Hydrochloric Acid → (3S*,5R*)-5-(3,3-Dimethyl-butyrylamino)-piperidine-3-carboxylic acid cyclopropyl-(2,3-dichloro-benzyl)-amide

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Reaction Steps

To a stirred, ice-cooled mixture of (3S*,5R*)-5-tert-butoxycarbonylamino-piperidine-1,3-dicarboxylic acid 1-(9H-fluoren-9-ylmethyl) ester (2.33 g, 5 mmol), cyclopropyl-(2,3-dichloro-benzyl)-amine (see WO 03/093267) (1.12 g, 5.2 mmol) and N-ethyldiisopropylamine (6.85 ml, 40 mmol) in dimethylacetamide (30 ml), propylphosphonic anhydride solution (˜50% in DMF, 4.8 ml, ˜7.5 mmol) is added. After stirring for 14 h at RT, DMA is evaporated and the residue is distributed between ethyl acetate and 10% aqueous K2CO3 solution. The organic layer is dried (Na2SO4), evaporated in vacuo and the residue purified by preparative HPLC (YMC-Pack, Pro C18, 10-100% CH3CN+0.1% TFA/H2O+0.1% TFA, 20 min, flow 20 ml/min). The combined pure fractions are treated with solid K2CO3, CH3CN is removed in vacuo and the residual aqueous layer is extracted twice with CH2Cl2. The combined organic layers are dried (Na2SO4) and evaporated. The residue is stirred with HCl in 2-propanol (5 N, 10 ml, 50 mmol) and evaporated to afford the title compound as a white amorphous solid. tR (HPLC, Nucleosil C18; 5-100% CH3CN+0.1% TFA/H2O+0.1% TFA for 8 min, flow 1.5 ml/min): 6.22 min.

Provenance & Evidence