Laevo-rotatory

The anthur and Bennett have sbowu that (as is especially the case with Spanish oilsi pure spike oli may bo slightly laevo-rotatory up to - 3, and also yield a laevo-rotatory IracLiou on distiLlabion as above. 

It is soinble in about 1 volumes of IQ 24 volumes of "0 per cent, alcohol. I /H-piuene and tracea ot salicylic aud honicol was cousidered probable, but Phellaudrecc was not present, and u aldehydes or ketones, phenols or camphor. The chief conatitnent pinene, a mixture of the dextro-aud laevo-rotatory vatielief... 

There appear-to be either several isomerides of pinonic acid, or such closely related oxidation products as to render the purification of the acid a matter of great difiiculty. The characters of the dextro- and laevo-rotatory forms of this acid have, ho t ever, been settled by the researches of Barbier and Grignard and himmel Co, ... 

By oxidation of d- and Z-pinene of high rotatory power, Barbier and Grignard obtained the optically active forms of pinonic acid. Z-pinene from French turpentine oil (boiling-point 155 to 157 , od - 37 2 157 to 160 , tto - 32 3°) was oxidised with permanganate. From the product of oxidation, which (after elimination of the volatile acids and of nopinic acid) boiled at 189 to 195 under 18 mm. pressure, Z-pinonic acid separated out in long crystalline needles, which, after recrystallisation from a mixture of ether and petroleum ether, melted at 67° to 69 . The acid was easily soluble in water and ether, fairly soluble in chloroform, and almost insoluble in petroleum ether. Its specific rotation is [a]o - 90-5 in chloroform solution. Oximation produced two oximes one, laevo-rotatory, melting-point 128 and the other, dextro-rotatory, melting-point 189° to 191°. 

It is convenient to here mention the hydrocarbon verbenene, C,gH,4, on account of its relationship with pinene. It results from the action of acetic anhydride on verbenol, thei alcohol corresponding with the ketone, verbenone. So produced it is laevo-rotatory. The dextro-rotatory and racemic varieties are also known. The sesquiterpenes have the following characters when regenerated from their respective dibromides —... 

Very characteristic derivatives are obtained by the action of organic bases on the limonene nitrosochlorides. If d-a-limonene nitrosochloride be so treated, two nitrolamines are obtained, a-nitrolamine (dextro-rotatory), and /S-nitrolamine (laevo-rotatory). If d-)8-limonene nitrosochloride be treated in the same manner, exactly the same reaction products are obtained. If, on the other hand f-a-nitrosochloride or f-)8-nitrosochloride be treated in the same manner, a mixture of a-nitrolamine (laevo-rotatory) and )8-nitrolamine (dextro-rotatory) is obtained. 

He found that the d-phellandrene from elemi and bitter fennel oils were identical, and that i-phellandrene from eucalyptus oil is the laevo-rotatory variety of the same terpene. To these he assigned the names d-a-phellandrene and i-a-phellandrene. The d-phellandrene from water fennel oil differs from these and is named d-/3-phellandrene. The following are the characters of the purest specimens of natural phellandrene yet obtained —... 

The fraction of oil of cade boiling at 260° to 280° is converted into cadinene dihydrochloride by saturating its solution in dry ether with dry hydrochloric acid gas. The hydrochloride is separated, dried, and leorystallised, and the hydrochloric acid removed by heating it with aniline or with sodium acetate in glacial acetic acid. The liberated cadinene is rectified in a current of steam. Cadinene from oil of cade is highly laevo-rotatory, the dextro-rotatory variety being obtained from Atlas cedar oil and West Indian sandalwood oil. 

Deussen termed the inactive caryophyllene, as further experiments showed it to be, a-caryophyllene, and the laevo-rotatory compound, )8-caryophyllene. A third body was obtained, which yielded no blue nitrosite at all, to which Deussen assigned the name -y-caryophyllene. This body... 

Formula (1) would thus indicate the natural dextro-caryophyllene of clove stems formula (2) indicates the highly laevo-rotatory caryophyllene resulting from regeneration by means of pyridine, and (3) may represent the a-caryophyllene of Deussen. 

A sesquiterpene has been isolated from the essential oil of Cannabis Indica. This may fairly be considered a definite body, as it has been isolated by many different observers and described by them at different times. Valenta first mentions it. Vignolo describes it as a mobile liquid boiling at 256°, of specific gravity -897 at 15°, and slightly laevo-rotatory. Wood, Spivey, and Easterfield give the boiling-point as 258° to 259°, the specific gravity as -898 at 18°, and the rotation as - 8-6°. 

