Patent ID: 8003808

Claim:
3-Hydrazino-2,5-dioxopyrrolidine-3-carboxylates of the formula (I): wherein R 1 is a C 1-6 alkyl group; a C 3-8 cycloalkyl group; a benzyl group in which the benzene ring moiety may be optionally substituted by one or two atoms or groups independently selected from the group consisting of a halogen atom, a C 1-4 alkyl group, a C 1-4 alkoxy group and a cyano group; or an aryl group or a heteroaryl group optionally substituted by one or two groups independently selected from the group consisting of a C 1-4 alkyl group and a C 1-4 alkoxy group; R 2 is a hydrogen atom or a COOR 3 group; wherein when R 1 is a C 1-6 alkyl group other than a tert-C 4-6 alkyl group; a C 3-8 cycloalkyl group; or an aryl group or a heteroaryl group optionally substituted by one or two groups independently selected from the group consisting of a C 1-4 alkyl group and a C 1-4 alkoxy group, then R 3 is a tert-C 4-6 alkyl group; a 2,2,2-trichloroethyl group; or a benzyl group in which the benzene ring moiety may be optionally substituted by one or two atoms or groups independently selected from the group consisting of a halogen atom, a C 1-4 alkyl group, a C 1-4 alkoxy group, a cyano group and a nitro group; when R 1 is a tert-C 4-6 alkyl group, then R 3 is a 2,2,2-trichloroethyl group; or a benzyl group in which the benzene ring moiety may be optionally substituted by one or two atoms or groups independently selected from the group consisting of a halogen atom, a C 1-4 alkyl group, a C 1-4 alkoxy group, a cyano group and a nitro group; when R 1 is a benzyl group in which the benzene ring moiety may be optionally substituted by one or two atoms or groups independently selected from the group consisting of a halogen atom, a C 1-4 alkyl group, a C 1-4 alkoxy group and a cyano group, then R 3 is a tert-C 4-6 alkyl group or a 2,2,2-trichloroethyl group, or a salt thereof.