Cesium carbonate → 1,1-Dimethyl-3-(4-((2-methyl-6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea

Participants

Reaction Conditions

Reaction Steps

A solution of Example A3 (8.0 g, 30 mmol) in dioxane (150 mL) was sparged with Ar under sonication for 20 min, treated with N,N-dimethylurea (10.6 g, 120 mmol), XANTPHOS (3.48 g, 6.02 mmol), and Cs2CO3 (1.226 g, 3.76 mmol), sparged with Ar under sonication for 30 min, treated with Pd2(dba)3 (2.76 g, 3.01 mmol), sparged again with Ar under sonication for 30 min and heated at 100° C. overnight. The mixture was cooled to RT and diluted with EtOAc. The solids were removed via filtration through diatomaceous earth and washed with EtOAc. The filtrates were concentrated to dryness. The residue was partitioned into EtOAc and water. The aqueous layer was back-extracted with EtOAc (3×) and the combined organics were dried (Na2SO4) and concentrated. MeCN was added and the mixture was sonicated. The solids were collected by filtration to provide 1,1-dimethyl-3-(4-((2-methyl-6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea, crop 1. The filtrate was concentrated to dryness. Fresh MeCN was added and the mixture was again sonicated. The solids were collected by filtration to provide 1,1-dimethyl-3-(4-((2-methyl-6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea, crop 2. The filtrate was concentrated in vacuo and purified via silica gel chromatography (MeOH/EtOAc) to afford 1,1-dimethyl-3-(4-((2-methyl-6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea, crop 3. Crops 1-3 of 1,1-dimethyl-3-(4-((2-methyl-6-nitropyridin-3-yl)oxy)pyridin-2-yl)urea were combined (5.2 g, 54%). MS (ESI) m/z: 288.1 (M+H+).

Provenance & Evidence