-CO/
by the condensation of succinic acid with sodium ethylate, followed by saponification and elimination of carbon dioxide:- CH2-CH2-CO,
CH2-CH2
and from the condensation of ethyl oxalate with esters of other 2C2H4(CO2H)2-)(:O
dibasic acids in presence of sodium ethylate (W. Dieckmann, B@f~,1897,3°, D- 147°§ 1899>32yP-1933)3 CO1R /COZR CO-CH2
| +CH2 -> | /CH, .
COQR COQR CO-CH2
Acids may be prepared by the action of dihalogen parafiins on sodio-malonic ester, or sodio-aceto-acetic ester (W. H. Perkin, jun., Jouru. Chem. Soc., 1888, 53, p. 194):- C2H 4Br2+2NaCH (CO2R)2->(CH2)2C (CO2R)2 -I-CH2 (CO2R)2;- ethyl butane tetra car boxy late is also formed which may be converted into a tetra methylene carboxylic ester by the action of bromine on its disodium derivative (W. H. Perkin and Sinclair, ibid., 1829, 61, p. 36). The esters of the acids may also be obtained by condensing sodio-malonic ester with a-halogen derivatives of unsaturated acids:- /CH-COQR
CH;-CH: CBr-CO2R+NaCH(CO2R)2->CH;, -CH .|; C(CO2R)2
by the action of diazomethane or diazoacetic ester on the esters of unsaturated acids, the pyrazoline carboxylic esters so formed losing nitrogen when heated and yielding acids of the cyclopropane series (E. Buchner, Ber., 1890, 23, p. 703; Ann., 1895, 284, p. 2I2§ I'I.V.P€Cl1I1'l3.1'1I1, Ber., 1894, 27, p. 1891):- CH-COQR N:N-CH-CO2R CHCOZR
CH2N2+ ll > | | ->H2C/,
CH~CO2R HQC-CH-CO2R cHc0.R
and by the Grignard reaction (S. Malmgren, Ber., 1903, 36, pp. 668, 2622; N. Zelinsky, ibid., 1902, 35, p. 2687).
Cyclo-propane Group.
Trimethylene, C$_3$H$_6$, obtained by A. Freund (M ouats., 1882, 3, p. 625) by heating trim ethylene bromide with sodium, is a gas, which may be liquefied, the liquid boiling at −35° C. (749 mm.). It dissolves gradually in concentrated sulphuric acid, forming propyl sulphate. Hydriodic acid converts it into n-propyl iodide. It is decomposed by chlorine in the presence of sunlight, with explosive violence. It is stable to cold potassium permanganate.
Cyclo-propane carboxylic acid, C3H5-COQH, is prepared by heating the 1.1-dicarboxylic acid; and by the hydrolysis of its nitrile, formed by heating 'y-chlorbutyro-nitrile with potash (L. Henry and P. Dalle, Chem. Centralblatt, 1901, I, p. 1357; 1902, 1, p. 913). It is a colourless oil, moderately soluble in water.
The 1.1 dicarboxylic acid is prepared from ethylene dibromide and sodio-malonic ester. The ring is split by sulphuric or hydrobromic acids. The cis 1.2-cyclo-propane dicarboxylic acid is formed by eliminating carbon dioxide from cyclo-propane tricarboxylic acid -1.2.3 (from aB-dibrompropionic ester and sodio-malonic ester). The trans-acid is produced on heating pyrazolin-4.5-dicarboxylic ester, or by the action of alcoholic potash on α-bromglutaric ester. It does not yield an anhydride.
Cyclo-butane Group.
Cyclo-butane, C$_4$H$_8$, was obtained by R. Willstätter (Bern, 1907, 40, p. 3979) by the reduction of cyclobutene by the Sabatier and Senderens method. It is a colourless liquid which boils at 11–12° C, , and its vapour burns with a luminous flame. Reduction at 180–200° C. by the above method gives ri-butane. Cyclo-butene, C4H¢, formed by distilling trim ethyl-cyclo-butyb ammonium hydroxide, boils at 1.5–2.0° C. (see N. Zelinsky, ibid., p. 4744; G. Schweter, ibid., p. 1604).
When sodio-malonic ester is condensed with trim ethylene bromide the chief product is ethyl pentane tetracarboxylate, tetramethylene 1.1-dicarboxylic ester being also formed, and from this the free acid may be obtained on hydrolysis. It melts at 154–156° C., losing carbon dioxide and passing into cyclo-butane carboxylic acid, C4H-, CO2H. This basic acid yields a monobrom derivative which, by the action of aqueous potash, gives the corresponding hydroxycyclo-butane carboxylic acid, C4H6(OH)-COZH. Attempts to eliminate water from this acid and so produce an unsaturated acid were unsuccessful; on warming with sulphuric acid, carbon monoxide is elingnated and cyclo-butanone (keto-tetra methylene) is probably forme .
