Diisopropylethylamine → 4-Methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-N-(thiadiazol-2-yl)-benzamide

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Reaction Steps

4-Methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-benzoic acid (2.0 g, 7.63 mmol), DIPEA (4 ml, 22.89 mmol) and HATU (3.05 g, 8.02 mmol) were dissolved in DMF (20 ml) and stirred at room temperature for 15 mins. 2-Aminothiadiazole (810 mg, 8.01 mmol) was added and the reaction stirred at room temperature for 18 hours. The solvent was evaporated under vacuum and the reaction partitioned between ethyl acetate (250 ml) and hydrochloric acid (2N, 150 ml). The aqueous was extracted with ethylacetate (2×250 ml). The combined organic extracts were dried (magnesium sulphate) and the solvent evaporated under vacuum. The residue was absorbed onto silica and purified by flash column chromatography eluting with cyclohexane/ethyl acetate (4:1 then 1:1). The solvent was evaporated from the product fractions under vacuum to 4-methyl-3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-N-(thiadiazol-2-yl)-benzamide (0.95 g). LCMS: retention time 3.34 min, MH+ 346. NMR: δH [2H6]-DMSO 13.08,(1H, b), 9.22,(1H, s), 8.35,(1H, d), 8.11,(1H, dd), 7.38,(1H, d), 2.55,(3H, s), 1.34, (12H, s).

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