Hydrochloric Acid → 5-Benzoyl-1-methylpyrrole-2-acetonitrile

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Reaction Conditions

Reaction Steps

To a chilled suspension of 9.7 g. (0.07 mole) of aluminum chloride in 45 ml. methylene chloride is added 9 ml. (0.07 mole) benzoyl chloride. The resulting solution is added dropwise to a solution of 1-methylpyrrole-2-acetonitrile in 30 ml. methylene chloride while cooling externally with an ammonium chloride ice bath (temperature below 5° C.). After the addition is complete, the reaction mixture is stirred at 0° C. for fifteen minutes and then poured into ice acidified with 3N hydrochloric acid. The acidic fraction is extracted three times with methylene chloride. The organic fractions are combined and washed consecutively with N,N-dimethyl-1,3-propanediamine and 3N hydrochloric acid. The organic solution is dried over anhydrous magnesium sulfate. The solvent is then evaporated off to yield an oily residue which is column chromatographed on neutral alumina using hexane, benzene and ethylacetate as successive solvents. The first few fractions having ultraviolet absorption in the 240-260 mμ range contain the desired product. These fractions are combined, the solvent evaporated off, and the oily residue, when triturated with methanol, yields the crystalline product, 5-benzoyl-1-methylpyrrole-2-acetonitrile, m.p. 106-108° C.

Provenance & Evidence