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Chiral salalen ligands derived from (S)-proline and derivatives of salicyaldehydes were synthesized, and their in-situ generated Cu (II) complexes were evaluated in the asymmetric Henry reaction. Salalen ligand of different substituents on the phenyl moiety showed remarkable effect on the enantioselectivity of nitro-aldol product of 4-nitrobenzaldehyde and nitromethane. Cu (II) complex generated in situ with (S)-2-(tert-butyl)-6-((2-(((2-hydroxy-3-methylbenzylidene)amino)methyl)pyrrolidin-1-yl)methyl) phenol (10 mol%) and Cu (OAc)2 .H2 O (10 mol%), found to be better catalyst for nitro-aldol reaction between 4-nitrobenzaldehyde and nitromethane, gave corresponding product in 85% yield and 88% enantiomeric excess (ee) in isopropanol at 35°C after 40 hours. The catalyst also used for the Henry reaction with different substituted benzaldehydes and corresponding products were obtained in 22% to 99% yields with 66% to 92% ee. Henry reaction of 4-nitrobenzaldehyde and prochiral nitroethane gave anti-selective product (dr = 79/21; anti/syn) in a 91% yield with 80% ee.

Azanucleosides, in which the 4'-oxygen atom has been replaced with a nitrogen atom, have drawn much attention owing to their anticancer and antivirus activity, and tolerance towards nucleases. However, the traditional synthetic strategy requires multiple steps and harsh conditions, thereby limiting the structural and functional diversity of the products. Herein we describe the synthesis of azanucleosides by an electrochemical reaction in a lithium perchlorate-nitroethane medium, followed by postmodification at the 4'-N position. N-Acryloyl prolinol derivatives were converted into azanucleosides by anodic activation of the N-α-C-H bond. Moreover, the use of nitroethane instead of nitromethane lowered the oxidation potential of the N-acryloyl prolinols and increased the Faradic yield. The prepared azanucleosides were efficiently functionalized at the 4'-N-acryloyl group with a lipophilic alkanethiol and a fluorescent dye by conjugate addition and olefin cross-metathesis, respectively.

Enantiopure Cu(II), Ni(II) and Zn(II) chiral complexes CuLR, CuLS, NiLR, NiLS, ZnLR and ZnLS were synthesised by using ligands LR and LS, which were derived from the (R)-(+)-1,1’-Binaphthyl-2,2′-diamine or (S)-(−)-1,1’-Binaphthyl-2,2’-diamine with pyridine-2-aldehyde. These six complexes are characterised and applied as a catalyst for asymmetric nitroaldol reaction. The enantiopure chiral ligand upon complexation transfers its chirality from ligand to metal and generate “Δ or Λ” chirality at the metal centre. All these associated chiral responses were monitored using circular dichroism. Ensuring the enantiopure nature of the complexes they have been demonstrated as an efficient enantioselective catalyst for nitroaldol reaction. Further, this asymmetric catalytic study has been extended to various nitroalkanes such as nitromethane, nitroethane and nitropropane with substituted benzaldehydes leading to the synthesis of various diastereoselective β-nitroalcohols.

The nitroaldol (Henry) reaction is a valuable C−C bond-forming reaction resulting in β-nitro alcohols, which are important building blocks for the synthesis of bioactive compounds. Metal-dependent bacterial hydroxynitrile lyases with a cupin fold couple nitromethane or nitroethane and various aldehydes to yield (R)-β-nitro alcohols with up to 90 % conversion and up to ≥99 % enantiomeric excess.

Polydentate ligands 1 and 2, which incorporate a terminal pyridyl moiety and an oxygen-rich oxalate dihydrizide/malonic dihydrizide spacer moiety, as well as their binuclear metal complexes [Cu212] and [Cu222], which adopt a 1:1 metal/ligand ratio, were synthesized and characterized. Both complexes were screened for their catalytic activity in the nitroaldol reaction, in which [Cu212] worked efficiently as catalyst for both substituted benzaldehyde and pyridinecarboxaldehyde, whereas [Cu222] is highly substrate specific and showed activity towards nitro-substituted aldehydes and pyridinecarboxaldehyde. Furthermore, as helicates are intrinsically chiral, the stereochemical architecture in the binuclear double-stranded Cu2 helicates as catalyst favored the diastereoselective syn product with nitroethane and nitropropane and their respective diastereoselectivities were determined by using 1H NMR spectroscopy.

