Trifluoroacetic acid → HCID 70528331, compound

Participants

Reaction Steps

Diphenylmethyl (6R,7R,2'R and S)-7-(2'-hydroxy-2'-[thien-2-yl]-acetamido)-3-methylceph-3-em-4-carboxylate (543mg, 1.05mmole) was dissolved in anisole (4ml) and stirred with trifluoroacetic acid (4 ml) at +20° to +25° for 7 mins. The anisole and trifluoroacetic acid were evaporated and the residue partitioned between 3%-aqueous sodium bicarbonate solution (ca 50ml) and ethyl acetate (ca 50ml). The aqueous layer was washed with ethyl acetate (3xca 50ml), layered with ethyl acetate and adjusted to pH 2.5. The ethyl acetate layer was combined with the ethyl acetate backwash of the aqueous layer, dried, and evaporated to give (6R,7R,2'R and S)-7-(2'-hydroxy-2'-[thien-2-yl] -acetamido)- 3-methylceph-3-em-4-carboxylic acid as a foam (337mg, 91%). This foam was dissolved in acetone (3ml) and stirred with a solution of sodium 2-ethylhexanoate (186mg, 1.05mmole) in acetone (2ml) and ether (2ml). The precipitated material was filtered off, washed with ether, and dried to give the title compound containing 2mole-equivalents of water (i.r., microanalysis) and one-sixth mole-equivalents of ether (n.m.r., microanalysis) as a pale-brown solid (183mg, 0.486 mmole, 46.4%); λmax (pH6-buffer) 237.5nm, inflexion at 255nm (ε12,640 and 9,250 respectively); νmax (nujol) 3380 (NH,H2O), 1760 (azetidin-2-one), 1680 and 1528 (CONH), and 1600 cm-1 (CO2 -); τ (Me2SO-D6) 1.48 and 1.63 (total 1H, 2d,J9Hz,NH), 2.54 to 3.10 (3H, m, thiophene protons), 4.46 (ca 1H, m, C7 -H), 4.60 and 4.62 (total ca 1H, 2S, CHOH), 5.00 (1H,d,J4.5Hz, C7 -H), 6.49 and 6.87 (2H, ABq, J18Hz, C2 -H2), 8.01 (3H,s, C3 -CH3). A signal at τ 8.89 revealed the presence of one-sixth mole-equivalent of diethyl ether. (Found: C,41.1, 41.4; H,3.6,3.8; N,6.6, 7.0; S,14.5. C14H13N2NaO5S2. One-sixth C2H5OC2H5. 2H2O (424.7) requires C,41.5; H,4.4; N,6.5; S,15.1%).

Provenance & Evidence