86100-07-4Relevant academic research and scientific papers
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.
