METHOD OF 6-[3-(2-CHLOROPHENYL)-5-METHYLISOXAZOL-4-CARBAMINO]-PENICILLANIC ACID SODIUM SALT PREPARING Russian patent published in 2003 - IPC

FIELD: antibiotics, chemical technology. SUBSTANCE: invention relates to method of preparing 6-[3-(2-chloro-phenyl)-5-methylisoxazol-4- carbamino] -penicillanic acid sodium salt that is highly effective antibiotic. Method is carried out by synthesis of cloxacillin by acylation of 6-aminopenicillanic acid Na-salt in aqueous-acetone medium with 3-(2- chlorophenyl)-5-methylisoxazol-4-carboxylic acid chloroanhydride at maintenance of medium hydrogen index in the range pH 6.0-9.5, isolation of cloxacillin as acid form from the obtained solution by reduction of pH value to 2.5-3.5, dissolving cloxacillin hydrated paste in butanol in addition of sodium hydroxide solution to suspension followed by crystallization of product in the process of distillation of aqueous-butanol azeotrope from reaction mass under vacuum and the following filtration and drying 6-[3-(2-chlorophenyl)-5-methylisoxazol-4-carbamino]-penicillanic acid sodium salt (cloxacillin) under vacuum. The claimed method provides the possibility to obtain product with the yield 85-91% of theoretical value as measured for 6- aminopenicillanic acid. The preparation prepared by the claimed method is white crystalline powder with specific rotation 168,5^° (1% solution in freshly boiled water). Optical density of 1% solution in water at 430 nm due to the presence of light-absorbing impurities (by derivatives of penicillenic acid) is 0.02-0.04 (in cell with layer thickness 10 mm). EFFECT: improved method of preparing, simplified technological process, reduced raw consumptions. 1 tbl, 11 ex