B. Jelen, A. Štimac, B. Stanovnik
Feb 1, 1991
Citations
0
Influential Citations
9
Citations
Journal
Journal of Heterocyclic Chemistry
Abstract
6-Methoxy-2-methylpyridazin-3(2H)-one (1) gave with 2-diazopropane (8) a mixture of 3H-pyrazolo[3,4-d]-pyridazin-4(5H)-one derivative 12, as the main product, and -7(6H)-one derivative 10, as the minor product. On the other hand, 4-substituted pyridazin-3(2H)-ones 2, 3, and 4 gave 3H-pyrazolo[3,4-d]pyridazin-7(6H)-one 10, exclusively, while 5-substituted pyridazin-3(2H)-ones 5, 6, and 7 produced only the isomeric 3H-pyrazolo[3,4-H]pyridazin-4(5H)-one 12. The 5-phenylsulfonyl derivative 13 gave with 8 by elimination of a molecule of nitrogen, followed by rearrangement, 1,2-diazepine derivative 15 and with an excess of 8 3H-pyrazolo[3,4-d][1,2]diazepine derivative 16. 1,2-Dimethylpyridazine-3,6-(1H,2H)-dione and its derivatives 18 and 19 produced 3H-pyrazolo[3,4-d]pyridazine-4,7(5H,6H)-dione derivative 23, while from 17 and 1-diazoindane (24) the spiro compound 27 was obtained. The 1,2-dihydro and 3a,7a-dihydro intermediates 21 and 25 were isolated.