A highly convenient method for the synthesis of 2-substituted pyrrole derivatives 7a-c from pyrrole using phosgene was developed. Successively, 7-methyl-6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1a and 6,7-dihydro-1H,5H-pyrrolo[2,3-c]azepine-4,8-dione 1b (aldisin) were synthesized by phosphorus pentoxide/methanesulfonate and polyphosphoricacid cyclization.
Ring Construction of Several Heterocycles with Phosphorus Pentoxide-Methanesulfonic Acid (PPMA)
作者:Hidetsura Cho、Shinsuke Matsuki
DOI:10.3987/com-95-7238
日期:——
The cyclization reactions with CH3SO3H/P2O5 (PPMA) or CF3SO3H/P2O5 (PPTMA) at 80-100 degrees C for 3-10 min afforded several heterocycles (6,7-dihydropyrrolo[2,3-(c) under bar]azepin-4,8(1 (H) under bar, 5 (H) under bar)-dione, 4-oxo-4,5,6,7-tetrahydrothianaphthene, carbostyril derivatives).