— 182 — 



Isocitral is left as a residue when reduced enolised citral is treated with 

 phthalic anhydride (for the purpose of isolating ^sogeraniol), and, when 

 regenerated from the bisulphite-compound, forms a liquid with the fol- 

 lowing constants: b. p. 103 to 108° (15 mm.), d 20 o 0,8976, n D 1,4810. It yields 

 a-«socitryl-/?-naphthocinchoninic acid, m. p. 206° (from glacial acetic acid). 



Benzaldehyde. For the purpose of preparing the labile benzaldehyde- 

 phenylhydrazone discovered byThiele and Pickard 1 ), F. B. Thole 2 ) saturates 

 a suspension of this hydrazone in concentrated hydrochloric acid with 

 hydrogen chloride gas. The resulting red suspension is poured into excess 

 of soda-solution, when the labile benzaldehydephenylhydrazone is precipi- 

 tated in the form of a yellowish-white deposit. Recrystallised from glacial 

 acetic acid, it melts at 136°, and when repeatedly recrystallised from this 

 solvent it is gradually transformed into the stable modification, m. p. 152°. 



Fatty-aromatic Aldehydes. ). v. Braun and O. Kruber 3 ) state that 

 in the fatty-aromatic aldehydes, as in the fatty-aromatic alcohols, the 

 odour gradually diminishes in intensity as the polymethylene chain leng- 

 thens 4 ). The authors prepared synthetically a series of fatty-aromatic 

 aldehydes and found that with the majority the methods which have been 

 worked out for preparing these bodies were failures, or yielded poor results. 

 They obtained satisfactory yields, however, by reducing primary nitro- 

 compounds into aldoximes by Konowaloffs method 5 ), and recovering the 

 aldehydes from the latter by saponification. Thus, for example, for the 

 purpose of preparing the hydrocinnamic aldehyde, /-iodopropylbenzene and 

 silver nitrite were allowed to react, the result being /-phenyl-propylnitrite 

 and a satisfactory yield of phenylnitropropane. The sodium compound of 

 phenylnitropropane in aqueous solution having been reduced with sub- 

 chloride of tin and hydrochloric acid, the reaction-mixture was neutral- 

 ised with soda and the resulting hydrocinnamic aldoxime extracted with 

 ether. The best method of isolating the aldehyde is to heat at once with 

 dilute sulphuric acid the residue which remains behind when the ether 

 has been distilled off, after which the aldehyde may be distilled off with 

 steam. Hydrocinnamic aldehyde yields a characteristic diphenylmethane 

 dimethyldihydrazone, m. p. 99 to 100°. Working by the same method 

 the authors obtained the following aldehydes: d-phenylbutyric aldehyde 

 (b. p. 129 to 131° at 7 mm.; odour fainter than that of hydrocinnamicj., 

 aldehyde), ^-phenyl-n-valeraldehyde (b. p. 129 to 131° at 10 mm.; odour 



1 ) Berl. Berichte 31 (1898), 1250. 



2 ) Proceed, chem. Soc. 27 (1911), 278. 



3 ) Berl. Berichte 45 (1912), 384. 



4 ) Comp. p. 181. 



5 ) Chem. Zentralbl. 1899, I. 597, 1074. 



