[Research for the improvement of acylation conditions in antistaphylococcal penicillin synthesis].

AIM: The 6-aminopenicillanic acid acylation with certain acyl chlorides was performed in order to obtain antistaphylococcal penicillins with bigger crystals, easy to filtrate (shorter filtration time), much pure, and an increased output.

MATERIAL AND

METHODS

Oxacillin sodium salt was synthesized by acylating an aqueous solution of 6-aminopenicillanic acid sodium salt (NaHCO3 not in excess) with an ethylacetate solution of 5-phenyl-3-methyl-isoxazolyl-4-carboxilic acid chloride. The crystallization was performed with a 40.5% sodium 2-ethyl hexanoate izopropanolic solution. All tests (IR spectrum, iodometric titration, and microbiological dosage) were performed according to the Xth Romanian Pharmacopoeia standards.

RESULTS

The amount of synthesized oxacillin was higher and the output of 88,21%. Oxacillin had a high chemical purity (98,72%), and a very good microbiological activity (95% of the standard activity).

CONCLUSIONS

Oxacillin crystals were bigger, the filtration speed was increased, and process efficacy improved. The output of the process was also improved being higher than with classical acylation.