反应详情

To a cooled (-10°) and stirred solution of p-nitrobenzyl 2-(4-acetylthio-2-oxo-1-azetidinyl)-2-hydroxy-acetate (102 g., 0.250 mole) in tetrahydrofuran (2000 ml.) were added in succession pyridine (27.1 ml., 0.287 mole) and thionyl chloride (25.2 ml., 0.287 mole); the thionyl chloride addition was done over ca 15 minutes. The mixture was stirred for 30 minutes at -10° and filtered. Concentration of the filtrate left a yellow oil which was partially purified by absorption on a pad of silica gel (800 ml.) and elution with chloroform (ca 3000 ml.). Concentration of the eluates gave an oil (92.9 g., 100%) which was found to contain a minimum of 90% of the title ester as a mixture of epimers.

1. temperatureTo a cooled (-10°)
2. waitwas done over ca 15 minutes
3. filtrationfiltered
4. waitConcentration of the filtrate left a yellow oil which
5. customwas partially purified by absorption on a pad of silica gel (800 ml.) and elution with chloroform (ca 3000 ml.)
6. customConcentration of the eluates gave an oil (92.9 g., 100%) which
7. additionas a mixture of epimers