Abstract: The invention provides alkali metal salt of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluoromethyl)phenyl]methyl]benzamide and its hydrate. A method has been found, wherein, upon preparing KRP-297, the alkali metal salt of KRP-297 and its hydrate are formed in the reaction system and, after separation and purification, they are freed again from salt, thereby KRP-297 can be advantageously purified industrially for preparation.

Abstract: A homogeneous crystal having excellent stability which is suitable for the industrial-scale production of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluoromethyl)phenyl]methyl]benzamide (KRP-297). The novel crystal of KRP-297 is produced through recrystallization from an alcohol solvent. It is characterized by having diffraction angles (2&thgr;) at at least 9.7°, 15.0°, and 22.5° in X-ray powder diffractometry.

Abstract: A homogeneous crystal having excellent stability which is suitable for the industrial-scale production of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluoromethyl)phenyl]methyl]benzamide (KRP-297). The novel crystal of KRP-297 is produced through recrystallization from an alcohol solvent. It is characterized by having diffraction angles (2&thgr;) at at least 9.7°, 15.0°, and 22.5° in X-ray powder diffractometry.

Abstract: The invention provides alkali metal salt of 5-[(2,4-dioxothiazolidin-5-yl)methyl]-2-methoxy-N-[[4-(trifluoromethyl)phenyl]methyl]benzamide and its hydrate. A method has been found, wherein, upon preparing KRP-297, the alkali metal salt of KRP-297 and its hydrate are formed in the reaction system and, after separation and purification, they are freed again from salt, thereby KRP-297 can be advantageously purified industrially for preparation.

Abstract: The present invention provides novel thiazolidine-2,4-dione derivatives possessing blood sugar-lowering action and aldose reductase-inhibitory action, their salts, their preparative processes and drugs containing them, and relates to thiazolidine-2,4-dione derivatives represented by a general formula (1) ##STR1## [wherein R.sup.1 and R.sup.2 denote identically or differently hydrogen atoms or lower alkyl groups, R.sup.3 denotes a phenyl group, naphthyl group, benzoyl group or 5-membered or 6-membered heteroring and its benzene-condensed ring, which may have one or more substituents, A denotes a carbonyl group, sulfonyl group or bonding hand, and B denotes a lower alkylene, lower alkenylene or bonding hand], or their salts, or thiazolidine-2,4-dione derivatives represented by a general formula (2) ##STR2## [wherein R.sup.4 denotes a hydrogen atom or lower alkyl group, and R.sup.1 and R.sup.3 are same as above ], or their salts.

Abstract: The present invention provides novel thiazolidine-2,4-dione derivatives possessing blood sugar-lowering action and aldose reductase-inhibitory action, their salts, their preparation processes and drugs containing them, and relates to thiazolidine-2,4-dione derivatives represented by a general formula (1) ##STR1## [wherein R.sup.1 and R.sup.2 denote identically or differently hydrogen atoms, halogens, lower alkyl groups, hydroxyl groups, lower alkoxy groups, nitro groups or amino groups (said amino group may be substituted with lower alkyl group or lower alkanoyl group, R.sup.3 denotes a hydrogen atom or lower alkyl group, A denotes a lower alkylene or carbonyl group, and B and W denote differently lower alkylenes, carbonyl groups or bonding hands], or their salts.

Abstract: The present invention relates to quinazoline-3-alkanoic acid derivatives having both an inhibitory effect on platelet aggregation and a hindering effect on aldose reductase together, represented by a general formula [I] ##STR1## [wherein R is hydrogen or a protecting group for carboxyl group, R.sup.1 is a lower alkyl group, alkenyl group, alkinyl group, lower alkoxy group, lower alkylthio group, halogen, phenyl group (this phenyl group may be substituted by one to three of lower alkyls, lower alkoxys, halogens, trifluoromethyls, carboxyethylenes or ethoxycarbonylethylenes, naphthyl group, heterocycle (this heterocycle may be substituted by one to three of lower alkyls), cycloalkyl group or benzoyl group (this benzoyl group may be substituted by lower alkyl or halogen), R.sup.2 and R.sup.3 are identically or differently hydrogens, halogens, lower alkyl groups, lower alkoxy groups, aralkyl groups which may be substituted, nitro groups, imidazolyl groups, imidazolylmethyl groups or ##STR2## (R.sup.4 and R.sup.