反应详情

A solution of p-methoxybenzyl 7α-azido-3-hydroxy-3-methyl-cepham-4-carboxylate (310 mg., 0.82 mMol) and Et3N (1.72 μl, 1.23 mMol) in anhydrous CH2Cl2 (4 ml.) is cooled in an ice bath under N2. A solution of MeSO2Cl (83 μl, 1.07 mMol) in anhydrous CH2Cl2 (1 ml.) is added dropwise with stirring over 6 min. The resulting solution is stirred 15 more min. in the cold, then diluted with ice cold CH2Cl2 (5 ml.) and washed with ice cold H2O (5 ml.), 5% HCl (5 ml.), and 5% NaHCO3 (5 ml.). The CH2Cl2 solution is dried over MgSO4, filtered, and evaporated in vacuo to provide p-methoxybenzyl 7α-azido-3-methanesulfonyloxy-3-methyl-cepham-4-carboxylate (355 mg.) as a pale yellow gum: ir (CHCl3) 4.78, 5.63, 5.78, 6.64, 7.43, 7.99, 8.48, and 11.08μ; nmr (CDCl3) δ2.03 (s, 3, CH3), 2.68 (s, 3, SO2CH3), 3.00 (d, l, J=14Hz, SCH), 3.80 (s, 3, OCH3), 3.82 (d, l, J=14Hz, SCH), 4.47 (d, l, J=1.3Hz, H7), 4.65 (s, l, H4), 4.97 (d, l, J=1.3 Hz, H6), 5.00 and 5.28 (ABq, 2, J=10.5 Hz, CH2Ar), and 6.87 and 7.33 (two d's, 4, J=9Hz, ArH).

1. stirringThe resulting solution is stirred 15 more min
2. washwashed with ice cold H2O (5 ml.), 5% HCl (5 ml.), and 5% NaHCO3 (5 ml.)
3. dry with materialThe CH2Cl2 solution is dried over MgSO4
4. filtrationfiltered
5. customevaporated in vacuo