Triethylamine → 4-(Benzothiazol-2-ylamino)-piperidine-1-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A mixture of 2-chloro-benzothiazole (2.00 g, 12.0 mmol, 1.0 equiv), ethyl 4-amino-1-piperidine carboxylate (2.44 g, 14.0 mmol, 1.2 equiv) and triethylamine (1.79 g, 18.0 mmol, 1.5 equiv) was heated by microwave irradiation to 180° C. for 5 min. To the crude reaction mixture was added dichloromethane (10 mL) and the suspension quickly poured onto tert-butyl methylether (200 mL). The hydrochloric salts of remaining ethyl 4-amino-1-piperidine carboxylate and triethylamine precipitated out and were removed by filtration. The filtrate was evaporated to dryness and the residue purified with column chromatography on silica eluting with dichloromethane/methanol (95:5) to yield 2.7 g (75%) of the title compound as a white solid. 1H NMR (300 MHz, DMSO): δ 1.19 (t, J=7.1 Hz, 3H), 1.31-1.44 (m, 2H), 1.96-2.01 (m, 2H), 2.98-3.06 (m, 2H), 3.88-3.98 (m, 3H), 4.04 (q, J=7.1 Hz, 2H), 7.01 (t, J=7.4 Hz, 1H), 7.21 (t, J=7.8 Hz, 1H), 7.39 (d, J=7.4 Hz, 1H), 7.65 (d, J=7.8 Hz, 1H), 8.01 (d, J=7.3 Hz, 1H). MS (ISP): 306.0 [M+H]+.

Provenance & Evidence