Fenchyl alcohols

Komppa and Eoschier now propose a revision of the nomenclature of the fenchene terpenes, Wallach s D-fenchene being termed a-fenchene, D-Z-fenchene becoming Z-o-fenchene, and D-d-fenchene becoming d-a-fenchene. The fenchene obtained by Bertram and Helle s method, by dehydrating fenchyl alcohol with potassium bisulphate, is now termed y8-fenchene. This nomenclature is certainly preferable as it contains no suggestion that the two bodies are identical in chemical constitution, nor is there any particular evidence that D-Z-fenchene and L-Z-fenchene are not the same actual terpene, and equally so in the case of D-d-fenchene and L-d-fenchene. 

Accepting the later nomenclature, y8-fenchene can be prepared almost free from the a- variety by heating fenchyl alcohol with KHSO4. After repeated fractionation over sodium, /8-fenchene has the following characters —... 

The chemistry of fenchyl alcohol, Cj HjgO, must be regarded as in a somewhat unsettled state, as questions of isomerism arise which are as yet unsolved. It was ori nally prepared by Wallach by reducing the ketone fenchone, a natural constituent of several essential oils, by means of sodium. Later he obtained it in fairly large quantities as a byproduct in the preparation of fenchone-carboxylic acid, by passing a current of C(X through an ethereal solution of fenchone in the presence of sodium. Fenchyl alcohol has, so far, been found in one essential oil only, namely, that of the root wood of Pinus palustris. 

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

The naturally occurring fenchyl alcohol is optically inactive and melts at 33° to 35°, which agrees with the observations of Wallach, a mixture of the two optically active forms, each of which melted at 45°, melting at 33° to 35°. 

Pickard, Lewcock and Yates have prepared fenchyl alcohol by the reduction of laevo-rotatory. On 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. 

Fenchyl alcohol yields a phenylurethane melting at 88° when prepared from the optically inactive alcohol, and at 82-5° when prepared from the optically active form. It yields fenchone on oxidation, which can be identified by its crystalline combinations (vide fenchone). 

Fenchyl alcohol has, according to Semmler, the following constitution —... 

When the terpene a-fenchene (isopinene) is hydrated by means of acetic and sulphuric acids, it yields an isomer of fenchyl alcohol, which is known as isofenchyl alcohol (q.v.), and which on oxidation yields iso-fenchone, as fenchyl alcohol yields fenchone. The two ketones, fenchone and isofenchone, are sharply differentiated by isofenchone yielding iso-fenchocamphoric acid, Cj Hj O, on oxidation with potassium permanganate, which is not the case with fenchone. According to Aschan,i the hydrocarbon found in turpentine oil, and known as /9-pinolene (or cyclo-fenchene—as he now proposes to name it), when hydrated in the usual manner, yields both fenchyl and isofenchyl alcohols, which on oxidation yield the ketones fenchone and isofenchone. According to Aschan the relationships of these bodies are expressed by the following formulae —... 

By reduction fenchone is converted into fenchyl alcohol, melting at 45°. The alcohol, however, has the opposite optical rotation to that of the ketone from which it is prepared. 

Eugenol, ml08 Eugenol methyl ether, a84 Fenchone, t376 Fenchyl alcohol, t375 A -9/7-(2-Fluorenyl)acetainide, al3... 

During studies of its application as a catalyst in the enantioselective addition of diaUcylzinc compounds to aldehydes and its stereochemical mning, a series of methylzinc derivatives of ex(7-(2-aryl-substituted) fenchyl alcohols (Figure 76) have been prepared and structurally characterized in the solid state. ... 

The oleoresinous exudate or "pitch of many conifers, but mainly pines, is the raw material for the major products of the naval stores industry. The oleoresin is produced in the epithelial cells which surround the resin canals. When the tree is wounded the resin canals are cut. The pressure of the epithelial cells forces die oleoresin to the surface of die wound where it is collected. The oleoresin is separated into two fractions by steam distillation. The volatile fraction is called gum turpentine and contains chiefly a mixture of monoterpenes but a smaller amount of sesquiterpenes is present also. The nonvolatile gum rosin 5 consists mainly of llie dilerpenuid resin acids and smaller amounts of esters, alcohols and steroids. Wood turpentine, wood rosin and a fraction of intermediate volatility, pine oil are obtained together by gasoline extrachon of the chipped wood of old pine stumps. Pine oil is largely a mixture of the monoterpenoids terpineol. borneol and fenchyl alcohol. Sulfate turpentine and its nonvolatile counterpart, tall oil, 5 are isolated as by-products of the kraft pulping process. Tall oil consists of nearly equal amounts of saponified fatty acid esters and resin acids. 

Eugenol, m99 Fenchone, t351 Fenchyl alcohol, t350... 

Approximately 45 constituents have been determined from fennel seed oil (Fig. 12.1), the main constituents being transanethole (60-65%, but up to 90%), fen-chone (2-20%), estragol (methyl chavicol), limonene, camphene, a-pinene and other monoterpenes, fenchyl alcohol and anisalde-hyde. The major compounds in supercritical... 

In summary, Foeniculum is stated to have three species, F. vulgare (fennel), F. azoricum Mill. (Florence fennel) and F. dulce (sweet fennel). Fennel is widely cultivated, both in its native habitat and elsewhere, for its edible, strongly flavoured leaves and seeds. The flavour is similar to, but milder than, that of anise and star anise. Anethole and fenchone are the major constituents of the solvent extract of seed phenols, free fatty acids, carbohydrates, proteins, vitamins and minerals have been reported in varying proportions. In the mature fruit, up to 95% of the essential oil is located in the fruit, greater amounts being found in the fully ripe fruit. Approximately 45 constituents have been determined from fennel seed oil, the main constituents being frans-anethole, fenchone, estragol (methyl chavicol), limonene, camphene, a-pinene and other monoterpenes, fenchyl alcohol and... 

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