- Letrozole production process
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Provided is a method for preparing letrozole, which includes reacting an activated bis-(4-cyanophenyl)-methane with a triazole to produce letrozole, and, optionally, purifying the letrozole. Also provided are highly pure letrozole, and a method of purifying letrozole, which method includes precipitating letrozole, e.g., by selective precipitation from a reaction mixture and/or by subjecting the letrozole to one or more crystallizations.
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Page/Page column 7
(2008/06/13)
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- PROCESS FOR THE PREPARATION OF LETROZOLE
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The present invention relates to the process for the preparation of Letrozole free from its regioisomer (7) and other impurities by selective extraction of desired intermediate (3) using suitable solvent and mixture of solvents.
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Page/Page column 5; 11-12
(2008/06/13)
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- ALPHA-HETEROCYCLC SUBSTITUTED TOLUNITRILES
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The invention is concerned with aromatase inhibiting compounds of formula I wherein R and Ro represent hydrogen or lower alkyl; or R and Ro located on adjacent carbon atoms and together when combined with the benzene ring to which they are attached form a naphthalene or tetrahydronaphthalene ring; R1 and R2 independently represent hydrogen, lower alkyl, (lower alkyl, aryl or aryl-lower alkyl)-thio, lower alkenyl, aryl, aryl-lower alkyl, C3-C6-cycloalkyl, or C3-C6-cycloalkyl-lower alkyl; or R1 and R2 combined represent lower alkylidene, mono or di-aryl-lower alkylidene; R1 and R2 combined also represent C4-C6-straight chain alkylene, lower alkyl-substituted straight chain alkylene or ortho-phenylene bridged-C2-C4 -straight chain alkylene, each forming with the carbon atom attached thereto a corresponding optionally substituted or benzo-fused 5, 6 or 7-membered ring; W represents 1-imidazolyl, 1-(1,2,4- or 1,3,4)-triazolyl or 3-pyridyl; or W represents 1-imidazolyl, 1-(1,2,4 or 1,3,4)-triazolyl or 3-pyridyl substituted by lower alkyl; and pharmaceutically acceptable salts thereof
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