反应详情

To a cooled (0°) and stirred solution of p-nitrobenzyl 2-(4-acetylthio-2-oxo-1-azetidinyl)-2-hydroxyacetate (3.79 g., 10.7 mmole) in tetrahydrofuran (40 ml.) and dioxane (40 ml.) was added pyridine (0.97 ml., 12 mmole) followed by SOCl2 (1.43 g., 0.88 ml., 12 mmole). The mixture was stirred 30 minutes at 0°, the precipitate was removed and washed with toluene, and the combined filtrates were concentrated on a rotary evaporator to leave a yellow oil. Partial purification was achieved by filtering the residue over a silica gel pad and washing with chloroform. δ(ppm, CDCl3): 8.2 (2H, m, aromatic), 7.55 (2H, m, aromatic), 6.12 (1H, s, CHCl), 5.65 (1H, m, H-4), 5.35 (2H, two s, benzylic H), 3.62 (1H, dd, J3-3 =16, J3-4 cis =6, H-3), 3.08 (1H, m, H-3), 2.35 (3H, two s, CH3). The product was obtained as a mixture of two epimers.

1. temperatureTo a cooled (0°)
2. customthe precipitate was removed
3. washwashed with toluene
4. concentrationthe combined filtrates were concentrated on a rotary evaporator
5. customto leave a yellow oil
6. customPartial purification
7. filtrationby filtering the residue over a silica gel pad
8. washwashing with chloroform
9. customThe product was obtained as a mixture of two epimers