Novel β-lactam condensed 3-thiaquinolines: an efficient synthesis and structural characterization

Quinoline analog 2-aryl-4H-3,1-benzothiazine derivatives 8-13, obtained by the condensation of o-aminobenzyl chloride 1 with substituted thiobenzamides 2-7, were transformed to azeto[2,1-a][3,1]benzothiazin-1-one derivatives 18-23a,b,c and 24d,e by reaction with the corresponding substituted acetyl chlorides 14-17 in the presence of triethylamine. The structures of the new molecules were determined by NMR spectroscopy and electron ionization (EI) mass spectrometry. The typical EI+ mass spectrometric fragmentations of 8-13 and 18-23a,b,c and 24d,e are discussed in detail.

Graphical abstractA series of novel monochloro-, dichloro-, and phenyl-substituted (R3 or/and R4) β-lactams condensed with 3,1-benzothiazines were obtained by Staudinger reaction and studied by NMR spectroscopy and mass spectrometry. Download full-size image