HCID 67382699, compound → HCID 67383175, compound

Participants

Reaction Steps

A suspension of 7-bromo-6-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one and 7-bromo-8-fluoro-3-iodo-5H-chromeno[2,3-b]pyridin-5-one (1:4 mixture) (76 g, 182 mmol) in 1 L dioxane was placed under argon and was heated with a heat gun until it became a homogenous solution. The solution was allowed to cool to room temperature and stir 72 hours. The reaction mixture was then cooled to −10° C. and was treated with methylmagnesium chloride (106 mL, 319 mmol) dropwise with stirring over 30 min. After stirring for an additional 60 min, the reaction mixture was quenched with MeOH (25 mL). Water (250 mL) was added, followed by concentrated NH4Cl solution (250 mL). The reaction mixture was concentrated in vacuo to remove most of the organics. The remaining aqueous solution was extracted with EtOAc (3×500 mL). The organics were washed with brine, dried over MgSO4 and concentrated. The crude residue was taken up in ˜300 mL CH2Cl2 and was again concentrated. This process was repeated 3×. The crude black solid was triturated with MeOH and was again dried to provide a 1:10 mixture of 7-bromo-6-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine and 7-bromo-8-fluoro-3-iodo-5-methylene-5H-chromeno[2,3-b]pyridine (59.200 g, 142 mmol, 78% yield). This material was used without purification.

Provenance & Evidence