Formation of 2,5-Dihydro-3H-pyrazolo[4,3-c]quinolin-3-ones from Ethyl 3-Amilino-2-(2-tert-butyl-2H-tetrazol-5-yl)acrylates
摘要:
Thermal cyclization of ethyl 2-(2-tert-butyl-2H-tetrazol-5-yl)-3-(4-chloroanilino)acrylate (5) did not afford the intended 4-quinolinone derivative (6), but yielded 2,5-dihydro-3H-pyrazolo[4,3-c]-quinolin-3-one (7). The reaction mechanism is thought to have been double cyclization of the nitrile imine intermediate (C).