Iodine → 1,6-Dihydro-2,3-dimethyl-6-(4-methylphenyl)-1-phenoxycarbonyl pyridine

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Reaction Conditions

Reaction Steps

A solution of p-bromotoluene (13.5 g) in 50 ml of tetrahydrofuran was added to magnesium (1.5 g) and 1 crystal of iodine in a little tetrahydrofuran, and the mixture was refluxed for 1 hour. In a separate flask, a solution of 2,3-lutidine (6.5 g) in 100 ml of tetrahydrofuran was cooled to about -60° C., and the magnesium complex prepared above added, followed by phenyl chloroformate (8 ml). The mixture was stirred for 1 hour at -60° C., then at room temperature overnight. The solvent was removed under reduced pressure, the residue partitioned between ether and 200 ml of 20% ammonium chloride, the organic layer washed with water, followed by dilute hydrochloric acid. The solvent was evaporated under reduced pressure, and the residue flash-chromatographed on silica gel, eluting with 1% ethyl acetate in heptane, to yield 12.4 g of 1,6-dihydro-2,3-dimethyl-6-(4-methylphenyl)-1-phenoxycarbonyl pyridine, m.p. 106° C.

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