反应详情

A solution of (RS)-1-acetoxyethylbromide (267mg) in 1-methyl-2-pyrrolidinone (2ml) was added dropwise, over 1 hour, to an ice cold mixture of sodium (6R,7R)-7-[2-(2-aminothiazol-4-yl)-2-(Z)-methoxyiminoacetamido]-3-[(S)-tetrahydrofuran-2-yl]ceph-3-em-4-carboxylate (190mg) and potassium carbonate (110mg) in 1-methyl-2-pyrrolidinone (1ml). After 15 minutes the mixture was diluted with ethyl acetate, washed with water, brine, dried (MgSO4), concentrated and flash chromatographed on silica gel eluting with 50,70,80 and 90% ethyl acetate in hexane to give the title compound (172mg); vmax (CHCl3) 3019, 2929, 1786, 1683, 1520, 1376 and 1135cm-1 ; δH (CDCl3, 250MHz) 1.45-1.75 (4H,m), 1.90-2.10 (2H,m), 2.09 and 2.10 (together 3H, 2s), 2.30-2.50 (1H,m), 3.36 and 3.65 (2H, ABq, J 18.8Hz), 4.93-5.10 (2H,m), 5.90-6.05 (1H,m), 6.94 and 7.07 (together 1H,q,J 5.8Hz), 7.10 and 7.15 (together 1H, 2s) and 7.60 and 7.67 (together 1H,2d, J 7.4Hz); [Mass spectrum: +ve ion (3-nitrobenzyl alcohol, sodium acetate) MNa+ (562)].

1. washwashed with water, brine
2. dry with materialdried (MgSO4)
3. concentrationconcentrated
4. customflash chromatographed on silica gel eluting with 50,70,80 and 90% ethyl acetate in hexane