ETHYL <£>3-NITROACRYLATE

Another approach is the Michael addition to ethyl (3-nitroacrylate, as shown in Eq. 7.123, which has been used in the synthesis of a-methylenebutyrolactone, a moiety characteristic of many sesquiterpenes. ... 

This procedure for the synthesis of ethyl 3-nitroacrylate is essentially that of Stevens and Emmons.2 Four major changes have been introduced by the submitters rapid introduction of dinitrogen tetroxide no purification of the intermediate nitro iodo ester use of dry, finely powdered sodium acetate for elimination of hydroiodic acid and percolation of the final product through a mat of alumina. With these modifications, the preparation is reproducible and highly efficient (80-90% overall). 

Ethyl 3-nitroacrylate is an extremely reactive receptor in the Michael reaction. It has found use in the synthesis of the a-methylene-butyrolactone moiety3 characteristic of many sesquiterpenes, as shown... 

Diels-Alder reaction between ethyl ( )-3-nitroacrylate and 108 and an 32a-Cope-Mannich reaction as key steps to form the main polycyclic framework (Scheme 1.16). 

The powerful activation provided by the nitro group can even be enhanced by the presence of an additional EWG, such as an ester moiety. Accordingly, the bioreduction of ethyl (3-nitroacrylates such as 84 proceeded very efficiently with OYEl affording the optically enriched saturated (J )-nitroesters, which were employed to prepare (3 -amino acids, for example R)-86, challenging synthetic targets of undiscussed relevance in both chemistry and biology (Scheme 3.24, see Chapter 13 for further details) [105]. 

Cycloalkanone enamines react with ethyl / -nitroacrylate to form adducts which yield y-lactones on treatment with sodium borohydride. Base-induced elimination of the elements of nitrous acid gives oe-methylenebutyrolactones 23 (equation 16)35. 

C -Nitro polymers from monomers with a vinyl group Nitroallyl acetate polymer Ethyl nitroacrylate Nitroelhyl acrylate Nilroethyl methacrylate Trinitroethyl acrylate Dinitropropyl acrylate (DNPA)... 

Ethyl nitroacrylate 411 Eihvlenc dinitroaminc (EDNA. Haleite) 362- 365(111/18)... 

The preparation of 5-ACETYL-l,2,3,4,5-PENTAMETHYLCYCLO-PENTADIENE is of value in the synthesis of pentamethyleyclo-pentadiene and many pentamethylcyclopentadienyl metal carbonyl derivatives that are more soluble in organic solvents than those derived from cyclopentadiene. Simple preparations of 5,6-DIHYDRO-2-PYRAN-2-0NE and 2-//-PYRAN-2-ONE make these hitherto rather inaccessible intermediates available for cycloaddition and other reactions. The already broad scope of the Michael reaction has been widened further by including an efficient preparation of ETHYL (E)-3-NITROACRYLATE. Workers in the field of heterocyclic chemistry will find a simplified method for the preparation of 2,3,4,5-TETRA-HYDROPYRIDINE of help. 

Ethyl nitrite, 58,113,115 ETHYL 7-3-NITROACRYLATE, 56,65 Ethyl JV-nitroso-JV-(p-tolylsulfonylmethyl> carbamate, 57, 96 Ethyl nonanoate, 59, 110 Ethyl 7-oxo-l-cycloheptene-l-carboxylate,... 

Functionalized nitroalkenes are important dienophiles in the Diels-Alder reaction. For example, ( )-methyl P-nitroacrylate is an important reagent in organic synthesis. The nitro group can be readily eliminated the Diels-Alder reaction of P-nitroacrylate is equivalent to that of ethyl propiolate with an inverse regiochemistry (Eq. 8.4).11... 

The nitro derivatives were also obtained by direct synthesis starting from ethyl j8-ethoxy-a-nitroacrylate [Eq. (11)]. 

Ethylacrylate and derivs 6 E201-E202 ethyl-2-nitroacrylate 6 E202... 

Nitro-4H-pyrimido[2,l-a]isoquinolin-4-one (241) was obtained via 240 in 68% yield when 1-aminoquinoline and ethyl 3-ethoxy-2-nitroacrylate were reacted in ethanol for 2 h at ambient temperature, and then the reaction mixture was evaporated in vacuo to dryness and the residue was cy-clized in polyphosphoric acid at 95°C for 50 min (77CB2480). 

Nitro-3-pyrazolones (52) have been prepared recently by reaction of ethyl-jS-ethoxy-a-nitroacrylate and -crotonate with hydrazine and its derivatives [Eq. (17)].48... 

Ethyl 2-pyridylacetate has been converted into l-carbethoxy-3-nitro-4H-quinolizin-4-one (102) by condensation with ethyl /J-ethoxy-a-nitroacrylate [Eq. (33)].94... 

Ethyl 3-ethoxy-a-nitroacrylate with 1,1-diphenylhydrazine in ethanol followed by heating has been shown to give l,4-bis(diphenylamino)-2,5-diethoxycarbonyl-l,4-dihydropyrazine (1586). A small amount of 2,5-dicyano-l,4-bis(dimethylamino)-1,4-dihydropyrazine was obtained from the reaction of 2-chloro-3-(2, 2-dimethyl-hydrazino)propionitrile [(Me)2NNHCH2CH(Cl)CN] with sodium hydride (1587). Hexaalkyl-l,4-dihydropyrazines and other 1,4-dialkyl-1,4-dihydropyrazines can be obtained by thermolysis of the products of reaction of a-(alkylamino)carboxylic acid esters with alkylmagnesium bromide. Thus the reaction of ethyl a-s-butyl-aminopropionate with ethylmapesium bromide, followed by heating in vacuo to 250-300°, gave 2,5-dimethyl-3,6-diethyl-l,4-di-s-butyl-l,4-dihydropyrazine (1588). 

Reactions of nitroalkenes and enamines take place not only in good chemical yields but also in excellent diastereomeric yields (>W%) . A topological rule has been formulated for carbon-carbon bond-forming processes between prochiral centres in enamines and nitroalkenes as well as other systems The reaction of enamines and imines with acrylamide results in aza-annulation ° . Other electrophilic alkenes which have been us to alkylate enamines and the products used in hetero- or carbocyclic synthesis include ethyl /5-nitroacrylate, where reaction occurs beta to the nitro not the ester group, 2- phenylseleno)prop-2-enenitrile [CH2 = C(SePh)CN] , phenyl a-phenylselenovinyl sulphone [CH2 = C(SePh)-S02Ph] and phenyl a-bromovinyl sulphone. An electrophilic allene, phenylsulpho-nylpropadiene, has also been used to alkylate enamines (Scheme 44). 

By analogy to the preparation of pyrazoles described earlier, the reactions of ethyl 8-ethoxy-Q -nitroacrylates 309 with hydrazines lead to the enaminone intermediates 310, which spontaneously cyclize to the 4-nitropyrazolinones 311, Scheme 87 (77S136),... 

---