Facile oxidation of fused 1,4-dimethoxybenzenes to 1,4-quinones using NBS: fine-tuned control over bromination and oxidation reactions.
[figure: see text] Fused 1,4-dimethoxybenzenes could be oxidized to benzoquinones by either direct oxidation or demethylation-oxidation. The oxidative demethylation of 5,8-dimethoxy-2-methylquinoline using 1.1 equiv of NBS in aqueous THF and a catalytic amount of H2SO4 at 20 degrees C for 5 min gave 2-methylquinoline-5,8-dione in 98% yield without bromination. Moreover, we can control either bromination or oxidative demethylation, or both reactions.
Kim
D W
DW
Department of Chemistry, Inha University, 253 Yonghyundong Namgu, Inchon 402-751, Korea.
Choi
H Y
HY
Lee
K J
KJ
Chi
D Y
DY
D000840:Anisoles / Q000737:chemistry*; D016227:Benzoquinones / Q000737:chemistry; D006842:Hydrocarbons, Brominated / Q000737:chemistry; D008745:Methylation; D010084:Oxidation-Reduction; D011809:Quinones / Q000138:chemical synthesis*
D000840:Anisoles; D016227:Benzoquinones; D006842:Hydrocarbons, Brominated; D011809:Quinones; C031200:1,4-dimethoxybenzene