METHOD OF OBTAINING SODIUM SALT OF 6-[3-(2,6-DICHLROPHENYL)-5METHYL-ISOXAZOLE-4-CARBAMINO]-PENICILLANIC ACID Russian patent published in 2009 - IPC C07D499/16 C07D499/76 C07D499/12 

FIELD: chemistry.

SUBSTANCE: present invention relates to an improved method of producing sodium salt of 6-[3-(2,6-dichlorophenyl)-5-methyl-isoxazole-4-carbamino]-penicillanic acid (dicloxacillin) through acylating 6-aminopenicillanic acid with acid chloride of 3-(2,6-dichlorophenyl)-5-methyloxazole-4-carboxylic acid with subsequent extraction of the target product from the reaction mass. Acylation is carried out in a water-acetone medium through simultaneous addition into the reaction mixture acetone solution of acid chloride of 3-(2,6-dichlorophenyl)-5-methyloxazole-4-carboxylic acid and an aqueous solution of sodium hydroxide while maintaining the pH value of the medium between 6.0 and 9.5. The medium for carrying out the acylation process usually contains 3.0 to 4.0 kg of water per 1.0 kg of 6-aminopenicillanic acid. Extraction of the sodium salt of 6-[3-(2,6-dichlorophenyl)-5-methyl-isoxazole-4-carbamino]-penicillanic acid (dicloxacillin) is usually done by adding to the reaction mixture a saturated solution of sodium chloride or acetate in amount, sufficient for reducing concentration of the target product to a value which does not exceed 5 g/l or through diluting the reaction mixture with aliphatic alcohol until reduction of water concentration in it to 10.0-12.0%. Sodium chloride is separated from the water-alcohol solution of the sodium salt of dicloxacillin and the target product is crystallised during distillation of the water-alcohol azeotrope. The aliphatic used can be isopropyl or butyl alcohol.

EFFECT: reduced expenditure of raw materials and simplification of the process.

5 cl, 4 ex