Synthesis and Structures of 3-Ethyl 1,2-Dimethyl 5-Chloroindolizine-1,2,3-Tricarboxylate and 3-Ethyl 1,2-Dimethyl 5-Bromoindolizine-1,2,3-Tricarboxylate from 2-Chloro-1-(2-Ethoxy-2-Oxoethyl)Pyridin-1-Ium Bromide

Abstract

Abstract: In this title compounds 3-ethyl 1,2-dimethyl 5-chloroindolizine-1,2,3-tricarboxylate 3 and 3-ethyl 1,2-dimethyl 5-bromoindolizine-1,2,3-tricarboxylate 4, there are two molecules in the asymmetric unit. This crystal was prepared by one-pot multicomponent reaction of 2-chloro-1-(2-ethoxy-2-oxoethyl)pyridin-1-ium bromide salt 1 with dimethyl acetylenedicarboxylate 2 in the presence triethylphosphite at room temperature in high yield. The indolozine products were confirmed with IR, mass, 1H, and 13C NMR. X-ray crystallographic technique was also conducted and the result showed the crystal belong to monoclinic system, space group pbca with a = 17.6696(7), b = 7.9336(3), c = 23.2275(9)Å, v = 3093.1(2)Å3, Dc = 1.521 mg/m3, µ = 0.31 mm−1. In both compounds no typical hydrogen bonding interactions could be located. Graphical Abstract: Synthesis, and crystal structure of two 3-ethyl 1,2-dimethyl 5-chloroindolizine-1,2,3-tricarboxylate and 3-ethyl 1,2-dimethyl 5-bromoindolizine-1,2,3-tricarboxylate are reported.[Figure not available: see fulltext.]