2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 2,4-Dichloro-5-methoxy-6-vinylpyrimidine

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Reaction Steps

2,6-Dichloro-5-methoxy-6-vinyl pyrimidine may be prepared using 2,6-dichloro-5-methoxy pyrimidine, which is commercially available. 2,6-Dichloro-5-methoxy pyrimidine (12.5 g, 69.8 mmol) was combined in a flask with THF (125 mL) and placed in a room temperature water bath. Vinyl magnesium bromide (78 mL, 76.8 mmol) was added in three portions. The mixture was stirred for 5 h. Acetone was added to quench any remaining Grignard reagent. DDQ (19 g, 83.8 mmol) was added to the mixture, and the mixture was stirred overnight. The mixture was then concentrated to remove the THF. Dichloromethane (DCM) was added, triturated, and allowed to stand over the weekend before being filtered, concentrated, and purified by column chromatography on silica gel using a 5-30% ethyl acetate/hexane gradient. This produced the title compound (7.95 g), which was observed to be a light yellow solid that turned grey in light.

Provenance & Evidence