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Review | Regular issue | Vol 4, No. 12, 1976, pp.1921-1932
Published online, 1st January, 1970
DOI: 10.3987/R-1976-12-1921
"Push-pull-acetylenes" as Versatile Intermediates in Heterocyclic Synthesis

Hans-Joachim Gais and Klaus Hafner*

*Institut für Organische Chemie, Technische Hochschule Darmstadt, Petersenstrasse. 22 64287 Darmstadt, Germany

Abstract

Phosgene and oxalyl chloride add to “push-pull-acetylenes” (1) to give excellent yields of highly reactive adducts of type (3) and (4). A variety of specifically substituted heterocyclic compounds, like pyrazolo-oxazinones (6), pyrazoles (7), oxazinones (9), (10), (12) and (13) or furanones, e.g., (21) and (22) (Table 1), can be synthesized taking advantage of the bifunctionality of these adducts. From the acetylenes (1) and phenylhydrazine the isomeric pyrazoles (25) and (26) as well as pyrazolones (27) and (28) (Table 1) are obtained due to their ambident electrophilic reactivity.