Tertiary Nitro Compounds Research Articles

Organocatalytic Michael Addition of Unactivated α-Branched Nitroalkanes to Afford Optically Active Tertiary Nitrocompounds.

The direct, asymmetric conjugate addition of unactivated α-branched nitroalkanes is developed based on the combined use of chiral amine/ureidoaminal bifunctional catalysts and a tunable acrylate template to provide tertiary nitrocompounds in 55-80% isolated yields and high enantioselectivity (e.r. up to 96:4). Elaboration of the ketol moiety in thus obtained adducts allows a fast entry to not only carboxylic and aldehyde derivatives but also nitrile compounds and enantioenriched 5,5-disubstituted γ-lactams.

Catalytic Hydrogenation of Aliphatic Nitro Compounds with Polysilane/Bone Charcoal‐Supported Palladium Catalysts under Continuous‐Flow Conditions

AbstractHydrogenation of aromatic nitro compounds has been widely studied, however, the catalytic hydrogenation of aliphatic nitro compounds remains a challenging topic. Herein, a polysilane/bone charcoal‐supported Pd catalyst with excellent catalyst activity for the hydrogenation of aliphatic nitro compounds under continuous‐flow conditions is described. The catalyst was synthesized by a simple procedure and analyzed by STEM and energy dispersive X‐ray spectroscopy (EDX) measurements. This polysilane/bone charcoal‐supported Pd catalyst demonstrated higher catalyst activity than conventional Pd/C, and a wide substrate scope including secondary and tertiary nitro compounds was achieved. Furthermore, no catalyst deactivation was observed during 120 h of continuous‐flow reaction without leaching of Pd.

ChemInform Abstract: Metal‐Free C‐Arylation of Nitro Compounds with Diaryliodonium Salts.

AbstractThis method allows the α‐arylation of various nitroalkanes and nitroesters.

Metal-Free C-Arylation of Nitro Compounds with Diaryliodonium Salts.

An efficient, mild, and metal-free arylation of nitroalkanes with diaryliodonium salts has been developed, giving easy access to tertiary nitro compounds. The reaction proceeds in high yields without the need for excess reagents and can be extended to α-arylation of nitroesters. Nitroalkanes were selectively C-arylated in the presence of other easily arylated functional groups, such as phenols and aliphatic alcohols.

Thermochemical properties for n‐propyl, iso‐propyl, and tert‐butyl nitroalkanes, alkyl nitrites, and their carbon‐centered radicals

AbstractDensity functional theory (DFT) based calculations are performed on a series of alkyl nitrites and nitroalkanes representing large‐scale primary, secondary, and tertiary nitro compounds and their radicals resulting from the loss of their skeletal hydrogen atoms. Geometries, vibration frequencies, and thermochemical properties [S°(T) and C°p(T) (10 K ⩽ T ⩽ 5000 K)] are calculated at the B3LYP/6‐31G(d,p) DFT level. ΔfH°298 values are from B3LYP/6‐31G(d,p), B3LYP/6‐31+G(2d,2p), and the composite CBS‐QB3 levels. Potential energy barriers for the internal rotations have been computed at the B3LYP/6‐31G(d,p) level of theory, and the lower barrier contributions are incorporated into entropy and heat capacity data. The standard enthalpies of formation at 298 K are evaluated using isodesmic reaction schemes with several work reactions for each species. Recommended values derived from the most stable conformers of respective nitro‐ and nitrite isomers include −30.57 and −28.44 kcal mol−1 for n‐propane‐, −33.89 and −32.32 kcal mol−1 for iso‐propane‐, −42.78 and −41.36 kcal mol−1 for tert‐butane‐nitro compounds and nitrites, respectively. Entropy and heat capacity values are also reported for the lower homologues: nitromethane, nitroethane, and corresponding nitrites. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 181–199, 2010

Reactions of 1-haloadamantanes and ethylmercury chloride with nitronate anions by the SRN1 mechanism

Secondary or tertiary nitro compounds can be easily obtained by photostimulated reaction of the anions corresponding to primary or secondary nitroalkanes with either 1-iodoadamantane (1-AdI) or ethylmercury chloride (EtHgCl) by the SRN1 mechanism. Only 1-AdI requires the presence of the enolate anion of acetone as an entrainment reagent. The procedure works well with the nitroanions derived from 1-nitropentane, nitroethane or 6-nitrohex-1-ene, but with 2-nitropropane ion the outcome depends on the substrate and solvent.

