Abstract: A process for one pot synthesis of citalopram is disclosed. The process comprises subjecting 5-cyano phthalide to Grignard reduction followed cyclization and followed by C-alkylation reaction to obtain citalopram without isolation and purification of any intermediates. In another embodiment, 5-cyano phthalide is subjected to sequential Grignard reactions followed by cyclization to obtain citalopram without isolation and purification of any intermediate stages.

Abstract: A method is provided for the isolation of high purity crystalline citalopram (1-[3-dimethylamino)propyl}-1-(4-fluorophenyl)-1, 3-dihydro-5-isobenzofurancarbonitrile) base directly from the alkylation reaction mixture of 5-cyanophthalane with N,N-dimethylaminoprpylchloride in a polar aprotic solvent using a strong base. The method comprises: (a) diluting the reaction mixture with ice cold water and extracting the resulting mixture with a water-immiscible organic solvent; (b) re-extracting the water-immiscible organic solvent extract with an aqueous acid; (c) diluting the aqueous acid extract with a substantially equal volume of a water miscible organic solvent, based on the volume of water in the aqueous acid extract; (d) adjusting the pH to basic with an inorganic base to precipitate free crystalline base and (e) further isolating the precipitated free crystalline base by filration.

Abstract: A process for the preparation of 10-methoxycarbamazepine, an important intermediate in the preparation of 10-oxo-10, 11-dihydro-5H-dibenz(b,f)azepine-5-carboxamide(oxcarbazepine) from 10-methoxy-5H-dibenz(b,f)azepine(10-methoxyiminostilbene), is disclosed, which process comprises reacting 10-methoxyiminostilbene with cyanic acid (HOCN) in the presence of a mild acidic reagent in a solvent. Also disclosed is an improved method for the hydrolysis of 10-methoxycarbamazepine to oxcarbazepine, which method comprises carrying out the hydrolysis in a biphasic system chosen such that the oxcarbazepine is substantially insoluble in both phases, whereas the by-products or impurities are soluble in at least one of the phases. The oxcarbazepine thereby prepared is an anticonvulsant, and has been proposed for use as an anti-epileptical agent in the treatment of AIDS-related neural disorders, and for the treatment of Parkinson's disease and/or Parkinsonian syndromes.

Abstract: A process for the preparation of 10-methoxycarbamazepine, an important intermediate in the preparation of 10-oxo-10, 11-dihydro-5H-dibenz(b,f)azepine-5-carboxamide(oxcarbazepine) from 10-methoxy-5H-dibenz(b,f)azepine(10-methoxyiminostilbene), is disclosed, which process comprises reacting 10-methoxyiminostilbene with cyanic acid (HOCN) in the presence of a mild acidic reagent in a solvent. Also disclosed is an improved method for the hydrolysis of 10-methoxycarbamazepine to oxcarbazepine, which method comprises carrying out the hydrolysis in a biphasic system chosen such that the oxcarbazepine is substantially insoluble in both phases, whereas the by-products or impurities are soluble in at least one of the phases. The oxcarbazepine thereby prepared is an anticonvulsant, and has been proposed for use as an anti-epileptical agent in the treatment of AIDS-related neural disorders, and for the treatment of Parkinson's disease and/or Parkinsonian syndromes.

Abstract: A process for preparing carbamazepine from iminostilbene is disclosed. The iminostilbene is reacted with urea in a protonating medium. This process results in improvements over prior art processes involving iminostilbene. Carbamazepine is a known muscle relaxant, anticonvulsant and antidepressant drug.

Abstract: A process for preparing an erythromycin derivative, such as roxithromycin, from the corresponding oxime is disclosed. The oxime is reacted with a metal alkoxide and results in improvements over prior art processes involving the oxime. Roxithromycin is a known anti-bacterial agent.