1 - -2-nitroethylene,

Unsaturated compounds activated by electron-attracting groups can also effect alkylation at the 3-position. An important example is the reaction with nitroethylene to form 3-(2-nitroethyl)indole [31731-23-4] (14). 

Other methods of generating a-aminoketones in situ are common, if somewhat less general than the methods already described. 2-Nitrovinylpyrrolidine, which is readily available, yields 2,3-bis(3-aminopropyl)pyrazine on reduction and this almost certainly involves ring opening of the intermediate enamine to an a-aminoketone which then dimerizes under the reaction conditions (Scheme 59) (78TL2217). Nitroethylene derivatives have also served as a-aminoketone precursors via ammonolysis of the derived epoxides at elevated temperatures (Scheme 60) (76S53). Condensation of 1,1-disubstituted hydrazine derivatives with a-nitro-/3-ethoxyethylene derivatives has been used in the synthesis of l,4-dialkylamino-l,4-dihydropyrazines (Scheme 61) (77S136). 

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). 

Nitroisoxazoles have been synthesized by reaction of l-chloro-2-nitroethylene with nitrile N-oxides (75C350). 

Cyclopropenones react with nitrosobenzene by an O-initiated attack at C-1 to produce isoxazolin-5-ones (75TL3283, 78USP4053481), and an isoxazolin-5-one was produced as a by-product in the photolysis of nitroethylene (78AJCU3). Substituted oxazolin-5-ones have... 

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... 

Indole magnesium iodide reacts with nitroethylene to give 3-(2-nitroethyl)indole (351) in good yield (Noland and Hartman ). Noland et al. subsequently showed that this reaction, which is usually carried out in ether at 0°, was of general applicability and reported... 

Dehydration of fi-nitro iilcohols provides an important method for the preparation of nitroalkenes. Because lower nitroalkenes such as nitroethylene, Tnitro-Tpropene, and 3-nitro- Tpropene tend to polymerize, they must be prepared careftdly and used immediately after preparation. Dehydration v/ith phthalic anhydride is the most reliable method for such lower nitroiilkenes. Such lower nitroalkenes have been used as important reagents for Michael acceptors or dienophiles in the Diels-Alder reacdon, which v/ill be... 

Nitroethylene Dehydration of l-nitroethanol using phthahc anhydnde f80% is the best choice of preparation bp 38-39 C/80 mm Hg. 

The Michael type reaction of f3/f -5-r-butyldimethysiloxy-3-phenyl-l//-pyrrolo[l,2-c oxa2ole with nitroethylene proceeds in the presence of Lev/is acid to give the alkylated product in good chemical yield and diastereoselecdvity In the case of nitroethylene, the Diels-Alder type transition state is favored to give the ryu-adduct selectively fEq 4 72 ... 

The totiil synthesis of frodosinB, which isapotendally usefiddnigfor HIV, has been reported fScheme 8 8 The key steps in the synthesis are a Friedel-Crafts reacdon to form the seven-membered ring and a Diels-Alder reacdon of nitroethylene to biuld the six-membered ring, thereby fixing the double bond in the proper posidon ... 

Strongly acidic monomers, such as nitroethylene, can only be grafted under anionic conditions. Also, anionic grafting is useful for conventional monomers such as acrylonitrile and methylmethacrylate. In addition to the... 

Nitroethylene, IT2C — CHNCH, is a sensitive compound that must be prepared with great care. Attempted purification of nitroethylene by distillation often results in low recovery of product and a white coating on the inner walls of the distillation apparatus. Explain. 

Sequential radical cyclizations are also featured in an efficient and clever synthesis of the cedrane framework 83 (see Scheme 15).30 Compound 81, the product of a regioselective Diels-Alder reaction between isoprene (79) and nitroethylene (80), participates in a nitroaldol reaction (Henry reaction) with 5-methyl-4-hexenal in the presence of a basic resin to give 82. Because the nitro group in... 

Nitroalkenes are good dienophiles and the variety of transformations available for nitro groups makes them versatile intermediates.65 Nitro groups can be converted to carbonyl groups by reductive hydrolysis, so nitroethylene can be used as a ketene equivalent.66... 

Nitroethylene Dehydration of 2-nitroethanol44 using phthalic anhydride (80%) is the best choice of preparation 43 bp 38-39 °C/80 mm Hg. 

Nitroethylene, 1-nitro-l-propene and 2-nitro-l-propene, see Encyclopedia of Reagents for Organic Synthesis, ed. by L. Paquette, Wiley, New York, 1996. 

Nitroethylene is extremely reactive and sensitive to strong basic conditions, but various ketone and ester enolates undergo alkylation with nitroethylene at low temperature (Eq. 4.5165 and Table 4.1). 

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... 

The Diels-Alder reaction of morphinan-6,8-dienes with nitroethene affords a novel type of opium alkaloids (Eq. 8.3).10a High reactivity of nitroethylene is demonstrated for the Diels-Alder reaction with thermally unstable dienes, and this is used for synthesis of polycyclic kopsane-like alkaloids.1013... 

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). 

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