Acetic Acid → Erythromycin Thiocyanate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

In a three-necked flask, 12 g of erythromycin was dissolved in butyl acetate or acetone, added with 2M acetic acid aqueous solution and 10% sodium thiocyanate solution (in a molar ratio to erythromycin of 1:1:1-1.2), and stirred continuously at 15-60° C. After complete reaction, the mixture was added with water, cooled to a temperature between −25° C. and 10° C., filtered, the resultant solid was washed with water, filtered under a reduced pressure, and dried at 60° C. for about 4 h to obtain an off-white crystal powder. HPLC analysis: the main peak of the sample had a retention time in consistent with that of erythromycin control, in which the content of erythromycin was 88.46% (the theoretical value: 88.54%); melting point: 165.8-169.8° C. (not corrected), water content by Karl Fischer method was 4.62% (the theoretical value: 4.35%), TG-DTG: weight loss before 140° C. was about 4.51%, which was in the error range of the sample having 2 crystal water (see FIG. 6), MS (ESI, FAB) m/z: 793, 792, 734, 733, 59, 58. Element analysis: found: C, 54.93; H, 8.87; N, 3.29; S, 3.76; calculated: C, 55.05; H, 8.75; N, 3.38; S, 3.87. The obtained sample having 2 crystal water was added to a sodium carbonate solution to generate a precipitate, the precipitate was washed with water, recrystallized from water-ethanol, and the product was consistent with raw material erythromycin in terms of specific optical rotation and MS data.

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