1,3-Dipolar cycloadditions of N-(5-nitro-2-furfuryl)isoquinolinium bromide in the synthesis of benzoindolizines

Abstract

Substituted 3-(5-nitro-2-furyl)benzo[g]indolizines III-XII were synthesized by a 1,3-dipolar cycloaddition of the ylide II formed in situ from N-(5-nitro-2-furfuryl)isoquinolinium bromide (I) and dimethyl butinedioate, diethyl butenedioate, 1-nitro-2-phenylethylene, ethyl 2-propenoate, ethyl 3-(5-nitro-2-furyl)-2-propenoate, 1,3-diphenyl-2-propenone, 1,3-diphenyl-2-propinone, 2-propenenitrile, 1-phenyl-3-(5-nitro-2-furyl)-2-propenone, and methyl 2-cyano-3-(4-nitrophenyl)-2-propenoate. Structure of these products was verified by spectral evidence.