ChemInform Abstract: Unusual Denitrohydrogenation of Allylic Tertiary Nitro Compounds During Hydrogenation.

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Unusual Denitrohydrogenation of Allylic Tertiary Nitro Compounds During Hydrogenation

Abstract Unusual denitrohydrogenations of α, α-disubstituted nitromethylcycloalk-1-enes during their hydrogenation in the presence of Pd-C have been reported. The possible mechanism of action has been suggested.

The invention of radical reactions. Part 32. Radical deoxygenations, dehalogenations, and deaminations with dialkyl phosphites and hypophosphorous acid as hydrogen sources

Reagents, containing a P-H bond, such as dimethyl phosphite, diethyl phosphite, hypophosphorous acid and various salts of hypophosphorous acid are effective radical reducing agents for organic amides, thionoesters, and isocyanides affording high yields of the corresponding hydrocarbons. Reduction of tertiary phenyl selenides and tertiary nitro compounds are not efficient under these conditions. Oleamination of 1,2-diols is also accomplished via the corresponding thiocarbonyl derivatives using hypophosphorous acid and triethylamine in the presence of a suitable «sacrificial olefin» in moderate to good yields

Relative molecular mass information from aliphatic nitro compounds: A chemical ionization study

AbstractThe mass spectra of a number of aliphatic nitro compounds have been studied using electron Ionization (EI) and a variety of chemical Ionization (CI) techniques in attempts to obtain relative molecular mass information. The use of positive ion ammonia chemical Ionization techniques gave very satisfactory results, providing abundant [M + NH4]+ ions, not only from both primary and secondary nitro compounds, but also from the much more labile tertiary nitro compounds. However, the use of methane and isobutane positive ion CI or EI conditions resulted in facile fragmentation with little relative molecular mass information being made available. Negative ion CI using methane, isobutane or ammonia as moderating gases all gave abundant [M − 1]− ions with primary and secondary nitro compounds but at much reduced sensitivity.

Alkyl nitrate nitration of active methylene compounds. Nitration of 2‐substituted 2‐oxazolines

Abstract2‐Alkyl‐ and 2‐aralkyl‐2‐oxazolines are readily converted to the corresponding α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines on treatment with an alkali metal amide such as potassium or sodium amide in liquid ammonia or with lithium diisopropylamide (LDA) in THF and an alkyl nitrate. Tertiary nitro compounds, such as 2‐(2‐nitro‐2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (16) and 2‐(diphenylnitromethyl)‐4,4‐dimethyl‐2‐oxazoline (17) are obtained in good yield when the anions of 2‐(2‐propyl)‐4,4‐dimethyl‐2‐oxazoline (14) and of 2‐(diphenylmethyl)‐4,4‐dimethyl‐2‐oxazoline (23), generated by LDA are added to the nitrate in THF (inverse addition). The spectral data of the primary and secondary α‐nitroalkyl‐ and α‐nitroaralkyl‐2‐oxazolines reveal that they exist mostly in their dipolar structure. These compounds are readily converted to the corresponding α‐halonitro‐2‐oxazolines on treatment with potassium hypobromite or hypochlorite.

ChemInform Abstract: FORMATION OF QUATERNARY CARBON CENTERS FROM TERTIARY NITRO COMPOUNDS BY FREE RADICAL METHODS

AbstractDie tertiären Nitroverbindungen (I) können radikalisch an Doppelbindungen addiert werden.

