Photochemistry and Photophysics of Papaverine N-Oxide

The photochemistry and photophysics of papaverine N-oxide in polar aprotic and protic solvents has been studied in detail. Complex energy and charge-transfer phenomena between chromophores occur in papaverine. New photochemistry for the papaverine N-oxide system is reported. Irradiation in protic media results in the formation of an emissive charge-transfer state with ensuing intramolecular hydroxylation in high isolated yields (75–80%).     

Photoisomerization of Styryl Derivatives of Pyridine N-Oxide

Russian Journal of Physical Chemistry A - The trans–cis- and cis–trans-isomerization of styryl derivatives of heterocyclic N-oxides in acetonitrile and ethanol is studied. The...     

Reaction of Substituted Cyanonitromethanes with Acetonitrile N-Oxide

Russian Journal of Organic Chemistry -     

The Reaction of N-Oxide with Ethyl Bromoacetate

The reaction of 4-methoxypyridine 1-oxide with ethyl bromoacetate was found to produce a high yield of ethyl glyoxylate, trimethylamine N-oxide and pyridine 1-oxide also afforded the glyoxylate but in lower yield in the reaction, and 4-nitropyridine 1-oxide was found to be inactive with bromoacetate. Pyridine 1-oxide and trimethylamine N-oxide exhibit the same stoichiometry, while 4-methoxypyridine 1-oxide follows a different course.     

Oxidation of Organoboranes with Trimethylamine N-Oxide Dihydrate

Recently it has been reported that the commercialy available, easily handled trimethylamine N-oxide dihydrate is an effective oxidizing agent for organoboranes. An examination of the efficiency and reactivity of this reagent under various reaction conditions was conducted. Alkenes were hydroborated to the corresponding alkylboranes, and the subsequent oxidations to alcohols were carried out using a slight excess of trimethylamine N-oxide dihydrate. The product yields at different tiem intervals were determined by glpc analysis.The oxidation can be carried out in hydrocarbon as well as ethereal solvents. The rate of oxidation is proportional to temperature. Furthermore, long reaction times at moderate temperatures are not detrimental to yields. The rates of reaction of alkyl groups in the organoborane were determined to be tertiary > cyclic secondary > acyclic secondary > $\text{n}$-primary > branched primary > vinyl.     

Reaction of 4-Azidoquinoline N-Oxide with Dimethyl Acetylenedicarboxylate

The reaction of 4-azidoquinoline N-oxide with dimethyl acetylenedicarboxylate occurs via a 1,3-dipolar cycloaddition mechanism at the N-oxide and not at the azide group.     

Transition Metal Chloride Chelates with 1,10-Phenanthroline N-Oxide

1,10-Phenanthroline N-oxide(L) interacts with 3d metal chlorides to yield the following chelates: [CrL₂Cl₂]Cl · H₂O; [FeL₂Cl₂]Cl; [FeLCl₂]_x (x = 1 or 2); [MnL₂Cl₂]; [ClLMnCl₂MnLCl] · 2 H₂O; [CoL₂Cl₂] · H₂O; [CoLCl₂] · H₂O; [NiL₂Cl₂] · 2 H₂O; [CuL₂Cl]Cl · 2 H₂O or [CuL₂Cl₂] · 2 H₂O; and [ZnL₃][ZnCl₄] · 2 H₂O. These complexes were characterized by means of their infrared and electronic spectra, magnetic susceptibilties, X-ray powder diffraction patterns and molar conductivities.     

Alkaloids of Nitraria sibirica. Dihydroschoberine and Nitrabirine N-Oxide

Two alkaloids were isolated from the aerial part ofNitraria sibirca. Their structures were determined using chemical transformations and spectral data.     

Alkaloids of Nitraria komarovii. N-Allylnitrarine and Komarovidine N-Oxide

Two new alkaloids, N-allylnitrarine and komarovidinine N-oxide were isolated from the aerial part ofNitraria komarovii.Their structures were established by chemical transformations and spectral data.     

Reductive Amination of Quinoline N-Oxide with Aminopyridines and Their N-Tozyl Derivatives

In reaction of quinoline N-oxide with 2-aminopyridine in the presence of tosyl chloride the substrate undergoes reductive amination into 2-pyridyl(2-quinolyl)amine, and with 3- and 4-aminopyridines reductive tosylamination occurs to furnish N-tosyl derivatives of the corresponding 3- and 4-pyridyl(2-quinolyl)amines. N-tosyl derivatives of aminopyridines also react along reductive tosylamination pathway.     

Mechanism of oxidation of cyclohexane by the radical cation of pyridine N-Oxide

Oxidation of pyridine N-oxide in the presence of cyclohexane was studied on platinum and carbon glass rotating disk electrodes using the method of cyclic voltammetry in 0.2 N LiClO₄ in acetonitrile. It was hypothesized that the electrochemically generated N-oxide radical cation reacts with cyclohexane according to the mechanism of hydrogen atom cleavage.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1488–1491, July, 1990.     

Thermochemistry of Dissolution of Glucose in Binary Systems N-Methylmorpholine N-Oxide Monohydrate-Aprotic Solvent

Glucose enthalpies of solution in binary systems N-methylmorpholine N-oxide monohydrateaprotic solvent at 75°C are measured.     

N-Oxide heterocycles and imidazoles replacing ring D of calanolides against Mycobacterium tuberculosis

We have explored the chemistry of N-oxide heterocycles and imidazoles replacing ring D of the natural product(+)-calanolide A, and have synthesized 12 new analogues, two of which were active against both R Mtb and NR Mtb with MIC values of 12.5μg/mL, which would lead to further optimization for more potent anti-TB candidates.     

氨基硝基吡啶及其氮氧化物的亲核取代胺化反应

以盐酸羟胺、1,1,1-三甲基肼碘化物(TMHI)和4-氨基-1,2,4-三唑(ATA)为胺化剂,研究了2-氨基-3,5-二硝基吡啶(1)和2-氨基-3,5-二硝基吡啶-1-氧化物(3)的亲核取代（VNS）胺化反应。 结合VNS胺化反应机理讨论了胺化剂活性、胺化剂和胺化底物的立体、电子效应对产物的组成和收率的影响。 以羟胺为胺化剂时,氨基可被引入到底物的6-位和4-位,胺化产物的收率在64%~89%之间;以TMHI和ATA为胺化剂时,氨基只能被引入到底物的6-位,胺化产物的收率在90%以上;在相同条件下,胺化产物的收率随胺化剂活性的提高而提高;受N+→O-的影响,化合物3的胺化产物收率稍高于化合物1的胺化产物收率。