Pyrazines. 3^e Communication. Synthèse de 5<i>H</i>‐cyclopenta[<i>b</i>]pyrazines alkylées

Abstract

Synthesis of alkyl‐5 H ‐cyclopenta[ b ]pyrazines. Alkyl‐5 H ‐cyclopenta[ b ]‐pyrazines (sometimes together with 5‐alkylidene‐5 H ‐6,7‐dihydrocyclopenta[ b ]pyrazines) are prepared by thermal degradation of 5‐acetoxy‐5 H ‐6,7‐dihydrocyclopenta[ b ]pyrazines; these are obtained by treatment of alkyl‐5 H ‐6,7‐dihydrocyclopenta[ b ]pyrazine N ‐oxides with acetic anhydride. Cyclopenta[ b ]pyrazines which are potentially present in roasted food flavors possess interesting organoleptic properties.