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Tricarbonylmethane acylhydrazones: Reactions under acylating conditions and formation of fused isoxazole derivatives with concomitant NN bond cleavage
Author(s) -
Somogyi László,
Sohár Pál
Publication year - 1995
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.1995199510268
Subject(s) - chemistry , isoxazole , coumarin , bond cleavage , derivative (finance) , pyran , azole , acylation , hydrazone , medicinal chemistry , organic chemistry , stereochemistry , antifungal , medicine , dermatology , financial economics , economics , catalysis
Reactivity of 3‐(1‐acylhydrazonoethyl)‐2 H ‐pyran‐2‐ones 1a–k and 4a–d towards various acetylating agents and nitrous acid, respectively, is studied. Treatment of dehydroacetic acid (DHA) (thio)acylhydrazones 1a, c, f with Ac 2 O/Et 3 N afforded the 3‐(1‐triacetylhydrazinoethenyl) derivative 3a. The analogous coumarin derivative 5 was obtained by treatment of acetylhydrazone 4a with AcCl/PhNMe 2 . With concomitant N–N bond cleavage acylhydrazones 1c–f were converted to the pyrano‐isoxazole 6 by treatment with NaNO 2 /AcOH whereas coumarin derivative 4d was converted to the imine 4e .