The asymmetric Michael reaction of nitroalkanes and β,β-disubstituted α,β-unsaturated aldehydes was catalyzed by diphenylprolinol silyl ether to afford 1,4-addition products with an all-carbon quaternary stereogenic center with excellent enantioselectivity. The reaction is general for β-substituents such as β-aryl and β-alkyl groups, and both nitromethane and nitroethane can be employed. The addition of nitroethane is considered a synthetic equivalent of the asymmetric Michael reaction of ethyl and acetyl substituents by means of radical denitration and Nef reaction, respectively. The short asymmetric synthesis of (S)-ethosuximide with a quaternary carbon center was accomplished by using the present asymmetric Michael reaction as the key step. The reaction mechanism that involves the E/Z isomerization of α,β-unsaturated aldehydes, the retro-Michael reaction, and the different reactivity between nitromethane and nitroethane is discussed.

Addition of nitroalkanes into n-alkanes can lower the activation barriers of free-radical production and accelerate the decomposition of n-alkanes at relatively low temperatures. Four initial decomposition mechanisms of the n-butane/nitroethane binary mixture were proposed for the promoting effect and considered theoretically at the B3LYP, BB1K, BMK, MPW1K, and M06-2X levels with MG3S basis set. Energetics above was compared to high-level CBS-QB3 and G4 calculations. Calculated results confirm the feasibility of the four initial decomposition pathways: (I) the CNO2 bond rupture of nitroethane to produce ethyl and ·NO2, (II) HONO elimination from nitroethane followed by decomposition to ·OH and ·NO, (III) rearrangement of nitroethane to ethyl nitrite which further dissociates into CH3CH2O· and ·NO, and (IV) direct hydrogen-abstraction of nitroethane with n-butane.

The flavoprotein nitroalkane oxidase catalyzes the oxidative denitrification of a broad range of primary and secondary nitroalkanes to yield the respective aldehydes or ketones, hydrogen peroxide and nitrite. With nitroethane as substrate the D2O(k(cat)/K(M)) value is 0.6 and the D2Ok(cat) value is 2.4. The k(cat) proton inventory is consistent with a single exchangeable proton in flight, while the k(cat)/K(M) is consistent with either a single proton in flight in the transition state or a medium effect. Increasing the solvent viscosity did not affect the k(cat) or k(cat)/K(M) value significantly, establishing that nitroethane binding is at equilibrium and that product release does not limit k(cat).

Ethylenediamine (H2NCH2CH2NH2) was found to be a highly effective catalyst for the condensation of aryl aldehydes with nitromethane (or nitroethane). When 1%–2% (mol%) of ethylenediamine was used as the catalyst, the one-pot reaction of aryl aldehydes with nitromethane (or nitroethane) by refluxing for 3–10 h efficiently afforded various arylnitroalkenes 1a–1y in 85%–97% yields.

A new bifunctional copper complex of the aminoisoborneol Schiff base – Cu2(SBAIB-d)2 – has been developed for the effective direct catalytic asymmetric Henry reaction. One mol% of this catalyst produces the expected Henry products in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The utility of the present catalyst was also extended to the Henry reaction with nitroethane and 1-nitropropane that furnished the corresponding products in moderate to high yields (up to 99%) with moderate to high enantioselectivities of syn (up to 98% ee) and anti (up to 98% ee) diastereomers. The highlights of this catalytic system are easy manipulation, air and moisture tolerance, the need for 1 mol% of an easily synthesizable catalyst and the high enantioselectivities achieved for a wide range of substrates.

The synthesis and characterization of copper(I) complexes of the novel pyridine-containing macrocyclic ligand (PC-L) and their use as catalysts in the Henry reaction are reported. The pyridine-based 12-membered tetraaza macrocyclic (PC-L) ligand 1 can be obtained in good overall yield (85%) from commercially available starting materials. The Cu(I) complexes showed good catalytic activities in the Henry reaction of different aldehydes and nitroalkanes. Remarkable diastereoselectivity was observed when isatine was reacted with nitroethane under catalytic conditions. Copyright © 2011 John Wiley & Sons, Ltd.

