Fumaronitrile, addition

The reactions of anhydro 2-aryl-3-hydroxythiazolo[2,3-a]phthalizinium hydroxides (171) with methyl propiolate (87EUP226196 88EUP294599), dimethyl acetylenedicarboxylate (85JOC1677), or fumaronitrile (85JOC1677) gave 4//-pyrido[2,l-a]phthalazin-4-ones (173) via cycloadducts 171. When methyl vinyl ketone was reacted with 171 (R = H), in addition to 9% of 4//-pyrido[2,l-a]phthalazin-4-one (173, R = H, R = COMe), a cycloadduct was also isolated (85JOC1677). 

Addition of electron-poor alkenes such as /ran -stilbene, diethyl fumarate and maleate, and fumaronitrile to (50) do not cause nitrogen evolution. Even on heating cycloaddition products were not isolated, although decomposition was induced. Addition of bases such as benzylamine had no influence on the decomposition rate <78JCS(P1)1440>. 

However, use of a less reactive reagent where [R = R =(CH2)4, (CH2)s, (CH2)20(CH2)2] led to the isolation of products 61 and 62, with a reduction in the yields of the desired cycloadducts. The product 62 arises from Michael addition of the liberated methanethiol to A-methylmaleimide. The protocol was further extended to olefinic dipolarophiles with dimethyl fiimurate, dimethyl maleate, fumaronitrile, and 2-chloroacrylonitrile leading to the corresponding adducts, although these dipolarophiles proved somewhat less reactive with reduced yields being observed. Where applicable, the alkene configuration was reflected in the relative stereochemistry of the cycloadducts (Fig. 3.5). 

When acrylonitrile or ethyl acrylate was used as the dipolarophile, the azomethine adducts (134) and (135) were formed no thiocarbonyl ylide addition products were isolable in refluxing toluene or xylene, although the isoindoles (136a) and (136b) derived from them were isolated. In contrast to the reactions with fumaronitrile or AT-phenylmaleimide, the azomethine adducts (134) and (135) were still present at higher reaction temperatures — almost 50% in toluene and 4-5% in xylene. Under the same reaction conditions other electron-deficient dipolarophiles like dimethyl fumarate, norbornene, dimethyl maleate, phenyl isocyanate, phenyl isothiocyanate, benzoyl isothiocyanate, p-tosyl isocyanate and diphenylcyclopropenone failed to undergo cycloaddition to thienopyrrole (13), presumably due to steric interactions (77HC(30)317). 

With fumaronitrile and maleic anhydride, IR spectra, after adding olefin and HCN to NiL3, showed only the very stable (olefin)NiL2 complexes. In these cases the oxidative addition of HCN is evidently suppressed by the strongly electron withdrawing character of the olefins. Small amounts of the reduction products were detected by GC/MS after the solutions had stood for a day, however. The failure of allyl chloride to hydrocyanate is no doubt due... 

The Paterno-Biichi reaction has been employed in the synthesis, often in high yield, of a large variety of substituted oxetanes. In addition to simple aliphatic and aromatic alkenes, cycloaddition of ketones to, for example, fumaronitrile,284 l,3-diacetylimidazolin-2-one288 [Eq. (73)], and allenes286 has been reported. Allenes yield both 1,5- and l,6-dioxaspiro[3.3]heptanes as well as the 2-alkylidene-oxetane this is illustrated for benzophenone and tetramethylallene in Eq. (74). Cycloaddition of ketones to ketenimines to form 2- and... 

Heat-resistant ABS resins can also be produced by polymerizing styrene with modified nitriles, such as fumaronitrile and maleonitrile. Fumaronitrile can be produced from acrylonitrile (Figure 15.7) in a two-step process involving the addition of hydrogen cyanide followed by oxydehydrogenation over metal oxide catalysts. The compatibility of styrene-co-acrylonitrile-co-fumaronitrile (SANF) terpolymers and SAN has been studied [75]. High-gloss, heat-resistant... 

A recent patent by DSM [121] claims catalysts very similar to those reported by Furuoya [120]. Indeed, the catalyst preparation is the same as the one described by Furuoya [120bj. The only difference concerns the addition of siUca in relevant amounts, in the form of silica sol. This is claimed to give better reproducibiUty in performance for catalysts prepared in the powder form (by spray-drying). The best performance reported is 95% conversion and 58% yield to nitriles (fumaronitrile -1-maleonitrile -1- succinonitrile, the saturated dinitrile). The authors report the use of a low O2 concentration, with a feed composition of 0.50% butadiene, 2.50% ammonia and 4.4% oxygen (the balance being nitrogen). 

