1 -Nitro-1 - -propene, reaction

A mixture of 50 g l-(3-methoxy-4,5-methylenedioxyphenyl)-2-nitro-propene and 26 g racemic a-methylbenzylamine was heated on the steam bath. The mixture gradually formed a clear solution with the steady evolution of nitroethane. When the reaction became quiet, there was added a mixture of 20 mL concentrated HC1 in 100 mL H20. The reaction mixture dissolved completely, and as the temperature continued to rise there was the abrupt solidification as the formed myristicinaldehyde crystallized out. This product was removed by filtration and, when combined with a second crop obtained by the hexane extraction of the filtrate, gave 36.9 g of myristicinaldehyde. The mp of 128-129 °C was raised to 133-134 °C by recrystallization from hexane. 

A wide array of compounds undergo the Nef reaction. These include simple nitro compounds, as well as complex multifunctional species. For example, the carbohydrate in equation (2) was isolated as its hy-drazone derivative in 72% yield. Nitronate anions generated in situ can be acidified to give good yields of aldehydes and ketones. As an illustration, Michael addition of the dianion of hexanoic acid to 2-nitro-propene gives the expected keto acid after acidification (equation 3). ... 

Nitro-propene or 2-butene and 1 gave ketofuran adduct 130 and 131 (R = Me), respectively (75CC726, 80JOC2945). A stereoisomeric mixture of hydroxyimino dihydrofuran 132 was obtained in the presence of KE Reaction of 1 with l-nitro-l-(phenylthio)-propene in the presence of KF afforded a diastereomeric mixture of dihydrofuran 133 along with... 

The influence of the furan ring substituents on exo/endo selectivity was also noted in the reaction of 2,5-disubstituted furans with l,l,l-trichloro-3-nitro-propene [10]. Here, the... 

What goes on in this conversion is that the p-Nitropropene undergoes a catalytic reduction whereby it loses its propene double bond, and the nitro s oxygens get replaced with hydrogens. All this happens in one pot with, usually, just one reaction. 

The basis of the demonstration can be based on already published data on the surface reaction between NOz and adsorbed organic compounds. Yokoyama and Misono have shown that the rates of N02 reduction over zeolite or silica are proportional to the concentration of adsorbed propene [29], whereas Il ichev et al. have demonstrated that N02 reacts with pre-adsorbed ethylene and propylene on H-ZSM-5 and Cu-ZSL-5 to form nitro-compounds [30], Chen et al [2-4] have observed the same nitrogen-containing deposits on MFI-supported iron catalysts. The question on the pairing of nitrogen atoms is not considered here. 

Dehydration of P-nitro alcohols provides an important method for the preparation of nitroalkenes. Because lower nitroalkenes such as nitroethylene, 1-nitro-1-propene, and 2-nitro-l-propene tend to polymerize, they must be prepared carefully and used immediately after preparation. Dehydration with phthalic anhydride is the most reliable method for such lower nitroalkenes.42,43 Such lower nitroalkenes have been used as important reagents for Michael acceptors or dienophiles in the Diels-Alder reaction, which will be... 

A simple synthesis of allethrolone, the alcohol component of the allethrine (commercially important insecticide), is shown in Scheme 4.11. The conjugated addition of 3-phenylthio-5-hexene-2-one to 1-nitro-l-propene followed by the Nef reaction and aldol condensation gives allethrolone in good yield.68... 

The reaction of enamines with 2-nitro-2-propen-l-yl pivalate gives 4-nitrocyclohexanones, which is regarded as formal [3 + 3] carbocyclization. The reaction proceeds in high diastereoselectivity (60% to >95% selectivity), see Eq. 4.69 88 If chiral enamines such as that in Eq. 4.68 are employed, the products are obtained with high ee. 

TABLE 24. Second-order rate constants (M 1 s ) for the Diels-Alder reaction of 3(4-nitro-phenyl)-l-(2-pyridyl)-2-propen-l-one in different media at 25 °C... 

Frankel synthesized 2-nitro-3-acetoxy-l-propene (139) by heating l,3-diacetoxy-2-nitropropane (138) with sodium acetate under reduced pressure. The reaction of 2-nitro-3-acetoxy-l-propene with 1,1-dinitroethane yields 2,2,4,6,6-pentanitroheptane. The same reaction with nitroform provides 1,1,1,3,5,5,5-heptanitropentane (142), a powerful explosive (VOD 9230 m/s) with an excellent oxygen balance. The synthesis of 1,1,1,3,5,5,5-heptanitropentane from2-nitro-l,3-propanediol and 2-nitro-l-propen-3-ol has also been reported and involves a similar mechanism. 

The addition reactions of aryl azides onto enamines bearing a carbonyl, sulfonyl, or nitro group in the 0 position with respect to the nitrogen atom have been investigated by Italian authors.240-241 The expected triazoline derivatives could not be isolated but were immediately converted into the corresponding 1,2,3-triazoles (49) and secondary amines. The reaction of p-nitrophenyl azide with l-benzoyl-2-morpholino-l-propene (48) is given as a typical example. 

