Syntheses of Arylated p-Benzoquinones

Abstract

Reactions of p-benzoquinone (1) with /V, N-dimethylaniline (2a), /V, N-diethylaniline (2b), N, Ndimethylm-anisidine (2c) and /V, N-diethyl-m-anisidine (2d) were carried out. The corresponding monoarylated p-benzoquiones (3) were obtained and diarylated p-benzoquinones were also obtained from reactions of 1 with 2c and 2d. Furtheremore, using a variety of subsutituted p-benzoquinones (5)(subsutituent: a: MeO; b: F; c: Cl; d: COMe; e: COPh; f: COOMe; g: CN; h: Ph; i: p-O₂NC₆H₄), 2-[4-(dimethylamino) phenyl] -p-benzoquinone (3a), 2- [2-methoxy-4- (dimethylamino) phenyl] -p-benzoquinoe (3c), 2, 5- and 2, 6-dichloro-p-benzoquinones (10, 11), same reactions were carried out. Reactions of monosubstituted p-benzoquinones with 2 are susceptible to the natures of those substituents, occurred at 5-position in case of 5a-c, 3-position in csae of 5d-g and 6-position in case of 5h, 5i, 3a and 3c, respectively. It was confirmed by an isolation of the corresponding intermediate hydroquinones in case of 5d-f that reactions in this work proceed via a Michael 1, 4-addition.