Methanamine, N-methoxy-, hydrochloride (1:1) → N,2-dimethoxy-N-methyl-2-(4-(5-methyl-1,3,4-oxadiazol-2-yl)phenyl)acetamide

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Reaction Steps

To an ice-cold solution of 2-methoxy-2-(4-(5-methyl-1,3,4-oxadiazol-2-yl)phenyl)acetic acid (6.8 g, 27.4 mmol) in anhydrous CH2Cl2 (270 mL) and diisopropylethylamine (17 mL, 97 mmol) under argon was added bis(2-methoxyethyl)aminosulfur trifluoride (5.6 mL, 30.3 mmol) dropwise. After stirring over an ice bath for 45 min, N,O-dimethylhydroxylamine hydrochloride (3.40 g, 34.8 mmol) was added in three aliquots over a period of 15 min. The mixture was stirred for 15 min then the ice bath was removed. After 3 hrs, saturated aqueous NaHCO3 was added and stirred for 30 min. The layers were separated and the aqueous layer was extracted with CH2Cl2. The combined organics were washed with saturated aqueous NaHCO3, H2O and brine, dried over MgSO4, filtered through Celite and concentrated in vacuo. Purification by chromatography (75-100% EtOAc-hexanes then 0-5% EtOH-EtOAc) gave N,2-dimethoxy-N-methyl-2-(4-(5-methyl-1,3,4-oxadiazol-2-yl)phenyl)acetamide as an oil that solidified upon standing (2.06 g, 26% yield).

Provenance & Evidence