Acetonitrile, 2,2-diethoxy- → Methyl 2,2-diethoxyethanecarboximidate

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Reaction Steps

A solution of diethoxyacetonitrile (75 g, 0.579 mol) in methanol (210 mL) was added at room temperature to a solution of sodium methoxide (28.3 g, 0.522 mol) in methanol (450 mL). The mixture was stirred overnight, and then methanol was evaporated. The residue was diluted with dichloromethane (200 mL) and water (300 mL). The organic layer was separated, and the aqueous one was extracted with dichloromethane (2×150 mL). The combined organic layer was dried over Na2SO4 and evaporated to give 83 g of crude methyl 2,2-diethoxyacetimidate (˜90% yield). A solution of methyl 2,2-diethoxyacetimidate prepared above (0.6208 mol, 125.1 g of 80% purity) in methanol (300 mL) was added to a solution of 2,2-difluoro-N′-methylethanehydrazonamide hydrochloride (0.6208 mol, obtained in Step 1) in methanol (700 mL). Anhydrous sodium acetate (61.1 g, 0.745 mol) was added, and the mixture was stirred at 30° C. for 3 days. The reaction mixture was then evaporated, and the residue subjected to chromatography (ethyl acetate/hexane 1:4→1:1) on a silica gel column, followed by vacuum distillation to give 47.6 g (32.6%) of 5-(diethoxymethyl)-3-(difluoromethyl)-1-methyl-1H-1,2,4-triazole.

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