The truxillic acids, C18H16O4, which result by the hydrolytic splitting of truxilline, C3gH46N2O@, are phenyl derivatives of cyclo-butane. Their constitution was determined by C. Liebermann (Ber., 1888, 21, p. 2342; 1889, 22, p. 124 seq.). They are polymers of cinnamic acid, into which they readily pass on distillation. The o.-acid on oxidation yields benzoic acid, whilst the /3-acid yields benzil in addition. The o.-acid is diphenyl-2.4-cyclo-butane dicarboxylic acid -1.3; and the B-acid diphenyl-3.4-cyclo-butane dicarboxylic acid -1.2. By alkalis they are transformed into stereo-isomers, the a-acid giving γ-truxillic acid, and the β-acid -δ-truxillic acid. The a.-acid was synthesized by C. N. Riiber (Ber., 1902, 35, p. 2411; IQ04, 37, p. 2274), by oxidizing diphenyl-2.4-cyclo-butane-bismethylene malonic acid (from cinnamic aldehyde and malonic acid in the presence of quinoline) with potassium permanganate.
Cyclo-pentane Group.
Derivatives may be prepared in many cases by the breaking down of the benzene ring when it contains an accumulation of negative atoms (T. Zincke, Ber., 1886-1894; A. Hantzsch, Ber., 1887, 20, p. 2780; 1889, 22, p. 1238), this type of reaction being generally brought about by the action of chlorine on phenols in the presence of alkalis (see Chemistry: Organic). A somewhat related example is seen in the case of croconic acid, which is formed by the action of alkaline oxidizing agents on hexa-oxybenzene:—
HO~C-C(OH):C(OH) HO-C-CO~CO HO-C-CO
ll I -+, ll l -> ll. /CO
HO-C-C(OH) § C(OH) HO~C-CO-CO HO-C-CO
Hexa-oxybenzene. Rhodizonic acid. Croconic acid. Cyclo-pentaue, C 5H,0, is obtained from cyclo-pentanone by reducing it to the corresponding secondary alcohol, converting this into the iodo-compound, which is finally reduced to the hydrocarbon (J. Wislicenus, Arm., 1893, 275, p. 327). It is a colourless liquid which boils at 50-51° C. 'Methyl-cyclo-pentane, C5H9CH3, first obtained by F. Wreden (Ann., 1877, 187, p. 163) by the action of hydriodic acid and red phosphorus on benzene, and considered to be hexahydrobenzene, is obtained synthetically by the action of sodium on/ 1-5 dibromhexane; and by the action of magnesium on acetylbutyl iodide (N. Zelinsky, Ber., 1902, 35, p. 2684). It is a liquid boiling at 72° C. Nitric acid (sp. gr. 1·42) oxidizes it to succinic and acetic acids. Cyclo-pentane, C$_5$HS, a liquid obtained by the action of alcoholic potash on iodo-cyclo-pentane, boils at 45° C. Cyclo-pentadiene, C$_5$H$^6$, is found in the first runnings from crude benzene distillations. It is a liquid which boils at 41° C. It rapidly polymerizes to di-cyclo-pentadiene. The ·CH2- group is very reactive and behaves in a similar manner to the grouping ·CO·CH$_2$·CO· in open chain compounds, e.g. with aldehydes and ketones it gives the ​ fulvenes, substances characterized by their intense orange-red colour HC;CH
(J. Thiele, Bef., 1900, 33, p. 669). Phenylfulven, | C:CHPh, HC:CH/
obtained from benzaldehyde and cyclo-pentadiene, forms dark red plates. Diphenylfulven, from benzophenone and cyclo-pentadiene, crystallizes in deep red prisms. Dimethylfulven is an orange coloured oil which oxidizes rapidly on exposure. Concentrated sulphuric acid converts it into a deep red tar. Cyclo-penlanone, CEHSO, first prepared pure by the distillation of calcium adipate (J. l/Vislicenus, Arm., 1893, 275, p. 312), is also obtained by the action of sodium on the esters of pimelic acid; by the distillation of calcium succinate; and by hydrolysis of the cyclopentanone carboxylic acid, obtained by condensing adipic and oxalic esters in the presence of sodium ethylate. Reduction gives cyclo-pentanol, C5H9OH.
Croconic acid (dioxy-cyclo-pentene-trione), C5H2O5, is formed when triquinoyl is boiled with water, or by the oxidation of hexa-oxybenzene or dioxydiquinoyl in alkaline solution (T. Zincke, Bef., 1887, 20, p. 1267). It has the character of a quinone. On oxidation it yields cyclo-pentane-pentanone (leuconic acid). Derivatives of the cyclo-pentane roup are met with in the breaking-down products of the terpenes (ia).
