反应详情

21.5 g. (0.81 mole) of N-carbobenzyloxy-4-hydroxy-L-proline is oxidized in 1.2 liters of acetone with 83 ml. of 8 N chromic acid in sulfuric acid as described in J.A.C.S.79, 189 (l957). In order to facilitate the subsequent filtration of chromium salts, 30 g. of Celite (diatomaceous earth) is added to the acetone solution before introduction of the oxidizing agent. An air stirrer is employed. The reaction mixture is filtered and the acetone filtrate is concentrated to approximately 300 ml. before diluting with 1 liter of chloroform. The solution is washed with 300 ml. of saturated sodium chloride (four times), dried (MgSO4), filtered and the solvent evaporated to give N-carbobenzyloxy-4-keto-L-proline (22.8 g.) which is crystallized from ether (50 ml.)-hexane (150 ml.) to obtain 17.2 g. (81%) of product, m.p. 99°-101°, [α]D26 +17° (c, 1% in chloroform).

1. filtrationthe subsequent filtration of chromium salts, 30 g
2. additionof Celite (diatomaceous earth) is added to the acetone solution before introduction of the oxidizing agent
3. customAn air stirrer is employed
4. filtrationThe reaction mixture is filtered
5. concentrationthe acetone filtrate is concentrated to approximately 300 ml
6. additionbefore diluting with 1 liter of chloroform
7. washThe solution is washed with 300 ml
8. dry with materialof saturated sodium chloride (four times), dried (MgSO4)
9. filtrationfiltered
10. customthe solvent evaporated