反应详情

A solution of 2,2,2-trichloroethyl 3-bromomethyl-7β-phenoxyacetamidoceph-3-em-4-carboxylate (ca. 7 mmole) in ethyl acetate (25 ml) was stirred at 25° in the absence of light while a solution of triphenylphosphine (3.67g, 2 equiv.) in ethyl acetate (40 ml) was added over 10 minutes. The reaction mixture was stirred at 25° for 31/2 hours and the precipitated solid was filtered off washed with ethyl acetate and dried, (5.62 g), and redissolved in chloroform (40 ml). The filtered solution was diluted with a mixture of ether (20 ml) and light petroleum (b.p. 40° to 60°; 10 ml) and stirred for 30 minutes, and the precipitated solid was filtered off and dried to give the title phosphonium salt (5.47 g, 95%), m.p. 125 to 135°, [α]D23 +4.4° (C 1.06; (Me2SO), λmax. (EtOH) 268 nm (ε 9,250) and 275 nm (ε 8,850), νmax. (CHBr3) 3430 (NH), 1794 (azetidin-2-one), 1730 (CO2R), 1693 and 1520 (CONH) and 1442 cm-1 (P+-C6H5).

1. additionwas added over 10 minutes
2. filtrationthe precipitated solid was filtered off
3. washwashed with ethyl acetate
4. customdried, (5.62 g),
5. dissolutionredissolved in chloroform (40 ml)
6. additionThe filtered solution was diluted with a mixture of ether (20 ml) and light petroleum (b.p. 40° to 60°; 10 ml)
7. stirringstirred for 30 minutes
8. filtrationthe precipitated solid was filtered off
9. customdried