Abstract: A novel process for preparing risedronate sodium hemipentahydrate represented by the following formula 1 using 2-(3-pyridyl)-1-hydroxyethane-1,1-bisphosphonic acid (risedronic acid) and an aqueous solution of risedronate sodium is disclosed.

Abstract: Disclosed is a method for preparing 2?-deoxy-2?,2?-difluorocytidine of Formula I comprising, preparing an optically pure 3R-hydroxypropane amide compound of Formula VIII from an optical ester compound of Formula IX using an optically active chiral amine, preparing an optically pure D-erythro-2,2-difluoro-2-deoxy-1-oxoribose compound of Formula V from the compound of Formula VIII, glycosylating the compound of Formula V with a nucleobase to prepare the 2?-deoxy-2?,2?-difluorocytidine of Formula I as a ?-nucleoside. With the present invention, it is possible to prepare an optically pure compound of Formula I in a high purity and a high yield. In the Formulae, R1 and R2 are protecting groups and are each independently benzoyl, 4-methylbenzoyl, 3-methylbenzoyl, 4-cyanobenzoyl, 3-cyanobenzoyl, 4-propylbenzoyl, 2-ethoxybenzoyl, 4-t-butylbenzoyl, 1-naphthoyl or 2-naphthoyl, R3, R4 and R7 are each independently C1-C3 alkyl, R5 is methyl or ethyl, R6 is hydrogen, methyl or methoxy.

Abstract: Disclosed herein is a novel method for preparing lercanidipine hydrochloride which is highly effective for treating hypertension. The method comprises the steps of reacting 2,6-dimethyl-5-methoxycarbonyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid with a substituted chlorophosphate derivative to obtain a substituted phosphonoester derivative, and reacting the substituted phosphonoester derivative with 2, N-dimethyl-N-(3,3-diphenylpropyl)-1-amino-2-propanol. According to the preparation method, since little by-products are formed, the yield is improved, as compared to cases of conventional methods. In addition, the method involves simple isolation and purification processes of lercanidipine, thus realizing a high-quality product. Furthermore, the method has advantages of low preparation costs, substantial waste-free environmental-friendly process and applicability to industrial mass-production.

Abstract: Disclosed is a method for preparing 2?-deoxy-2?,2?-difluorocytidine of Formula I comprising, preparing an optically pure 3R-hydroxypropane amide compound of Formula VIII from an optical ester compound of Formula IX using an optically active chiral amine, preparing an optically pure D-erythro-2,2-difluoro-2-deoxy-1-oxoribose compound of Formula V from the compound of Formula VIII, glycosylating the compound of Formula V with a nucleobase to prepare the 2?-deoxy-2?,2?-difluorocytidine of Formula I as a ?-nucleoside. With the present invention, it is possible to prepare an optically pure compound of Formula I in a high purity and a high yield. In the Formulae, R1 and R2 are protecting groups and are each independently benzoyl, 4-methylbenzoyl, 3-methylbenzoyl, 4-cyanobenzoyl, 3-cyanobenzoyl, 4-propylbenzoyl, 2-ethoxybenzoyl, 4-t-butylbenzoyl, 1-naphthoyl or 2-naphthoyl, R3, R4 and R7 are each independently C1-C3 alkyl, R5 is methyl or ethyl, R6 is hydrogen, methyl or methoxy.

Abstract: A novel process for preparing risedronate sodium hemipentahydrate represented by the following formula 1 using 2-(3-pyridyl)-1-hydroxyethane-1,1-bisphosphonic acid (risedronic acid) and an aqueous solution of risedronate sodium is disclosed.