HOAt → 2,2-Dimethylpropionic acid 2-{(R)-3-[2-((S)-2-tert-butoxycarbonylaminobutyrylamino)-5-fluorophenylamino]piperidin-1-yl}ethyl ester

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Reaction Steps

To an ice-cooled mixture of 2,2-dimethylpropionic acid 2-[(R)-3-(2-amino-5-fluorophenylamino)piperidin-1-yl]ethyl ester (500 mg, 1.48 mmol), (S)-2-tert-butoxycarbonylaminobutyric acid (331 mg, 1.63 mmol) and HOAt (202 mg, 1.48 mmol) in DCM (30 mL) was added N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (341 mg, 1.78 mmol). The reaction mixture was stirred in the ice bath for 1 h, then diluted with DCM, washed with 2M Na2CO3, then water. The organic fraction was dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si—PCC, gradient 50-80% EtOAc in cyclohexane) affording the title compound as a pink gum (0.734 g, 95%). LCMS (Method B): RT 2.56 min [M+H]+ 523.

Provenance & Evidence