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Reactions of 2 H ‐3,1‐benzoxazine‐2,4‐(1 H )dione (isatoic anhydride) with anions of 1,4‐dihydro‐5 H ‐pyrazol‐5‐ones: Synthesis of pyrazolo[5,1‐ b ]quinazolin‐9‐ones
Author(s) -
Sircar Jagadish C.,
Capiris Thomas,
Kesten Stephen J.
Publication year - 1981
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570180124
Subject(s) - chemistry , nucleophile , medicinal chemistry , organic chemistry , acetic anhydride , ion , catalysis
Reactions of 2 H ‐3,1‐benzoxazine‐2,4‐(1 H )dione (isatoic anhydride) (1) with anions of 1,4‐dihydro‐5 H ‐pyrazol‐5‐ones (2) gave pyrazolo[5,1‐6]quinazolin‐9‐ones (3) via the nucleophilic attack of the anion 2b rather than 2a. However, in the case of 5‐methoxyisatoic anhydride ( 10c) , both products 3e and 11c were obtained. A new synthetic method of preparation of 5‐(alkylthio)‐2‐aminobenzoic acids (18) was described. These acids (18) were used to synthesize a series of substituted pyrazolo[5,1‐ b ]quinazolin‐9‐ones (3) .