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:
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:
The present invention relates to a novel, high-yield and low-cost method for preparing entecavir, [1-S-(1α,3α,4β)]-2-amino-1,9-dihydro-9-[4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl]-6H-purin-6-one, an antiviral agent, and novel intermediates used therein.
摘要:
The present invention relates to a novel, high-yield and low-cost method for preparing entecavir, [1-S-(1α,3α,4β)]-2-amino-1,9-dihydro-9-[4-hydroxy-3-(hydroxymethyl)-2-methylenecyclopentyl]-6H-purin-6-one, an antiviral agent, and novel intermediates used therein.
摘要:
The present invention relates to a method for preparing montelukast, an inhibitor against leukotrienes, and an intermediate used therein. According to the inventive method, high-purity montelukast or its sodium salt can be 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, an inhibitor against leukotrienes, and an intermediate used therein. According to the inventive method, high-purity montelukast or its sodium salt can be 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.