Tetrahydrofuran → HCID 59486435, compound

Participants

Reaction Steps

Boc-anhydride (2.2 ml, 11.1 mmol, 1.2 eq.) was added to a solution of (R)-methyl 4-(1-aminoethyl)benzoate hydrochloride (2.0 g, 9.2 mmol, 1.0 eq.) and TEA (2.4 ml, 18.4 mmol, 2.0 eq.) in DCM (50 ml) at 0° C. and the reaction mixture was stirred at RT for 16 h. The mixture was diluted with DCM (75 ml) and washed with water (50 ml) and brine (50 ml). The organic layer was dried over Na2SO4 and concentrated to give the crude product which was purified by column chromatography (silica gel; 20% ethyl acetate/hexanes) to yield the desired compound as a white solid. Yield: 64% (2.0 g, 7.16 mmol) 2. A solution of (R)-methyl 4-(1-(tert-butoxycarbonylamino)ethyl)benzoate (2.0 g, 7.16 mmol, 1.0 eq.) in THF (50 ml) was added dropwise to a suspension of LAH (326 mg, 8.6 mmol, 1.2 eq.) in THF (50 ml) at 0° C. and the reaction mixture was stirred at RT for 2 h. After completion of the reaction (monitored by LCMS) the reaction mixture was quenched with THF—H2O (9:1, 20 ml) and filtered through celite. The filtrate was concentrated under reduced pressure to give the crude product which was purified by column chromatography (silica gel; 30% ethyl acetate/hexanes) to yield the title compound as a yellow semi solid. Yield: 83% (1.5 g, 5.97 mmol) 3. Methanesulfonyl chloride (360 μl, 4.78 mmol, 1.2 eq.) was added to a solution of (R)-tert-butyl 1-(4-(hydroxymethyl)phenyl)ethylcarbamate (1.0 g, 3.98 mmol, 1.0 eq.) and TEA (1 ml, 7.96 mmol, 2.0 eq.) in DCM (30 ml) at 0° C. and the resulting reaction mixture was stirred at RT for 2 h. The reaction mixture was diluted with DCM (50 ml) and washed with water (20 ml) and brine (20 ml), and dried over Na2SO4. The solvent was evaporated under reduced pressure to yield the crude product which was used in the next step without further purification. 4. A mixture of (R)-4-(1-(tert-butoxycarbonylamino)ethyl)benzyl methanesulfonate (1.0 g, 3.03 mmol, 1.0 eq.), tert-butyl amine (1.6 ml, 15.15 mmol, 5.0 eq.) and K2CO3 (1.04 g, 7.59 mmol, 2.5 eq.) in THF (30 ml) was heated at reflux for 20 h. After completion of the reaction (monitored by TLC) the solvent was evaporated under reduced pressure and the residue was diluted with water (50 ml), extracted with DCM (100 ml) and dried over Na2SO4. The solvent was evaporated under reduced pressure to give the crude product which was purified by column chromatography (neutral alumina; 0.5% MeOH/DCM) to yield the title compound as a light yellow sticky solid. Yield: 32% (300 mg, 0.98 mmol) 5. TFA (1 ml) was added to a solution of (R)-tert-butyl 1-(4-((tert-butylamino)methyl)-phenyl)ethylcarbamate (370 mg, 1.2 mmol, 1.0 eq.) in DCM (4 ml) at 0° C. and the resulting reaction mixture was stirred at RT for 2 h. The solvent was evaporated under reduced pressure and the residue was azeotroped with toluene to yield the desired product which was used in the next step.

Provenance & Evidence