N-[3-(Dimethylamino)propyl]-N'-ethylthiourea

Conditions: temp:23.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a stirred solution of tert-butyl-(2-isothiocyanato-5-nitro-benzyloxy)-dimethyl-silane (Example C1) (2.0 g, 6.0 mmol; HPLC: 4.446 min) in acetonitrile (30 mL) at 23° C. was added 2-methoxybenzylamine (0.82 ml, 6.0 mmol; HPLC: 1.773 min) and the mixture was stirred at 23° C. for 15 min (HPLC: 3.487 min 100%). Added tetrabutylammonium fluoride trihydrate (TBAF.3H2O) (1.945 g, 6.0 mmol) and stirred at 23° C. for 1 h (HPLC: 2.188 min 100%). Added 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC.HCl) (1.772 g, 9.0 mmol) and stirred at 90° C. for 4 to 18 h (HPLC product at 1.667 min, 1-(3-dimethylamino-propyl)-3-ethyl-thiourea at 0.31 min). Cooled to rt, diluted with ethyl acetate and water, added little 1 M NaH2PO4.2H2O solution to achieve pH 4, separated phases, washed organic layer with brine and dried over sodium sulfate. Removal of the solvent in vacuum left a yellow foam, which was purified by flash chromatography on silica gel with n-heptane and ethyl acetate to give the title compound as a yellow foam (1.43 g, 74%), MS (ISP) m/e=288.8 [(M+H)+]. Cooled to rt separated phases washed organic layer with brine dried over sodium sulfate Removal of the solvent in vacuum left a yellow foam, which was purified by flash chromatography on silica gel with n-heptane and ethyl acetate