2-Aminothiazole → tert-Butyl 4-(2-oxo-2-(thiazol-2-ylamino)ethyl)piperazine-1-carboxylate

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Reaction Steps

To a round-bottomed flask containing 2-(1-tert-butoxycarbonyl-piperazin-4-yl)-acetic acid×2HCl (0.150 g, 0.54 mmol) was added 2-aminothiazole (0.059 g, 0.59 mmol) and anhydrous dichloromethane (7 ml). The reaction mixture was cooled into an ice-bath under argon, and then diisopropylethylamine (0.29 ml, 1.66 mmol) was added followed by PyBOP (0.280 g, 0.54 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 20 g isolute silica column which was eluted with 30 to 50% ethyl acetate in dichloromethane. The title compound was obtained as a colourless oil that solidified on standing at room temperature (0.123 g, 70%); 1H-NMR (500 MHz, DMSO-d6) 1.40 (s, 9H, C(CH3)3), 2.47 (br t obscured by solvent peak, piperazine NCH2), 3.31 (s, 2H, NCH2CO), 3.34 (br t, 4H, piperazine N(CH2)2), 7.22 (d, J=3.5 Hz, 1H, thiazole H), 7.47 (d, J=3.5 Hz, 1H, thiazole H), 11.84 (s, 1H, CONH);

Provenance & Evidence