- Silylation process
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A process for the silylation of 6-aminopenicillanic acid or 7-amino-desacetoxy-cephalosporanic acid by silylation in certain carboxylic acid esters and its use in the production of 6-alpha-aminoacyl-penicillins and 7-alpha-aminoacyl-desacetoxy-cephalosporins.
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- Beta lactam production
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A new process is described for the production of 6-alpha-amino-penicillins and 7-alpha-amino-desacetoxy-cephalosporins free from halogen-containing solvents by acylating 6-APA, 7-ADCA or a derivative thereof in a halogen-free solvent.
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- Substantially anhydrous crystalline cefadroxil and method for producing it
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The invention relates to a substantially anhydrous crystalline cefadroxil having a water content between about 0.8% and 3.9%. Such cefadroxil is obtained slurrying a cefadroxil solvate of dimethylacetamide, or of N-methyl-2-pyrrolidone or of monomethylformamide, with isopropyl alcohol with up to 4% of water and preferably in the presence of methanol in an amount lower than 60%, at a temperature of about +45° C. to +55° C. and then filtering the so obtained compound.
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- Method for preparing crystalline cefadroxil monohydrate
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The invention relates to a method for preparing crystalline cefadroxil monohydrate. According to such a method a cefadroxil solvate is slurried with isopropyl alcohol containing less 6% to 18% of water at a temperature between +45° to +55° C.: the crystalline cefadroxil monohydrate is isolated by filtration. Some of the cefadroxil solvates which can be used are novel: they are prepared by adding dimethylacetamide, N-methyl-2-pyrrolidone or monomethylformamide to an aqueous solution of cefadroxil at a pH between 5.5 and 6.
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- Substantially anhydrous crystalline cefadroxil and method for producing it
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The invention relates to a substantially anhydrous crystalline ce-fadroxil having a water content between about 0.8% and 3.9%. Such cefadroxil is obtained slurrying a cefadroxil solvate of dimethylacetamide, or of N-methyl-2-pyrrolidone or of monomethyl-formamide, with isopropyl alcohol containing either from about 2% to 4% of water of from about 0.1% to 4% of water and from 0% to about 60% of methanol, at a temperature in the range of about +45°C to +55°C and than filtering the desired cefadroxil so obtained.
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- Process for preparing cephalosporanic acid compounds
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A process for the preparation of [D-α-amino-p-hydroxyphenylacetamido]-penicillanic acid or cephalosporanic acid compounds comprising reacting a compound having a formula selected from the group consisting of STR1 wherein X is selected from the group consisting of hydrogen, acetoxy and five-membered heterocyclic group containing at least one hetero atom of the group consisting of oxygen, sulfur and nitrogen and optionally substituted with e.g. lower alkyl, this residue being attached to the 3-CH2 group via sulfur atom and wherein a NH radical if present has optionally been silylated with at least one mole equivalent of a silylating agent producing STR2 wherein R1, R2 and R3 are individually selected from the group consisting of lower alkyl, benzyl, cycloalkyl and phenyl in an inert anhydrous, organic solvent, preferably a water-inmiscible organic main-solvent, to form a compound having a formula selected from the group consisting of STR3 adjusting the pH to a scale value of 5.5 to 7.5 and reacting the resulting compounds in a pre-cooled solution with an at least equimolar amount of a compound of the formula wherein R4 is lower alkyl, R5 is selected from the group consisting of hydrogen and lower alkyl and R6 and R7 are lower alkoxy.
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- Process for the preparation of the crystalline monohydrate of 7-[D-α-aα-(p-hydroxyphenyl)acetamido]-3-methyl-3-cephem-4-carboxylic acid
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A novel crystalline monohydrate of 7-[D-α-amino-α-(p-hydroxyphenyl)acetamido]-3-methyl-3-caphem-4-carboxylic acid is prepared and found to be a stable useful form of the cephalosporin antibiotic especially advantageous for pharmaceutical formulations.
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