Cyclobutenedione derivative and process for preparing the same

Abstract

A novel cyclobutenedione derivative is provided, represented by formula (I): ##STR1## wherein Ar represents ##STR2## wherein R.sub.1 represents a CH.sub.3 group or a C.sub.2 H.sub.5 group; R.sub.2 represents a C.sub.2 H.sub.5 group, a C.sub.3 H.sub.7 group, a HOC.sub.2 H.sub.4 group, a CH.sub.3 OC.sub.2 H.sub.4 group or a CH.sub.3 group; R.sub.3 represents an alkyl group; Z represents O or S; and R.sub.4 and R.sub.5 each represents an alkyl group, and R.sub.0 represents ##STR3## wherein C* represents an asymmetric carbon atom. A process for preparing a cyclobutenedione derivative represented by formula (I) which comprises reacting a cyclobutenedione derivative represented by formula (II) with an amino acid derivative represented by formula (III): ##STR4## wherein Ar represents ##STR5## wherein R.sub.1 represents a CH.sub.3 group or a C.sub.2 H.sub.5 group, R.sub.2 represents a C.sub.2 H.sub.5 group, a C.sub.3 H.sub.7 group, a HOC.sub.2 H.sub.4 group, a CH.sub.3 OC.sub.2 H.sub.4 group or a CH.sub.3 group; R.sub.3 represents an alkyl group; and R.sub.4 and R.sub.5 each represents an alkyl group, and X represents a chlorine atom, a bromine atom, a methoxy group or an ethoxy group: NH.sub.2 R.sub.0 (III) wherein R.sub.0 represents ##STR6## wherein C* represents an asymmetric carbon atom. In a preferred embodiment, the reaction is effected in the presence of a basic compound.

Dependencies are inferred from the claim text.