Campholactone, C, H14O2, is the lactone of trim ethyl-2-2-3-cyclopentanol-5-carboxylic acid-3. For an isomer, isocampholactone
(the lactone of trim ethyl-2-2-3-cyclo-pentanol-3-carboxylic acid-1) see W. H. Perkin, jun., Proc. Chem. Soc., 1903, 19, p. 61. Lauronolic acid, CQHHOQ, is trim ethyl-2~2-3-cyclo-pentene-4~acid-I. Isolauronolic acid, C9H14¢, is trim ethyl-2-2-3-cyclo-pentene-3-acid-4. Campholic acid, C101-I, gO2, is tetra methyl-1-2-2-3-cyclo-pentane acid-3. Camphononic acid, C, H14O3, is trim ethyl-2-2~3-cyclo-pentanone-1-carboxylic acid-3. Camphorphorone, CQHUO, is methyl-2isobuty-lene-5-cyclo-pentanone-1. Isothujone, CWHNO, is dimethyl-1~2-isopropyl-3-cyclo-pentene-I-one-5. (F. W. Semmler, Bef.,
19001 33, P~ 275-)
L. Bouveault and G. Blanc (Comples rendus, 1903, 136, p. 1460), prepared hydrocarbons of the cycle-pentane series from cyclohexane compounds by the exhaustive methylation process of A. W Hofmann (see PYRIDINE). For phenyl derivatives of the cyclopentane group see F. R. Japp, Jour. Chem. Soc., 1897, 71, pp. 139, 144; H. Stobbe, Ann., 1901, 314, p. III; 315, p. 219 seq.; 1903 326. P~ 3471
Cyclo-hexane Group.
H hydrocarbons.-Cyclo-hexane, or hexahydro benzene, CSHW, is obtained by the action of sodium on a boiling alcoholic solution of 1~6-dibromhexane, and by passing the vapour of benzene, mixed with hydrogen, over finely divided nickel. It is a liquid with an odour like that of benzene. It boils at 80-81° C. Nitric acid oxidizes it to adipic acid. When heated with bromine in a sealed tube for some days at 150-200° C., it yields 1~2-4~5-tetrabrombenzene (N. Zelinsky, Ber., 1901, 34, p. 2803). It is stable towards halogens at ordinary temperature. Benzene hexachloride, C, H, ,Cl5, is formed by the action of chlorine on benzene in sunlight. By recrystallization from hot benzene, the a form is obtained in large prisms which melt at 157° C., and at their boiling-point decompose into hydrochloric acid and trichlorbenzene. The B form results by chlorinating boiling benzene in sunlight, and may be separated from the a. variet by distillation in a current of steam. It sublimes at about 310° Similar varieties of benzene hexabromide are known. Hexahydrocymene (methyl-1-isopropyl-4-cyclo-hexane), C10H2°, is important since it is the parent substance of many terpenes (.v.). It is obtained by the reduction of I-4 dibrommenthane with sodium (J. de Montgoliier, Ann. chim. ghys., 1880 [5], 19, p. 158), or of cymene, limonene, &c., by Sa atier and Senderens's method. It is a colourless liquid which boils at 180° C. Cyclo-hexene (tetra hydro benzene), CGHW, was obtained by A. v. Baeyer by removing the elements of hydriodic acid from iodocyclo-hexane on boiling it with quinoline. It is a liquid which boils at 82° C. Hypochlorous acid converts it into 2-chlor-cyclo-hexanol-1, whilst potassium perman anate oxidizes it to cyclo-hexandi-ol. Cyclo-hexadiene (dihycirobenzene), CGH8.-Two isomers are possible, namely cyclo-hexadiene-1-3 and cyclo-hexadiene-1-4. A. v. Baeyer obtained what was probably a mixture of the two by heating 1-4 dibrom-cyclo-hexane with quinoline. C. Harries (Ann., 1903, 328, p. 88) obtained them tolerably pure by the dry distillation of the phosphates of I-3-diamino and 1-4-diamino-cycle-hexane. The 1-3 compound boils at 81-82° C. and on oxidation yields succinic and oxalic acids. The 1-4 compound also boils at 81-82° C. and on oxidation gives succinic and malonic acids.
Alcohols.—Cyclo-hexanol, CQHUOH, is produced by the reduction of the corresponding ketone, or of the iodhydrin of quinite. Nitric acid oxidizes it to adipic acid, and chromic acid to c clo-hexanone. Qumite (cyclo-hexanediol-1-4) is prepared by reducing the corresponding ketone with sodium amalgam, cis-, and trans-modifications being obtained which may be separated by their acetyl derivatives. Phloroglucite (cyclo-hexane-triol-1-3-5) is obtained by reducing an aqueous solution of hloroglucin with sodium (W. Wislicenus, Bef., 1894, 27, p. 357). (Suercite (cycle-hexane-pentol-1-2-3-4-5), isolated from acoms in 1849 by H. Braconnot (Ann. chim. phys. [3], 27, p. 392), crystallizes in colourless prisms which melt at 234° C. When heated in vacuo to 240° C. it yields hydro quin one, quinone and pyrogallol. It is dextro-rotatory. A laevo-form occurs in the geaves of giymnema sylvestre (F. B. Power, Journ. Chem. Soc., 1904, 2 .