An anthracenyl-modified chiral bis(oxazoline) copper complex has been demonstrated to efficiently promote nitroaldol reactions between structurally varying aldehydes and nitromethane or nitroethane. The catalyst was recovered through formation of a charge transfer complex between the chiral ligand and trinitrofluorenone and its subsequent precipitation with pentane. The efficiency of this procedure was proved through several consecutive catalytic cycles that allowed the sturdy formation of the expected product with a high enantioselectivity. The catalyst′s stability was also put to the test in an original multi-substrate procedure. Following the same recovery concept, a new heterogeneous procedure was tested for which trinitrofluorenone was covalently linked to a silica support. Asymmetric heterogeneous catalysis was performed under these conditions as one of the few examples demonstrating the potential catalyst recycling in nitroaldol reactions through reversible, non-covalent interactions.

The thallous ion and silver ions are unique among univalent cations in forming fairly strong complexes with univalent anions. A review of previous evidence (involving measurements of solubilities, conductivities and reaction kinetics) indicates that thallous hydroxide is incompletely dissociated, having a thermodynamic dissociation constant of about 0.15. New data are reported on the effect of thallous ions on the velocity of the fast reaction between nitroethane and hydroxyl ions. These lead to a similar value for the dissociation constant if it is assumed that the species TIOH does not react. Measurements have also been made of the ultra-violet absorption of solutions containing thallous and hydroxide ions. The results show clearly the presence of two distinct absorbing species, and although it is not possible to derive unambiguously a dissociation constant for TIOH, the data are consistent with the value given above. The nature of the binding in TIOH is discussed in the light of the above findings.

Nitromethane and nitroethane have been photolyzed in the liquid and gaseous phases in order to distinguish the various possible primary processes occurring for each compound. In the case of nitromethane, a free radical split has been postulated to account for the products as For nitroethane, there are at least two primary processes occurring, namely Various secondary reactions are discussed for both compounds.

Several enantiomerically pure N(2)-substituted octahydroindazoles were prepared as bicyclic pyrazolidine derivatives of (+)-pulegone. Condensation of pulegone with hydrazine delivered a hexahydroindazole intermediate, which underwent N(2)-substitution with various electrophiles (alkyl halides, acyl chlorides, phenyl isocyanate). The resulting N(2)-substituted hexahydroindazoles could be reduced with LiBEt(3)H in THF to the target compounds. In addition, a N(2)-thiobenzoyl and some N(2)-carbamoyl derivatives as well as a N(1)-substituted octahydroindazole were synthesized. The compounds showed medium activity as iminium ion catalysts promoting quantitatively the Michael addition of nitroethane to cinnamaldehyde in up to 82% ee for the resulting syn-diastereoisomer and 78% ee for the anti-diastereoisomer. Unexpectedly, the N(2)-acyloctahydroindazoles were readily oxidized under aerobic conditions. Moreover, it was shown that an oxidation of methyl phenyl sulfide to the corresponding sulfoxide is promoted by an N(2)-acyloctahydroindazole in deuterochloroform as solvent. It is proposed that the oxidation of N(2)-acyloctahydroindazoles proceeds by in situ generation of hydrogen peroxide, which in turn can act as an oxidant.

Previous work in these laboratories and by Butzenlechner et al. and Culp et al. has demonstrated that the δ2H isotope value of industrial benzaldehyde produced by the catalytic oxidation of toluene is profoundly positive, usually in the range +300‰ to +500‰. Synthetic routes leading to amphetamine, methylamphetamine or their precursors and commencing with such benzaldehyde may be expected to exhibit unusually positive δ2H values. Results are presented for δ13C and δ2H isotope values of 1-phenyl-2-nitropropene synthesized from an industrial source of benzaldehyde, having a positive δ2H isotope value, by a Knoevenagel condensation with nitroethane. Results are also presented for δ13C and δ2H isotope values for amphetamine prepared from the resulting 1-phenyl-2-nitropropene. The values obtained were compared with δ13C and δ2H isotope values obtained for an amphetamine sample prepared using a synthetic route that did not involve benzaldehyde. Finally, results are presented for samples of benzaldehyde, 1-phenyl-2-nitropropene and amphetamine that had been seized at a clandestine amphetamine laboratory. Copyright © 2010 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.

