Synthesis of 2-acetyl-1-pyrroline, the principal rice flavor component

• Published in: Journal of agricultural and food chemistry Vol. 41; no. 9; pp. 1458 - 1461
• Main Authors: De Kimpe, Norbert G, Stevens, Christian V, Keppens, Marian A
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-09-1993
• Subjects: Aroma and flavouring agent industries; ARROZ; Biological and medical sciences; COMPOSE DE LA FLAVEUR; COMPOSE HETEROCYCLIQUE; COMPOSE ORGANOAZOTE; COMPUESTO ORGANICO DEL NITROGENO; COMPUESTOS DEL SABOR; COMPUESTOS HETEROCICLICOS; Food industries; Fundamental and applied biological sciences. Psychology; RIZ; Volatile compound; Synthesis; Flavoring agent; Nitrogen heterocycle; Aroma; Popcorn; Rice
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf00033a020

A new straightforward synthesis of 2-acetyl-l-pyrroline, the principal rice flavor component with a cracker-like flavor, is reported. The reaction sequence involves the conversion of pyrrolidine into tripyrroline, subsequent hydrocyanation of the latter into 2-cyanopyrrolidine, oxidation into 2-cyano-1-pyrroline, 1-and Grignard addition of methylmagnesium iodide, affording an overall yield of 16-19% from pyrrolidine. In similar way, 2-propionyl-1-pyrroline, a recently discovered flavor component of popcorn, was prepared in addition to several higher analogues,i.e.,2-acyl-1-pyrrolines. Also, the synthesis of 2-(acetyl-d3)-1-pyrroline, a deuterated derivative of the rice flavor compound which is useful for the stable isotope dilution assay, is described