An Improved Stereospecific Preparation of 7α-Alkoxycephalosporins

Reactions of cephalosporin sulfones 3. Synthesis of 2‐phenylhydrazonocephem‐sulfones. A new potential entry to 2‐aminocephems

“…This solution was used for the subsequent coupling reactions. To an ice-cold solution of 200 mg of 1a [9] in 20 ml of methanol a hydrochloric acid solution of diazoted aniline was added in several portions (prepared from 1.9 ml of aniline as described above) until no starting material could be detected by thin layer chromatography. After 1 hour in the cold the reaction mixture was diluted with 30 mL of water, extracted twice with dichloromethane (10 mL).…”

“…COOCH 3 ),4.23, 4.37 (2H, ABq, J = 18.20 Hz, 2-CH 2 ),5.33 (H, d, J = 4.68 Hz, 6.04 (H, dd, J = 4.68,9.39 Hz, 7-H), 6.86-7.00 (5H, m, aromatic), 8.60 (H, d, J = 9.39 Hz, NH); 13 C nmr (500 MHz, deuteriodimethylsulfoxide): δ 19.40, 52.54, 55.36, 57.61, 66.81, 67.10, 114.70, 121.26, 121.99, 129.48, 130.43, 156.83, 161.18, 163.10, 168.27. …”