Abstract: The present invention is to provide a 3-substituted oxyglutaric acid diester compound represented by the following formula (I): wherein R1 may be the same or different from each other, and represents a substituted or unsubstituted alkyl group, R2 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, and an optically active 3-substituted oxyglutaric acid monoester compound represented by the following formula (IV): wherein R1 and R2 have the same meanings as defined above, and processes for preparing the same.

Abstract: The present invention is to provide a process for producing a 2′-O-acetyl-4″-O-formyl-8,9-anhydroerythromycin A 6,9-hemiketal compound 4, and it provide a process for producing an erythromycin compound which comprises reacting a formylating agent with a 2′-O-acetylerythromycin A compound 2 to obtain 2′-O-acetyl-4″-O-formylerythromycin A compound 3, then, acting an acid on Compound 3 to subject to hemiketalation, and then adding an aqueous basic solution in an aqueous solution to precipitate Compound 4 as free crystals.

Abstract: The present invention provides a novel 7a-alkoxy-4H-pyrano-[3,2-d]-oxazol-2(3H)-one represented by the formula (I): wherein R1 and R2 each represent a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or an aralkyl group; R3 represents an alkyl group, a cyclo-alkyl group, an alkenyl group, an aryl group or an aralkyl group, provided that a 2-alkenyl group is excluded from the alkenyl group of R3; and R4 represents an alkyl group, an aryl group, an alkoxycarbonyl group or a cyano group, and a process for producing the same which comprises reacting 5-alkoxy-2(3H)-oxazolone with an &agr;,&bgr;-unsaturated ketone in the presence of a Lewis acid in a solvent.

Abstract: The present invention provides a novel 7a-alkoxy-4H-pyrano-[3,2-d]-oxazol-2(3H)-one represented by the formula (I): 1

Abstract: The present invention is to provided a trifluoro-substituted benzoic acid, an ester thereof, particularly 2,3,4-trifluoro-5-iodobenzonic acid, 2,3,4-trifluoro-5-trifluoromethylbenzonic acid, esters thereof, which are useful as a starting material for synthesizeing a quinolonecarboxylic acid compound useful as a medicine, an anti-bacterial agent or an antiviral agent, and processes for preparing these compounds and 2,4,5-trifluoro-3-iodobenzonic acid, 2,4,5-trifluoro-3-trifluoromethylbenzoic acid and esters thereof.

Abstract: The present invention is to provide a trifluoro-substituted benzoic acid, an ester thereof, particularly 2,3,4-trifluoro-5-iodobenzoic acid, 2,3,4-trifluoro-5-trifluoromethylbenzoic acid, esters thereof, which are useful as a starting material for synthesizing a quinolonecarboxylic acid compound useful as a medicine, an anti-bacterial agent or an antiviral agent, and processes for preparing these compounds and 2,4,5-trifluoro-3-iodobenzoic acid, 2,4,5-trifluoro-3-trifluoromethylbenzoic acid and esters thereof.

Abstract: A 2-silyloxy-4,5,6,7-tetrahydrothieno?3,2-c!pyridine represented by the formula (I): ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 each independently represent an alkyl group having 1 to 10 carbon atoms or an aryl group,and a salt thereof and a process for preparing the same, and a 5-alkyl-2-silyloxy-4,5,6,7-tetrahydrothieno?3,2-c!-pyridine represented by the formula (IV): ##STR2## wherein R.sup.1, R.sup.2 and R.sup.3 represent the same meanings as described above; R.sup.4 represents a hydrogen atom, an alkoxycarbonyl group having 2 to 10 carbon atoms, an acyl group having 2 to 10 carbon atoms or a cyclo-alkylcarbonyl group having 4 to 10 carbon atoms; andR.sup.5 represents a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms,which is useful as a synthetic intermediate of an antiplatelet medicine and an elastase inhibitor, etc., and a process for preparing the same.