SUBSTITUTED 3-AMINOTHIENO[2,3-B]PYRIDINE-2-CARBOXAMIDE AS A SYNTHON FOR POLYHETEROCYCLIC COMPOUNDS - PREPARATION OF NEW PYRIDOTHIENO-1,2,3-TRIAZINES AND RELATED DERIVATIVES

Pyrido[3',2':4,5]thieno[3,2-d]-1,2,3-triazines (2) and (3) were synthe sized from 3-aminothieno[2,3-b]pyridine (1) by diazotization and subse quent treatment with electrophilic reagents. Reaction of triazinone (2 ) with phosphorus oxychloride lead to a mixture of the triheterocyclic compound (4) and the 4-chlorosubstituted triazine (5). Aminolysis of 4 with either hydrazine or primary and secondary amines yielded the de rivatives (7a-h). Nitrosation of 7a afforded the 4-substituted triazin one (8). Finally, substituted 1,3,4-oxadiazole (9) was prepared from a cylhydrazine (7a) and triethyl orthoformate.