5I1i)ositelicyclo-hexane-hexol), C.~, H6(OH)6.-The inactive form occurs in the muscles of the heart and in other parts of the human body. The d-form is found as a methyl ether in pinite (from the juice of Pinus lambertina, and of caoutchouc from Mateza roritina of Madagascar), from which it may be obtained by heating with hydriodic acid. The I-form is also found as a methyl ether in quebrachite. B y mixing the d- and l- forms, a racemic variety melting at 253° C. is obtained. A dimethyl ether of inactive inosite is dambonite which occurs in caoutchouc from Gabon.
Ketones.-Cyclo-hexanone, CGHNO, is obtained by the distillation of calcium pimelate, and by the electrolytic reduction of phenol, using an alternating current. It is a colourless liquid, possessing a peppermint odour and boiling at 155° C. Nitric acid oxidizes it to adipic acid. It condenses under the influence of sulphuric acid to form dodecahydrotriphenylene, C181-124, and a mixture of ketones (C. Mannul, Ber., 1907, 40, p. 153). Methyl-1-cyclo-hexanone-3, CH, ~C6H, O, is prepared by the hydrolysis of pulegone. It is an optically active liquid which boils at 168-169° C. Homologues of menthone may be obtained from the ketone by successive treatment with sodium amide and alkyl halides (A. Haller, Complex fendus, 1905, 140, p. 127). On oxidation with nitric acid (sp. gr. 1-4) at 60-70° C., a mixture of -and- -methyl adipic acids is obtained (W. Markownikoff, Ann., 1905, 236, p. 299). It can be transformed into the isomeric methyl-1-cyc1o- xanone-2 (O. Wallach, Ann., 1904, 329, p. 368). For methyl-1-cyclo-hexanone-4, obtained by distilling ~/-methyl pimelate with lime, see O. Wallach, Bef., 1906, 39, p. 1 92. ~
C4clo-hexane-dione-1-3 (dihydroresorcin), C¢H@O¢, was obtained by Merling (Ami, 1894, 278, p. 28) by reducing resorcin in hot alcoholic solution with sodium amalgam. Cyclo-hexane-dione-1~4 is obtained by the hydrolysis of succino-succinic ester. On reduction it yields quinite. It combines with benzaldehyde, in the presence of hydrochloric acid, to form 2-benzyl-hydro quin one. Cyclohexane-trione-1»3-5 (phloroglucin) is obtained by the fusion of many resins and of resorcin with caustic alkali. It may be prepared synthetically by* fusing its dicarboxylic ester (from malonic ester and sodio malonic ester at 145° C.) with potash (C. W. Moore, Journ. Chem. Soc., 1904, 85, p. 165). It crystallizes in prisms, which melt at 218° C. With ferric chloride it gives a dark violet coloration. It exhibits tautomerization, since in many of its reactions it shows the properties of a hydroxylic substance. Rhodizonic acid (dioxydiquinoyl), C6H2O5, is probably the enolic form of an oxypentaketo-cyclo-hexane. It is formed by the reduction of triquinoyl by aqueous sulphurous acid, or in the form of its potassium salt by washing potassium hexa-ox benzene with alcohol (R. Nietzki, Bef., 1885, 18, pp. 513, 1838§ . Triquinoyl (hexaketo-cyclo-hexane) C506-8H2O, is formed on oxidizing rhodizonic acid or hexa-oxybenzene. Stannous chloride reduces it to hexa-oxybenzene, and when boiled with water it yields croconic acid (dioxy-cyclo-pentene-trione).-Cyclo-hexenones.—Two types of ketones are to be noted in this
group, namely the aB and By ketones, depending upon the position of the double linkage in the molecule, thus:
CH, ' CH CH-CH,
H c / ' co HC/ c0
2 CH2-CH2/ CH2-CH2/
(ac) (nw)
These two classes show characteristic differences in properties. For example, on reduction with zinc and alcoholic potash, the a|8 compounds give saturated ketones and also bi-molecular compounds, the By being unaffected; the B-y series react with hydroxylamine in a normal manner, the 11,8 yield oxamino-oximes. M ethyl-1-cyclo-hexene-1-one-3, CH3-C6H7O, is obtained by condensing sodium aceto-acetate with methylene iodide, the ester so formed being then hydrolysed. Isocamphorphofone, CQHHO, is trim ethyl 1-6-6.-cyclo-hexene-1-one 6. Isocamphor, CwH,6O, is methyl-1isopropyl-3-cyclo-hexene-I-one 6.
