Acetic Acid → 1-(3-Fluoro-4-nitrobenzyl)-4-methylpiperazine

N-methyl piperazine (1.97 mL, 17.8 mmol) was added dropwise to a solution of 3-fluoro-4-nitrobenzaldehyde (1.50 g, 8.88 mmol) and acetic acid (0.20 mL, 3.54 mmol) in toluene (8.4 mL) at room temperature. The reaction mixture was stirred for 1.5 h at room temperature before the addition of further toluene (3.15 mL) and sodium triacetoxyborohydride (2.97 g, 14.0 mmol). The reaction mixture was stirred for 70 min and then further sodium triacetoxyborohydride (0.40 g, 1.9 mmol) was added. The reaction mixture was stirred for 50 min, and then quenched by the addition of MeOH (2 mL) and saturated aqueous NaHCO3 (10 mL). The reaction mixture was stirred for 30 min. The phases were separated and the aqueous layer was extracted with toluene (2×20 mL, 1×10 mL). The combined organic extracts were concentrated under reduced pressure and purified by flash column chromatography (EtOAc:MeOH:NEt3 19:1:0.1) to give the title compound (1.85 g, 82%) as an orange oil.

1. stirringThe reaction mixture was stirred for 50 min
2. customquenched by the addition of MeOH (2 mL) and saturated aqueous NaHCO3 (10 mL)
3. stirringThe reaction mixture was stirred for 30 min
4. customThe phases were separated
5. extractionthe aqueous layer was extracted with toluene (2×20 mL, 1×10 mL)
6. concentrationThe combined organic extracts were concentrated under reduced pressure
7. custompurified by flash column chromatography (EtOAc:MeOH:NEt3 19:1:0.1)

ORD record

ord-32a53f11d4a14eb9bf33606e7789e498

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08236954B2