3,4-Dichlorobenzyl chloride → 4-{2-[3-(1-tert-Butoxycarbonylmethyl-piperidin-4-yl)-1-(3,4-dichloro-benzyl)-1H-indazol-6-yl]-(E)-vinyl}-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

Sodium hydride (12.2 mg; 0.304 mmol) was added to a stirred solution of 4-{2-[3-(1-tert-butoxycarbonylmethyl-piperidin-4-yl)-1H-indazol-6-yl]-(E)-vinyl} piperidine-1-carboxylic acid tert-butyl ester (145 mg; 0.276 mmol) in dry DMF (5 ml) and the mixture was stirred at 23° under nitrogen for 25 min. 3,4-Dichlorobenzyl chloride (0.043 ml, 0.304 mmol; Aldrich) was added, and the mixture was stirred at 23° for 18 h. The solvent was evaporated in vacuo and the residue partitioned between water (25 ml) and ethyl acetate (3×20 ml). The organic layers were washed with 50:50 brine: water (30 ml) and brine, dried (MgSO4) and evaporated in vacuo to give a yellow oil (193 mg). Purification by flash chromatography on silica gel (Merck 9385), eluting with ether: cyclohexane 70:30 gave the title compound as a colourless oil (117 mg; 62%).

Provenance & Evidence