Carbamic acid, ethyl ester → Diethyl(4-Cyano-2-fluorophenyl)methylenedicarbamate

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Reaction Conditions

Reaction Steps

In a three-necked round bottom flask equipped with a drying tube filled with calcium chloride and an inlet for nitrogen, 3-fluoro-4-formylbenzonitrile (5.00 g, 33.5 mmol) and ethyl carbamate (6.57 g, 73.7 mmol) are heated at 150° C. The flask is being purged with a flow of nitrogen, and concentrated sulfuric acid (200 μL) is added drop by drop within 10 min. The mixture is heated at 150° C. for 6 h and then cooled at room temperature. The mixture is ground, treated with water (400 mL) and then stirred for 3 h. The precipitate is filtered and dried. Yield: 6.50 g; ESI mass spectrum: [M+Na]+=332; Retention time HPLC: 0.58 min (Z011_S03).

Provenance & Evidence