Reaction of vitamin A with acceptors of electrons. Formation of radical anions from 7,7,8,8-tetracyanoquinodimethane and tetrachloro-1,4-benzoquinone

Abstract

1. The interactions of retinol and retinoic acid with two electron acceptors, 7,7,8,8-tetracyanoquinodimethane (TCNQ) and tetrachloro-1,4-benzoquinone (chloranil), were studied in an investigation on the ability of vitamin A to behave as a donor of electrons. 2. Retinol reacts with TCNQ in polar organic solvents with the formation, as judged by spectral studies, of the radical anion of TCNQ. 3. Addition of the products of this reaction to water is accompanied by a rapid consumption of OH− ions. 4. Consumption of OH− ions is also a feature of the reactions between retinol and chloranil, but the spectrum of the radical anion of chloranil is observed only when retinol and chloranil are suspended in aqueous salt solutions. 5. Retinoic acid behaves similarly to retinol in its reactions with TCNQ and chloranil, but it appears to be a weaker electron donor than retinol. 6. The reaction products that may be formed from retinol in its reactions with TCNQ and chloranil are discussed. 7. It is suggested that the ability of vitamin A to behave as a donor of electrons may be an important aspect of its biochemical mode of action.