Potassium Phosphate, Tribasic → 5-Methyl-2-isopropyloxy-4-(pyridine-4-YL)-nitrobenzene

Participants

Reaction Conditions

Reaction Steps

4-Pyridineboronic acid (147 mg, 1.20 mmol, 1.1 equiv.) is dissolved in a 2:1 v/v mixture of dioxane and H2O (15 mL) and N2 is bubbled through for 5 minutes. Tris(dibenzylidene acetone)dipalladium (0) (100 mg, 0.109 mmol, 0.1 equiv.), 2-dicyclohexylphosphine-2′-6′-dimethoxy biphenyl (112 mg, 0.272 mmol, 0.25 equiv.), 1-chloro-5-isopropoxy-2-methyl-4-nitro-benzene (Intermediate 4, 250 mg, 1.09 mmol, 1.0 equiv.) and K3PO4 (462 mg, 2.18 mmol, 2.0 equiv.) are added under a N2 blanket. The reaction vessel is sealed and heated with microwave irradiation to 150° C. for 20 min. After cooling to room temperature, the reaction is diluted with ethyl acetate and washed with 1 N aqueous NaOH (2×), the organic layer is then dried over Na2SO4 and filtered. After concentration, the crude product is purified by silica gel chromatography (gradient from hexanes to 30% ethyl acetate in hexanes) to give 4-(5-Isopropoxy-2-methyl-4-nitro-phenyl)-pyridine as a brown solid: ESMS m/z 273.1 (M+Ft).

Provenance & Evidence