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

N-methyl piperazine (0.95 mL, 8.56 mmol) was added dropwise to a suspension of 3-bromo-4-nitrobenzaldehyde (0.985 g, 4.28 mmol) and acetic acid (0.29 mL, 5.14 mmol) in toluene (5.5 mL) at room temperature. The reaction mixture was stirred for 1 h at room temperature before the addition of sodium triacetoxyborohydride (1.36 g, 6.42 mmol). The reaction mixture was stirred for 2 h. Further toluene (2.1 mL) and sodium triacetoxyborohydride (0.18 g, 0.86 mmol) was added and the reaction mixture was stirred for 2 hours and then quenched by the addition of MeOH (0.99 mL). The reaction mixture was stirred for 30 min, saturated aqueous NaHCO3 (6.01 mL) was then added and the reaction mixture was stirred overnight. The phases were separated and the aqueous layer was extracted with toluene (4.0 mL). The combined organic extracts were concentrated under reduced pressure and purified by flash column chromatography (EtOAc:MeOH:NEt3 9:1:0.1) to give the title compound (1.18 g, 88%) as a low melting point waxy brown solid.

1. stirringthe reaction mixture was stirred for 2 hours
2. customquenched by the addition of MeOH (0.99 mL)
3. stirringThe reaction mixture was stirred for 30 min
4. additionsaturated aqueous NaHCO3 (6.01 mL) was then added
5. stirringthe reaction mixture was stirred overnight
6. customThe phases were separated
7. extractionthe aqueous layer was extracted with toluene (4.0 mL)
8. concentrationThe combined organic extracts were concentrated under reduced pressure
9. custompurified by flash column chromatography (EtOAc:MeOH:NEt3 9:1:0.1)

ORD record

ord-67945868ae8b45be898962c3f7a3d891

Source dataset

uspto-grants-2012_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08236954B2