Cl[C:2]1[CH:7]=[CH:6][N:5]=[CH:4][C:3]=1[N+:8]([O-:10])=[O:9].B([C:14]1[CH:15]=[C:16]([CH:20]=[CH:21][CH:22]=1)[C:17]([OH:19])=[O:18])(O)O.C(=O)([O-])[O-].[K+].[K+]>O1CCOCC1>[N+:8]([C:3]1[CH:4]=[N:5][CH:6]=[CH:7][C:2]=1[C:14]1[CH:15]=[C:16]([CH:20]=[CH:21][CH:22]=1)[C:17]([OH:19])=[O:18])([O-:10])=[O:9]To a degassed mixture containing 4-chloro-3-nitropyridine (3.0 g, 18.9 mmol), 3-boronobenzoic acid (3.7 g, 22.7 mmol), potassium carbonate (5.2 g, 37.8 mmol) and dioxane (189 mL) was added tetrakis(tiphenylphosphine)palladium(0) (0.30 g, 0.28 mmol) in one portion under a nitrogen atmosphere. The mixture was heated with fast stirring at 100° C. for 15 h, cooled to room temperature, filtered and concentrated to afford 3-(3-nitropyridin-4-yl)benzoic acid as a tan residue which was used without further purification. LCMS: retention time: 1.375 min. LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a Waters-Sunfire, 5u, C18, 4.6×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 4 mL/min, a gradient of 100% solvent A/0% solvent B to 0% solvent A/100% solvent B, a gradient time of 3 min, a hold time of 1 min, and an analysis time of 4 min where solvent A was 10% CH3CN/90% H2O/10 mM TFA and solvent B was 10% H2O/90% CH3CN/10 mM TFA. MS data was determined using a Micromass Platform for LC in electrospray mode. m/z 245 (MH+).
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