Acids.-Hexahydrobenzoic acid, C6H,1-CO¢H, is obtained by the reduction of benzoic acid, or by the condensation of I-5 dibrompentane with disodio-malonic ester. It crystallizes in small plates which melt at 30-31° C. and boil at 232-233° C. (J. C. Lumsden, Joum. Chem. Soc., 1905, 87, p. 90). The sulphochloride of the acid on reduction with tin and 'hydrochloric acid gives hexahydrothiophenol, CGHHSH, a colourless oil which boils at 158-160° C. (W. Borsche, Bef., 1906, 39, p.
Quinic acid, C6 1 OH)¢CO2H (tetra-oxy-cyclo-hexane carboxylic acid), is found in cofiee beans and in quinia bark. It crystallizes in colourless prisms and is optically active. When heated to about 250° C. it is transformed into quinide, probably a lactone, which on heating with baryta water gives an inactive quinic acid. Hexahydrophthalic acids, C6H10(CO2H)¢ (cyclo-hexanedicarboxylic acids).-Three acids of this group are known, containing the Carboxyl-groups in the 1-2, 1~3, and 1-4 ositions, and each exists in two stereo-isomeric forms (cis- and trans-g. The an hydride of the cis-1»2 ​ acid obtained by heading the an hydride of the trans-acid, forms prisms which melt at 192° C. .When heated with hydrochloric acid it passes into the trans-variety. The racemic trans-acid is produced by the reduction of the dihydrobromide of A*-tetrahydrophthalic acid or AM dihydrophthalic acid. It is split into its active components by means of its quinine salt (A. Werner and H. E. Conrad, Bef., 1899, 32, p. 3046). Hexahydroisophthalic acids (cyclo-hexane-1~3dicarboxylic acids) are obtained by the action of methylene iodide on disodio-pentane tetracarboxylic ester (W. H. Perkin, Joum. Chem. Soc., 1891, 59, p. 798); by the action of trim ethylene bromide on disodio-propane tetracarboxylic ester; and by the reduction of isophthalic acid with sodium amalgam, the tetrah dro acids first formed being converted into hydro bromides and fiiirther reduced (A. v. Baeyer and V. Villiger, Ann., 1893, 276, p. 255). The cisand trans- forms can be separated by means of their sodium salts. The trans-acid is a racemic compound, which on heating with acetyl chloride gives the an hydride of the-cis-acid.-Hexahydroterephthalic acids (cyclo-hexane~1-4-dicarboxylic acids). These acids are obtained by the reduction of the hydro bromides of the di- and tetra-hydroterephthalic acids or by the action of ethylene dibromide on disodio-butane tetracarboxylic acid. An important derivative is succino-succinic acid, C61-l6O2(CO¢H)2, or cyclo-hexanedione-2-5-dicarboxylic acid-1-4, which is obtained as its ester gyhtihe action of sodium or sodium Iethylate on succinic ester (H. e ing, mi., 1844, 49, p. 192; .
Hermann, Ann., 1882, 211, p. 306). 5”d'“"“"" It crystallizes in needles or prisms, and dissolves in alcohol to form a bright
blue fluorescent liquid, which on the
with acetic an hydride. When boiled, with caustic soda it isomerizes to a mixture of the AM and AM dihydrophthalic acids. The A24 acid is obtained by boiling the dihydrobromide of the AM acidwith alcoholic potash or by continued boiling of the AM acid with caustic soda.
The AM acid is formed when phthalic acid is reduced in the cold by sodium amalgam or by heating the AM and AM acids with caustic soda. The trans-modification of A3'5 acid is produced when phthalic acid is reduced by sodium amalgam in the presence of acetic acid. When heated for some time with acetic an hydride it changes to the cis-form. The trans-acid has been resolved by means of its strychnine salts into two optically active isomer ides, both of which readily pass to AM dihydrophthalic acid (A. Neville, Journ. Chem. Soc-. 1906. 89. P- 1744)- .
