Sulfuric Acid → (2S)-5-[(benzyloxy)amino]-2-cyanopiperidine

Participants

Reaction Conditions

Reaction Steps

Sulphuric acid (11.7 ml, 0.217 mol) was slowly added to a stirred solution of (2S)-5-[(benzyloxy)imino]-2-cyanopiperidine (IX) (10 gm, 0.0436 mol, prepared according to the procedure described in step 6) in ethyl acetate (150 ml) at −10° C. After 10 minutes of stirring, sodium triacetoxy borohydride (NaHB(OOCCH3)3) (11.7 gm, 0.0519 mol, 95% purity) was added in small portions while maintaining temperature below −5° C. After completion of the addition, stirring was further continued for 2 hour at the same temperature. The pH of the reaction mixture was adjusted to about pH 7 by using 30% aqueous potassium hydrogen carbonate solution. The mixture was allowed to warm to 25° C. and the reaction mixture was filtered under suction. The organic layer was separated and the aqueous layer extracted with fresh ethyl acetate (50 ml). The combined organic layer was washed with water (50 ml) and brine (50 ml), dried over anhydrous sodium sulphate and the solvent evaporated under reduced pressure to obtain 8.88 gm of (2S)-5-[(benzyloxy)amino]-2-cyanopiperidine (X) as an oil, in 88% yield. This was used as such for the next step without further purification.

Provenance & Evidence