Trifluoroacetic acid → 5-(4-((4-Fluoropiperidin-4-yl)methylamino)-5-(4-methoxyphenyl)pyridin-2-ylamino)pyrazine-2-carbonitrile

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Reaction Steps

5-Aminopyrazine-2-carbonitrile (5.45 mg, 0.045 mmol), Xantphos (1.749 mg, 3.02 μmol), tris(dibenzylideneacetone)dipalladium(0) (1.384 mg, 1.511 μmol), and cesium carbonate (24.62 mg, 0.076 mmol) were added to tert-butyl 4-((2-chloro-5-(4-methoxyphenyl)pyridin-4-ylamino)methyl)-4-fluoropiperidine-1-carboxylate (17 mg, 0.038 mmol) in a 0.2 mL microwave reaction vial. The vial was sealed and an inert atmosphere was introduced before dry dioxane (291 μL) was added. Nitrogen was bubbled through the mixture for 5 min. The mixture was heated at 150° C. for 1 hr by microwave irradiation. After cooling the mixture was diluted with 20% dichloromethane in MeOH and loaded onto a preparative thin layer chromatography plate. Elution with 50% EtOAc in hexane gave tert-butyl 4-((2-(5-cyanopyrazin-2-ylamino)-5-(4-methoxyphenyl)pyridin-4-ylamino)methyl)-4-fluoropiperidine-1-carboxylate (1.5 mg, 2.81 μmol, 7% yield) as a light yellow powder. LCMS (4) Rt=2.35 min; m/z (ESI+) 534 (MH+). Trifluoroacetic acid (0.1 mL, 1.298 mmol) was added to tert-butyl 4-((2-(5-cyanopyrazin-2-ylamino)-5-(4-methoxyphenyl)pyridin-4-ylamino)methyl)-4-fluoropiperidine-1-carboxylate (1.5 mg, 2.81 μmol) dissolved in dichloromethane (0.5 mL) and the solution was stirred for 1 hr. The volatiles were removed in vacuo and the crude product was purified by ion exchange on Isolute SCX II acidic resin (1 g), followed by preparative thin layer chromatography, eluting with 10% MeOH/1% NH3/89% dichloromethane, to give 5-(4-((4-fluoropiperidin-4-yl)methylamino)-5-(4-methoxyphenyl)pyridin-2-ylamino)pyrazine-2-carbonitrile (1 mg, 2.307 μmol, 82% yield) as a yellow powder.

Provenance & Evidence