Density 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

Metal complexes of boron-bridged bisoxazolines (borabox ligands) were evaluated as catalysts for the Henry reaction. Copper(II) complexes induced high enantio- and diastereoselectivity in reactions with nitroethane and nitropropane. The amount of base added had a strong influence on the formation of the chiral complex and the enantioselectivity. Comparison with the corresponding dimethylmethylene-bridged bisoxazoline and other privileged ligands showed that borabox was the most suitable ligand system for the enantio- and diastereoselective formation of nitroalcohols derived from nitropropane and aliphatic aldehydes.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

An integrated Feynman path integral-free energy perturbation and umbrella sampling (PI-FEP/UM) method has been used to investigate the kinetic isotope effects (KIEs) in the proton transfer reaction between nitroethane and acetate ion in water. In the present study, both nuclear and electronic quantum effects are explicitly treated for the reacting system. The nuclear quantum effects are represented by bisection sampling centroid path integral simulations, while the potential energy surface is described by a combined quantum mechanical and molecular mechanical (QM/MM) potential. The accuracy essential for computing KIEs is achieved by a FEP technique that transforms the mass of a light isotope into a heavy one, which is equivalent to the perturbation of the coordinates for the path integral quasiparticle in the bisection sampling scheme. The PI-FEP/UM method is applied to the proton abstraction of nitroethane by acetate ion in water through molecular dynamics simulations. The rule of the geometric mean and the Swain–Schaad exponents for various isotopic substitutions at the primary and secondary sites have been examined. The computed total deuterium KIEs are in accord with experiments. It is found that the mixed isotopic Swain–Schaad exponents are very close to the semiclassical limits, suggesting that tunneling effects do not significantly affect this property for the reaction between nitroethane and acetate ion in aqueous solution.

The hydroxynitrile lyase from Hevea brasi- liensis not only catalyzes - according to the natural activity of this enzyme - the formation and cleavage of cyanohydrins but also the reaction of nitroalkanes with aldehydes (Henry reaction). This is the first ex- ample of an enzymatic nitroaldol reaction. With ni- tromethane and nitroethane a broad range of alde- hydes can be transformed into the corresponding nitro alcohols in yields up to 77 % and enantiomeric excess (ee )u p to 99 %.

Effects of 2-nitro-1-propanol, 2-nitroethanol, nitroethane, and 2-nitro-methyl-propionate (0, 10, and 20 mM) on growth of Campylobacter jejuni were tested during culture in Bolton broth adjusted to pH 5.6, 7.0, or 8.2. The nitrocompounds were similarly tested against C. coli but at pH 8.2 only. Viable cell counts measured during incubation revealed main effects (P < 0.05) of all nitrocompounds on the survivability of C. jejuni. An effect of pH (P < 0.05) on the survivability of C. Jejuni during incubation with nitrocompounds was observed, with greater inhibition observed at pH 8.2 than at pH 5.6 or 7.0 for nitroethane, 2-nitro-l-propanol, and 2-nitroethanol, but not for 2-nitro-methyl-propionate, which showed greatest inhibition at pH 5.6. Except for 2-nitro-methyl-propionate, which was ineffective, all nitrocompounds elicited similar effects on C. coli. The effect of nitroethane and 2-nitro-l-propanol (10 mM) on naturally occurring Campylobacter was investigated during incubation of porcine fecal suspensions, where Campylobacter concentrations decreased more rapidly (P < 0.05) in suspensions with added 2-nitro-l-propanol than in unsupplemented or nitroethane-supplemented suspensions, thus reiterating the superior inhibitory effect of 2-nitro-l-propanol.

New rhodium(I) complexes [Rh(CO)(L)] ( 1 – 3 ) were prepared by the reaction of [RhCl(CO)(PPh 3 ) 2 ] with 9,10-phenanthrenequinone-N-substituted thiosemicarbazones (HL 1-3 ) and characterized by elemental and spectral analyses (IR, UV–Vis, 1 H and 13 C NMR, ESI-Mass). The structure of the complex, [Rh(CO)(L 1 )] ( 1 ) has been established by single-crystal X-ray diffraction analysis. The structure has also been optimized by DFT method using LANL2DZ basis set. The synthesized complexes used as catalysts for the diastereoselective nitroaldol reaction of benzaldehyde with nitroethane in presence of ionic liquid at room temperature. The optimized catalyst 2 was found efficient in the asymmetric Henry reaction between various aromatic aldehydes and nitroalkane. The reusability of the catalyst was checked up to five catalytic runs. The result shows marginal loss in yield and the product retains the diastereoselectivity. It is believed that this procedure provides an opportunity for facilely synthesize of large amounts of diastereomerically enriched β -nitroalcohol.

The asymmetric nitroaldol reaction of nitroethane with aromatic, heteroaromatic, or α,β-unsaturated aldehydes gives the anti-β-nitroalcohols as main isomers.

