Hanmi Pharm. Co., Ltd.

Hanmi Science Co., Ltd.

Chul-Hyun Park

Young-Kil Chang

Gwan-Sun Lee

Gha-Seung Park

Jae-Heon Lee

Cheol-Kyung Kim

Gwan Sun Lee

Jae-cheol Lee

Hong-Sun Kim

Young-ho Moon

Dong Jun Kim

Jaeheon Lee

Young Ho Moon

Young Kil Chang

Kyung-Ik Lee

Eun-Ju Park

Eun Jung Lim

Keum-Shin Jung

Suk Man Jang

Choong-Hahn Kim

Kyung Ik Lee

The present invention relates to a method for preparing Montelukast acid or its sodium salt by reacting a thiol compound with a Montelukast intermediate in the presence of a base in a medium comprising an ionic liquid compound. In accordance with the inventive method, highly pure Montelukast acid or its sodium salt, which is advantageously used as a raw material in the preparation of Montelukast, a leukotriene antagonist, can be easily prepared in a high yield.

Method for preparation of Montelukast acid in ionic liquid medium

High purity cefdinir is prepared in a high yield by a process comprising the steps of: treating a crystalline salt of a cefdinir intermediate with a formic acid-sulfuric acid mixture or a formic acid-methanesulfonic acid mixture to obtain a crystalline salt of cefdinir and reacting the crystalline salt with a base in a solvent.

Crystalline acid salts of cefdinir and process for preparing cefdinir using same

A 3-(Z)-propenyl cephem compound is selectively prepared by reacting a phosphoranylidene cephem compound with acetaldehyde in the presence of a base in a solvent mixture comprising diethyl ether, formula (I), wherein R is a carboxyl protecting group; Ris hydrogen or RCHCO&#x2014;; and Ris ethyl, 2-thiophenyl, phenyl, p-hydroxyphenyl or phenoxy 

Process for the selective preparation of 3-(z) propenyl-cephem compound

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

A method for preparing a 1-androstene derivative which comprises reacting a 2-iodo-androstane derivative with an oxidizing agent while maintaining the pH of the reaction mixture at a specific range gives the 1-androstene derivative with high purity and yield.

Method for the preparation of highly pure 1-androstene derivatives

Highly pure cefpodoxime proxetil can be prepared by a simple process comprising the step of reacting a cefpodoxime salt with 1-iodoethylisopropylcarbonate in an organic solvent in the presence of a crown ether.

Method of preparing highly pure cefpodoxime proxetil

7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid of formula (I) can be easily prepared by reacting 7-aminocephalosporanic acid of formula (II) with an azeotropic mixture of trimethyl borate and methanol in the presence of methanesulfonic acid:

Process for preparing 7-amino-3-methoxymethyl-3-cephem-4-carboxylic acid

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Seongnam-si, South Korea

Chul-Hyun Park