FORMATION OF QUATERNARY CARBON CENTERS FROM TERTIARY NITRO COMPOUNDS BY FREE RADICAL METHODS

Abstract The radical intermediates generated by denitration of tertiary nitro compounds with tributyltin hydride undergo the carbon–carbon bond forming reaction with double bonds, which provides a useful method for the construction of quaternary carbon centers.

Réduction électrochimique de γ-nitrocétones. Conditions expérimentales d'accès à des dérivés de la pyrroline et de la pyrrolidine

Optimal conditions for electrosynthesis, at a mercury cathode in hydroalcoholic media, of three classes of nitrogen heterocyclic compounds are set up from an exhaustive study of the electrochemical behaviour of γ-nitroketones 1 and their reduction products.Pyrroline-N-oxides 3 are obtained by cyclization of the hydroxylamine when the nitro compounds are reduced at sufficiently low cathodic potentials. Quantitative yields are achieved in the case of tertiary nitro compounds. In other cases (primary and secondary nitro compounds), simultaneous formation of ketone-oximes 6 occurs.According to the nature of the α-substituent of the carbonyl, the other heterocyclic derivatives can be prepared as follows. In the case of a methyl substituent, pyrrolines 4 can be obtained by reduction of nitro compounds 1 or of N-oxyde pyrrolines 3. Pyrrolidines 5 are prepared by reduction of 1, or 3 and 4 in the case of tertiary compounds. In the case of a phenyl substituent, pyrrolines 4 can only be obtained by reduction of compounds 3 arising from a tertiary nitro compound. Pyrrolines 5 are prepared by direct reduction of 1 (primary and secondary nitro compounds) or of 3 and 4 (tertiary nitro compounds).

Nitro compounds as alkylating reagents in friedel-crafts conditions : Reaction of 2-nitropropane with benzene

Friedel-Crafts reaction of benzylic or tertiary nitro compounds with benzene gave normal alkylation products. Similarly, 2-nitropropane ( 2-NP) gave cumene ( 1) which underwent further transformation affording a mixture whose behaviour with time was investigated : results were consistent with oxidative formation of the cumyl carbonium ion ( 7').

Controlled potential electrolysis—XIII : Polarographic behaviour and controlled potential electrolyses in acetonitrile of several aliphatic tertiary nitro compounds

The electrochemical reduction of aliphatic t-nitro compounds was studied in anhydrous acetonitrile by polarography and large scale controlled potential electrolysis. The first step of the electrode process involved a one-electron transfer leading to an unstable nitro anion radical which cleaved to nitrite ion and the corresponding free radical. This mechanism was substantiated by controlled potential electrolysis of t-nitrobutane and three α-nitroisobutyric acid derivatives. The differences in polarographic behaviour between t-nitrobutane and α-nitroisobutyric acid derivatives and the results of their electrolysis in the presence of a proton donor were related to the stability of the nitro anion radical and the reducibility of the nitroso derivatives. The predominant factor governing the half-wave potential was the inductive effect of the substituent. An extended Hückel MO calculation was carried out, but the results are unsatisfactory.

Controlled potential electrolysis—XIV : Electron spin resonance spectra of free radicals generated electrochemically from several aliphatic tertiary nitro compounds

Six aliphatic tertiary nitro compounds were reduced electrolytically in acetonitrile, and their electron spin resonance spectra studied. t-Nitrobutane, 2-methyl-2-nitro-1-propanol and tris(hydroxymethyl)nitromethane gave the ESR spectra of tertiary nitro anion radicals, showing only one 14N splitting during electrolysis, but α-nitroisobutyramide gave a 6-line spectrum showing one 14N and one proton splitting. The 6-line spectrum was assigned to the 2-nitropropane anion radical which was produced by decomposition of the anion radical of α-nitroisobutyramide. Di-alkylnitroxides were obtained from all the above comopounds after electrolysis, but tris(hydroxymethyl)nitromethane and α-nitroisobutyramide gave in addition another unidentified radical. Ethyl α-nitroisobutyrate and α-nitroisobutyronitrile gave no ESR spectrum either during or after electrolysis.