Synthesis and antibacterial activity of new carbapenems containing isoxazole moiety

The synthesis and biological activity of a series of new 1β-methylcarbapenems Scheme 5 and containing 5′-isoxazolopyrrolidin-3′-ylthio derivatives as C-2 side chain are described. Most compounds exhibited potent and well-balanced antibacterial activity as well as high stability to DHP-I comparable to that of meropenem. Scheme 5 and showed the best combination of antibacterial activity and stability to DHP-I, respectively. Scheme 5. Reagents and reaction conditions: (i) DIPEA, CH3CN, rt, 1 h; (ii) Zn, phosphate buffer (pH 6.0), THF, rt, Diaion HP-20; (iii) iodomethane, acetone, rt; (iv) iodoacetamide, acetone, rt.