反应详情

p-Nitrobenzyl 5-hydroxy-5-acetoxymethyl-5,6-dihydro-4H-1,3-thiazine-4-carboxylate (1.27 g., 3.45 mMol) and Et3N (0.58 ml., 4.16 mMol) in anhydrous CH2Cl2 (50 ml.) is stirred under a N2 atomsphere at room temperature while a solution of N3CH2COCl (0.36 ml., 4.13 mMol) in anhydrous CH2Cl2 (20 ml.) is added dropwise over 90 min. After stirring 30 more min., the solution is washed twice with H2O and brine, dried with MgSO4, filtered, and evaporated in vacuo. The residual oil us chromatographed on a column of Baker silica gel. Elution with 3:1 PhH-EtOAc yields p-nitrobenzyl 7α-azido-3-hydroxy-3-acetoxymethyl-cepham-4-carboxylate.

1. additionis added dropwise over 90 min
2. wash, the solution is washed twice with H2O and brine
3. dry with materialdried with MgSO4
4. filtrationfiltered
5. customevaporated in vacuo
6. customThe residual oil us chromatographed on a column of Baker silica gel
7. washElution with 3:1 PhH-EtOAc