Polydentate ligands 1 and 2, which incorporate a terminal pyridyl moiety and an oxygen-rich oxalate dihydrizide/malonic dihydrizide spacer moiety, as well as their binuclear metal complexes [Cu212] and [Cu222], which adopt a 1:1 metal/ligand ratio, were synthesized and characterized. Both complexes were screened for their catalytic activity in the nitroaldol reaction, in which [Cu212] worked efficiently as catalyst for both substituted benzaldehyde and pyridinecarboxaldehyde, whereas [Cu222] is highly substrate specific and showed activity towards nitro-substituted aldehydes and pyridinecarboxaldehyde. Furthermore, as helicates are intrinsically chiral, the stereochemical architecture in the binuclear double-stranded Cu2 helicates as catalyst favored the diastereoselective syn product with nitroethane and nitropropane and their respective diastereoselectivities were determined by using 1H NMR spectroscopy.

Cellulose acetate was prepared from locally available low grade pulps containing α-cellulose in the range of 79–94%. The chemical and spectroscopic characterization confirmed the acetylation of all the cellulosic sources studied in the work. The effect of concentrated sulfuric acid as a catalyst and nitroethane as a solvent in the acetylation medium in reducing the insoluble residues was studied. The gravimetric analysis has indicated that these reagents reduce the insoluble residues. This was further confirmed by the optical microscopic photographs. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1765–1771, 2005

Reaction of the CuII complex of the podand hexamine “sen”, CH3C(CH2NHCH2CH2NH2)3, with formaldehyde and nitroethane under basic conditions provides, as one of the principal products, a complex containing a new ligand which is not only macrocyclic but which has resulted also from reactions to extend one podand arm, to introduce an aminal bridge and to oxidise one of the donor-N atom units to an imine. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

The formation of the kinetically controlled 1,2-adduct of nitroethane onto α,β-enimines and its further conversion is examined.

The asymmetric Michael reaction of nitroalkanes and β,β-disubstituted α,β-unsaturated aldehydes was catalyzed by diphenylprolinol silyl ether to afford 1,4-addition products with an all-carbon quaternary stereogenic center with excellent enantioselectivity. The reaction is general for β-substituents such as β-aryl and β-alkyl groups, and both nitromethane and nitroethane can be employed. The addition of nitroethane is considered a synthetic equivalent of the asymmetric Michael reaction of ethyl and acetyl substituents by means of radical denitration and Nef reaction, respectively. The short asymmetric synthesis of (S)-ethosuximide with a quaternary carbon center was accomplished by using the present asymmetric Michael reaction as the key step. The reaction mechanism that involves the E/Z isomerization of α,β-unsaturated aldehydes, the retro-Michael reaction, and the different reactivity between nitromethane and nitroethane is discussed.

Development of methodology for the preparation of nitroolefins is of significant interest to organic chemists. Recently, numerous useful methods have been developed, mainly including direct nitration of olefinic C–H bonds, nitro-decarboxylation of aromatic α,β-unsaturated carboxylic acids, ipso-nitration of vinylboronic acids and multidehydrogenative cross-coupling reaction of (hetero)arenes with nitroethane. This review will focus on recent achievements in nitroolefin synthesis and the mechanisms of the reactions are also discussed.

We thank the Spanish Ministerio de Ciencia e Innovacion (Grant No. CTQ2007-65218, Consolider Ingenio 2010-CSD-2007-00006 and CTQ2011-24165), the Generalitat Valenciana (Grant No. PROMETEO/2009/039 and FEDER) and the University of Alicante for generous and continuous financial support.

A wide range of tri- and tetrasubstituted imidazole derivatives is prepared from amidines, aldehydes and nitromethane or nitroethane, respectively.

A modified Flory-Huggins model is presented, considering a concentration-and temperature-dependent interaction parameter, and using the methodology of Continuous Thermodynamics to take into account both polydispersity and its effect on phase equilibrium of polymeric systems. This model describes all commonly found, as well as other unusual polymer + solvent and polymer + polymer, liquid-liquid phase diagrams and is easily extended to take all possible pressure effects into consideration. Modeling and least-squares fit of polystyrene + nitroethane liquid-liquid cloud-point data have produced results in good accord with the experimental ones by using meaningfully physical parameters. These results have been used to discuss polystyrene molecular weight, pressure, and isotopic substitution effects on polystyrene + nitroethane systems. A first-order interpretation of phase equilibrium isotopic substitution effect has also been applied. It combines the simplest form of the Flory-Huggins model with the statistical theory of condensed phase isotope effects.