Of the dihydroterephthalic acids, the Am acid is obtained by heat ing the dibromide of theA' tetra hydro acid with alcoholic potash. It cannot be prepared by a direct reduction of terephthalic acid. On warming with caustic soda it is converted into the AN acid. TheA"“ acid is also obtained by the direct reduction of terephthalic acid. It is the most stable of the dihydro acids. The A” acid is obtained by boiling the cis- and trans-AM acids with water, which are obtained on reducing terephthalic acid with sodi um amalgam in faintly alkaline solution. The relationships existing between the various hydrophthalic acids may be shown as follows:- algam (hat) Sodium amalgam + acetic acid PHTHALIC Acm-Sodium
amalgam (cold)
A3'5 Dmvmzo (TRANS.) A
Cyclo-heptane Group.
addition of ferric chloride becomes A2 and A4 TETRAHYDR0 Sodium A 2-5 Dgypao Alkali J/ Acetic' an hydride cherry red. The acid on heating loses ~ J/Heat #"m1l§ Gm(h0t) A3'5 DmyDp 0(¢15) CO2 and gives cyclo-hexanedione-1-4. MT H3'f";1b7Z""'1ia'”;"h, Tetrahydrobenzaic acid (cyclo-hexene- ETRAHY“° V am 0" P" S 1-carboxylic acid-1), CGH9-COgH. Three AN Drnvmio structural isomers are possible. The Hydfvbfvmifk A1 acid results on boiling the A' acid
with alkalis, or on eliminating hydro bro mic acid from 1-brom-cyclo-hexanecarboxylic acid-1. The A' acid is
formed on the reduction of benzoic acid with sodium amalgam. The A3 acid is
obtained by eliminating the elements of water from 4-oxy-cyclo-hexane-1-carboxylic acid (W. H. Perkin, °un., Journ.
Chem. Soc., 1904, 85, p. 431) Shikimic
acid (3-4-6-trioxy-A1-tetrahydrobenzoic acid) is found in the fruit of Illicium feligiosum. On fusion with alkalis it
yields para-oxybenzoic acid, and nascent hydrogen reduces it to hydroshikimic
acid. Sedanolic acid, CHHNO3,
which is found along withlsedanonic
acid, C12H1@3, in the higher boiling
fractions of celery oil, is an ortho-A
H Dnnnno
Anhydride with
acetic an hydride
on reduction
HEXAHYDRO /
A 1'4 DLHYDRO
TEREPHTHALIC Acm
Sodium amalgam in
Sogfum faintly alkaline solution
“'" g“"' V sodium
Bail wah A2'5 Drmmizo amalgam
L Boil with water (hot)
wat" A 1'5 Dmvrmo
/'Sodium amalgam Bo”+ NaOH
3 A2 Tmmuvnno A 1 Tnrulnvnno
Dibmmide + H ydrobromida
Reduce alcoholic potash an reduction
/ Remove H Br from
A 1'3 DIHYDRO, Hrxmnnno
dibromide
oxyamyl-A5-tetrahydrobenzoic acid, sedanonic acid being orthovaleryl-A1-tetrahydrobenzoic acid (G. Ciamician and P. Silber, Bef., 1897, 30, pp. 492, 501, 1419 seq.). Sedanolic acid readily decomposes into water and its lactone sedanolid, C1¢H1gO2, the odorous constituent of celery oil.
Tetrahydrophthalic acids (cyclo - hexene dicarboxylic acids), C5H., (CO1H)2. Of the ortho-series four acids are known. The A* acid is obtained as its an hydride by heating the A2 acid to 220° C., or by distilling hydropyromellitic acid. Alkaline potassium permanganate oxidizes it to adipic acid. The A” acid is formed along with the A4 acid by reducing phthalic acid with sodium amalgam in hot solutions. The A* acid exists in cis- and transforms. The trans-variety is produced by reducing phthalic acid, and the cis-acid by reducing A24 dihydrophthalic acid. In the meta-series, four acids are also known. The A2 acid is formed along with the A4 (cis) acid by reducing isophthalic acid. The trans A4 acid is formed by heating the cis-acid with hydrochloric acid under pressure. The A' acid is formed when the an hydride of tetra hydro rimesic acid is distilled (W. H. Perkin, junr., Journ. Chem. Soc., 1905, 87, p. 293).-In
the para-series, three acids are known. The A1 acid is formed by the direct reduction of terephthalic acid; by boiling the A” acid with caustic soda; and by the reduction (in the heat) of Ai* dihydroterephthalic acid. The A' acid exists in cis- and trans- forms; these are produced simultaneously in the reduction of A" or AW dihydroterephthalic acids by sodium amalgam.
There are five possible dihydrobenzoic acids. One was obtained in the form of its amide by the reduction of benzamide in alkaline solution with sodium amal am (A. Hutchinson, Ber., 1891, 24, p. 177). The A" acid is oihtained on oxidizing dihydrobenzaldehyde with silver oxide or by the reduction of meta-trimethylaminobenzoic acid (R. Willstatter, Ber., 1904, 37, p. 1859). Cyclo-heptane (suberane), C1Hi4, obtained by the reduction of suberyl iodide, is a liquid which boils at 117° C. On treatment with bromine in the presence of aluminium bromide it gives chiefl pentabromtoluene. When heated with hydriodic acid to 230° it gives rnethylhexamethylene. On oxidation with nitric acid (sp. r. 1°4) it yields pimelic acid. Disuberyl, C, H13-C, H,3, a thick oily hquid, boiling at 290-291° C., is obtained by the reduction of suberyl bromide.
