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

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