Piperidine → 5-(2-Oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoic acid (4-amino-2-hydroxyphenyl)-amide

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Reaction Steps

{3-Hydroxy-4-[5-(2-oxo-hexahydro-thieno[3,4-d]imidazol-4-yl)-pentanoylamino]-phenyl}-carbamic acid 9H-fluoren-9-ylmethyl ester (390) (0.152 g, 0.266 mmol) was dissolved in a mixture of THF (10 mL) and DMF (4 mL). Piperidine (0.53 mL, 5.3 mmol) was added. The mixture was shaken at room temperature for 3 h. LC-MS indicated complete de-protection at this point. The mixture was diluted with EtOAc (100 mL), water (2×50 mL) and brine (2×50 mL) via extraction, dried over MgSO4 and concentrated under reduced pressure to give an oil. Purification by flash chromatography on silica gel using a gradient of hexane and EtOAc (eluting with 15–100% EtOAc/hexane in 30 minutes) gave the desired product (391) as a beige oil (0.076 g, 0.217 mmol, 81.6% yield). LC-MS (ESI): (exact mass: 350.14) m/e=351.3 [M+1]+ (100%), 701.3 [2M+1]+ (15%).

Provenance & Evidence