反应详情

温度

0 °C

4-Methoxybenzyl (6R,7R)-7-amino-3-[(R)-tetrahydrofuran-2-yl]ceph-3-em-4-carboxylate (136 mg, 0.35 mmol)(See example 6] in THF (10 ml) was stirred in an ice bath with dicyclohexylcarbodiimide (108 mg, 0.52 mmol) then (R)-2-t-butoxycarbonylamino-2-(4-hydroxyphenyl)acetic acid (139 mg, 0.52 mmol) in THF (3 ml) was added dropwise over 2 min. The mixture was stirred at 0° C. for 30 min then at room temperature for 30 min. It was filtered and evaporated and the residue chromatographed on silica gel eluting with ethyl acetate/hexane mixtures. The title compound was obtained as a white solid (212 mg, 95%); δH (CDCl3) 1.10-2.0 (4H,m), 1.42 (9H,s), 3.18 and 3.43 (2H,ABq, J 17 Hz), 3.80 (3H,s), 3.77-3.88 (2H,m), 4.89 (1H,d, J 5 Hz), 5.10 (1H,t, J 7 Hz), 5.11 (1H,d, J 5 Hz), 5.19 (2H, s), 5.65 (1H,d, J 5 Hz exch), 5.69 (1H,dd, J 4.9 Hz), 6.72 (2H,d, J 8 Hz), 6.81 (1H,d, J 9 Hz exch), 6.88 (2H,d, J 9 Hz), 7.10 (2H,d, J 8 Hz) and 7.33 (2H,d,J 9 Hz). [Mass spectrum: +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (938)].

1. waitat room temperature for 30 min
2. filtrationIt was filtered
3. customevaporated
4. customthe residue chromatographed on silica gel eluting with ethyl acetate/hexane mixtures