86100-07-4Relevant articles and documents
La(OTf)3 catalyzed reaction of salicylaldehyde phenylhydrazones with β-ketoesters and activated alkynes: Facile approach for the preparation of chromenopyrazolones
Hariprasad, Kurma Siva,Prasad, Kasagani Veera,Raju, Bhimapaka China
, p. 108654 - 108661 (2016/11/30)
A facile approach has been developed for the preparation of chromenopyrazolones (5a-o, 7a-k) by the reaction of salicylaldehyde phenylhydrazones (3a-o) with β-ketoesters (4a, 4f-g) and activated alkynes (6a-e) in the presence of La(OTf)3 with good yields. However, the reaction of salicylaldehyde phenylhydrazones (3a, 3c, 3j-k, 3n) with ethyl 4-chloro-3-oxobutanoate (4e) underwent cyclization with reductive dechlorination and provided the methyl chromenopyrazolones instead of chloromethyl chromenopyrazolones. The present solvent free protocol provided the novel heterocyclic compounds.
4-Oxo-1H-and-2H-[1]benzopyrano[4,3-c]pyrazoles. Preparation from 4-hydroxycoumarin or 3-chromonecarboxylic acid derivatives
Chantegrel,Nadi,Gelin
, p. 381 - 384 (2007/10/02)
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