Arylpropionyl-alpha-pyrone antibacterial agents

A compound of formula I:

• wherein:
• R1 is one of aryl and heteroaryl, and optionally is substituted with one or more groups independently selected from halo, hydroxy, carboxy, cyano, nitro, trifluoromethyl, trifluoromethoxy, (C1-C6)alkyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, heteroaryl, aryloxy, heteroaryloxy, and —NRaRb;
• R2 is one of H, halo, hydroxy, carboxy, cyano, (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, heteroaryl, aryloxy, heteroaryloxy, or —NRcRd, wherein any (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, and heteroaryl, and is optionally substituted with one or more halo, hydroxy, carboxy, cyano, nitro, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy or —NRcRd;
• R3 is one of H, halo, hydroxy, carboxy, cyano, (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, heteroaryl, aryloxy, heteroaryloxy, or —NReRf, wherein any (C1-C6)alkyl, (C2-C6)alkenyl, (C2-C6)alkynyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, and heteroaryl, and is optionally substituted with one or more halo, hydroxy, carboxy, cyano, nitro, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy or —NReRf;
• R4 is (C2-C6)alkyl or (C2-C6)alkenyl, which (C2-C6)alkyl or (C2-C6)alkenyl is optionally substituted with one or more groups independently selected from oxo, halo, hydroxy, carboxy, cyano, nitro, trifluoromethyl, trifluoromethoxy, (C1-C6)alkyl, (C1-C6)alkoxy, (C1-C6)alkoxycarbonyl, (C1-C6)alkanoyloxy, aryl, heteroaryl, aryloxy, heteroaryloxy, and —NRgRh;
• Ra and Rb are each independently H, (C1-C6)alkyl, aryl, heteroaryl, aryl(C1-C6)alkyl, or heteroaryl(C1-C6) alkyl;
• or Ra and Rb together with the nitrogen to which they are attached form a morpholino, piperazino, pyrrolidino or piperidino;
• Rc and Rd are each independently H, (C1-C6)alkyl, aryl, heteroaryl, aryl(C1-C6)alkyl, or heteroaryl(C1-C6) alkyl;
• or Rc and Rd together with the nitrogen to which they are attached form a morpholino, piperazino, pyrrolidino or piperidino;
• Re and Rf are each independently H, (C1-C6)alkyl, aryl, heteroaryl, aryl(C1-C6)alkyl, or heteroaryl(C1-C6) alkyl;
• or Re and Rf together with the nitrogen to which they are attached form a morpholino, piperazino, pyrrolidino or piperidino;
• and
• Rg and Rh are each independently H, (C1-C6)alkyl, aryl, heteroaryl, aryl(C1-C6)alkyl, or heteroaryl(C1-C6) alkyl;
• or Rg and Rh together with the nitrogen to which they are attached form a morpholino, piperazino, pyrrolidino or piperidino;
• or a salt thereof.