Notes on scientific research. 147 



when using an amalgamated tin or lead cathode, the cathode solution consisting of 

 a mixture of 75 per cent, sulphuric acid (40 to 45 cc.) with 94 per cent, alcohol (35 to 

 40 cc.) at a temperature below 15°. The current used is 6 to 8 amperes per 100 sq. cm. 

 at 11 to 13 volts. The yield of menthol is only 25 per cent., and the product was 

 difficult to purify. An oily by-product is always obtained, which is a more highly 

 reduced body, possibly menthane. 



By reducing thujamenthone with hydrogen and nickel at 280°, M. Godchot 1 ) obtained 

 dimethyl-l,2-isopropyl-3-q/c/opentane, a liquid of terpene-like odour with the constants: 

 b. p. 148 to 149°, diso 0,793, n D150 1.4364. The same body had been prepared years ago 

 by Godchot and F. Taboury 2 ) from dihydrocamphorone. On treating thujamenthone with 

 magnesium methyl iodide, Godchot obtained a mixture of two isomeric trimethyl-1,2,3-iso- 

 propyl-4-q/dopentenes which on further reduction with hydrogen and nickel at 180° yielded 

 the same body, trimethyl-l,2,3-isopropyl-4-q/c/opentane (b. p. 157 to 158°; d 130 0.7833; 

 n D13 o 1.4326), likewise with a terpene-like odour. 



Additionally, the author prepared a new bicyclic ketone, dimethyl-2,3-isopropyl-4- 

 ci/c/opentylidene-dimethyl-2,3-isopropyl-4-c^/c/opentanone-l, by condensing thujamenthone 

 by means of calcium hydride 3 ). This new product was a light yellow liquid with a cam- 

 phoraceous odour and the constants: b.p. 182 to 184° (12 mm.); di 5 o 0.9123; n D15 o 1.4825. 



Camphor. — By acting with sodium isoamylate on camphor at 140°, in presence of 

 an excess of isoamyl alcohol, F. Martin 4 ) obtained in a good yield, a mixture of alkyl 

 derivatives of camphor and borneol ("camphor). He tnen treated the reaction product, 

 dissolved in benzene, with potassium permanganate and obtained isoamylcamphor 

 (b. p. 273°; « D180 59.22 05 ) [in alcoholic solution]; semicarbazone, m. p. 188°). By reducing 

 the reaction-product of camphor and sodium isoamylate with sodium and absolute alcohol 

 the author arrived at a white greasy body smelling of borneol; b.p. 190° (61 mm.); 

 dj| 0.9611; « D 16.55 ° 5 ) (in alcoholic solution), which consisted of a mixture of stereo- 

 meric bodies. On heating, for three hours, at 140° with the equal part of acetic an- 

 hydride and some sodium acetate, the body yielded acetylisoamylcamphol (b.p. 169 to 

 170° [30 mm.]; d^ 0.9402; « D + 7.42° [in alcoholic solution]; phenylurethane of iso- 

 amylcamphol, m. p. 111°). 



H. Rupe and W. Diehl 6 ) prepared the following derivatives of hydroxy methylene 

 camphor: — methylene camphor-phenylhydroxylamine (m. p. 106 to 107°), the methyl 

 ether of this body (m. p. 75 to 76, very sensitive to light; on exposure to sunlight the 

 compounds deliquesces to a brown mass and separates a sublimate of delicate yellow 

 needles, m. p. 196 to 198°, probably camphor quinone, the ethyl ether of methylene 

 camphor-phenylhydroxylamine (m. p. 162 to 164°), the_p-nitrobenzoate of the same body 

 (m. p. 179.5 to 180°). On reducing methylene camphor-phenylhydroxylamine, anilido- 

 methylene camphor resulted (m. p. 165 to 167°), which was identical with the anilide 

 obtained by Bishop, Claisen, and Sinclair 7 ) by condensing hydroxymethylene camphor 

 with aniline. 



By heating camphor and fural with sodamide in benzene solution, Wolff 8 ) arrived 

 at fural camphor, m. p. 64°, easily soluble in ether, alcohol, and benzene, less soluble 



!) Compt. rend. 172 (1921), 686. — *) Bull. soc. chim. IV. 13 (1913), 601. — 3 ) Cf. Compt. rend. 169 (1919), 

 62. — *) JfAirn. de Pharm. et Chim. VII. 21 (1921), 417. As per Bull. Roure-Bertrand Fils, April 1921, 104. 

 — 5 ) The direction of rotation is not given. — 6 ) Helvet. chim. acta 4 (1921), 388. — 7 ) Liebig's Annalen 

 281 (1894), 358. — 8 ) Cwnpt. rend. 172 (1921), 1357. 



10* 



