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Ring nitrogen functionalization of 2‐aminothiazol‐4‐acetic acid derivatives. I. Synthesis and properties of novel 2‐aminothiazole N ‐oxides
Author(s) -
Perrone Ettore,
Alpegiani Marco,
Giudici Franco,
Bedeschi Angelo,
Pellizzato Renato,
Nannini Giuliano
Publication year - 1984
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.5570210435
Subject(s) - chemistry , hydroxylamine hydrochloride , synthon , acetic acid , tautomer , thiazole , hydroxylamine , organic chemistry
Cyclization of thiocyanomethylketone oximes with hydroxylamine hydrochloride and oxidation of 2‐aminothiazole derivatives with peracids are shown to afford the same products, which can be formulated either as 2‐imino‐3‐hydroxy‐2,3‐dihydrothiazolines or 2‐aminothiazole N ‐oxides. Compounds of this type bearing at position 4 an acetic or α‐oxyiminoacetic residue are useful synthons for highly active β‐lactam antibiotics; the problems connected with their preparation in a suitably protected form are examined. Scope and limitations of this previously unreported oxidation of the thiazole nucleus are discussed. All the products show limited stability in alkaline media: the 4‐acetic derivatives, in addition, undergo a transposition to afford 4‐methylidenethiazolidines. Possible types of isomerism and tautomerism are discussed in the light of the acquired spectral data. The uv and ir spectra of the compounds synthesized lend support to their formulation as 2‐aminothiazole N ‐oxides.