Patent ID: 7141603

Claim:
A compound of formula I: wherein R 1 is CH 2 -(sulfur-linked-cysteine)-R x or CH 2 -(sulfur-linked-N-acylcysteine)-R x wherein R x is an amino acid or a peptide comprising 2 to 24 amino acids; R 2 is carboxy, (C 1 –C 6 )alkanoyl, (C 1 –C 6 )alkoxycarbonyl, halo(C 1 –C 6 )alkyl, —C(═O)NR d R e , a saccharide, an amino acid, a peptide, or (C 1 –C 6 )alkyl substituted by 1 or 2 hydroxy, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkanoyloxy, carboxy, amino acids, peptides, saccharides, or —C(═O)NR d R e ; R 3 is hydrogen, (C 1 –C 6 )alkyl, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkylthio, aryl, heteroaryl, aryloxy, or heteroaryloxy; R 4 is hydrogen or (C 1 –C 6 )alkyl; and R 5 is hydroxy, (C 1 –C 6 )alkoxy, or (C 1 –C 6 )alkanoyloxy; or R 4 and R 5 taken together are ethylenedioxy; R 6 is hydrogen, carboxy, (C 1 –C 6 )alkanoyl, (C 1 –C 6 )alkoxycarbonyl, halo(C 1 –C 6 )alkyl, —C(═O)NR f R g , a saccharide, an amino acid, a peptide, or (C 1 –C 6 )alkyl optionally substituted by 1 or 2 hydroxy, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkanoyloxy, carboxy, amino acids, peptides, saccharides, or —C(═O)NR f R g ; R d , R e , R f and R g are each independently hydrogen, (C 1 –C 6 )alkyl, (C 1 –C 6 )alkanoyl, phenyl or benzyl; or R d and R e , or R f and R g , together with the nitrogen to which they are attached, are pyrrolidino, piperidino, or morpholino; wherein any aryl, heteroaryl, aryloxy, or heteroaryloxy of R 3 may optionally be substituted by 1, 2, or 3 (C 1 –C 6 )alkyl, (C 1 –C 6 )alkoxy, (C 1 –C 6 )alkanoyl, (C 1 –C 6 )alkanoyloxy, (C 1 –C 6 )alkoxycarbonyl, hydroxy(C 1 –C 6 )alkyl, halo(C 1 –C 6 )alkyl, hydroxy, halo, carboxy, mercapto, nitro, or —N(R h )(R j ); wherein each R h and R j is independently hydrogen, (C 1 –C 6 )alkyl, (C 1 –C 6 )alkanoyl, phenyl or benzyl; or R h and R j together with the nitrogen to which they are attached are pyrrolidino, piperidino, or morpholino; or a pharmaceutically acceptable salt thereof.