[CH2:1]([N:8]1[CH2:13][CH2:12][CH:11]([C:14]([OH:16])=O)[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.C(Cl)(=O)C([Cl:20])=O>>[CH2:1]([N:8]1[CH2:13][CH2:12][CH:11]([C:14]([Cl:20])=[O:16])[CH2:10][CH2:9]1)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=10.278 g (0.00127 mol) of 1-benzylpiperidine-4-carboxylic acid was boiled at reflux in 5 ml of oxalyl chloride for 2 hrs. The excess oxalyl chloride was distilled off. The residue was taken up twice in toluene and concentrated each time. 0.3 g (99%) of 1-benzylpiperidine-4-carboxylic acid chloride was obtained as a pale beige solid. This was dissolved in 20 ml of toluene, treated with 0.265 ml (0.0019 mol) of triethylamine and 0.17 g (0.00165 mol) of benzyl alcohol and boiled at reflux for 18 hrs. After removal of the solvent the residue was chromatographed on silica gel with ether/hexane (1:2) as the eluent. 0.246 g (80%) of benzyl 1-benzylpiperidin-4-carboxylate was obtained as a yellow oil. MS: me/e=310 (C2H23NO2+).
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