An efficient hetero Diels-Alder approach to imidazo[4,5-c]pyridazines as purine analogues
作者:Paymaneh Y.F. Deghati、Martin J. Wanner、Gerrit-Jan Koomen
DOI:10.1016/s0040-4039(98)00806-5
日期:1998.6
Reaction of sulfonamide protected 5-vinylimidazole with 4-phenyl-1,2,4-triazoline-3,5-dione in methanol gave the Diels-Alder adduct 8 in 85% yield. Deprotection of the resulting N-phenyltriazole was efficiently accomplished by ring opening with hydrazine followed by heating in DMSO. The completely deprotected and aromatized purine analogue 1 was obtained directly from this one-pot reaction in 48% yield