Abstract: The present invention is a process for preparing (3R)-2?-(4-bromo-2-fluorobenzyl)spiro-[pyrrolidine-3,4?(1?H)-pyrrolo[1,2-a]pyrazine]-1?,2,3?,5(2H?)-tetraone, comprising, for example, the following steps: (1) reacting a compound of the formula (III) wherein R is a C1-6 alkyl group, with 2,5-dimethoxytetrahydrofuran to provide a compound of the formula (IV) wherein R is a C1-6 alkyl group; (2) reacting the compound of the formula (IV) wherein R is a C1-6 alkyl group, with trichloroacetyl chloride to provide a compound of the formula wherein R is a C1-6 group; and (3) reacting the compound provided in step (2) with 4-bromo-2-fluorobenzylamine to provide (3R)-2?-(4-bromo-2-fluorobenzyl)spiro-[pyrrolidine-3,4?(1?H)-pyrrolo[1,2-a]pyrazine]-1?,2,3?,5(2H?)-tetraone.

Abstract: The present invention provides a compound of the formula (III): wherein R is a C1-6 alkyl group, as a novel optically active intermediate for preparing tetrahydropyrrolo[1,2-a]pyrazin-4-spiro-3?-pyrrolidine derivatives such as Ranirestat being a promising therapeutic agent for diabetic complications in a short process, in an economically advantageous manner and in high yields, and the process for preparing the same.

Abstract: The present invention provides a compound of the formula (III): wherein R is a C1-6 alkyl group, as a novel optically active intermediate for preparing tetrahydropyrrolo[1,2-a]pyrazin-4-spiro-3?-pyrrolidine derivatives such as Ranirestat being a promising therapeutic agent for diabetic complications in a short process, in an economically advantageous manner and in high yields, and the process for preparing the same.

Abstract: The present invention provides a compound of the formula (III): wherein R is a C1-6 alkyl group, as a novel optically active intermediate for preparing tetrahydropyrrolo[1,2-a]pyrazin-4-spiro-3?-pyrrolidine derivatives such as Ranirestat being a promising therapeutic agent for diabetic complications in a short process, in an economically advantageous manner and in high yields, and the process for preparing the same.

Abstract: The present invention provides 2-furancarboxylic acid hydrazide compounds represented by General Formula (I) below, and prodrugs, physiologically acceptable salts, hydrates, solvates thereof: wherein A is a group represented by Formula (a) or the like: (wherein either R4 or R5 represents cyano, nitro or the like, and the other represents a hydrogen atom or the like); either R1 or R2 represents a group: -D-(X)m-R6 or the like, and the other represents a group: -E-(Y)n-R7, hydrogen atom, aryl or the like; R3 is a hydrogen atom or the like; D and E independently represent aryl; X and Y independently represent O or the like; R6 and R7 independently represent alkyl, aryl, arylalkyl or the like; and m and n are independently 0 or 1, provided that the aryl is optionally substituted.

Abstract: The present invention provides 2-furancarboxylic acid hydrazide compounds represented by General Formula (I) below, and prodrugs, physiologically acceptable salts, hydrates, solvates thereof, methods for producing them and pharmaceutical compositions containing them: wherein A is a group represented by Formula (a) or the like: (wherein either R4 or R5 represents cyano, nitro or the like, and the other represents a hydrogen atom or the like); either R1 or R2 represents a group: -D-(X)m-R6 or the like, and the other represents a group: -E-(Y)n-R7, hydrogen atom, aryl or the like; R3 is a hydrogen atom or the like; D and E independently represent aryl; X and Y independently represent O or the like; R6 and R7 independently represent alkyl, aryl, arylalkyl or the like; and m and n are independently 0 or 1, provided that the aryl is optionally substituted.

Abstract: Tetrahydropyrrolo[1,2-a]pyrazine-4-spiro-3'-pyrrolidine derivatives of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are independently hydrogen, halogen, trifluoromethyl, alkyl having 1 to 6 carbon atoms, alkoxy having 1 to 6 carbon atoms, or nitro, and R.sup.3 is hydrogen, halogen or alkyl having 1 to 6 carbon atoms, and pharmaceutically acceptable salts thereof, processes for preparation thereof, and pharmaceutical composition containing the same. Said compounds and their salts show excellent aldose reductase inhibitory activity and are useful for the prevention and treatment of diabetic complications.