Pyridinethiones. XI. Diastereoselective aldol condensations with 2(1H)‐pyridones, 2(1H)‐pyridinethiones, and the crystal structure of 3‐(1‐hydroxy‐2‐methyl‐3‐oxo‐3‐(4‐chlorophenyl)propyl‐1‐isoprpyl‐2(1H)‐pyridinethione

Abstract

Aldol condensation of 3‐formyl‐2(1H)‐pyridinethiones and the corresponding pyridones with ketones such as acetophenones in aqueous base yields 3‐hydroxy‐1‐propanones in high yields. Reaction with propiophenone showed this reaction to be highly diastereoselective as only the erythro‐isomer is formed at room temperature. This assignment was based on an X‐ray crystallographic investigation of the compound given in the title. Aldol condensations of a number of related 3‐acetyl‐2(1H)‐pyridinethiones with benzaldehyde yielded the corresponding trans‐vinyl ketones.