140 Report of Schimmel $ Co. April 1913. 



or hydrazones of the aldehydes or ketones with an absolute solution of sodium ethylate. 

 If the heating-temperature is not sufficiently high the semicarbazones afford the hydra- 

 zones as intermediary products, and at a higher temperature the latter are converted 

 into the hydrocarbons. The reaction proceeds as follows: — 



> C : N-NH-CONH 2 + H 2 = > C : N-NH 2 + C0 2 + NH 8 

 >C:N-NH 2 =>CH 2 + 2N. 



The method is applicable to aliphatic and aromatic ketones; in fact, to cyclic 

 ketones generally, as well as to ketonic acids. In the case of unsaturated aldehydes 

 and ketones the reaction has this advantage over other reduction-methods that the 

 double bonds are preserved, although the possibility of a displacement must be 

 reckoned with. 



Menthone hydrazone (b. p. 124° at 11 mm.) was obtained from the semicarbazone 

 (m. p. 184°) by heating with soda liquor to 160°. It is, however, also obtainable by 

 heating menthone for 6 hours with hydrazine hydrate to 160°. A 10 hours' heating 

 of the hydrazone with sodium ethylate solution to 170° afforded hexahydrocymene 

 (menthane). Camphor hydrazone (m. p. 55°: b. p. 119 to 120° at 13 mm.) yielded camphane, 

 m. p. 156 to 157°; b. p. 161° (757 mm.). When exposed to air camphor hydrazone 

 liquifies, giving rise to a hydrate, m. p. 44°. 



d-Fenchone ([«] D -j- 62,8°), when heated with hydrazine hydrate, was converted into 

 d-hydrazone: m. p. 56 to 57°, b. p. 230 to 231°, [«] D + 46,4° (11 p. c. alcoh. solution). 

 When heated with sodium ethylate, the hydrazone yields Z-fenchane, b. p. 149°: 

 df#0,8316, [«] D — 18,11° (1,058 grams fenchane in 20 cc. alcohol), n D20 o 1,4462. It is a 

 noteworthy fact that fenchane is laevorotatory, whereas the fenchone which has been 

 employed and its hydrazone are dextrorotatory. In other cases also, Wolff has observed 

 a reversal of the direction of rotation; e. g. in d-carvone, which is converted into a 

 mixture of Mimonene and dipentene. It is therefore possible that the fenchane may 

 not be optically uniform. 



Vanillin semicarbazone or hydrazone yields with sodium ethylate, creosol (b.p.221°). 



Citronellal hydrazone when heated with sodium ethylate gives rise to a mixture 

 of dimethyl octene and citronellol. 



Citral. Continuing his experiments in the electrolytic reduction of aldehydes and 

 ketones, H. D. Law 1 ) has ascertained that the presence of finely-divided copper acce- 

 lerates reduction. When copper foil was used as a cathode the addition of copper 

 sulphate to the cathode solution proved to be very useful, inasmuch as it causes the 

 deposition, during electrolysis, of a precipitate of finely-divided, highly-active copper 

 upon the cathodes. 50 grams of citral yielded the following quantities of substance 

 volatilisable with steam, cathodes of various descriptions being employed: — 



Sheet lead cathode (10, mm.) 7,5 g. 



Sheet Copper „ (0,7 mm.) 10 g. 



Copper Foil „ (0,06 mm.) . . 27 g. 



Sheet lead „ (0,06 mm.) + 1 g. Copper sulphate 45 g. 



The volatile reduction-product was identical with the geraniol-mixture described 

 in the author's previous communication 2 ). 



x ) Joum.chem. Soc. 101 (1912), 1544; Report October 1912, 154. — 2 ) Journ. chem. Soc. 101 (1912), 1024; 

 Comp. Report October 1912, 155. 