Vinylpyrroles and vinylindoles are extremely sensitive to acid-catalyzed dimerization and polymerization and it is significant that much of the early research was conducted on systems which were produced in situ. Even by this approach, the dimerization of, for example, 2-(3-indolyl)propene and l-(3-indolyl)-l-phenylethylene was difficult to prevent (see the formation of 110 and 120, Section 3.05.1.2.8). Similarly, although it is possible to isolate ethyl 2-(2- and 3-indolyl)propenoates, they appear to be extremely unstable at room temperature even in the absence of acid (81UP30500) to give [ 4 + 2] cycloadducts of the type (348) (cf. 77JCS(P1)1204>. For many years simple vinylpyrroles also eluded isolation, on account of their facile acid-catalyzed polymerization. Application of the Wittig reaction, however, permits the synthesis of vinyl-pyrroles and -indoles under relatively mild and neutral conditions (see Section 3.05.2.5). In contrast, heteroarylvinyl ketones, esters, nitriles and nitro compounds, obtained by condensation of the appropriate activated methylene compound with the heteroaryl aldehydes (see Section 3.05.2.5), are thermally stable and... 

Oxygen-transfer reactions have been shown to occur from cobalt(III)-nitro complexes to alkenes coordinated to palladium.472 Thus ethylene and propene have been oxidized stoichiometrically in quantitative yields to acetaldehyde and acetone respectively, with the concomitant reduction of the nitro- to the nitrosyl-cobalt analog. A catalytic transformation with turnover numbers of 4-12 can be achieved at 70 °C in diglyme. The mechanism shown in Scheme 11 has been suggested. 

A well-stirred solution of 6.8 g of the mixed isomers of 1 -(2,3,6-tri-methoxyphenyl)propene in 40 g of dry acetone was treated with 3.2 g pyridine and cooled to 0 °C with an external ice bath. There was then added 6.5 g tetranitro-methane over the course of 1 min, the stirring was continued for an additional 2 min, and then the reaction mixture was quenched by the addition of 2.2 g KOH in 40 mL H20. There was additional H,0 added, and the organics were extracted with 3x75 mL CH,C12. The solvent from the pooled extracts was removed under vacuum, and the 5.3 g residue distilled at 0.2 mm/Hg. A fraction boiling at 150-170 °C proved to be largely 2,3,6-trimethoxybenzaldehyde. A second fraction (170-200 °C at 0.2 mm/Hg) also spontaneously crystallized to a yellow solid. This was recrystallized from MeOH to provide, after drying to constant weight, 2.8 g of 2-nitro-1 -(2,3,6-trimethoxyphenyl)propene with a mp of 73-74 °C. Anal. (C 2H N05) C,H. 

A solution of 5.0 g 2,4,5-triethoxybenzaldehyde and 2.6 g nitroethane in 14.8 g glacial acetic acid was treated with 1.6 g anhydrous ammonium acetate and heated on the steam bath for 2 h. The addition of an equal volume of H20 gave a slightly turbid solution which, upon the administration of a small amount of externally developed seed, smoothly set up as orange crystals as the reaction mix returned to room temperature. The product was removed by filtration, washed with a little 50% acetic acid, and allowed to air dry to constant weight. There was thus obtained 2.5 g of fluffy yellow-orange (almost yellow) crystals of 2-nitro-l-(2,4,5-triethoxyphenyl)propene with a mp of 91-92.5 °C. Anal. (Cl5H2 N05) C,H. 

Introduction of nitro and fluorosulfonoxy groups can be carried out by reaction of ionic 02N0S02F with fluoroolefins [8,116-118]. Nitronium fluorosulfa-te is not as active as halogen fluorosulfates addition to CH2=CF2 and CFH=CF2 proceeds only at ambient temperature [117]. Reaction with TFE and chloro-fluoroethylene proceeds at a noticeable rate at temperature above 50 °C, while addition to 2-H-F-propene only at temperatures higher than 120 °C [117] ... 

In several recent studies, nitro-substituted olefins have been shown to exhibit high electrophilic reactivities in superacid-promoted reactions.29 NMR studies have been used to identify some of the superelectrophilic intermediates in these reactions. For example, it was found that nitroethy-lene reacts with benzene in the presence of 10 equivalents of CF3SO3H to give deoxybenzoin oxime in 96% yield (eq 29). Since the reaction does not occur with only one equivalent of TfOH, it was proposed that the N,N-dihydroxy-iminium-methylium dication (51) is generated. In spectroscopic studies, l-nitro-2-methyl-l-propene (52) was dissolved in CF3SO3H, and at —5°C the stable dication (53) could be directly observed by and 13 C NMR spectroscopy (eq 30). 

Enaminothiones derived from acetophenones using Vilsmeier methodology yield substituted 2//-thiopyrans on reaction with various dienophiles. The dihydrothiopyran from the cycloadducts with propenal and but-3-enone spontaneously eliminate dimethylamine, but the cycloadduct can be isolated when l-nitro-2-phenylethene is used as the dienophile and later converted to the thiopyran (Scheme 113) <1994JPR434>. 

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