Synthesis of Nitro-Substituted 4-Oxo-4H-pyrimido[2,1-b]benzothiazole-3-carboxylic Acids and Their Spectral Characteristics

Abstract

The Gould-Jacobs reaction of all position isomeric 2-aminonitrobenzothiazoles II with diethyl ethoxy- methylenemalonate has been studied. The structure of substitution (IV) and cyclization (VI) products and of the corresponding acids (VIII) was confirmed by elemental analysis, IR, UV, 1H and 13C NMR spectra. Analogous derivatives III, V and VII, derived from the unsubstituted 2-aminobenzothiazole I, were used as standards in interpretation of the spectra. The synthesized derivatives I - VIII were tested for antimicrobial activity.