c-Thioacylation by the Willgerodt–Kindler reaction. Structure of the anomalous products from salicylaldehydes. X-Ray crystal structure of the betaine from 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine, sulphur, and 3,5-dichlorosalicylaldehyde
Abstract
1,2-Dimethyl-1,4,5,6-tetrahydropyrimidine (1), on reaction with salicylaldehydes (3) in the presence of sulphur, does not lead to the expected C-thioacylated products (4); instead, the products obtained are the betaines (5). The structure of (5b) from 3,5-dichlorosalicylaldehyde has been established by X-ray diffraction analysis.