Synthesis of some new Pyrazoline Carbothioamides and Pyrimidinethiols Derivatives from Bis-α, β-Unsaturated Carbonyl Compounds

Abstract

In our research, new bis-α, β-unsaturated carbonyl compounds (Z2-Z4) were prepared via Claisen- Schmidt reaction, by the condensation of 2,6-dimethyl-3,5-diacetyl-1,4-dihydropyridine (Z1) with different appropriate benzaldehyde, like (benzaldehyde, m-nitro benzaldehyde and o-chloro benzaldehyde) using 10% aqueous sodium hydroxide as a base. A simple and efficient method has been applied for the synthesis 2,6-dimethyl-3,5-diacetyl-1,4-dihydropyridine (Z1) by multi components Rudolf-Hantzsch condensation reaction which included heating the starting materials (paraformaldehyde, acetylacetone and ammonium acetate) at 80 degrees centigrade in aqueous medium. Bis-α, β-unsaturated carbonyl compounds (Z2-Z4) can be considered as useful intermediates leading to the formation of several heterocyclic compounds such as pyrazoline carbothioamide (Z5-Z7) and pyrimidinethiole (Z8-Z10). The titled compounds (Z5-Z7) and (Z8-Z10) were prepared by interacting with thiosemicarbazide in neutral medium, and thiourea in basic medium respectively. These mentioned compounds (Z1-Z10) were characterized by Ferrier Translate-Infrared spectrum (FT-IR) and Ultraviolet spectrum (UV), in addition to some physical properties. Also, all these reactions followed by thin layer chromatography (TLC) technique and calculate the retardation factor (R f ) values.