— 185 — 



d~ 0,9355, n D20 o 1,46660, mol. refr. 36,788. As stated above it is probably 

 identical with l-«'soprop; 

 calculated was 36,488. 



A 



w identical with l-«'sopropylene-2-ketopentamethylene, for which the mol. refr. 



Santenone. According to Rimini 1 ), the action of nitrous acid upon 

 santenone oxime gives rise to a body possessing all the properties of a 

 pernitroso-derivative; with hydroxylamine and with semicarbazide nitrous 

 oxide is given off, with formation of santenone oxime or semicarbazone. 

 If the body is treated with cold concentrated sulphuric acid, nitrous oxide 

 is also given off, and an unsaturated compound results which yields a 

 semicarbazone, m. p. 180°. The saturated santenone, when subjected to 

 the same treatment, remains unchanged, and also yields a semicarbazone 

 with m. p. 224°; hence the reaction first described had given rise to an 

 isomeride, to which Rimini has given the name of isosantenone. The oxi- 

 dation- and reduction-products of the new body which have been obtained 

 up to the present hardly bear out the accuracy of Semmler's 2 ) santenone- 

 formula. 



It is expected that Rimini will shortly publish a more detailed paper 

 showing how the process of conversion into an unsaturated body takes 

 place; possibly, as in the case of camphor, there is a rupture of the bridge- 

 formation and an "erection" of the bridge itself. 



Menthone. In view of the circumstance that the reduction of 

 menthone in alcoholic solution gives a poor yield, V. Skworzow 3 ) has 

 reduced this ketone by Sabatier and Senderens* method, but also without 

 obtaining favourable results. Ultimately, however, the following method 

 was found to be effective: the ketone [consisting, in the case under review, 

 of Z-menthone ([«] D — 14°) from buchu oil] is dissolved in a brass auto- 

 clave in ten times its volume of methyl or ethyl alcohol and treated with 

 more than double the calculated quantity of sodium, in the course of 

 which manipulation the liquid acquires a temperature of between 70 and 

 80°. The closed autoclave is shaken until the contents have cooled down 

 completely and the reaction-product is then distilled off with steam. The 

 result is a quantitative yield of a mixture of solid ([«] D + 37,87 °) and 

 liquid (a D -(-16°) menthol. By the same method the reduction of pulegone 

 (b. p. 222 to 223°; d^ 0,938; « D + 24°) gives an almost quantitative yield 

 of a mixture of solid and liquid Z-menthol (b. p. 200 to 218°; « D — 12°). 

 * When applied to the reduction of dipentene, pinene, camphene, terpineol, 

 and thymol, the method failed to yield positive results. 



On the reduction of menthone, see also p. 183. 



x ) Rendiconti della Soc. chim. ital., Ser. 2, Vol. 4, Part 1, p. 2 (12 January 1912). 



-) Comp. Report October 1910, 120. 



3 ) Journ. f. prakt. Chem. II. 84 (1911), 422. 



