摘要:
A novel method for the preparation of stavudine polymorphic form I and form II is described. 5′-acetate-2′,3′-diacetyl-5-methyluridine is reacted with catalytic amounts of sodium methoxide in a C1-C4 alcoholic solvent, resulting in crude stavudine form II. Crude stavudine form II can be converted into polymorphic stavudine form I by slurry at reflux in isopropanol, without isolating or purifying the crude stavudine form II.
摘要:
Process for preparing oxcarbazepine according to the steps of chlorocarbonylating (a), ammonolysis (b), and deprotecting (c). The invention is characterized by the use of triphosgene as chlorocarbonylating agent in step a).
摘要:
A process for the preparation of citalopram and the pharmaceutically acceptable salts therof is disclosed by reacting 5-cyanophthalide with a 4-fluorophenyl magnesium halide, reducing the 3-hydroxymethyl-4-(4-fluorobenzoyl)benzonitrile with an agent reducing ketones to alcohols, submitting the thus-obtained 3-hydroxymethyl-4-[(4-fluorophenyl)hydroxymethyl)benzonitrile to a cyclization reaction to give 1-(4-fluorophenyl)-1,3-dihydro-5-isobenzofurancarbonitrile without 1,1-bis(4-fluorophenyl)-1,3-dihydro-5-isobenzofurancarbonitrile and treating 1,1-bis(4 fluorophenyl)-1,3-dihydro-5-isobenzofurancarbonitrile with a 3-(dimetylamino)propyl halide in the presence of a base.
摘要:
A method for the preparation of citalopram and its pharmaceutically acceptable salts is described; it's obtained starting from 5-cyanophthalide by reaction with a mixture of 4fluorophenyl magnesium bromide and 3-dimethylaminopropyl magnesium chloride. The intermediate obtained is showed here-be-low: wherein X is an halogen, preferably chlorine or bromine, which is cyclized without any isolation.