Pyridine‐2( 1 H )‐thiones: Versatile precursors for one‐pot synthesis of new nicotinonitrile‐thiazole hybrids

In the current study, we report a facile procedure for the preparation of a new series of nicotinonitrile‐thiazoles, in excellent isolated yields. For this purpose, pyridine‐2(1 H )‐thiones were investigated as key building blocks for the synthesis of new nicotinonitrile‐linked 2‐hydroxybenzaldehyde derivatives. To prepare the target thiazole hybrids, a facile one‐pot procedure was developed involving amine‐mediated reaction of the prior aldehydes, thiosemicarbazide, and the appropriate of hydrazonyl chlorides. The reaction conditions of this one‐pot protocol were optimized by repeating the reaction using different solvents and amines. The optimized conditions were conducting the reaction in dioxane containing triethylamine at 100°C for 5 h. The prior protocol gave, in each case, new series of nicotinonitrile‐linked thiazole and thiazol‐4(5 H )‐one hybrids, bearing aryldiazenyl or arylhydrazineylidene units. Repeating the prior one‐pot protocol using the appropriate halogen containing reagents instead of hydrazonyl chlorides afforded the target thiazoles in excellent isolated yields. By considering their elemental analyses and spectral findings, the structures of the new hybrids were clarified.