Cyclo-heptene, C7H12, is obtained by the action of alcoholic potash on suberyl iodide; and from cyclo-heptane carboxylic acid, 'the amide of which by the action of sodium hypo bro mite is converted into cyclo-hep tan amine, which, in its turn, is destructively methylated (R. Willstatter, Ber., 1901, 34, 131). Cyclo-heptadiene I-3, C7Hm, is obtained from cyclo-heptene (Willstatter, loc. cit.). It is identical with the hydrotropilidihe, which results by the destructive methylation of tropane.-Euterpeiie
(trim ethyl-1 -4-4-cyclo-heptadiene I -5), CWHM, is prepared from dihydroeucarveol. By the action of hydro bro mic acid (in glacial acetic acid solution) and reduction of the resulting product it yields 1-2-dimethyl-4-ethyl benzene (A. v. Baeyer, Bei., 1897, 0, p. 2075). Cyclo-heptatriene (tropilidine), C7Hg, , is formed on (Tistilling tropine with baryta; and from cyclo-heptadiene by forming its addition product with bromine and heating this with quinoline to ISO-160° C. (R. Willstiitter, loc. cit.). Chromic acid oxidizes it to benzoic acid and benzaldehyde. With bromine it forms a dibromide, which then heated to 110° C. decomposes into hydro bro mic acid and benz l bromide. 4
Cyclo-heptariol, C, Pi;3OH, is formed by the reduction of suberone, and by the action of silver nitrite on the hydrochloride of cyclohexanamine (N. Demjanow, Ceiitralblatt, 1904, i. p. 1214). Cyclo-hep tan one (suberone), C7H12O, is formed on the distillation of suberic acid with lime and from
y G
Of the dihydrophthalic acids, five are known in the ortho-series, carboxylic acid by treatment with baryta and two of which are stereo-isomers of the cis- and trans-type, and a similar number are known in the para-series. The Al" acid is obtained as its an hydride by heating A" dihydrophthalic an hydride tion over lead peroxide (R. Willstatter, Bef.. It is a colourless liquid having a peppermint at 178-5-170-5° C. Nitric acid oxidizes it -brom-cyclo-heptane
subsequent distilla-1898.
31, D. 25Q7)odour,
and boiling
to n-pimelic acid. ​Tropilene, Cyl-li0O, is obtained in small quantities by the distillation of a-methyltropine methyl hydroxide, and by the hydrolysis of /Smethyltropidine with dilute hydrochloric acid. It is an oily liquid, with ati odour resembling that of benzaldehyde. It forms a benzal compound, and gives an oyxrnethylene derivative and cannot be oxidized to an acid, reactions which point to it being a ketone containing the grouping -CH2~CO-. It is thus to be regarded as a cyclo-heptene-1-one-7.
Cyclo-heptane carboxylic acid (suberanic acid), C7H|3CO2H, is obtained by the reduction of cyclo-heptene-I-carboxylic acid; from brom-cyclo-heptane by the Grignard reaction; and by the reduction of hydrotropilidine carboxylic acid by sodium in alcoholic solution (R. Willstiitter, Ber., 1898, 31. p. 2504). The corresponding oxyacid is obtained by the hydrolysis of the nitrile, which is formed by the addition of hydrocyanic acid to suberone (A. Spiegel, Ann., 1882, 211, p. 117).
Four cyclo-heptene carboxylic acids are known. Cyclo-heptene-1carboxylic acid-1 is prepared from oxysuberanic acid. This acld when heated with concentrated hydrochloric acid to I2O-130° C. yields a chlor-acid, which on warming with alcoholic potash is transformed into the cyclo-heptene compound. Cyclo-heptene-2-carboxylic acid-1 is formed by the reduction of cycla-heptatriene 2~4°6-carboxylic acid-1. On boiling with caustic soda it isomerizes to the corresponding 1-acid.
Cyclo-heplatriene carboxylic acids, C, H-, COZH. All four are known. According to F. Buchner (Ber., 1898, 31, p. 2242) they may be represented as follows:-
n co, n com, Zn
A.I,5.s»~L AL5.¢°vP~ A|.4 s°rr, ;z¢ c, .s
The at-acid (a-isophenylacetic acid) is obtained by the hydrolysis of pseudophenylacetamide, formed by condensing diazoacetic ester with benzene, the resulting pseudophenyl' acetic ester being then left in Contact with strong ammonia for a long time. B-Isoplienylacelic acid is formed by strongly heating pseudophenylacetic ester in an air-free sealed tube and hydrolysing the resulting B-isophenylacetic ester. 7-Isophenylacelic acid is obtained by heating the B and 5 acids for a long time with alcoholic potash (A. Einhorn, Ber., 1894, 27, p. 2828; E. Buchner, Ber., 1898, 31, p. 2249). 6-Isophenylacetic acid is obtained by heating the iodmethylate of anhydroecgonine ester with dilute caustic soda (A. Einhorn, Bef., 1893, 26, P- 329)-
Numerous amino-derivatives of the cyclo-heptane series have been prepared by R. Willstatter in the course of his investigations on the constitution of tropine (q.z'.). Amino-cyclo-hepiane (suberylamine) is obtained by the reduction of suberone oxime or by the action of sodium hypo bro mite on the amide of cycloheptane carboxylic acid. Cyclo-octane Group.
