Identification of 1:2 molar adducts from 2-methylquinolines as cyclobuta[4,5]pyrrolo[1,2-a]quinolines by X-ray diffraction and 13C nuclear magnetic resonance studies

Abstract

One of the products from 6-bromo-2-methyl-quinoline and dimethyl acetylenedicarboxylate has been identified as tetramethyl 3-bromo-7a,8,9,9a-tetra-hydrocyclobuta[4,5]pyrrolo[1,2-a]quinoline-7,r-7a,t-9,c-9a-tetracarboxylate by an X-ray diffraction study, and its c-9 isomer has been identified by a comparison of the ¹³C n.m.r. and other spectra.