ethyl (Z)-2-bromomethylbut-2-enoate → [(Z)-2-ethoxycarbonylbut-2-enyl] (6R,7R)-7-[[(2Z)-2-(2-amino-1,3-thiazol-4-yl)-2-methoxyiminoacetyl]amino]-8-oxo-3-[(2S)-oxolan-2-yl]-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylate

Participants

Reaction Steps

Sodium (6R,7R)-7-[2-(2-aminothiazol-4-yl)-2-(Z)-methoxyiminoacetamido]-3-[(S)-tetrahydrofuran-2-yl]ceph-3-em-4-carboxylate, (0.35g) in 1-methyl-2-pyrrolidinone (4ml) was treated with a solution of ethyl (Z)-2-bromomethylbut-2-enoate, (0.16g) in 1-methyl-2-pyrrolidinone (1ml) and stirred at ambient temperature overnight. The solution was diluted with ethyl acetate and washed with water (3x), brine and then dried. After removal of solvent in vacuo, the residue was purified by flash chromatography on silica gel, eluting with 70, 90% ethyl acetate-hexane and then ethyl acetate. The title compound was obtained as a pale yellow foam (0.368g, 86%); vmax (CH2Cl2) 3480, 3389, 3320, 1781, 1726, 1682, 1606 and 1532cm-1 ; δH (CDCl3) 1.30 (4H, t, J 7.1Hz, overlapping M), 1.66 (1H, m), 1.97 (3H, d, J 7.3Hz), 2.35 (1H, m), 3.33 and 3.64 (2H, ABq, J 18.7Hz), 3.88 (2H, m), 4.08 (3H, s), 4.22 (2H, q, J 7.1Hz), 4.93 (1H, m), 5.05 (3H, m), 5.80 (2H, br s, exch.), 5.99 (1H, dd, J 4.8, 9.0Hz, collapses to d, J 4.8Hz on exch.), 6.83 (1H, s), 7.21 (1H, q, J 7.3Hz) and 7.73 (1H, d, J 9.0Hz, exch.). [Mass spectrum: +ve ion (thioglycerol) MH+ (580)].

Provenance & Evidence