2-Methyl-1-butene → 4-(3-Phenylpyrazolo[1,5-a]pyrimidin-6-yl)benzoic acid

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Reaction Steps

A solution of 4-(3-phenylpyrazolo[1,5-a]pyrimidin-6-yl)benzaldehyde (1-5, 250 mg, 0.835 mmol, 1 equiv) in a 4:1 mixture of THF and t-BuOH (20 mL) was treated with 2-methyl butene (5 mL), an aqueous solution of sodium phosphate monobasic (0.14 M, 230 mg, 1.67 mmol, 2 equiv) and sodium chlorite (194 mg, 2.15 mmol, 2.57 equiv). After 1 hour at 23° C., additional solid sodium phosphate monobasic (230 mg, 1.67 mmol, 2 equiv) and sodium chlorite (194 mg, 2.15 mmol, 2.57 equiv) were added. The reaction mixture was stirred for an additional 4 hours, concentrated, and the residue dissolved in EtOAc (100 mL) then washed with a 25:1 mixture of aqueous 10% sodium bisulfite solution and 10% potassium hydrogen sulfate solution (2×100 mL). The organic layer was dried over sodium sulfate and concentrated to afford 4-(3-phenylpyrazolo[1,5-a]pyrimidin-6-yl)benzoic acid (3-1) as a yellow solid. LRMS m/z: Calc'd for C19H14N3O2 (M+H) 316.35, found 316.1.

Provenance & Evidence