Tetrahedron

[1] Benzopyrano [4, 3-c] pyrazoles by intramolecular nitrile imine addition to acetylenes

D Janietz, WD Rudorf

文献索引：Janietz, Dietmar; Rudorf, Wolf-Dieter Tetrahedron, 1989 , vol. 45, # 6 p. 1661 - 1666

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被引用次数: 8

摘要

2-Alkynyloxy-benzaldehydes 1 are obtained by alkylation of the corresponding salicylaldehydes either with p-toluenesulfonic acid propargylester or 1-acetoxy-4-chloro-but- 2-yne. The aldehydes 1 are converted into the hydrazones 2 by reaction with p- toluenesulfonylhydrazide. Dehydrogenation of 2 with lead tetraacetate yields 2, 4-dihydro [1] benzopyrano [4, 3-c] pyrazoles 3. In one case the acylated by-product 4 has been formed.