Trifluoroacetic acid → 5-(1-ethylsulfonyl-3,6-dihydro-2H-pyridin-4-yl)-3-(5-phenyl-1,3,4-oxadiazol-2-yl)pyridin-2-amine

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Reaction Steps

tert-Butyl 4-[6-(tert-butoxycarbonylamino)-5-(5-phenyl-1,3,4-oxadiazol-2-yl)-3-pyridyl]-3,6-dihydro-2H-pyridine-1-carboxylate (141.7 mg, 0.2727 mmol) was dissolved in DCM (2 mL) and treated with TFA (373.1 mg, 252.1 μL, 3.272 mmol) at ambient temperature. The reaction was allowed to stir at ambient temperature for 3 hours and then concentrated in vacuo. The resultant residue was redissolved in DCM and treated with triethylamine (55.19 mg, 76.02 μL, 0.5454 mmol) followed by ethanesulfonyl chloride (17.54 mg, 12.93 μL, 0.1364 mmol). The mixture was allowed to stir at ambient temperature for 16 hours and then concentrated in vacuo. The resultant residue was purified by reverse phase preparative HPLC [Waters Sunfire C18, 10 mM, 100 Å column, gradient 10%-95% B (solvent A: 0.05% TFA in water; solvent B: CH3CN) over 16 minutes at 25 mL/min]. The fractions were collected, passed through a sodium bicarbonate cartridge and freeze-dried to give the title compound as an off-white solid (47 mg, 42% Yield). 1H NMR (400.0 MHz, DMSO) δ 1.25 (t, 3H), 2.67 (br s, 2H), 3.16 (br s, 2H), 3.47 (br s, 2H), 3.94 (br s, 2H), 6.25 (br s, 1H), 7.44 (s, 2H), 7.64-7.69 (m, 3H), 8.22-8.24 (m, 2H), 8.29 (s, 1H) and 8.39 (s, 1H) ppm; MS (ES+) 411.95.

Provenance & Evidence