Triethylamine → (R)-(1-(6-amino-5-nitropyridin-2-yl)piperidin-3-yl)(pyrrolidin-1-yl)methanone

Participants

Reaction Conditions

Reaction Steps

To a suspension of (R)-piperidin-3-yl(pyrrolidin-1-yl)methanone hydrochloride (45.56 g, 208.3 mmol) in anhydrous acetonitrile (200 mL) at 10° C. was added triethylamine (50 mL). The suspension was poured into a 2 L 3-neck flask equipped with a thermometer and a magnetic stirrer. To the original flask was added anhydrous acetonitrile followed by sonication and addition of triethylamine (80 mL). The suspensions were combined and cooled to 10° C. and 6-chloro-3-nitropyridin-2-amine (32.97 g, 190 mmol) was added. The bright yellow solution was stirred under nitrogen while the temperature was increased gradually to 80° C. over 1 h. The reaction mixture was cooled to room temperature. The resulting suspension was filtered and the solids were rinsed with ethyl acetate. The filtrate was concentrated under reduced pressure. A saturated aqueous solution of ammonium chloride (500 mL) was added to the residue and the mixture was extracted into ethyl acetate (2×). The combined organics were washed with brine, dried over magnesium sulfate, filtered, concentrated under reduced pressure and dried for 18 h under high vacuum to afford (R)-(1-(6-amino-5-nitropyridin-2-yl)piperidin-3-yl)(pyrrolidin-1-yl)methanone as a yellow foam (63.51 g). 1H NMR (400 MHz, CD3OD) δ 1.47-1.64 (m, 1H) 1.71-2.07 (m, 7H) 2.68 (tt, 1H) 3.01 (q, 2H) 3.33-3.46 (m, 2H) 3.52 (dt, 1H) 3.60-3.70 (m, 1H) 4.41 (br s, 1H) 4.71 (d, 1H) 6.23 (d, 1H) 8.05 (d, 1H); MS (ES+) (M+H) 320.4.

Provenance & Evidence