Reaction Steps
Methanesulphonyl chloride (203μl, 2.62mmol) was added to 2-(2-aminothiazol-4-yl)-2-(Z)-methoxyiminoacetic acid (528mg, 2.63mmol) and N,N-diisopropylethylamine (458μl, 2.63mmol) in DMF (8ml) at -30° C. After stirring at -30±10° C. for 30min., a solution of 4-methoxybenzyl (6R,7R)-7-amino-3-[(S)-tetrahydrofuran-2-yl]ceph-3-em-4-carboxylate (930mg, 2.38mmol) in DMF (5ml) was added, followed by pyridine (213 μl, 2.63mmol). The reaction mixture was transferred to an ice-bath and stirring continued for a further 1h. After dilution with ethyl acetate, the solution was washed successively with saturated sodium hydrogen carbonate solution, 5% aqueous citric acid, water (x2) and brine, dried and then concentrated in vacuo. The residue was purified by chromatography on silica gel eluting with 50, 70 and 90% ethyl acetate in hexane to give the title compound as a yellow foam (1.138g, 83%); vmax (CH2Cl2) 3389, 1783, 1732, 1682, 1516cm-1 ; δH (CDCl3, 250MHz) 1.53-1.70 (1H, m), 1.88-2.01 (2H, m), 2.28-2.41 (1H, m), 3.33 and 3.62 (2H, ABq, J 18.7Hz), 3.79-3.98 (2H, m), 3.81 (3H, s), 4.08 (3H, s), 4.94 (1H, dd, J 9.0, 6.7Hz), 5.04 (1H, d, J 4.8Hz), 5.18 (2H, s), 5.88 (2H, br s, exch.), 5.98 (1H, dd, J 9.0, 4.8Hz), 6.90 (2H, d, J 8.6Hz), 6.94 (1H, s), 7.35 (2H, d, J 8.6Hz), 7.50 (1H, br. d, J 9.0Hz, exch.). [Mass spectrum: +ve ion (thioglycerol) MH+ (574)].
