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

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Reaction Steps

A trifluoromethanesulfonate derivative may be produced by reacting a 7-benzyloxy-4-chloroquinoline derivative with a suitable reducing agent, for example, hydrogen gas/palladium hydroxide to give an alcohol (step (i) above) and then reacting the alcohol with trifluoromethanesulfonic anhydride (step (ii) above) to give a trifluoromethanesulfonate derivative. A quinoline derivative may be produced by reacting the trifluoromethanesulfonate derivative with an alkyltin reagent, for example, tri-n-butyl-(2-pyridyl)-tin or an alkylboronic acid reagent, for example, 3-pyridylboronic acid in the presence of a suitable transition metal catalyst, for example, tetrakis triphenylphosphine palladium (step (iii) above) and reacting the resultant compound with a suitable oxidizing agent, for example, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, to give a quinoline derivative (step (iv) above). Next, a 6-hydroxyquinoline derivative may be produced by reacting the quinoline derivative with a suitable reagent, for example, boron tribromide (step (v) above). The contemplated compound may be produced by reacting the 6-hydroxyquinoline derivative with a 4-chloroquinoline derivative or a corresponding quinazolone derivative in a suitable solvent, for example, o-dichlorobenzene, or in the absence of a solvent, for example, at 120 to 180° C. (step (vi) above).

Provenance & Evidence