Trifluoromethanesulfonic anhydride → HCID 57309348, compound

Participants

Reaction Steps

To a solution of 4-nitrobenzyl (2R, 5R, 6R)-3,7-dioxo-6-(1-methoxy-1-methylethyl)-1-azabicyclo[3.2.0]heptane-2-carboxylate (450 mg) and 4-(N,N-dimethylamino)pyridine (14.6 mg) in methylene chloride (22.5 ml) was added a solution of N,N-diisopropyl-N-ethylamine (0.249 ml) in methylene chloride (2.241 ml) at -30° C. To the mixture was added further a solution of trifluoromethanesulfonic anhydride (0.211 ml) in methylene chloride (1.899 ml) at -30° C. After stirring for 30 minutes at the same temperature, a solution of 4-(N,N-dimethylamino)pyridine (2.9 mg) and N,N-diisopropyl-N-ethylamine (0.0498 ml) in methylene chloride (0.448 ml) and then a solution of trifluoromethanesulfonic anhydride (0.0422 ml) in methylene chloride (0.38 ml) were added thereto at -30° C. After stirring for 30 minutes at the same temperature a solution of N,N-diisopropyl-N-ethylamine (0.833 ml) in methylene chloride (7.497 ml) and a solution of pyridine-4-thiol (159.5 mg) in N,N-dimethylformamide (5.63 ml) were added successively thereto at -30° C. The resultant solution was stirred for 30 minutes at the same temperature and for additional 30 minutes at 0° C. The solvent was distilled off and the residue was dissolved in ethyl acetate, washed twice with water and a saturated aqueous sodium chloride. After drying over magnesium sulfate, the solution was filtered and evaporated. The residue was chromatographed on deactivated silica gel with 10% water (13.5 g), eluting with a mixture of benzene and acetone (100:1 to 6:1) to give 4-nitrobenzyl (5R, 6R)-6-(1-methoxy-1-methylethyl)-7-oxo-3-(4-pyridylthio)-1-azabicyclo[3.2.0]-hept-2-ene-2-carboxylate (379 mg) as a pale yellow solid.

Provenance & Evidence