3-Thujone

These cbemials iJerilioed the follo virio l >dies in he oil a-pineno, oineol, thujone, eainpbor, and inactive terpene , n obab y consisting of a mixture qf dipentene and terp.iDenc. 

It is therefore probable that the alcohol is formed in the first instance, which is afterwards esterified to thujyl esters and oxidised to thujone. 

According to its discoverer, this body is the true. terpene of the thujone series, and he prefers to call Semmler s thujene or tanacetene, isothujene, as being the true terpene of the isothujone series. 

By the dry distillation of trimethyl - thujylammonium hydroxide, Tschugaeff obtained a thujene quite similar to the above, but of considerably higher optical rotation. He therefore considers that two stereoisomers may result from different methods of preparation from thujone. 

Thujyl alcohol, Cj Hj OH, occurs in the oils of wormwood and thuja leaves, etc., and also results from the reduction of its ketone, thujone, by means of sodium. It is identical with the body originally described by Semmler under the name tanacetyl alcohol. 

Paolini has separated from the reduction products of thujone the acid phthalate of / -thujyl alcohol, HOOC. C H. COO. Cj(,Hjj, melting at 120°, and having a specific rotation -t- 91 27°. This body yields a silver salt which melts at 85° to 86°, and a strychnine salt melting at 177° to 178°. On saponifying the phthalate y8-thujyl alcohol results, which has the following characters —... 

It can be identified by oxidation with chromic acid, when its ketone, thujone, results. This can then be characterised by its oxime, melting at 54 ... 

Semmler, however, has carried out a very exhaustive examination of the ketone, and considers that its constitution is that of a bicyclic ketone of the thujone series, as follows —... 

This ketone, of the formula Cj H O, isomeric with those above described, is found in the oils of thuja, tansy, wormwood, and sage. It is identical with the bodies formerly described under the names tan-acetone and salvone. It is best prepared in a state of purity from oil of wormwood. According to Semmler, 200 c.c. of the oil, 0 c.c. of a saturated solution of sodium bisulphite, 75 c.c. of water, and 300 c.c. of alcohol are well shaken at intervals during a fortnight. The crystals formed, consisting of the compound of thujone with the sodium bisulphite, are separated, washed with alcohol-ether, and pressed. On treatment with caustic soda solution, the thujone, amounting to over 40 per cent, of the oil used, separates, and can be distilled with steam. 

The hitherto unanswered question whether the chemically identical thujonas isolated from various essential oils are also physically identical, or whether they are physically isomeric, has now been decided by Wallach in the last-named sense. He has succeeded in establishing the presence of two and possibly of three thujones, although with regard to the third the more probable view is, that it represents a mixture of the other two. His examination has, moreover, proved that thuja oil contains essentially... 

Boiling-point. Specific Gravity. Refractive Index. Thujone. 200° to 201° -912 1-4503... 

Tiemann gives the boiling-point of thujone (tanacetone) as 230° and of carvotanacetone as 230°. 

Thujone is best identified by its tribromo-compound, CjflHjgBrgO, melting at 121° to 122°. It is obtained by adding 5 c.c. of bromine (at once) to a solution of 5 grams of thujone in 30 c.c. of petroleum ether. The tribromo-compound separates on evaporation of the solvent and is washed with alcohol and recrystallised from boiling acetic ether. 

These constitutions have recently received support from the work of A. Haller. If they are correct, then thujone should be capable of yielding trialkyl substitution products, whilst isothujone should not be able to go beyond the dialkyl stage. By alkylation with the assistance of sodium amide, triallylthujone could be prepared, but no higher substitution product than dimethylisothujone could be prepared from isothujone. In the course of his work, Haller prepared the following alkyl derivatives of the two ketones —... 

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. 

Eine Epimerisierung wird bei der Reduktion von (+)-Thujon-(3), (-)-Isothujon-(3) und Mcnthon mit Na-triumboranat in abs. Alkoholen oder Bis-[2-methoxy-athyl]-ather, nicht jedoch in wasserhaltiger Losung beob-achtet1. 

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