(Cyanovinyl) ketenes from azafulvenones. An apparent retro-Wolff rearrangement

GGH Qiao, W Meutermans, MW Wong…

Index: Qiao; Meutermans; Wong; Traubel; Wentrup Journal of the American Chemical Society, 1996 , vol. 118, # 16 p. 3852 - 3861

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Citation Number: 30

Abstract

Flash vacuum pyrolyses or pulsed pyrolysis of azole esters 1b and 20 and their carboxylic acids 1a and 19 or acid chloride 1c give five-membered ring ketenes (azafulvenones) 2 and 24 which dimerize to diketopiperazines 3 and 21 but also undergo efficient rearrangement to (cyanovinyl)-and (o-cyanophenyl) ketene (6 and 27). The same products are obtained by elimination of alcohol from esters of these (cyanovinyl) ketenes. Both types of ketenes are ...