Synthesis of Some Pyrazole, Thiazole, Pyridine, and 1,3,4-Thiadiazole Derivatives Incorporating 2-Thiazolyl Moiety

Nitrileimines as an alternative to azides in base-mediated click [3 + 2] cycloaddition with methylene active nitriles

Nitrileimines were implemented in practical click protocols with oxopropanenitriles for the straightforward 5-amino-1H-pyrazole synthesis via 1,3-dipolar cycloaddition. The reaction proceeds at room temperature in a short time with base catalysis and no chromatographic purification. High purity products were isolated by simple filtration. The selectivity of the reaction was observed.

l-Proline catalyzed one-pot synthesis of polysubstituted pyridine system incorporating benzothiazole moietyviasustainable sonochemical approach

The efficient, highly convenient synthesis of polysubstituted pyridine derivatives was established via the reaction of N-(benzothiazol-2-yl)-2-cyanoacetamides with an assortment of arylidene malononitriles and arylidene ethyl cyanoacetates in the presence of l-proline as an efficient organocatalyst for this type of ultrasonic-mediated Michael addition. The mechanistic pathway and factors affecting this reaction were also established. The main characteristics of this procedure are high yields, use of a cost-effective catalyst, and easy work-up and purification.

The l-proline catalyzed ultrasonic-mediated synthesis of polysubstituted pyridone derivatives through the reaction of N-(benzothiazol-2-yl)-2-cyanoacetamides with an assortment of arylidenes has demonstrated as an efficient protocol.