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

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.