(2008/06/13)
1,3-Dihydroxy-4-oxo-2-p-tolylamino-cyclopent-2-enecarboxylic acid methyl ester
1,3-Dihydroxy-2-(4-nitro-phenylamino)-4-oxo-cyclopent-2-enecarboxylic acid methyl ester
2-(4-Bromo-phenylamino)-1,3-dihydroxy-4-oxo-cyclopent-2-enecarboxylic acid methyl ester
1,3-Dihydroxy-4-oxo-2-phenylamino-cyclopent-2-enecarboxylic acid methyl ester
1,3-Dihydroxy-2-(4-methoxy-phenylamino)-4-oxo-cyclopent-2-enecarboxylic acid methyl ester