Synthesis of New 2-Azetidinone Derivatives and Related Schiff Bases from 3-Phenyl-2,3,6,7-tetrahydroimidazo [2,1-b] Thiazolo [5,4-d] Isoxazole

Abstract

2-Azetidinones, commonly known as β-lactams, are well-known heterocyclic compounds. Herein we described the synthesis of a series of novel β-lactams. The efficient and rapid synthesis of novel β-lactams has been established in good yields starting from (R)-3-phenyl-2, 3, 6, 7-tetrahydroimidazo [2', 1':2, 3] thiazolo [5, 4-d] isoxazole 1. First, (R)-3-phenyl-2, 3, 6, 7-tetrahydroimidazo [2', 1':2, 3] thiazolo [5, 4-d] isoxazole 1 on condensation with ethylchloro acetate yielded Ethyl (R) 2-(3-phenyl- 6, 7-dihydroimidazo [2', 1':2,3] thiazolo [5, 4-d] isoxazole-2(3H)-yl) acetate 2, which on amination with hydrazine hydrate yielded (R) 2-(3-phenyl- 6, 7-dihydroimidazo [2', 1':2, 3] thiazolo [5, 4-d] isoxazol -2(3H)-yl) acetohydrazide 3. Then, condensation between compound 3 and various aromatic aldehydes give Schiff base derivatives 4a-j, which upon dehydrative annulation in the presence of chloroacetyl chloride and triethylamine yielded N-((3S, 4S)-3-chloro-2-oxo-4-phenylazetidin-1-yl)-2-((R)-3-(Aryl)-6, 7-dihydroimidazo [2', 1':2, 3] thiazolo [5, 4-d] isoxazol -2(3H)-yl) acetamide 5a-j. All synthesized compounds were characterized by elemental analyses, IR, 1H-NMR and 13C-NMR data.