Ethyl 2-methylacetoacetate → 5-Ethyloxycarbonyl-5-methyl-6-oxo-1-heptanesulfonic acid

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Reaction Steps

Ethyl 2-methylacetoacetate (43.2 g) in N,N-dimethylformamide (25 ml) was added to a suspension of sodium hydride (12.0 g of 60% NaH in mineral oil) in N,N-dimethylformamide (100 ml), dropwise with ice-bath cooling. This mixture was allowed to warm to ambient temperature for 30 mins before re-cooling. 1,4-butanesultone (40.8 g) in N,N-dimethylformamide (25 ml) was then added dropwise. The final mixture was heated at 50° C. for 18 hrs, then quenched with 50 ml of water. The solvent was evaporated under vacuum; the residue was partitioned between water and diethyl ether. The aqueous layer was collected, washed with fresh diethyl ether and evaporated under vacuum; final drying was under high vacuum over phosphorus pentoxide. A yield of 103 g of 5-(ethoxycarbonyl)-5-methyl-6-oxoheptane-1-sulfonic acid was obtained.

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