Boron trifluoride → 7-Aminodeacetoxycephalosporanic acid

Beteiligte Stoffe

Reaktionsschritte

To a 250 ml. 3-necked round bottom flask equipped with a thermometer, stirrer, condenser and dropping funnel were added 10.88 g. (40 mmole) of 7-aminocephalosporanic acid and 70.5 ml. of trifluoroacetic acid. Triethylsilane (17.2 g., 150 mmole, 23.6 ml.) was added to the solution followed by 33.6 ml. of methylene chloride. The resulting solution was stirred at room temperature and 27.1 g. (190.7 mmole, 23.6 ml.) of boron trifluoride etherate were added. The temperature of the reaction mixture rose to about 55° C. following the addition of the boron trifluoride. After the temperature of the mixture had cooled to room temperature, the mixture was poured with stirring into 250 ml. of diethyl ether. The precipitate of the trifluoroacetate salt of 7-aminodesacetoxycephalosporanic acid was separated by filtration and was dissolved in 100 ml. of water containing 50 ml. of acetone. The pH of the orange-colored solution was adjusted to 4.0 with ammonium hydroxide to precipitate 7-ADCA in the zwitterionic form. The product was separated by filtration and was washed with aqueous acetone, acetone, and then with diethyl ether and was dried. There were obtained 7.23 g. (84.5% yield) of 7-ADCA as a fine off-white powder.

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