3-Chloroaniline → tert-Butyl 4-(2-(3-chlorophenylamino)-2-oxoethyl)piperazine-1-carboxylate

Participants

Reaction Steps

To a round-bottomed flask containing 2-(1-tert-butoxycarbonyl-piperazin-4-yl)-acetic acid×2HCl (0.100 g, 0.36 mmol) was added 3-chloroaniline (0.050 g, 0.40 mmol) with the aid of anhydrous dichloromethane (4.5 ml). The reaction mixture was cooled into an ice-bath under argon, and then diisopropylethylamine (0.139 g, 1.08 mmol) was added followed by PyBOP (0.187 g, 0.36 mmol). The ice-bath was removed and the reaction mixture was allowed to stir for 20 h under argon. The solvent was removed in vacuo, the residue was absorbed on silica gel and the free running powder was placed on a 10 g isolute silica column which was eluted with 25% ethyl acetate in dichloromethane. The title compound was obtained as a white solid (0.079 g, 62%). 1H-NMR (500 MHz, DMSO-d6) 1.40 (s, 9H, C(CH3)3), 2.46 (br s, 4H, piperazine N(CH2)2), 3.39 (br s, 4H, piperazine N(CH2)2), 3.16 (s, 2H, NCH2CO), 7.11 (d, J=8.59 Hz, 1H) and 7.55 (d, J=8.19 Hz, 1H) (4-ArH and 6-ArH), 7.34 (t, J=8.19 Hz, 1H, 5-ArH), 7.84 (t, J=1.9 Hz, 1H, 2-ArH), 9.89 (s, 1H, CONH);

Provenance & Evidence