Journal of the American Chemical Society p. 6498 - 6503 (1980)
Update date:2022-08-24
Topics:
Ball, Sheldon
Bruice, Thomas C.
Kinetic and product studies have been carried out for the reaction of 12 tertiary amines, secondary amines, and secondary hydroxylamines with the 4a-hydroperoxide of N5-ethyl-3-methyllumiflavin (4a-FlEtOOH).All reactions were found to be first order in 4a-FlEtOOH and amine in t-BuOH solvent.Transfer from t-BuOH to the aprotic solvent dioxane decreases the second-order rate constant by ca. threefold, but does not change the kinetic order in reactants (i.e., no external proton source is required).The reactions with the secondary and tertiary amines are quantitative, yielding secondary hydroxylamines and tertiary amine oxides along with the flavin pseudobase (4a-FlEtOH).Secondary hydroxylamines yield with 4a-FlEtOOH nitrones and 4a-FlEtOH.The free radical trap 2,6-di-tert-butyl-4-methylphenol does not influence the rate constants or product yields.This finding, along with the observation that rate constants are not related to the stability of cation radicals derived from amine, establishes that free radical processes are not involved in the N-oxidation reactions.The N-oxidation reactions are best explained as occurring through nucleophilic attack of amine nitrogen upon the terminal oxygen of the 4a-FlEtOOH molecule with back donation of the hydroperoxy hydrogen to the internal peroxy oxygen.Comparison of the second-order rate constants ( on the basis of the amine pKa's in H2O) provides the nucleophilic order secondary hydroxylamines > tertiary amines > secondary amines.The disappearance of 4a-FlEtOOH from solution in the presence of primery amines is much slower than with secondary amines and the reaction does not follow a simple rate law nor is 4a-FlEtOH a major product.In t-BuOH the spontaneous first-order rate constant for decomposition of 4a-FlEtOOH exceeds that for the decomposition of H2O2 by more than 400-fold while the second-order rate constant for N-oxidation of N,N-dimethylbenzylamine by 4a-FlEtOOH exceeds that for N-oxidation by H2O2 by 36000-fold (and N-oxidation by t-BuOOH by > 400000).These results are discussed in terms of the involvement of 4a-hydroperoxyflavin cofactor in the metabolism of amines by the hepatic flavoprotein microsomal oxidase.
View MoreWUHU HUAHAI BIOLOGY ENGINEERING CO LTD
Contact:+86-553-3836920
Address:7/F NO.82 LAODONG ROAD WUHU CHINA
Chengdu Pukang Biotechnology Co., Ltd
Contact:+86-28-82550498
Address:No. 558 Rulin Road,Xinjin county,Chengdu city, China
chengdu firsterchem Pharmaceutical Co., Ltd.
Contact:028-66825849
Address:chengdu
Zhejiang Sucon Silicone Co.,Ltd
Contact:+86-575-88046692
Address:Qisheng Rd., Paojiang Industrial Zone, Shaoxing, Zhejiang, China.
Shanghai Yurui Biotechnology(Anyang) Pharmaceutical Co., Ltd
Contact:+86-0372-3662335 +86-0372-3661988
Address:hanling industrial park anyang
Doi:10.3390/molecules24224122
(2019)Doi:10.1016/j.cclet.2015.07.009
(2015)Doi:10.1039/b608558j
(2006)Doi:10.1021/ja01228a027
(1945)Doi:10.1016/j.tetlet.2021.153234
(2021)Doi:10.1039/c7ra09727a
(2017)