Patent ID: 6900244

Claim:
A compound of Formula I: wherein: b is 0-3; R 1 is hydrogen, acyl, or optionally substituted alkyl, heterocyclo, or aralkyl; R 2 and R 3 are independently hydrogen or optionally substituted alkyl, aryl, heteroaryl, aminoalkyl, hydroxyalkyl, or thioalkyl; one of R 2 and R 3 , or R 2 and R 3 together with the atom to which they are attached may form a carbocyclic or heterocyclic ring; R 4 is hydrogen or together with R 1 and the atoms to which they are attached form a heterocyclic ring; Z is —CO 2 Z 1 , —CH 2 NZ 1 Z 2 , —C(O)Z 1 , —CH(OH)Z 1 , —CH 2 OZ 1 , —CH 2 OC(O)Z 1 , or —C(O)NZ 1 Z 2 , and Z 1 and Z 2 are independently hydrogen or optionally substituted alkyl, heterocyclo, or aralkyl; provided, however, when R 1 is hydrogen and one of R 2 and R 3 is hydrogen, the other of R 2 and R 3 is not hydrogen or methyl.