p-Toluenesulfonic acid monohydrate → HCID 70621000, compound

Participants

Reaction Steps

In a separate experiment, the crude amine mixture (226 mg.) in EtOAc (1 ml.) is treated with a solution of p-toluenesulfonic acid monohydrate (98 mg., 0.52 mMol) in EtOAc (4 ml.). The resulting solution is stored at 0° C. for ca. 5 hrs., during which time a fine, white precipitate forms. The precipitate is collected, washed with cold EtOAc and hexane, and dried in vacuo to yield the p-toluenesulfonic acid salt of p-nitrobenzyl 7-amino-6-methoxy-3-acetoxymethyl-ceph-3-em-4-carboxylate (71 mg.): mp 170°-175° C. (dec.). The salt (71 mg., 0.12 mMol) is shaken with aqueous K2CO3 (18 mg., 0.13 mMol in 5 ml.) and EtOAc (5 ml.). The layers are separated and the aqueous portion is extracted with more EtOAc (3 × 3 ml.). The combined EtOAc solution is washed with brine, dried with MgSO4, filtered and evaporated in vacuo to provide the major isomer of p-nitrobenzyl 7-amino-6-methoxy-3-acetoxymethyl-ceph-3-em-4-carboxylate (53 mg.) as a pale yellow oil: ir (neat) 3.97, 5.60, 5.74, 6.55, and 7.40μ; nmr (CDCl 3) δ 1.93 (s, 2, NH2), 2.08 (s, 3, COCH3), 3.25, 3.58 (ABq, 2, J=18Hz, SCH2), 3.52 (s, 3, OCH3), 4.28 (s, 1, H7), 4.80, 5.15 (ABq, 2, J=14Hz, CH2OAc), 5.38 (s, 2, CH2Ar), and 7.60, 8.23 (ABq, 4, J=9Hz, ArH); mass spectrum m/e 437 (M+), 380, 321, 257, 186, 169, and 136.

Provenance & Evidence