Abstract: A pharmaceutical compound of the formula in which R1 is C1-10 alkyl, C2-10 alkenyl, C2-10 alkynyl, C3-10 cycloalkyl, C3-10 cycloalkyl-C1-10 alkyl, C3-10 cycloalkyl-C2-10 alkenyl, C3-10 cycloalky-C2-10 alkynyl, optionally substituted phenyl-C1-10 alkyl, optionally substituted phenyl-C2-10 alkenyl, optionally substituted phenyl-C2-10 alkynyl, optionally substituted naphthyl, optionally substituted naphthyl-C1-10 alkyl, C1-10 alkoxy-C1-10 alkyl, C3-10 cycloalkoxy-C1-10 alkyl, optionally substituted heterocyclyl, optionally substituted heterocyclyl-C1-10 alkyl, optionally substituted phenyl fused to C5-10 cycloalkyl, optionally substituted tricyclic, optionally substituted tricyclic-C1-10 alkyl, or [optionally substituted phenyl(CH2)n]2-C1-10 alkyl, where n is 0 or 1 to 4, and R2 is hydrogen or one of the values for R1; or a salt or ester thereof.