Synthesis and biological activity of sulfur containing derivatives of chalcone. II. The reaction of chalcone oxides with thiols

Abstract

The reaction of chalcone oxide (I) with arylthiol in the presence of triethylamine, or with alkylthiol in the presence of sodium ethoxide, progressed easily to afford aryl or alkyl phenacyl sulfide and benzaldehyde. Similarly 4'-substituted (OCH3, CH3, Cl, NO2) chalcone oxides (II, III, IV, V) reacted with thiophenol in the presence of triethylamine to give the corresponding phenyl 4-substituted phenacyl sulfide and benzaldehyde. 4-Substituted (OCH3, CH3, Cl, NO2) chalcone oxide (VI, VII, VIII, IX) reacted with thiophenol under the same condition to afford phenyl phenacyl sulfide and the corresponding aromatic aldehyde, while, in the case of VIII or IX, additional to give 1-aryl-1-hydroxy 2-phenylthio-3-phenyl-3-propanone (X or XII) as an adduct. The adduct (X or XII) underwent gradual breakdown to phenyl phenacyl sulfide and aromatic aldehyde (p-Cl, p-NO2) in the presence of thiophenol and triethylamine. This fact indicates that an intermediate like X or XII is first formed by the addition of thiols to chalcone oxides and then the intermediate breaks down to the above two components.