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Novel heterocycles. 4 . Synthesis of the pyrido[2,3‐ c ]‐1,2‐thiazine ring system
Author(s) -
Coppola Gary M.,
Hardtmann Goetz E.
Publication year - 1979
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.5570160714
Subject(s) - chemistry , thiazine , tautomer , sodium hydride , ring (chemistry) , hydrolysis , stereochemistry , lactam , alkylation , medicinal chemistry , organic chemistry , catalysis
The reaction of 2‐chloronicotinonitrile with N ‐methylmethanesulfonamide and subsequent treatment with base furnished the novel pyrido[2,3‐ c ]‐1,2‐thiazine ring system 7 . Spectrally, it was determined that the predominant tautomer in solution was the 4‐amino form 7a . Acidic hydrolysis of 7 furnished the 4‐oxo tautomer 8b , compound 8b was alkylated on oxygen with 1‐bromopentane in the presence of sodium hydride. Reaction of 8b with isocyanates occurs at the 3 position to produce carboxanilides 10 . Spectral characteristics of these compounds are also discussed.