Acetone → 1-Isopropyl-4-(4-nitrophenyl)piperazine

Participants

Reaction Steps

A suspension of 1-(4-nitrophenyl)piperazine (20 g, 190 mmol, 2 eq), sodium triaectoxyborohydride (41 g, 97 mmol, 2 eq), and acetone (18.8 g, 21.3 mL, 290 mmol, 3 eq) in DCE (400 mL) is stirred in a water bath at rt for 32 h. Water (100 mL) is slowly added (gas evolution) and resulting biphasic solution is stirred for 1 h. The phases are separated and the DCE extract is washed with water (2×100 mL). The combined aqueous extracts are extracted with DCE (2×50 mL), and the combined DCE extracts are filtered through a phase separation tube. The filtrate is concentrated on a rotary evaporator and the yellow oil obtained dried under vacuum for a further 2 h. The oily product obtained solidified on standing to provide 1-isopropyl-4-(4-nitrophenyl)piperazine as a yellow solid (16.5 g, 66% recovery). The product is used in the next step without further purification. LCMS Purity: 80% by ELS detection; LCMS-ESI (m/z): calcd for C13H19N3O2 249.1; [M+H]+ found, 250.3.

Provenance & Evidence