Anthracene Vilsmeier-Haack reaction

The Vilsmeier-Haack reaction of electron-rich carbocyclic aromatic compounds (Ar—H) with chloromethyleneiminium salt (1) gives aldehyde derivatives (Ar—CHO), generally in good yield. The intermediate iminium salt (cf. salt 5 Scheme 1) can be treated with hydroxylamine to obtain nitrile derivatives (Ar—CN). Benzene and naphthalene are not sufTiciently electron rich to participate in the Vilsmeier-Haack reaction, but polycyclic hydrocarbons, such as anthracene, do react. Benzene and naphthalene derivatives that possess an electron-releasing substituent (—OMe,—SMe,—NMe2, etc.) af-... 

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