Faolini and Divizia have succeeded in partially resolving inactive linalol into its optically active isomers hut only to the extent of optical rotations of + 1° 70 and — 1° 60 respectively. Linalol was converted into its acid phthalate, and an alcoholic solution of this compound was treated with the equivalent quantity of strychnine. By fractional crystallisation the laevo-rotatory salt, yielding dextro-rotatory linalol, separates first, leaving the more soluble dextro-rotatory strychnine salt, which yielded laevo-rotatory linalol in the mother liquor. 

The authors found that on elimination of the halogen acid from this compound, rhodinol, and not citronellol, is regenerated, dextro-rhodinol from dextro-citroneUol, and laevo-rhodinol from the laevo-rotatory alcohol from oil of rosesior geranium, the two bodies, in the latter case being identical. 

The more soluble cinchonine salt remaining in the mother liquors, gave a laevo-rotatory thujyl alcohol, but the highest rotation obtained was - 9-12°. 

Wallach gives the following characters for the laevo-rotatory fenchyl alcohol —... 

Pickard, Lewcock and Yates have prepared fenchyl alcohol by the reduction of conversion into its hydrogen phthalate and fractionally crystallising the magnesium and cinchonine salts, they obtained a fraction, which on saponification yielded Za w-fenchyl alcohol, having a specific rotation of - 15 5°, which is probably the correct value for this figure. 

Natural menthol is laevo-rotatory. The reduction of both laevo-menthone and dextro-menthone yields a mixture in which laevo-menthol predominates. The constitution of menthol is as follows —... 

Schimmel Co. attempted to acetylise the alcohol by means of acetic anhydride, but the reaction product only showed 5 per cent, of ester, which was not submitted to further examination. The bulk of the alcohol had been converted into a hydrocarbon, with loss of water. Ninety per cent, formic acid is most suitable for splitting off water. Gne hundred grams of the sesquiterpene alcohol were heated to boiling-point with three times the quantity of formic acid, well shaken, and, after cooling, mixed with water. The layer of oil removed from the liquid was freed fi-om resinous impurities by steam-distillation, and then fractionated at atmo.spheric pressure. It was then found to consist of a mixture of dextro-rotatory and laevo-rotatory hydrocarbons. By repeated fractional distillation, partly in vacuo, partly at ordinary pressure, it was possible to separate two isomeric sesquiterpenes, which, after treatment with aqueous alkali, and distillation over metallic sodium, showed the following physical constants —... 

Cubeb camphor, CuHjgO, is a sesquiterpene alcohol which is found in oil of cuhebs, especially in old samples of the oil. It is laevo-rotatory, melts at 68° to 70°, and boils at 248° with decomposition. Nothing is known of its constitution. 

It is soluble in 3 volumes of 70 per cent, alcohol. The commercial product is usually a mixture of dextro-rotatory and laevo-rotatory bornyl acetate. It should contain not less than 98 per cent, of ester, and... 

The odour of the ester varies slightly, according as it is made from the dextro-rotatory or the laevo-rotatory variety of the alcohol. That of the former is rather fuller and deeper in its rose odour than that of the latter. Both esters blend excellently with the corresponding citronellols, and are very useful in preparing synthetic otto of rose. 

Citronellal prepared from Java citronella oil is laevo-rotatory to the extent of about - 3°. 

According to Read and Smith i piperitone is, under natural conditions, optically inactive. By fractional distillation under reduced pressure, it is prepared, by means of its sodium bisulphite compound, in a laavo-rotatory form. The slight laevo-rotation is probably due to the presence of traces of cryptal. By fractional distillation alone, it is usually obtained in a laevo-rotatory form whether this is due to decomposition products or not is unknown. Piperitone has a considerable prospective economic value, as it forms thymol by treatment with formic chloride, inactive menthone by reduction when a nickel catalyst is employed, and inactive menthol by further reduction. Its char-Mters are as follows —... 

Pinocamphone, Cj Hj O, is the principal constituent of oil of hyssop, in which it occurs in its laevo-rotatory variety. It is a saturated ketone having the constitution —... 

The laevo-rotatory form is the ordinary malic acid while the dextrorotatory form is an ethylene oxide resulting from the migration of the hydrogen of the hydroxyl on the asymmetric carbon to the carbonyl oxygen of the carboxyl group. 

Enantiomers possess identieal physieal properties namely, melting point, boiling point, refraetive index, ete. They only differ with respeet to the rotation of plane polarised light. If one of the enantiomer is dextro rotatory, the other will be laevo rotatory. 

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