31776-35-9Relevant academic research and scientific papers
The acid-catalyzed oxidation of methoxybenzenes to p-benzoquinones by dimethyldioxirane
Adam,Shimizu
, p. 560 - 562 (1994)
Methoxybenzenes 1 were oxidized to phenols and/or p-benzoquinones by dimethyldioxirane; in the presence of strong acids, the intermediate phenols were effectively converted to the p-benzoquinones 3.
Synthesis of coenzyme Q0 through divanadium-catalyzed oxidation of 3,4,5-trimethoxytoluene with hydrogen peroxide
Zalomaeva, Olga V.,Evtushok, Vasilii Yu.,Maksimov, Gennadii M.,Maksimovskaya, Raisa I.,Kholdeeva, Oxana A.
, p. 5202 - 5209 (2017/04/27)
The selective oxidation of methoxy/methyl-substituted arenes to the corresponding benzoquinones has been first realized using aqueous hydrogen peroxide as a green oxidant, acid tetrabutylammonium salts of the γ-Keggin divanadium-substituted phosphotungstate [γ-PW10O38V2(μ-O)2]5- (I) as a catalyst, and MeCN as a solvent. The presence of the dioxovanadium core in the catalyst is crucial for the catalytic performance. The reaction requires an acid co-catalyst or, alternatively, a highly protonated form of I can be prepared and employed. The industrially relevant oxidation of 3,4,5-trimethoxytoluene gives 2,3-dimethoxy-5-methyl-1,4-benzoquinone (ubiquinone 0 or coenzyme Q0, the key intermediate for coenzyme Q10 and other essential biologically active compounds) with 73% selectivity at 76% arene conversion. The catalyst retains its structure under turnover conditions and can be easily recycled and reused without significant loss of activity and selectivity.
Oxidation of Methoxy- and/or Methyl-Substituted Benzenes and Naphthalenes to Quinones and Phenols by H2O2 in HCOOH
Orita, Hideo,Shimizu, Masao,Hayakawa, Takashi,Takehira, Katsuomi
, p. 1652 - 1657 (2007/10/02)
The oxidation of a number of arenes (methoxybenzenes, methylbenzenes, and naphthalenes) to quinones and phenols by H2O2 in HCOOH has been examined.Methoxybenzenes were much more easily oxidized to p-benzoquinones than methylbenzenes (e.g., 1,3,5-trimethoxybenzene was oxidized to 2,6-dimethoxy-p-benzoquinone in a 75percent yield and 1,2,4-trimethylbenzene to 2,3,5-trimethyl-p-benzoquinone in a 16percent yield).Electron-withdrawing substituents, such as nitro, cyano, and chloro groups, lowered the conversion of reactants and changed the product selectivity from quinones to phenols.Methoxybenzonitriles were oxidized to corresponding phenols in a moder ate yield (e.g., 2,6-dimethoxybenzonitrile to 3-hydroxy-2,6-dimethoxybenzonitrile in a 39percent yield and a 64percent selectivity).
Metalation of Phenols. Synthesis of Benzoquinones by the Oxidative Degradation Approach
Saa, Jose M.,Llobera, Antonia,Garcia-Raso, Angel,Costa, Antonio,Deya, Pedro M.
, p. 4263 - 4273 (2007/10/02)
In a effort to explore the potential of so-called oxidative degradation approach for the synthesis of quinones, we have investigated the direct metalation of a number of simple phenols such as o- and p-hydroxybenzyl alcohols, benzyl methyl ethers and N,N-dimethylbenzylamines.Apparently, only those phenolic substrates having available both a coordinating group for chelation and an electron-withdrawing group in a 1,3-relationship are efficiently lithiated, by the action of n-BuLi, in a regioselective manner.Those positions on the aromatic nucleus just flanked by a coordinating, or an acid-base, group could be metalated by action of the t-BuLi/THP system, in favorable cases.
