Improvements to patent number 8702020 for a new process for the preparation of famotidine polymorphs. The preparation of crystalline structures of the Famotidine polymorph having a low melting point which have high and low bulk density is described. From a solution of a salt of Famotidine in methanol the desired crystalline structures are precipitated or crystallised out by the incorporation of a tertiary organic base and subsequent dilution with a chlorinated hydrocarbon. Seeding with high-dens...

Improvements to patent number 8702020 for a new process for the preparation of famotidine polymorphs. The preparation of crystalline structures of the Famotidine polymorph having a low melting point which have high and low bulk density is described. From a solution of a salt of Famotidine in methanol the desired crystalline structures are precipitated or crystallised out by the incorporation of a tertiary organic base and subsequent dilution with a chlorinated hydrocarbon. Seeding with high-dens...

N-sulfamyl-propionamidine derivatives are prepared by the reaction of 3-substituted-propionitriles with an oxonium hydrochloride, preferably of 1,4-dioxane, in the presence of sulfamide in a close system at pressures between 0.5 kg/cm and 4.0 kg/cm. These compounds are useful in the preparation of famotidine, an anti-ulcer agent.

Craytalline famotidine polymorphs exhibiting a specified X-ray diffraction pattern, the crystals being stable, are claimed. They may be prepd. by (a) reacting a soln. in methanol of a salt of famotidine selected from hydrochloride, hydrobromide, sulphate, nitrate or phosphate with a tertiary organic base such as triethylamine, 1,8-diazabicyclo (5.40) undec-7-ene or diazabicyclo (4.3.0) non-5-ene, (b) diluting the resulting soln. at 50-65 deg. c with a chlorinated hydrocarbon pref. selected from ...

New 2-guanidino-thiazol compounds with the general formulas where R DEG represents an hydrogen atom or an alkyl group of low molecular weight, m = 2 to 7, n = 2 to 4, and being R an alkyl group of low molecular weight and that may contain from one N-alkylsilyl group, that are important intermediates for the famotidine preparation, medically used as inhibitor of the gastric secretion.

It is described the preparation of the famotidine polymorphs with low melting point and relative high or low apparent densities. They differ from the polymorph of high melting point and high density, in the physical-chemical and biological properties, of interest in galenic formulations and preparation of the drug.