Few members of this group are known. By the distillation of the calcium salt of azelaic acid H. Mayer (Ann., 1893, 275, p. 363) obtained azelain ketone, CBHMO, a liquid of peppermint odour. It boils at 90-91° C. (23 mm.) and is readily oxidized by potassium permanganate to oxysuberic acid. It is apparently cyclo-octanone (see8a;so W. Miller and A. Tschitschkin, Cenlralblalt, 1899, 2., p. 1 1
Pseudapelletierine (methyl granatonine), C91-INNO, an alkaloid of the pomegranate, is a derivative of cyclo-octane, and resembles tropine in that it contains a nitrogen bridge between two carbon atoms. It is an inactive base, and also has ketonic properties. On oxidation it yields methyl granatic ester, which, by the exhaustive methylation process, is converted into homopiperylene dicarboxylic ester, HO2C~Cl-l:CH~C'H2-CH2'CH:CH~CO2H, from which suberic acid may be obtained on reduction. When reduced in alcoholic solution by means of sodium amalgam it yields methyl ranatoline, C, ,H', ;OH-NCI-lg; this substance, on oxidation with colri potassium permanganate, is converted into granatoline, CSHHNO, which on distillation over zinc dust yields pyridine. Methyl granatoline on treatment with hydriodic acid and red phosphorus, followed by caustic potash, yields methyl granatinine, CQHWN, which when heated with hydriodic acid and phosphorus to 240° C. is converted into methyl granatanine, CSHWNCH3, and granatanine, CBHHNH. The hydrochloride of the latter base when distilled over zinc dust yields a-propyl pyridine. By the electrolytic reduction of pseudopelletierine, N-methyl granatanine is obtained, and this by exhaustive methylation is converted into A'des-dimethyl granatanine. This latter compound readily forms an iodmethylate, which on treatment with silver oxide yields the corresponding ammonium hydroxide. The ammonium hydroxide on distillation decomposes into trim ethyl amine, water and cyclo-octadiene-1~3.
CH¢-CH-CH2 CH2-CH-CHQ
CH2NMe C0 -» CH, NM¢ CH2 -»CH2HO-NMe2CH2-CH.-CH-CH. CH2-CH-CH,
Pseudopelletierine N-methyl,
granatanine
C H2-C H-C Hg
C Hr-C H-C H,
XXII. 2
CH2~CH-CH; CH2-CH-CHZ CH;-CH:CH
CH1 NMQ CH2+-CH2HO- N1v1e, CH.<-CH, CH
CH. CH = CH CH2 — CH =cH CH2~CH2~CH
A -*des-methyl cyclo-octadiene
granatanine
Cyclo-ocladiene, CSHU, as above prepared, is a strong-smelling oil which decolonizes potassium permanganate solution instantaneously . It readily polymerizes to a di-cyclo-octadiene and polymer (C8H, ¢§ , . (R. Willstatter, Bef., 1905, 38, pp. 1975, 1984; G. Ciamician and P. Silber, Bef., 1893, 26, p. 2750; A. Piccinini, Gazz., 1902, 32, 1 p. 260). B-cyclo-octadiene has been prepared from methyl granatinine iodmethylate.
Cyclo-octane, CSHH, is obtained by the reduction of the above unsaturated hydrocarbon by the Sabatier and Senderens's method. It is a liquid which boils at 146 '3-148° C. and possesses a strong camphor odour. On oxidation it yields suberic' acid (R. Willstatter, Bei., 1907, 40, pp. 957). O. Doebner (Ben, 1902, 35, pp. 2129, 2538; 1903, 36, p.- 4318) obtained compounds, which in all probability -are cyclo-octadienes, by the distillation of /3-vinyl acrylic acid, sorbic acid, and cinnamenyl acrylic acid with anhydrous baryta. Cyclo-nonane Group.
According to N. Zelinsky (Ber., 1907, 40, p. 780) cyclononanone, CQHNO, a liquid boiling at 95~97° C., is formed on distilling sebacic acid with lime, and from this, by reduction to the corresponding secondary alcohol, conversion of the latter into the iodide, and subsequent reduction of this with zinc, cyclo-nonane, CgH,8, .a liquid boiling at 170~172° C. is obtained.