Diisopropylamine → (S)-1-(4-ethylthiazol-2-yl)-2-(4-nitrophenyl)ethanamine

Participants

Reaction Conditions

Reaction Steps

A mixture of [2-(4-nitrophenyl)-1-(S)-thiocarbamoylethyl]-carbamic acid tert-butyl ester, 2, (0.245 g, 0.753 mmol), 1-bromo-2-butanone (0.125 g, 0.828 mmol) in CH3CN (5 mL) is refluxed 3 hours. The reaction mixture is cooled to room temperature and diethyl ether is added to the solution and the precipitate which forms is removed by filtration. The solid is dried under vacuum to afford 0.242 g (90% yield) of the desired product. ESI+MS 278 (M+1). Preparation of {1-[1-(4-ethylthiazol-2-yl)-2-(4-nitrophenyl)ethylcarbamoyl]-2-phenylethyl}carbamic acid tert-butyl ester (4): To a solution of 1-(S)-(4-ethylthiazol-2-yl)-2-(4-nitrophenyl)ethyl amine hydrobromide, 3, (0.393 g, 1.1 mmol), (S)-(2-tert-butoxycarbonylamino)-3-phenylpropionic acid (0.220 g, 0.828 mmol) and 1-hydroxybenzotriazole (HOBt) (0.127 g, 0.828 mmol) in DMF (10 mL) at 0° C., is added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDCI) (0.159 g, 0.828 mmol) followed by diisopropylamine (0.204 g, 1.58 mmol). The mixture is stirred at 0° C. for 30 minutes then at room temperature overnight. The reaction mixture is diluted with water and extracted with EtOAc. The combined organic phase is washed with 1 N aqueous HCl, 5% aqueous NaHCO3, water and brine, and dried over Na2SO4. The solvent is removed in vacuo to afford 0.345 g of the desired product which is used without further purification. LC/MS ESI+525 (M+1).

Provenance & Evidence