Facile synthesis of novel benzothiazolylpyrazolyl anchored 3-thio/seleno/chloro-beta-lactams: Synthetic intermediates for novel 3-sulfenyl/sulfonyl, C-3 functionalized monocyclic and spirocyclic beta-lactams

摘要

Efficient synthesis of a new series of 3-phenyl/benzylthio-4-benzothiazolylpyrazolyl-beta-lactams is described. Treatment of 2-phenylthio/benzylthioacetic acid with benzothiazolylpyrazolyl substituted Schiff's bases furnished trans-beta-lactams exclusively. Newly synthesized substituted Schiff's bases and beta-lactams were identified using FT-IR, H-1 NMR, C-13 NMR and elemental analysis (CHN). The trans configuration was assigned with respect to coupling constant values of C3-H and C4-H. The novel b-lactams will be the potential synthetic intermediates to access 3-sulfenyl/sulfonyl, C-3 functionalized monocyclic and spirocyclic beta-lactams of medicinal interest. The present manuscript provides first report on b-lactams linked to bulky group benzothiazolylpyrazolyl.