Citric Acid → [1-(5-Hydroxy-5,6-dihydro-4H-cyclopenta[b]thiophen-4-ylcarbamoyl)-2-phenyl-ethyl]-carbamic acid tert-butyl ester

Participants

Reaction Steps

To a mixture of the racemic cis-4-amino-5,6-dihydro-4H-cyclopenta[b]thiophen-5-ol (17.5 g, 0.112 mol) in dry DMF (400 mL) was added Boc-L-phenylalanin (30.51 g, 0.115 mol) HOBT (15.6 g, 0.115 mol) and EDAC (22.0 g, 0.115 mol). To the stirred mixture was added TEA (16 mL, 0.115 mol) and the mixture was stirred at room temperature overnight. The mixture was added to 5% citric acid and extracted three times with ethyl acetate. The organic phase was washed with brine and saturated sodium hydrogen carbonate (two times). The organic phase was dried with sodium sulphate and evaporated under reduced pressure. Yield: 43 g=95%

Provenance & Evidence