In this work nitroethane (NE) was selected as a chlorine-free inhibitor. The influence of NE and mixtures of NE and 1,2-dichloroethane (DCE) on the activity and selectivity of the catalyst was investigated. The demand of these inhibitor systems and the ethylene oxide selectivity were compared to those observed in tests in which only DCE was used.

Einkristalle der triklinen Verbindung NO2(NO)3[Zr(NO3)5]4 (a = 1376,3(6), b = 1376,9(11), c = 1632,0(7) pm, α = 114,63°(5), β = 114,90°(4), γ = 90,34°(5); P1, Z = 2) wurden rontgenographisch und schwingungsspektroskopisch untersucht. Die Verbindung konnte durch Umsetzung von N2O5 mit ZrCl4, anschliesender Sublimation und Umkristallisation in Nitroethan erhalten werden. Crystal Structure and Raman Spectrum of Nitroniumtrinitrosylpentanitratozirconate, NO2(NO)3[Zr(NO3)5]4 Single crystals of the triclinic compound NO2(NO)3[Zr(NO3)5]4 (a = 1376.3(6), b = 1376.9(11), c = 1632.0(7) pm, α = 114.63°(5), β = 114.90°(4), γ = 90.34°(5); P1, Z = 2) have been investigated by x-ray diffraction and Raman spectroscopy. The crystals were prepared by reaction of N2O5 with ZrCl4. The product was sublimed and crystallised in nitroethane.

The Pd-catalyzed multidehydrogenative cross-coupling reactions of arenes with nitroethane are described. The established methods afford β-aryl nitroethylenes that are an important class of synthetic intermediates and biologically active compounds in an atom- and step-economical fashion. The reactions were applicable to substituted benzenes and a variety of heterocycles such as benzothiophenes, benzofurans, and indoles. Mechanistic experiments indicated that β-nitroethylbenzene might be the intermediate in this transformation.

An effective asymmetric synthesis of optically active 1,3-dinitro compounds via the direct Michael addition of nitroalkanes onto nitroalkenes has been described. In the presence of readily modified cinchona alkaloid derivatives, nitroethane reacted well with a variety of aromatic and heterocyclic aromatic nitroalkenes to afford products with good diastereoselectivities (dr up to 72/28) and enantioselectivities (ee up to 94%). The catalyst loading can be decreased to 2 mol % without compromising the asymmetric induction or the reaction rate.

Because cellulose triacetate is prepared from low-grade dissolving pulp, a considerable amount of the insoluble residue was present in the acetylation medium of the acetic acid/acetic anhydride/sulfuric acid system. To reduce the insoluble residues, a solvent, such as nitromethane, nitroethane, or dichloroacetic acid, added to the acetylation medium was found to be very effective for its reduction. By exploring the optimum conditions for acetylation with these solvents, nitromethane added and dichloroacetic acid added systems with solvent/acetic acid = 3/7 (v/v) were found to have a particularly high transmittance at λ = 670 nm in their acetylation solution with a low insoluble residue. The obtained acetates revealed good thermal properties similar to that from high-grade dissolving pulps. Therefore, a high quality cellulose triacetate can be manufactured from acetylation systems with even low-grade dissolving pulps with an appropriate solvent added. © 1996 John Wiley & Sons, Inc.

Tetrahydrofuran (THF) was oxidized selectively with molecular oxygen catalyzed by magnesium oxide-based polyalumazane-supported platinum complexes under mild conditions. The selective oxidation of C–H bond α to the oxygen atom of ether and the oxidative path to ester other than ring cleavage to carboxylic acid were controlled by carrying out the reaction at 60°C with nitroethane as solvent. The platinum loading and the reaction time greatly affected the yield of γ-butyrolactone whereas the selectivity always remained at 100%. 76.92% γ-butyrolactone was obtained with 0.2811 mmol platinum loading per gram support within 12 hr. The single product of the THF oxidation was confirmed by 1H-nuclear magnetic resonance. X-ray photoelectron spectroscopy data also confirmed the more recent report on the activation of the C–H bond by the null valent platinum from the viewpoint of supported platinum catalyst. The oxidation path was also suggested.

