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Synthesis 2010(17): 2943-2948  
DOI: 10.1055/s-0030-1258155
PAPER
© Georg Thieme Verlag Stuttgart ˙ New York

A Convenient Synthesis of 1,4-Benzothiazepines from 1,3-Benzothiazines via the Ring Transformation of β-Lactam-Condensed 1,3-Benzothiazine Derivatives

Lajos Fodor*a,b, Péter Csomósa,b, Antal Csámpaic, Pál Sohár*c,d
a Central Laboratory, County Hospital, POB 46, 5701 Gyula, Hungary
b Institute of Pharmaceutical Chemistry, University of Szeged, and Research Group of Stereochemistry of the Hungarian Academy of Sciences, Eötvös u. 6., 6720 Szeged, Hungary
Fax: +36(66)526539; e-Mail: fodor@pandy.hu;
c Institute of Chemistry, Eötvös Loránd University, POB 32, 1518 Budapest, Hungary
Fax: +36(1)3722592; e-Mail: sohar@chem.elte.hu;
d Protein Modelling Research Group, Hungarian Academy of Sciences and Eötvös Loránd University, POB 32, 1518 Budapest, Hungary
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Publication History

Received 30 March 2010
Publication Date:
07 July 2010 (online)

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Abstract

A convenient synthesis was devised for rare 2,3-disubstituted 4,5-dihydro-1,4-benzothiazepines from 2-aryl-4H-1,3-benzothiazines. The Staudinger reaction of 1,3-benzothiazines obtained with chloroacetyl chloride selectively furnished trans-monochloro-β-lactam-condensed thiazines. The ring expansion of azeto[2,1-b][1,3]benzothiazin-1-one derivatives with sodium methoxide afforded 1,4-benzothiazepines as the sole product in good yields. The structures of the new molecules were proved by means NMR and IR spectroscopy.

Key words

1,4-benzothiazepine - 1,3-benzothiazine - β-lactams - ring expansion - S,N-heterocycles