Phosphoric Acid → HCID 5362051, Verbindung

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

The pH of the ceftazidime solution was lowered to 4.5 with 4M phosphoric acid, and the solution was seeded. The solution was stirred for 21/2 hr at 0-5° C., during which the pH had risen to 4.7 and a large amount of crystals had formed. Phosphoric acid (4M) was then added dropwise over a 1 hr period to achieve a pH of 3.7. More acid was added dropwise over the next 1/2 hr to maintain this pH. After the pH was stabilized, the slurry was stirred slowly in an ice bath for 1 hr. The crystals were filtered and washed twice with cold deionized water (2×30 mL) and then with cold acetone (30 mL). The product was dried overnight at ambient temperature at a pressure of about 80 mm Hg. This procedure gave 13.57 g of ceftazidime pentahydrate. The assay was 85.4%, and the corrected yield was 77.3%. Another 11.1% yield was obtained from the combined mother liquors and washes.

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