A new bifunctional copper complex of the aminoisoborneol Schiff base – Cu2(SBAIB-d)2 – has been developed for the effective direct catalytic asymmetric Henry reaction. One mol% of this catalyst produces the expected Henry products in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The utility of the present catalyst was also extended to the Henry reaction with nitroethane and 1-nitropropane that furnished the corresponding products in moderate to high yields (up to 99%) with moderate to high enantioselectivities of syn (up to 98% ee) and anti (up to 98% ee) diastereomers. The highlights of this catalytic system are easy manipulation, air and moisture tolerance, the need for 1 mol% of an easily synthesizable catalyst and the high enantioselectivities achieved for a wide range of substrates.

The condensation of 4,6-O-benzylidene-D-glucopyranose (1) with nitroethane gave the diastereomeric α-nitroethyl1 β-C-glucosides 2 (minor), and 6. The latter was only obtained pure by an acetylation-deacetylation procedure and was reduced by a mixture of elemental Fe0/Ni0 in aqueous THF under CO2 to α-aminoethyl β-C-glucoside 7, with retention of the 4,6-O-benzylidene blocking group. Acetylation of 2 produced an open-chain compound 3. An oxime derivative 5 was separated as a byproduct from the acetylation. The condensation of 1-nitropropane with 1, followed by acetylation, similarly gave diastereomers 8 and 9. Deacetylation of 8 gave 10.

The new bisoxazoline promotes the reaction of a number of aldehydes with nitromethane and nitroethane.

2-Bromonitroethane undergoes reductive coupling with aldehydes in the presence of indium powder to yield diastereomeric mixture of nitroalkanols.

An efficient and general method has been described for the synthesis of 3-hydroxy-3-(nitromethyl)indolin-2-one by the reaction of isatins with nitromethane/nitroethane in the presence of DABCO. The reaction is catalytic, very rapid, yields are very high and avoids the use of solvents for reaction. The protocol is applicable for substituted isatins as well as substituted nitroalkanes.

Under various basic solutions and reaction durations, 3-substituted 4-formyIsydnones and nitroalkanes containing α-active hydrogen (e.g. nitromethane and nitroethane) are converted to β-nitroalcohols, nitroalkenes and dinitroalkanes. β-Nitroalcohols are obtained only by electrochemical reaction on an electrogenerated base (EGB). The mechanism of overall reaction steps in particular is discussed.

Diastereoselective synthesis of 4-amino-7-hydroxyheptanoic acids 1 , new GABA analogues, was performed involving reduction of C-3 functionalized 5,6-dihydro-4 H -1,2-oxazines available from nitroethane. Molecular docking studies showed that amino acids of type 1 may bind to GABA transaminase, however, no inhibition was observed in the experiments with the enzyme.

A wide range of aromatic and heteroaromatic aldehydes is reacted with nitromethane and nitroethane to afford the products with high yields, enantio- and in the case of nitroethane with high syn-selectivity.

The first metal-catalyzed methodology for the cross-coupling of a broad range of benzoic acids with nitroethane furnishing exclusively (E)-β-nitrostyrenes is described.

Reaction of (2,2′-[o-phenylenebis(methylenethio)]bis[ethanamine])copper(II) in alcoholic base with formaldehyde and nitroethane yields the macrocycle (8-methyl-8-nitro-6,10-diaza-3,13-dithia-1,15,16,17,18,19-dehydrobicyclo[13.4.0]nonadecane)copper (II), which incorporates an ortho-xylene unit as part of a 15-membered macrocyclic ring with cis-N2S2 donors which also carry pendent nitro and methyl groups. Zinc-acid reduction of the complex permits isolation of a potentially quinquedentate N3S2-donor ligand.

The template reaction of {bis[(S)-2-(aminomethyl)pyrrolidine]}copper(II) with formaldehyde, nitroethane, and base in MeOH yields optically pure {1,7-bis[(S)-pyrrolidin-2-yl]-4-methyl-4-nitro-2,6-diazaheptane}-copper(II) ([Cu((S,S)-mnppm)]2+) in high yield. The same reaction with rac-2-(aminomethyl)pyrrolidine is also described. Preparative details and spectroscopic and electrochemical properties of the Cu(II) complexes and of the free ligands are reported and compared with structural, spectroscopic, and electrochemical data of the Cu(II) complex of the unsubstituted parent ligand 1,7-bis[(S)-pyrrolidin-2-yl]-2,6-diazaheptane (ppm). The crystal structure of [CU(PPM)]Cl.ClO4 has been determined by X-ray diffraction methods.