2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 2-Chloro-4-(5-iodothiophen-2-yl)pyrimidine

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Reaction Conditions

Reaction Steps

nBuLi (16 mL, 1.6 M solution in hexane, 25 mmol) was added to a stirred solution of 2,5-diiodothiophene (7.0 g, 21 mmol) in THF (80 mL) at −50° C. The solution was stirred for 10 min at −50° C. before 2.9 g (25 mmol) of 2-chloropyrimidine was added. The reaction solution was stirred for 1 h at −20° C., then cooled to −50° C. and quenched by addition of 2 mL of AcOH in 10 mL of MeOH. Solid 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (10.4 g, 46 mmol) was added and the reaction solution was warmed to 0° C. and stirred for 1 h. The reaction mixture was then poured into 100 mL of a 0.5 M solution of sodium ascorbate, diluted with 250 mL of 1 M aqueous Na2CO3 and the crude product removed by filtration and washed repeatedly with water. The residue was azeotroped with toluene to give the product. MS (M+H)+ 323.

Provenance & Evidence