反应详情

A solution of (RS)-1-acetoxyethylbromide (267 mg) in 1-methyl-2-pyrrolidinone (2 ml) 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 (190 mg) and potassium carbonate (110 mg) in 1-methyl-2-pyrrolidinone (1 ml). 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 (172 mg); νmax (CHCl3) 3019, 2929, 1786, 1683, 1520, 13176 and 1135 cm-1 ; δH (CDCl3, 250 MHz) 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 18.8 Hz), 4.93-5.10 (2H,m), 5.90-6.05 (1H,m), 6.94 and 7.07 (together 1H,q,J 5.8 Hz), 7.10 and 7.15 (together 1H, 2s) and 7.60 and 7.67 (together 1H,2d, J 7.4 Hz); [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