Triethylamine → N,N'-Dicyclohexyl-1,2-ethanediamine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a chilled suspension of 7-amino-3-vinyl-3-cephem-4-carboxylic acid (50 gm) in a mixture of tetrahydrofuran (250 ml) and water (31.5 ml), triethylamine (45 gm) was added drop-wise at 20±2° C. over 30-45 minutes. 2-mercaptobenzothiazolyl (Z)-(2-aminothiazol-4-yl)-2-(trityloxyimino)acetate (130 gm) was added to the clear solution and the resulting mixture was stirred at 32±2° C. for 4-6 hours. The reaction was monitored by HPLC. After the completion of reaction, THF was completely removed under vacuum at 28-30° C. To the concentrated mass, acetone (300 mL) was added and stirred at 30° C., 1:1 Hydrochloric acid (200 mL) was added and the temperature was raised to 63-64° C. At this temperature, it was refluxed for about 35 min and then cold acetone of 1.8 Liter dumped to the reaction mass to bring down the temperature to 30° C., EDTA (0.5 g) was added and stirred for 10 min at 30-35° C., pH of the solution was adjusted to 2.5 using Triethyl amine (100 mL) at 30-35° C. To the reaction mixture hot solution of N,N′-Dicyclohexylethylenediamine (DDA) 40.0 g in Isopropyl alcohol (100 mL) was added slowly to adjust the pH of the solution 5.5 and stirred for 1.0 hour at 30-35° C. The precipitated material was filtered, washed with acetone and dried under vacuum at ˜40° C. to get N,N′-Dicyclohexylethylenediamine salt of 7β-[2-(2-amino-4-thiazolyl)-2-(Z-hydroxyimino)acetamido]-3-vinyl-3-cephem-4-carboxylic acid. Step-ii

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