A mixture of 200 mg (0.666 mmol) 1-(3-bromo-4-nitro-phenyl)-4-methyl-piperazine (as prepared in the previous step), 136 mg (0.999 mmol) and 77.0 mg (0.0666 mmol) of tetrakis(triphenylphosphine)palladium (0) under Ar was added 4.0 mL of degassed dimethoxyethane (DME) and 400 μL (0.799 mmol) of 2.0 M aq Na2CO3. The mixture was heated with stirring under Ar at 80° C. for 14 h. The cooled (RT) mixture was concentrated and chromatographed on a 10-g silica SPE column with 1-5% MeOH in dichloromethane-hexane (1:1). The product fractions were treated with 80 mg of decolorizing carbon, filtered, concentrated, and then rechromatographed on a similar column with 1-3% EtOH-dichloromethane to afford 265 mg of the title compound as a yellow resin (75% purity by 1H-NMR as a mixture with triphenylphosphine) that was used in the following reaction without further purification: Mass spectrum (ESI, m/z): Calcd. for C11H21N3O3, 312.2 (M+H), found 312.2.
