Diisopropylethylamine → 4-[4-(6-Chloro-benzo[b]thiophene-2-sulfonyl)-2-oxo-piperazin-1-ylmethyl]-piperidine-1-carboxylic acid tert-butyl ester

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Reaction Steps

To a solution of 4-(2-oxo-piperazin-1-ylmethyl)-piperidine-1-carboxylic acid tert-butyl ester (1.44 g, 4.8 mmol) in CH2Cl2 (75 mL) and MeCN (10 mL) is added diisopropylethylamine (1.3 mL, 4.8 mmol) followed by 6-chloro-benzo[b]thiophene-2-sulfonyl chloride (1.29 g, 4.8 mmol), and the reaction is allowed to stir 16 h. The reaction is diluted with CH2Cl2 and washed with 1N HCl and NaHCO3, dried and concentrated. The residue is purified by column chromatography (silica, 40% EtOAc/CH2Cl2) to provide 4-[4-(6-chloro-benzo[b]thiophene-2-sulfonyl)-2-oxo-piperazin-1-ylmethyl]-piperidine-1-carboxylic acid tert-butyl ester. 1H NMR (300 MHz, CDCl3) δ 7.88-7.83 (m, 3H), 7.47 (dd, 1H), 4.1 (br, 2H), 3.86 (s, 2H), 3.46 (bs, 4H), 3.25 (br, 2H), 2.61 (t, 2H), 1.87-1.75 (m, 1H), 1.51 (d, 2H), 1.41 (s, 9H), 1.10 (ddd, 2H); MS (Ion spray) 528 (M+H)+.

Provenance & Evidence