1-Fenchone

Fenchone is a liquid ketone closely resembling camphor. 

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Pine Oil. This oil is obtained by extraction and fractionation or by steam distillation of the wood of Pinuspalustris Mill, and other species. Most of the oil is produced ia the southeastern United States. The composition of the oil depends on the fractions chosen, but the chief constituents are terpene alcohols, mainly terpiaeol. Piae oil finds use as a germicide ia disiafectants and soaps as an ingredient ia iasecticides, deodorants, poHshes, sweepiag compounds, and catde sprays and as raw material for the manufacture of perfumery-grade terpiaeol [8000-41 -7], anethole [104-46-1], fenchone (137), and camphor (35). 

Me3SiOCH2CH20SiMe3, Me3SiOTf, 15 kbar (1.5 GPa), 40°, 48 h. These conditions were used to prepare the ketal of fenchone, which cannot be done under normal acid-catalyzed conditions. 

The oil Contaio- d-carophor, d-fenchone, and probably feuchyl-alcohol. 

The corresponding hydrocarbons obtained from Z-fenchone were termed by Wallach L-(Z-fenchene and L-Z-fenchene, the capital letter being used to indicate the rotation of the parent fenchone, and the small letter that of the terpene. 

By using d-fenchone a D-Z-fenchene was prepared, having an optical rotation — 32°, and yielding a dibromide melting at 87° to 88°. -... 

Bertram and Helle some years ago prepared a fenchene, which they termed isofenchene, by splitting off water from isofenchyl alcohol. L-d-fenchene prepared from Z-fenchone in a similar manner was found to have an optical rotation - 29°. 

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. 

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). 

Fenchone, Cj Hj O, is found in fennel oil and in the oil of Lavandula Stoechas, in its deirtro-rotatory form, and as laevo-fenchone in oil of thuja leaves. It can be extracted from these oils by treating the fraction boiling at 190° to 195° with nitric acid, or permar anate of potassium, and then steam distilling the unaltered fenchone. 

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 —... 

The most characteristic derivative for the identification of fenchone is its oxime. Five grams of fenchone are dissolved in 80 c.c. of absolute alcohol and a solution of 11 grams of hydroxylamine hydrochloride in 11 C.C. of boiling water containing 6 grams of caustic potash, is added. After a time the oxime separates in the form of fine crystals which on recrystallisation from alcohol melt at 164° to 165° (active form) or 158° to 160° (inactive form). 

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. 

Besides thujone, citroneUal, camphor, menthone, and fenchone did not react with the sodium sulphite at all. 

Mention has already been made of the fact that thujone and fenchone do not react with sodium sulphite consequently the method is useless for tansy, thuja, wormseed, and fennel oils. 

Identify the common atoms in fenchone (25) and suggest possible disconnections. 

The list of molecules whose PECD has been experimentally studied is quickly expanding, and in the VUV valence shell region now includes the prototypical chiral species camphor [36, 64, 65], bromocamphor [65, 80], fenchone and carvone [38], methyl oxirane [62, 63], glycidol [37, 38], and 3-hydroxytetrahy-drofuran [61]. Studies of camphor [56], fenchone [38], and carvone [55] have all been extended to cover the SXR C li core region. 

Figure 14. The C li core region XPS of fenchone recorded with a photon energy hv = 308.5eV. Included in the figure are bars indicating calculated AExxCPWSh — PW9I) + Qa core-binding energies. Data taken from Ref. [38]. The inset shows the structure of the (1S,4/ )-enantiomer.

The well-resolved C=0 li peak in the fenchone XPS provides an excellent opportunity to examine PECO from a single, well-characterized initial orbital. As has been previously mentioned, it might be thought that such a localized, spherically symmetric initial orbital would not be sensitive to the molecular enantiomer s handedness, but as can be seen in Fig. 15 (a) the dichroism in the electron yield recorded at the magic angle is sufficiently large to be easily visible by eye as a difference in the intensity of the Icp and rep spectra. 

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