- Dehydrogenation, oxidative denitration and ring contraction of N,N-dimethyl-5-nitrouracil by a Bacillus nitroreductase Nfr-A1
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Nfr-A1, a Bacillus subtilis nitroreductase, catalyzes the nitroreduction of a large panel of aromatic and heterocyclic nitro compounds, except those belonging to nitrouracil class of molecules. Besides nitroreduction, Nfr-A1 exhibits a strong NADH oxidase activity in the presence of oxygen, leading to high concentration of H2O2 (up to 200 μM). In the presence of (N,N)-dimethyl-5-nitrouracil 1 (dim-NU), Nfr-A1 achieves the reduction of dim-NU double bond to compounds 2 and 3 and in parallel the oxidation of dim-NU to the denitrated five membered derivatives 4 and 5. The reduction is catalyzed by the reduced flavin Fl-Red and resembles those catalyzed by dihydropyrimidine dehydrogenases (DPD), during the catabolism of pyrimidines. The oxidative denitration is catalyzed in part by hydrogen peroxide generated through the NADH-oxidase activity, and certainly by the peroxyflavin intermediate Fl-OOH for the other part. The mechanisms of reaction were proposed according to experimental data and literature. These findings together with our previous results on the potential biological role of Nfr-A1, confirm the large spectrum of catalysis supported by this enzyme. The oxidative denitration is sporadically reported in literature and represents a safe and green alternative for the remediation of nitro-compounds.
- Cortial, Sylvie,Chaignon, Philippe,Sergent, Didier,Dezard, Sophie,Ouazzani, Jamal
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experimental part
p. 1 - 8
(2012/04/17)
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- Photochemical Reactions of N,N'-Dimethylimidazolidinetrione with Alkenes. Solvent-Incorporated Addition via Hydrogen Abstraction
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Photoreactions of N,N'-dimethylimidazolidinetrione (1) with alkenes in benzene gave oxetanes in high yields.The reaction of 1 with stilbene proceeded via excitation of the alkene rather than 1, whereas that with 2,5-dimethylhexadiene took place via excitation of the ground-state complex of 1 with the diene.On irradiation in hydrogen-donating solvents such as alcohols, toluene, or cyclohexane, 1 underwent a quite rare solvent-incorporated addition to the alkenes via intermolecular hydrogen abstraction.
- Aoyama, Hiromu,Hatori, Hiroaki,Omote, Yoshimori
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p. 2359 - 2364
(2007/10/02)
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- Photolysis of N,N-Dimethylimidazolidinetrione: A Two Nitrogens-Three Carbonyls System
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Photolysis of N,N-dimethylimidazolidinetrione in hydrogen-donating solvents affords hydrogenated and solvent-addition products via the Norrish type II process.Keywords-N,N-dimethylimidazolidinetrione; hydrogen abstraction; Norrish type II reaction; hydantoin; triplet state; photochemistry
- Sato, Eisuke,Kanaoka, Yuichi
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p. 3006 - 3008
(2007/10/02)
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