Hanmi Pharm. Co., Ltd.

Kyung-Ik Lee

Young-ho Moon

Gwan-Sun Lee

Nam-Du Kim

Jae-cheol Lee

Young-Kil Chang

Gha-Seung Park

Chul-Hyun Park

Jong-Soo Woo

Kwan-Sun Lee

Young-Ho Moon

This invention relates to a method for selectively preparing the 3-oxo-4-aza-5&#xa5;&#xe1;-androstane compound which is used as an intermediate of finasteride by heating 3-oxo-4-aza-5-androstene in a mixture of formic acid and an alkanediol in the presence of zinc.

Method for the selective preparation of 3-oxo-4-aza-5&#x3b1;-androstane compound

Amlodipine camsylate of the present invention is a crystalline salt of amlodipine suitable for pharmaceutical formulation, which is prepared by using low toxic camphor sulfonic acid to meet required pharmaceutical properties for treating cardiovascular diseases.

Amlodipine camsylate and method for preparing thereof

Amlodipine is prepared in a high yield by subjecting a pyrrole derivative, methyl aminocrotonate and 2-chlorobenzaldehyde to a Hantzsch reaction, and converting the pyrrole residue of the resulting 1,4-dihydropyridine derivative to an amine group by the action of hydroxylamine hydrochloride.

Method for preparing amlodipine

Lansoprazole of formula (I) can be produced economically in a high yield using a simple, two-step method comprising reacting hydroxymethylpyridine and benzimidazole starting materials in the presence of a phosphine compound and a dialkyl azodicaboxlate and oxidizing the product of the first step in the presence of an organic radical catalyst:

High-yield method for preparing lansoprazole

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Anyang-si, South Korea

Kyung-Ik Lee