Acetic Acid → Tert-Butyl 4-(3-(Isopropylamino)Pyridin-2-Yl)Piperazine-1-Carboxylate

Participants

Reaction Steps

1-[1,1-Dimethylethoxycarbonyl]4-[3-amino-2-pyridinyl]piperazine (International Publication 88/08424, 2.0 g) is dissolved in 35 ml of methanol and acetone (0.48 g) is added. The reaction is cooled to 0° and acetic acid (to pH 4.0) is added. The reaction is stirred 15 min at 0° and then sodium cyanoborohydride (0.50 g) is added. The reaction is allowed to warm slowly to 20-25° and followed by TLC until completion. Additional acetic acid, sodium cyanoborohydride and acetone arc sometimes necessary to force the reaction to completion. The reaction is diluted with chloroform (100 ml), washed with saturated aqueous sodium bicarbonate (50 ml), saline (75 ml), dried over anhydrous sodium sulfate and concentrated in vacuo. Purification by flash column chromatography (75 g silica gel, 4:1 hexane/ethyl acetate) affords the title compound, NMR (300 MHz, CDCl3) 7.67, 6.91, 4.15, 3.57, 3.00, 1.48 and 1.23 δ.

Provenance & Evidence