Sulfuric Acid → 1-Methyl-3-oxo-1,3-dihydro-2,1-benzoxazole-5,7-dicarboxylic acid

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Reaction Steps

Crude 1C is dissolved in a slight excess of aqueous sodium carbonate solution and treated with a 10% excess of dimethylsulfate. The reaction is warmed on a steam bath under nitrogen with swirling until the solution becomes homogeneous. The warm reaction mixture is immediately made acidic with concentrated sulfuric acid and allowed to cool. The precipitate which forms on cooling is collected, dried and used directly in the next step. Mass spectrum, m/e 237 (m+).

Provenance & Evidence