— 99 — 



In his 66 th Treatise on terpenes and essential oils O. Wallach 1 ) 

 reports on the addition-products of nitrous acid and of nitrosyl chloride 

 to unsaturated compounds. After a historical introduction, the author 

 discusses the formula of those yellow compounds formed by the 

 action of alcoholic potash or of acetyl chloride on the nitrites of the 

 compounds containing the group RCH = CHR. Here he explains 

 the grounds which induced him to abandon his earlier formula 



R — CH — CR 



^O 



NO 



and to accept the formula drawn up by Angeli and lately by Wieland 



R — CH =- CR 



I 

 N0 2 



from which, for the nitrites and the nitroso chlorides, the formulae 



R— CH — CHR 



NO NO, 



and 



R — CH — CHR 



NO CI 



can be deduced. 



These addition products differ in their behaviour from those of the 



tri-alkyl type R 2 C = CHR. The latter show the same behaviour 



towards all reagents, whilst the nitrites of the type RCH = CHR for 



example with sodium methylate yield the unsaturated nitro-compound 



RCH = C(N0 2 )R, but the nitroso chlorides on the other hand yield 



substituted oximes : 



RC CHR 



II I 



NOH OCH 3 



As compounds of the last-named type, anethol, isosafrol, and 

 methyl isoeugenol were mentioned, for comparison with the previously 

 examined phellandrene. 



If anethol nitrite (melting point 1 2 1 °) is introduced into acetyl 

 chloride, or treated with sodium methylate, /?-nitro anethol is obtained 

 in the form of a yellow oil which, after distillation in vacuo, is obtained as 

 needles melting at 47 . Its constitution is C 6 H 4 (OCH 3 )CH : C(N0 2 )CH 3 . 

 If hydroxylamine is allowed to act on this compound, anise aldoxime is 

 split off; by heating with potash in alcoholic solution anisic aldehyde 

 is formed. The diketone which, according to Toennies' formula 



C 6 H 4 (OCH 3 )C — COCH3 

 II 

 NOH 



*) Liebig's Annalen 332 (1904), 305. 



