p-Toluenesulfonic acid → (R)-1-((2R,5R)-5-methyl-tetrahydro-furan-2-yl)-propylamine para-toluenesulfonate salt

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Reaction Steps

To an ice-cooled solution of [(R)-1-(2R,5R)-(5-methyl-tetrahydro-furan-2-yl)-propyl]-carbamic acid tert-butyl ester (416 mg, 1.71 mmol) in dry DCM (4 ml) was added TFA (200 μl, 1.41 mmol) under an inert atmosphere of nitrogen. After stirring at room temperature for 3 h, the mixture was diluted with EtOAc (15 ml) and washed with saturated aqueous Na2CO3. The organic portion was dried (Na2SO4) and then para-toluenesulfonic acid (147 mg, 0.77 mmol) was added. After stirring, the solvent was removed in vacuo and recrystallisation from MeCN affords the title compound as a white solid. 1H NMR (DMSO) 0.90 (3H, t, CH3), 1.20 (3H, d, CH3), 1.45 (2H, m, 2×CH), 1.59 (1H, m, CH), 1.65 (1H, m, CH), 1.95 (2H, m, CH2), 2.30 (3H, s, CH3), 2.93 (1H, m, CH), 3.75 (1H, dd, CH), 3.95 (1H, m, CH), 7.10 (2H, d, 2×CH), 7.48 (2H, d, 2×CH), 7.75 (3H, s, NH3+).

Provenance & Evidence