摘要:
The invention provides a process for preparing ondansetron hydrochloride dihydrate particles in which at least about 70% of the particles have a particle size of less than 250 μm, comprising the steps of: (a) preparing a solution comprising ondansetron hydrochloride and water; and (b) adding the solution into a precipitation medium which comprises a water-miscible nonsolvent for ondansetron hydrochloride, while maintaining the resulting mixture at a temperature of about 40° C. or less.
摘要:
The present invention provides a process for the preparation of a stable polymorph III of Atovaquone exhibiting characteristic peaks (expressed in degrees 2θ±0.2°θ) at about 6.9, 9.6, 14.1, 14.7, 17.0, 18.5, 19.1, 19.9, 20.3, 22.0, 22.6, 23.2, 24.2, 26.8, and 28.5, which comprises: (a) providing a sample of Atovaquone particles; (b) heating the sample of Atovaquone particles at a minimal temperature of between 140° C. to 160° C. depending on the particle size of the sample; and (c) cooling the sample to obtain the stable polymorphic form of Atovaquone.
摘要:
The present invention provides a novel process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid. In particular, the present invention provides a process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid by reacting 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid with a Lewis acid to selectively remove one methoxymethyl group from 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid.
摘要:
The present invention provides a novel process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid. In particular, the present invention provides a process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid by reacting 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid with a Lewis acid to selectively remove one methoxymethyl group from 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid.
摘要:
The present invention provides a rapid, high-yielding process for preparing 1,2,3,9-tetrahydro-9-methyl-3-methylene-4H-carbazol-4-one from 1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one without using a secondary amine as a catalyst, and without using glacial acetic acid as a solvent. The present invention further provides a rapid, high-yielding process for preparing ondansetron from 1,2,3,9-tetrahydro-9-methyl-3-methylene-4H-carbazol-4-one without using alumina as a catalyst.
摘要:
The invention provides a process for preparing ondansetron hydrochloride dihydrate particles in which at least about 70% of the particles have a particle size of less than 250 μm, comprising the steps of: (a) preparing a solution comprising ondansetron hydrochloride and water; and (b) adding the solution into a precipitation medium which comprises a water-miscible nonsolvent for ondansetron hydrochloride, while maintaining the resulting mixture at a temperature of about 40° C. or less.
摘要:
The present invention provides an improved process for the preparation of 17-desoxy corticosteroid derivatives in a single chemical step by reacting the 17-hydroxy starting material with an excess of Trimethylsilyl Iodide. The present invention is specifically advantageous in preparing 17-desoxy corticosteroid derivatives having one or more halogen groups at positions 2, 6, 7 or 9 of the corticosteroid such as Clocortolone of Desoximetasone.
摘要:
The present invention provides a novel process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid. In particular, the present invention provides a process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid by reacting 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid with a Lewis acid to selectively remove one methoxymethyl group from 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid.
摘要:
The present invention provides a novel process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid. In particular, the present invention provides a process for preparing 1-methoxymethyl-5,5-diphenylbarbituric acid by reacting 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid with a Lewis acid to selectively remove one methoxymethyl group from 1,3-bis(methoxymethyl)-5,5-diphenylbarbituric acid.
摘要:
The present invention provides a rapid, high-yielding process for preparing 1,2,3,9-tetrahydro-9-methyl-3-methylene-4H-carbazol-4-one from 1,2,3,9-tetrahydro-9-methyl-4H-carbazol-4-one without using a secondary amine as a catalyst, and without using glacial acetic acid as a solvent. The present invention further provides a rapid, high-yielding process for preparing ondansetron from 1,2,3,9-tetrahydro-9-methyl-3-methylene-4H-carbazol-4-one without using alumina as a catalyst.