Nitroalkyls

In most cases, the references include additional examples of the class alcohols. Nitroalkyl esters are known (6—7). 

Additional examples of the synthetic utility of this procedure are demonstrated in Eqs 3 50-3 53 The nitro and nitroalkyl groups in the products are Further converted into various Functional groups such as carbonyl, amino, and alkyl groups This is discussed in Chapter 6... 

Conphngs of nitroalkyl radicals v/ith nucleophiles such as CN ,N7, NOj, and other nitrogen nucleophiles provides a nsefiil method for the preparation of nitre compounds v/ith such groups at the cr-posidon. The alkylation of nkromethane v/ith trialkylborane is possible by electrolysis, in which alkyl radicals may be involved fEq. 5.46. ... 

Oxidadve cross-conphng reactions of alkylated derivatives of activated CH compounds, such as malonic esters, acetylacetone, cyanoacetates, and ceitain ketones, v/ithnitroalkanes promoted by silver nitrate or iodine lead to the formation of the nitroalkylated products. This is an alternative way of performing Spj l reactions using cr.-halo-nitroalkanes. 

K. Takahashi et al, The Polymerization and Copolymerization of Nitro Alkyl Acrylates and Nitroalkyl Methacrylates , JApplPolymerSci... 

Data For Nitric Esters, Nitramines, Nitroalkyl-benzenes, and Derivatives of Phenol, Aniline, Urea, Carbamic Acid, Diphenylamine, and Tri-phenylamine , AnalChem 23,1740-7 (1951) CA 46, 5434 (1952) 71) T.L. Cottrel S. 

The stereospecific base-cleavage of the trimethylsilyl group in 1,3-dithiane 1-oxides 499 enables to obtain the specifically deuteriated products 500 (equation 303), A nitro group in y-nitroalkyl sulphoxides 501 (obtained by the Michael addition of nitroalkanes to a, j8-unsaturated sulphoxides) is replaced by hydrogen by means of tributyltin hydride (equation 304). This reagent does not affect the sulphinyl function. The overall procedure provides an efficient method for the conjugate addition of alkyl groups to a, -unsaturated sulphoxides . ... 

Carboxymethylcellulose, polyethylene glycol Combination of a cellulose ether with clay Amide-modified carboxyl-containing polysaccharide Sodium aluminate and magnesium oxide Thermally stable hydroxyethylcellulose 30% ammonium or sodium thiosulfate and 20% hydroxyethylcellulose (HEC) Acrylic acid copolymer and oxyalkylene with hydrophobic group Copolymers acrylamide-acrylate and vinyl sulfonate-vinylamide Cationic polygalactomannans and anionic xanthan gum Copolymer from vinyl urethanes and acrylic acid or alkyl acrylates 2-Nitroalkyl ether-modified starch Polymer of glucuronic acid... 

K. F. Gotlieb, I. P. Bleeker, H. A. Van Doren, and A. Heeres. 2-Nitroalkyl ethers of native or modified starch, method for the preparation thereof, and ethers derived therefrom. Patent EP 710671,1996. 

Recently, Narasaka and co-workers have found that 1-nitroalkyl radicals are generated by oxidation of aci-nitroanions with CAN, and they undergo the intermolecular addition to electron-rich olefins.61 For example, when oxidation is carried out in the presence of silylenol ethers, (3-nitroketones are formed in good yield. (3-Nitroketones are readily converted into enones on treatment with base (see Section 7.3), as shown in Eq. 5.43. 

Interesting intramolecular cyclization of 1-nitroalkyl radicals generated by one-electron oxidation of aci-nitro anions with CAN is reported. As shown in Eq. 5.44, stereoselective formation of 3,4-functionalized tetrahydrofurans is observed.62 l-Nitro-6-heptenyl radicals generated by one electron oxidation of aci-nitroanions with CAN afford 2,3,4-trisubstituted tetrahydropyrans.63 The requisite nitro compounds are prepared by the Michael addition of 3-buten-l-al to nitroalkenes. 

Extension to carbocyclization of butadiene telomerization using nitromethane as a trapping reagent is reported (Eq. 5.48).72 Palladium-catalyzed carbo-annulation of 1,3-dienes by aryl halides is also reported (Eq. 5.49).73 The nitro group is removed by radical denitration (see Section 7.2), or the nitroalkyl group is transformed into the carbonyl group via the Nef reaction (see Section 6.1). 

Tamura and coworkers have reported a related substitution reaction cyclic a-(nitroalkyl) enones undergo regioselective substitution of the nitro group by sulfinate ion, amino, and carbon nucleophiles (Eq. 7.23).24 Several reaction pathways are envisioned for this useful... 

