Condensed Pyridazines. VIII. Reaction of Diazolopyridazines with Ynamine. Formation of Ben-zodiazoles and Diazolodiazocines

Abstract

Reaction of the 7-(methylsulfonyl)-1H-imidazo[4, 5-d]pyridazine (3) with 1-(N, N-diethylamino)-1-propyne (2) resulted in the formationo f the benzimidazole (5) and the 3H-imidazo[4, 5-d][1, 2]diazocine (4) through the [4+2]- and [2+2]-cycloadducts. Similarly, reaction of the 7-(methylsulfonyl)-(9) and the 7-cyano-1H-pyrazolo[3, 4-d]pyridazines (10) with 2 gave the corresponding indazoles (14, 16) and the 1H-pyrazolo[3, 4-d][1, 2]diazocines (15, 17). A similar reaction was also found to proceed between 7-(methylsulfonyl)-1H-1, 2, 3-triazolo[4, 5-d]pyridazine (18) and 2, affording the corresponding benzotriazole (20) and the 3H-1, 2, 3-triazolo[4, 5-d][1, 2]diazocine (19).