Water → N-amino-3-hydroxymethylpyridinium mesityl sulfonate

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Reaction Steps

A solution of O-mesitylenesulfonylhydroxylamine, ˜30-35% water, (14.5 g, 52 mmol) and CH2Cl2 (100 mL) is added to a solution of 3-pyridylcarbinol (5.0 mL, 52 mmol) and CH2Cl2 (100 mL) at 0° C. dropwise over 40 min. After 30 min at 0° C., the ice bath is removed and the solution is stirred at ambient temperature for 20 min. The volatiles are removed under reduced pressure to afford N-amino-3-hydroxymethylpyridinium mesityl sulfonate as a yellow oil. DMF (100 mL) and K2CO3 (15 g, 110 mmol) are added. The dark brown mixture is cooled in a water bath. Dimethyl acetylenedicarboxylate (6.9 mL, 56 mmol) are added dropwise over 10 min. After 15 min, the water bath is removed and the mixture is left to vigorously stir under air for 18 h. After filtering through Celite (CH2Cl2 rinse), the volatiles are removed under reduced pressure. The residue is slurried in EtOAc and the mixture is filtered through Celite (EtOAc rinse). The volatiles are removed under reduced pressure to afford a dark brown oil. Purification by flash column chromatography (2:1 hexanes:EtOAc to 1:1 hexanes:EtOAc) affords the title compound as a light yellow solid. LC-MS m/z (M+Na+): 287.08§.

Provenance & Evidence