Patent ID: 7176310

Claim:
A compound of formula (Ia): wherein, independently at each occurrence: R 1 is selected from aralkyl and aryl; R 2 is —N(R 5 )R 6 ; R 3 is selected from —O—R 7 and —S(O) t —R 7 where t is 0 to 2; R 4 is selected from hydrogen, halo, and alkyl; R 5 is hydrogen; R 6 is hydrogen; and R 7 is selected from aryl, aralkyl, heteroalkyl, heterocyclyl and heterocyclylalkyl; provided, however, that R 1 can not be phenyl substituted at the 2-position by carboxy or alkoxycarbonyl when R 2 and R 4 are both hydrogen and R 3 is —O—R 7 where R 7 is pyridinyl or 4-methoxyphenyl, or when R 2 and R 4 are both hydrogen and R 3 is —S—R 7 where R 7 is pyridinyl; and, provided that R 7 cannot be 4-t-butylphenyl, 4-fluorophenyl, or methylacetyl when R 3 is —O—R 7 ; as a single stereoisomer, a mixture of individual stereoisomers, or a racemic mixture; or pharmaceutically acceptable salts or solvates thereof.