tert-butyl N-[3-(4-aminophenoxy)propyl]carbamate

Conditions: temp:-15.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a cooled (−15° C.) solution of 1,1-thiocarbonyidiimidazole (756 mg, 4.115 mmol) (Aldrich) in N,N-dimethylformamide (11 mL) was added dropwise a solution of [3-(4-aminophenoxy)propyl]carbamic acid tert-butyl ester (1.02 g, 3.84 mmol) (from Step B above) in N,N-dimethylformamide (11 mL) over 25 minute. After the addition was complete, the mixture was stirred at −15° C. for 20 minute and then at room temperature for 1 h. Ice-water was added and the mixture was extracted with ether. The ether layer was dried (MgSO4), filtered, and evaporated. The residue was purified on silica gel with 85:15 hexane/ethyl acetate to give [3-(4-isothiocyanatophenoxy)propyl]-carbamic acid tert-butyl ester (1.07 g, 91% yield). HRMS, observed: 308.1197; Calcd for M+:308.1195. After the addition at room temperature for 1 h the mixture was extracted with ether The ether layer was dried (MgSO4) filtered evaporated The residue was purified on silica gel with 85:15 hexane/ethyl acetate