Simple efficient synthesis of pyranoquinoline alkaloids: flindersine, khaplofoline, haplamine and their analogues

D Thangavel, S Ravindran…

Index: Thangavel, Dhanabal; Ravindran, Sangeetha; Moonsamy, Gengan Robert; Palathurai, Mohan Subramaniam Journal of Chemical Research, 2007 , # 2 p. 124 - 126

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Citation Number: 5

Abstract

An efficient two step synthesis of pyranoquinoline alkaloids is described. Direct treatment of isoprene with 4-hydroxyquinolin-2 (1H)-one in the presence of polyphosphoric acid furnished dihydroflindersine in good yield, and which on dehydrogenation led to a new synthesis of flindersine. Khaplofoline, a linear pyranoquinoline alkaloid, was obtained as a minor product. The syntheses of derivatives are also documented.