Cesium carbonate → 2,3-Dimethoxy-6-[1,2,3]triazol-2-yl-benzoic acid

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To a 20 ml microwave vial containing 2-bromo-4,5-dimethoxybenzoic acid (3 g, 11.5 mmol), copper iodide (0.04 g, 0.5 mol %), cesium carbonate (7.5 g, 23 mmol), triazole (1.33 mL, 23 mmol) and finally (R,R)-(−)-N,N′-dimethyl-1,2-cyclohexanediamine ligand (0.36 mL, 2.3 mmol) was added DMF (12 mL). The resulting clumpy yellow slurry was stirred until evenly dispersed then heated to 120° C. for 10-20 min using a microwave. At this point the reaction mixture appeared as a blue slurry which was then diluted with 20 mL ether and 20 mL H2O. The resulting solution was thoroughly stirred and transferred to a separatory funnel then the RBF was subsequently rinsed with 20 mL ether and H2O each. The aqueous layer was separated from the organic layer and acidified to pH 1 with 6 mL conc. HCl. The now brown/lime green aqueous layer was extracted twice with EtOAc. The bright yellow organic layers were combined and dried with Na2SO4 and then conc. into a yellow powder under reduced pressure which was purified by FCC (0-5% MeOH in DCM w/0.5% AcOH) to afford 2,3-dimethoxy-6-[1,2,3]triazol-2-yl-benzoic acid (60%) and 2,3-dimethoxy-6-[1,2,3]triazol-1-yl-benzoic acid (20%). Data for 2,3-dimethoxy-6-[1,2,3]triazol-2-yl-benzoic acid, MS (ESI): mass calculated for C11H11N3O4, 249.23; m/z found 250.3 [M+H]+. 1H NMR (400 MHz, CD3OD): 7.87 (s, 2H), 7.47 (s, 1H), 7.18 (s, 1H), 3.94 (s, 3H), 3.91 (s, 3H).

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