5-(2-Oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoic acid → {3-Benzyloxy-4-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoylamino]-phenyl}-carbamic acid 9H-fluoren-9-ylmethyl ester

Participants

Reaction Steps

5-(2-Oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoic acid (388) (0.293 g, 1.2 mmol) and 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyl-uronium hexafluorophosphate (HBTU) (0.455 g, 1.2 mmol) were combined and dissolved in DMA (24 mL). iPr2EtN (0.313 mL, 1.8 mmol) was added and the mixture was shaken for 30 minutes at room temperature. The (4-amino-3-benzyloxy-phenyl)-carbamic acid 9H-fluoren-9-ylmethyl ester (65) (0.25 g, 0.573 mmol) was added and the mixture was shaken in a 40 mL I-Chem vial for 16 h. LC-MS indicated complete coupling at this point. The mixture was poured into ice-water and a very pale/purple powder precipitated. Collection by filtration under reduced pressure followed by drying under high vacuum for 16 h gave the desired product (389) as a white/purple solid (0.28 g, 0.422 mmol, 73.7% yield). LC-MS (ESI): (exact mass: 662.26) m/e 663.2 [M+1]+ (100%).

Provenance & Evidence