反应详情

Allyl(5R,6S)-2-(5-Ethyl-1-methylpyrazol-3-yl)-6-[(R)-1-hydroxyethyl]carbapen-2-em-3-carboxylate (348 mg) in 1:1 ethyl acetate/dichloromethane (8 ml), under argon was treated successively with sodium 2-ethylhexanoate (198 mg), triphenylphosphine (27 mg) and tetrakis(triphenylphosphine)palladium (0), (38 mg). After a few seconds an off-white precipitate was formed. The reaction mixture was stirred at room temperature for 30 m. T.l.c. analysis (20% acetone/ethyl acetate showed no remaining starting material. The solvents were removed in vacuo and the residual solid stirred with diethyl ether (20 ml). The white solid was filtered off washed with ether and dried. This solid was dissolved in water (10 ml) and chromatographed on HP20SS resin eluting with 1-5% tetrahydrofuran/water (100 ml portions ). The combined fractions containing the product (by h.p.l.c.), were concentrated and freeze-dried to give the title compound as an amorphous pale yellow solid, (3.14 mg, 95%); nmax (KBr) 1755, 1614, 1586 and 1386 cm-1 ; dH (D2O) 1.17 (3H, t, J7.5 Hz), 1.26 (3H, d, J6.4 Hz), 2.56 (2H, q, J7.5 Hz), 3.16 (2H, m), 3.44 (1H, dd, J2.8,6.0 Hz), 3.68 (3H, s), 4.21 (2H, m) and 6.47 (1H, s). m/z (Electrospray) 328 (MH+), 350 (MNa+), 633 (2MNa+, free acid), 655 (2MH+), 677 (22 MNa+).

1. customAfter a few seconds an off-white precipitate was formed
2. customThe solvents were removed in vacuo
3. stirringthe residual solid stirred with diethyl ether (20 ml)
4. filtrationThe white solid was filtered off
5. washwashed with ether
6. customdried
7. dissolutionThis solid was dissolved in water (10 ml)
8. customchromatographed on HP20SS resin
9. washeluting with 1-5% tetrahydrofuran/water (100 ml portions )
10. additionThe combined fractions containing the product (by h.p.l.c.)
11. concentrationwere concentrated
12. customfreeze-dried