Thoms

Many quinones, such as anthraquinone, do not react with phenylhydrazine or only with one molecular proportion, as in the case of naphthoquinone and phenan-thraquinone, whilst some, such as benzoquinone and toluquinone, oxidize it to benzene. Ortho-disubsti-tuted ketones frccjiiently do not react with phenylhydrazine, and certain unsaturated ketoalcohols, such as ethylic acetoacetate and ethylic camphoroxalate, yield monophenylhydrazides, the ketonic group being unaffected. Ilydroxyketones and aldehydes of the aliphatic scries yield phenylosazones, a portion of the phenylhydrazine being simultaneously reduced to aniline and ammonia.  

Osazones arc often most readily purified by solution 

Aliphatic aldehydes react quite rapidly with phenyl-hydrazine hydrochloride. Aliphatic ketones behave in the same manner towards the acetate, but react slowly, or not at all,with the hydrochloride. On this fact a method for their separation has been based. (Cf. p. 84),  

The chief substitution product of phenylhydrazine which has hitherto been employed for the preparation of phenylhydrazones js the parabromo-dcrivative. 

Parabromophenylhydrazine is well adapted for the identification of certain sugars, such as arabinose, and has also been used in the investigation of ionone and 

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The first complete formula (I) suggested for lupanine was that of Thoms and Bergerhoff, based mainly on the formation of 2-ethylpyridine when lupanine was distilled with zinc dust, which seemed to indicate a similarity between tropane and lupanine. 

Processes for the isolation and purification of yohimbine have been described by Thoms, Feldhoff, Chemnitius, Schwyzer, Raymond-Hamet and others. Some of these processes have been modified to provide for estimation of the yield of yohimbine, usually as the hydrochloride, from the bark, or to facilitate the identification of this alkaloid in commercial yohimbe bark, which is apt to vary both in quality and in botanical origin.According to Witkop (1943) modern technical yohimbine hydrochloride may contain a little isoyohimbine but no allo-yohimbine. 

Thoms olituined a vielJ of 7 per cent, of oil from the seeds, which had a specific gravdlv of 08136 and optical rotation - 5S-.5. The oil, from tvhich traces of free acids and pheooH were first removed, was fractionated in yaciio. 

In 1899 Thoms isolated an alcohol from Peru balsam oil, which he termed peruviol. This body was stated to have powerful antiseptic properties, but has not been further investigated until Schimmel Co. took up the subject. The oil after saponification was fractionated, and after benzyl alcohol had distilled over, a light oil with characteristic balsamic odour passed over. It boiled at 125° to 127° at 4 mm., and had a specific gravity 0 8987, optical rotation -1- 12° 22, and refractive index 1-48982. This body appeared to be identical with Hesse s nerolidol, whilst in physical and chemical properties it closely resembles peruviol. The characters of the various preparations were as follows —... 

It appeared that the impure alcohol isolated from balsam of Peru was, in fact, identical with nerolidol. When allowed to stand for three to four weeks with phenyl-isocyanate both alcohols yielded a phenyl-urethane, melting at 37" to 38°. A mixture of the two bodies suffered no depression in melting-point. The alcohols have the formula 15 260-The alcohol from balsam of Peru is therefore mixed with a small quantity -of an alcohol of higher specific gravity, the nature of which is still undetermined. Traces of benzyl alcohol were found in it, but not in sufficient quantity to account for the differences observed. Oxidation experiments did not throw any light on the question. It may therefore be safely assumed that the peruviol of Thoms consisted in the main of nerolidol, but contaminated with a substance of the same boiling-point to such an extent that its combustion figures pointed to the formula CjjH. jO instead of... 

For the determination of eugenol Thoms has elaborated the following method, the results of which are fairly accurate —... 

A denotes problems linked to Key ideas of this chaprer and testable in Thom son NOW. 

Thom son NOW Click Organic Interactive to manipulate three-dimensional models and assign R,S designations. 

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