1.1- Nitroethylene - from

T riethy laminej oxygen 1,1-Nitroethylene from ethylene derivs. 

Tryptamines can also be obtained from nitroethyl and nitrocthcnyl indoles. 3-(2-Nitroethyl)indolcs can be obtained in moderate to good yield by 3-alkylation with nitroethylene. The effective generation of this reactive alkene is the key to the success of the procedures. Ranganalhan and co-workers generated nitroethylene from a mixture of nitroethanol and phthalic anhydride heated to 175 -180 C. Nitroethylene was obtained by distillation at partial vacuum. Reaction of nitroethylene with indole gave 3-(2-nitroethyl)indole in 80% yield[8]. Another procedure involves in situ generation of nitroethylene from 2-nitroethyl acetate. This can be done in refluxing xylene in the presence of a radical chain inhibitor (c.g. ferf-butylcatcchol)[9]. 

Phenylisoxazole has been obtained from the ethylene acetal of /3-benzoylacetaldehyde (300 R = Ph) and hydroxylamine (60ZOB954), and also from benzonitrile iV-oxide and acetylene (49G703), vinyl chloride (70S344), vinyl acetate (62BSF2215) or nitroethylene (76S612). 

Nitroolefins also offer the possibilities of 1,2 cycloaddition (37,57) or simple alkylation (57-59) products when they are allowed to react with enamines. The reaction of nitroethylene with the morpholine enamine of cyclohexanone led primarily to a cyclobutane adduct in nonpolar solvents and to a simple alkylated product in polar solvents (57). These products are evidently formed from kinetically controlled reactions since they cannot be converted to the other product under the conditions in which the other... 

Ono and coworkers have devised a new acetylene equivalent for the Diels-Alder reaction namely, l-phenylsulfony-2-nitroethylene is a very reactive dienophile, and the radical elimination from the adduct gives the Diels-Alder adduct of acetylene, as exemplified in Eq. 7.113. Other acetylene equivalents are summarized in a review.156... 

Apparently, the synthesis of 3-cyanoisoxazoline-2 N-oxide from diazomethane and cyanodinitromethane derivatives also occurs through cycloaddition of diazomethane to intermediate 1-cyano-l-nitroethylene (84). 

Add a 1 M excess of nitroethylene dropwise to liquid 5-benzyloxyindole (or other indole) on a steam bath over two hours. Cool, filter and recrystallize from methylene chloride-petroleum ether. Hydrogenate at two atmospheres over 10% palladium-carbon... 

It appears that the radical cation of nitroethylene in the Xsec time frame rearranges to ionized nitrosoacetaldehyde via the 4//-oxazet N-oxide61. The informative part of the spectra corresponds to the ions originating from CHO and H2CO losses from the molecular ion61. 

The racemic polyzonimine (19) is prepared as shown in Scheme 33. The expoxide (314) is rearranged to the aldehyde (315) by refluxing with LiBr-HMPA in benzene. Morpholine enamine (316) derived from 315 is condensed with nitroethylene, generated in situ from 2-acetoxynitroethane, to afford the nitroaldehyde (317). Ethylene acetalization, reduction over Raney nickel, and subsequent deacetalization give ( )-polyzonimine (19) in 22% overall yield from the epoxide (314) 113). 

Aryl-l,2-dihydro-3-nitro[l,8]naphthyridines have been obtained by the 6jt-thermal electrocyclization of l-(2-arylide-neamino-3-pyridyl)-2-nitroethylenes, obtained in situ from aromatic aldehydes and l-(2-amino-3-pyridyl)-2-nitroethylene in xylene <2002SC747>. 2-Chlorotetrahydro[l,8]naphthyridines have also been obtained from 2,6-dichloropyridines using a free radical xanthate-mediated cyclization <20040L3671>. 

N 16.96% crysts(from EtOAc, MeOH xylene), mp 177° was obtd by addg dropwise an excess of nitroethylene (CH2 CHN02) in an inert solv (eth, dioxane, xylene, Nitrobenz) to benzidine in the same solv and heating at 60° for 2 hrs (Ref 2). No expl props reported Refs 1) Beil-not found 2) H. Hopff 8t M. Capaul, Helv 43, 1902, 1905, 1909(1960) ... 

N 16.59% crysts (from petr eth + eth, below 10°, 7 times), mp 66° was obtd by adding dropwise an excess of nitroethylene (CH2. CHN02) in an inert solv to benzyl-amine at -20° for 30 mins, isolating by treating the yel oil in ether with HC1, converting the resulting hydrochloride to base with aq NaOAc and recrystallizing as above (Ref 2)... 

Radiation-induced polymerization of nitroethylene in the liquid state was studied by Yamaoka and one of the present authors (K. H.). They verified that nitroethylene polymerizes in the anionic mechanism by radiation too, from the following three observations (7). Tetrahydro-furan is the most favorable solvent for the polymerization, among nitro-ethane, ethylether and tetrahydrofuran. The addition of hydrogen chloride remarkably retards the polymerization. Finally, nitroethylene copolymerizes with acrylonitrile. 

