摘要:
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.
摘要:
This invention relates to a method for selectively preparing the 3-oxo-4-aza-5¥á-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.
摘要:
This invention relates to a method for selectively preparing the 3-oxo-4-aza-5¥á-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.
摘要:
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.
摘要:
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.
摘要:
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; R1 is hydrogen or R2CH2CO—; and R2 is ethyl, 2-thiophenyl, phenyl, p-hydroxyphenyl or phenoxy
摘要翻译:通过在碱存在下将亚正膦基头孢烯化合物与乙醛反应在包含二乙醚,式(I)的溶剂混合物中,其中R是羧基保护基,选择性地制备3-(Z) - 丙烯基头孢烯化合物。 R 1是氢或R 2 CH 2 CO-; R 2是乙基,2-噻吩基,苯基,对羟基苯基或苯氧基
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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: