Synthesis of Polysubstituted Pyridopyrimidines, Pyrimidines, and Pyrazoles Based on 1,1-Bis(1H-benzotriazol-1-yl)-and 1,1-Bis(3,5-dimethyl-1H-pyrazol-1-yl)-3,4,4-trichloro-2-nitrobuta-1,3-dienes

The reaction of 3,4,4-trichloro-1,1-bis(3,5-dimethyl-1H-pyrazol-1-yl)-2-nitrobuta-1,3-diene with 2-aminopyridine gave a polysubstituted pyrido[1,2-a]pyrimidine derivative with an aminopyridine residue in the 2-position, whereas heterocyclization of 3,4,4-trichloro-1,1-bis(1H-benzotriazol-1-yl)-2-nitrobuta-1,3-diene with substituted 2-aminopyridines afforded 2-(1H-berrzotriazol-1-yl)pyrido[1,2-a]pyrimidines. 2-(Morpholin-4-yl), 2-amino, and 2-(2-hydroxyethylamino) derivatives of polysubstituted pyrido[1,2-a]pyrimidines were synthesized, and those containing a 2-hydroxyethylamino group were converted to the corresponding 4,5-dichloro-1,2-thiazole-1-carboxylates. Specific features of heterocyclizations of benzotriazolyl and dimethylpyrazolyl derivatives of trichloronitro-1,3-butadiene to pyrimidine and pyrazole systems were revealed.