In order to examine the new ESR spectrum, the glass containing a larger amount of nitroethylene (28 mole-%) was irradiated, which gives a signal shape as shown in Fig. 6b. When the temperature is raised, the seven-line spectrum due to the free radicals formed from 2-methyltetrahydrofuran disappears, leaving the spectrum of present interest as shown in Fig. 6c. The spectrum has the hyperfine structure due to three... 

Table I shows the effect of visible light illumination before raising the temperature of the irradiated glasses. It appears that polymerization is not initiated at the polymerization temperature in the absence of anion radicals in the glasses. The small but not zero values of conversion for the illuminated glasses may result from incomplete bleaching of the anion radicals, the diameter of the polymerization vessels (20 mm) being much larger than that of the ESR sample tubes (4 mm). The effect of pre-illumination on the conversion indicates that the anion radicals are involved in the initiation process of the radiation-induced polymerization of nitroethylene.

Ionic processes of monomers, nitroethylene, n-butylvinylether and styrene, in organic glass matrices of 2-methyltetrahydrofuran, 3-methyl-pentane and n-butylchloride irradiated by y-rays at 77° K, are studied by observing the electron spin resonance spectra of trapped electrons and ion radicals formed from the solute monomers. The primary ionic intermediates are the trapped electrons and their counterpart, cation radicals of matrix molecules. However, in 2-methyltetrahydrofuran glass, the anionic processes of solute monomers resulting from the trapped electrons proceed selectively. On the contrary, only the cationic processes proceed selectively in n-butylchloride glass. Both processes are able to occur in 3-methylpentane glass. 

The formation of ion radicals from monomers by charge transfer from the matrices is clearly evidenced by the observed spectra nitroethylene anion radicals in 2-methyltetrahydrofuran, n-butylvinylether cation radicals in 3-methylpentane and styrene anion radicals and cation radicals in 2-methyltetrahydrofuran and n-butylchloride, respectively. Such a nature of monomers agrees well with their behavior in radiation-induced ionic polymerization, anionic or cationic. These observations suggest that the ion radicals of monomers play an important role in the initiation process of radiation-induced ionic polymerization, being precursors of the propagating carbanion or carbonium ion. On the basis of the above electron spin resonance studies, the initiation process is discussed briefly. 

The reactivity profiles of the boronate complexes are also diverse.43 For example, the lithium methyl-trialkylboronates (75) are inert, but the more reactive copper(I) methyltrialkylboronates (76) afford conjugate adducts with acrylonitrile and ethyl acrylate (Scheme 16).44 In contrast, the lithium alkynylboronates (77) are alkylated by powerful acceptors, such as alkylideneacetoacetates, alkylidene-malonates and a-nitroethylene, to afford the intermediate vinylboranes (78) to (80), which on oxidation (peracids) or protonolysis yield the corresponding ketones or alkenes, respectively (Scheme 17).45a Similarly, titanium tetrachloride-catalyzed alkynylboronate (77) additions to methyl vinyl ketone afford 1,5-diketones (81).4Sb Mechanistically, the alkynylboronate additions proceed by initial 3-attack of the electrophile and simultaneous alkyl migration from boron to the a-carbon. 

Lespedamine (216) was first synthesized [78JCS(P1)1117] from 1-methoxyindole-3-carbaldehyde 217, which was itself isolated from Brassica oleracea (cauliflower) (87MI4) by treatment with nitromethane, giving the expected nitroethylene (218), lithium aluminum hydride reduc-... 

Asymmetric Michael addition to to-nitrostyrenes,2 The enamine (2) formed from cyclohexanone and this prolinol derivative reacts with 2-aryl-1-nitroethylenes (3) to form, after acid hydrolysis of the primary adduct, essentially only one (4) of the four possible y-nitro ketones. 

As seen in the gitonic and vicinal systems, ammonium and related cationic centers may be components of superelectrophiles and reactive dications having the 1,3-dicationic structure. Several types of superelectrophilic aza-carbo dications have been studied in which protonated nitro groups are involved. For example, it was found that nitroethylene reacts with benzene in the presence of 10 equivalents of CF3SO3H to give deoxybenzoin oxime in 96% yield (eq 58).71 Since the reaction does not occur with only one equivalent of CF3SO3H, the formation of the /V./V -dihydroxy iminium-methyl dication 197 was proposed. In spectroscopic studies, the stable dication (199) can be directly observed by H and 13C NMR spectroscopy from solutions of l-nitro-2-methyl-l-propene (198) in CF3SO3H (eq 59). 

Figure 2. Energy diagram of nitroethylene decomposition pathways. The energy values are in units of kcal/mol and have been calculated by performing singlepoint energy calculations with the MP4/6-311+G(d,p) method and the use of optimized geometries obtained from the MP2(FC)/6-31G(d,p) calculations. The energy values were corrected for ZPVE obtained from the MP2(FC)/6-31G(d,p) calculations. (After figure 3, ref 6)...

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