The thermally induced rearrangements in the furoxan series have also been found. In particular, the transformation of 3-R-substituted 4-(3-ethoxycarbonylthioureido)-l,2,5-oxadiazole 2-oxides into derivatives of 5-amino-3-(a-nitroalkyl)-l,2,4-thiadiazole and into (5-amino-l,2,4-thiadiazol-3-yl)nitroformaldehyde arylhydrazones has been reported (Equation 8) <2003MC188>. 

Intramolecular C,C-Coupling Reactions of Bis-N,N-(trimethylsiloxy) Iminium Cations Here we consider one of the mechanistic schemes of intramolecular C,C-coupling reactions of bis-/V,/V-(siloxy)iminium cations generated by silylation of P-nitroalkylated derivatives of malonic ester (382) (Scheme 3.216). 

Goumont et al. exploited this kind of reactivity for the nucleophilic substitution of the hydrogen atom in position 5 by carbon nuclophiles <20030BC2192> (Scheme 18). These authors reported that 6,8-dinitrotetrazolo[l,5- ]pyr-idine 11 easily reacts with potassium nitropropenide to yield an adduct similar to those obtained with alcohols 12. This adduct when oxidized by cerium ammonium nitrate yields the nitroalkyl-substituted aromatic compound 64. 

Although the generation of nitroalkyl radicals by oxidative transition-metal-mediated reactions is known for many years, their application in carbohydrate chemistry was not investigated until recently.41... 

Scheme 39 Racemization in the cyclization of a fi-nitroalkyl phosphate with an alcohol as nucleophile...

NITROALKYL PEROXONITRATES, NITROARYL COMPOUNDS NITROARYLPHOSPHINIC ACIDS, NITROBENZYL COMPOUNDS C-NITRO COMPOUNDS, A-NITRO COMPOUNDS ac/ -NITROQUINONOID COMPOUNDS, aci-NITRO SALTS POLYNITROALKYL COMPOUNDS, POLYNITROARYL COMPOUNDS POLYNITROAZOPYRIDINES Other relevant entries are ... 

Hydroxymethylation of 2- or 4-nitroalkyl-benzenes, (44), takes place by passing a catalytic amount of charge through a solution of (44) and (CH20) Scheme 40 [140]. (44) is reduced at the electrode and electron transfer from (44) to CH2O is envisaged [140]. The resulting formyl radical anion then acts as an EGB toward... 

In atmospheric chemistry, reactions between pure nitric oxide and a range of activated alkenes have been examined. However, no addition products were observed." Only in the presence of NO2 was addition to give jS-nitroalkyl radicals, followed by trapping to /3-nitronitroso compounds, observed. These final products can also trap other radicals to give aminoxyl radicals. 

Alkenes react with nitryl chloride to give jS-nitroalkyl chlorides, jS-chloroalkyl nitrites and vic-dichloroalkane products. Nitryl chloride reacts with enol esters to give o -nitroketones. ... 

A process known as alkene nitrofluorination has been extensively used for the synthesis of /3-nitroalkyl fluorides. Reagents used generate the nitronium cation in the presence of... 

A mixture of silver nitrite and iodine reacts with alkenes to give jS-nitroalkyl iodides, and therefore, provides a convenient route to a-nitroalkenes. Treatment of alkenes with ammonium nitrate and trifluoroacetic anhydride in the presence of ammonium bromide, followed by... 

Kaplan and Shechter found that certain oxidants react with the nitronate salts of secondary nitroalkanes to yield vic-dinitroalkanes (111) in a reaction referred to as oxidative dimerization. These reactions are believed to involve transfer of an electron from the secondary alkyl nitronate to the oxidant with the production of a nitroalkyl radical. The radical can then dimerize to the corresponding vtc-dinitroalkane (111) (Equation 1.2) or lose nitric oxide to form a ketone via the Nef reaction (Equation 1.3). Unfortunately, formation of the ketone is a major side-reaction during oxidative dimerization and is often the major product. 

The second class of benzo-fused heterocycles accessible from benzofuroxans are benzimidazole oxides. In this case only one carbon from the co-reactant is incorporated in the product. With primary nitroalkanes 2-substituted l-hydroxybenzimidazole-3-oxides (46) are formed via displacement of nitrite, and / -sulfones behave similarly. The nitrile group of a-cyanoacetamides is likewise eliminated to alford 2-amide derivatives (46 R = CONRjX and the corresponding esters are formed in addition to the expected quinoxaline dioxides from acetoacetate esters. Under similar conditions secondary nitroalkyl compounds afford 2,2-disubstituted 2//-benzimidazole-1,3-dioxides (47). Benzimidazoles can also result from reaction of benzofuroxans with phosphorus ylides <86T3631>, nitrones (85H(23)1625>, and diazo compounds <75TL3577>. 

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