Citric Acid → HCID 88421815, compound

Participants

Reaction Steps

A solution of 1,8-diazabicyclo[5.4.0]undec-7-ene (24 mg) in dry tetrahydrofuran (5 ml) was added over 5 min to a solution of diphenylmethyl 7β-amino-7α-formamido-3-methylenecepham-4-carboxylate (prepared above)(739 mg) in dry tetrahydrofuran (30 ml) containing diethyl dibromomalonate (999 mg) at -70° C. under argon. After 25 min the mixture was added to a mixture of ethyl acetate (150 ml) and 5% (w/v) aqueous citric acid (100 ml). The phases were separated and the organic phase washed with water (3×100 ml), brine (100 ml), then dried (anhyd. MgSO4), filtered and the filtrate evaporated to give a yellow solid. Trituration with dichloromethane (15 ml) followed by filtration provided the title compound (609 mg) as a white solid, m.p. 151°-153° C. (decomp.) (Found: C, 52.33; H, 4.00; N, 8.37; S, 6.50; Br, 15.59%. C22H20N3O4SBr requires C, 52.59; H, 3.98; N, 8.37; S, 6.38; Br, 15.94%). υmax (KBr) 3370, 3280, 3150, 1795, 1720, and 1670 cm-1 ; δH (250 MHz, d8 -THF) (major rotamer) 2.70 (2H, broad s, exch. D2O), 3.46 and 3.58 (2H, ABq, J 16.8 Hz), 4.34 and 4.42 (2H, ABq, J 10.0 Hz), 5.21 (1H, s), 6.95 (1H, s), 7.1-7.6 (10H, m), 8.15 (1H, d, J 1.0 Hz, becomes s on D2O exch.), and 8.17 (1H, broad s, exch. D2O); m/z (positive xenon F.A.B.; 3-nitrobenzyl alcohol-NaOAc) MNa;, 524.

Provenance & Evidence