Polymer-supported acylhydrazones. Use in Sc(OTf)3-catalyzed Mannich-type reactions providing an efficient method for the preparation of diverse pyrazolone derivatives
作者:Shū Kobayashi、Takayuki Furuta、Kasumi Sugita、Osamu Okitsu、Hidekazu Oyamada
DOI:10.1016/s0040-4039(98)02607-0
日期:1999.2
Polymer-supported acylhydrazones, prepared from polystyrene resin (1%-divinylbenzene), reacted with ketene silyl acetals in the presence of a catalytic amount of scandium triflate (Sc(OTf)(3)), to afford the corresponding beta-hydrazinoesters, which were cyclized and cleaved from the support simultaneously by treatment with a base to produce diverse pyrazolone derivatives. (C) 1999 Elsevier Science Ltd. All rights reserved.