The reaction of 5-ureidooxazoles with acrylonitrile or fumaronitrile yields 4-imino-8-methyl-3,4-dihydropyrido[3,4-rf]pyrimidin-2(li/)-ones, in the case of fumaronitrile with a 5-cyano group (R2 = CN).483 The reaction may be formulated via a Diels-Alder addition followed by closure of the pyrimidine ring between the terminal urea nitrogen and the cyano group, the resultant tricyclic system losing water to give the observed product. 

In the presence of an electron donor or acceptor, stilbenes can undergo a number of other reactions. Charge and electron transfer processes of frans-stilbene have been intensively studied by Lewis [492,493] and Hub et al. [494], Exciplex fluorescence was observed on addition of either secondary and tertiary amines or fumaronitrile to frans-stilbene in solvents of low polarity [492, 495-499]. Quenching of 9,10-dicyanoanthracene by stilbene leads to singlet exciplexes in nonpolar solvents [500] and to radical ions in acetonitrile [501,502],... 

Trans cis selectivity during additions to crotononitrile and fumaronitrile were predicted to be >95 5 and <95 5 respectively (Scheme 4). Experimentally, these ratios are 92 8 and 89 11 [13], Many other examples are presented. 

This reaction appears to be generally applicable to dienophiles. Acrylonitrile or fumaronitrile react with triethyl phosphite in ethanol to provide the corresponding j -cyanophosphonate esters (44% and 55%, respectively). Ethyl propiolate, triethyl phosphite, and ethanol furnish diethyl 2-carbethoxy-l-ethoxyethylphosphonate, which most probably arises by addition of ethanol to an intermediate species rather than to reactant or product. Reaction of crotonaldehyde with triethyl phosphite in phenol provides the diphenyl acetal of jS-(diethoxyphosphinyl) butyraldehyde (36) (82%). Substitution of ethanol for phenol in this reaction results in a somewhat lower yield (59%) of the corresponding diethyl acetal as well as a 19% yield of the ethyl enol ether of this same aldehyde. 

To the best of our knowledge, there is only one example in the literature of a photoaddition reaction influenced by CD and involving two different molecules, that is, the photocycloaddition of 5-X-adamantan-2-ones (X = F, Cl, Br, OH, phenyl, ferf-butyl) with fumaronitrile (Scheme 31) [319]. The reaction performed in p-CD aqueous solution led to a remarkable change in product distribution with respect to that found in isotropic solvent. The syn/anti ratio of the frans-oxetane formed was reversed (Table 23). The effect was maximum with the bulkier substituents and was not observed on addition of a- and y-CD. The rationale is that deep inclusion in the P-CD... 

There is little doubt that the addition of acrylonitrile and related compounds to a variety of substrates provides a useful synthetic path for the formation of many bicyclic compounds. Typical of this is the photoaddition of malononitrile or fumaronitrile to 3-methylcyclohex-2-enone which provides four adducts in a ratio of 29 15 21 35. The structure of the predominant isomer was determined by X-ray crystallography and was established to be the cyclobutane 279. The ratio of the products obtained from these experiments was shown to be independent of the dose of irradiation. Quantum yield... 

Recently, anodic generation of the CF3 radical and its trapping reactions have been systematically studied by Uneyama and his coworkers (Scheme 24). "" This work has demonstrated that tri-fluoromethyl radicals can be generated almost quantitatively by the oxidation of TFA at 0 °C in an aqueous MeOH/Pt system using a divided cell." Also, it has been found that additions of the tri-fluoromethyl radical to electron-deficient olefin can be controlled by the choice of current density, reaction temperature, and olefin substituents. Notably, anodic trifluoromethylation of fumaronitrile leading to 31 (Scheme 25) is greatly affected by the reaction temperature. The... 

Tsuchida and Tomono suggested fliat flic monomer-monomer complex described in the MCP model may dissociate upon addition to the chain, with only one unit adding. The concept was developed by Karad and Schneider who argued that the dissociation of the complex is likely since its heat of formation is typically less than the heat of propagation. As an example, fliey measured the heat of formation for a STY/fumaronitrile complex, and found that it was only 1.6 kcal/mol, significantly less than the heat of propagation (15-20 kcal/mol). Under a complex-dissociation mechanism, the role of the complex is merely to modify the reactivity of the reactant monomers. 

Another pioneer in the Diels-Alder reactions of vinylpyrroles was Noland, who also developed the reactions of vinylindoles to yield carbazoles. Some examples of the former are shown in Scheme 2 (equations 1 and 2) [4-7], Jones and his colleagues were equally active in this cycloaddition chemistry of vinylpyrroles (equations 3 and 4) [8-12], These workers measured the rates of the reaction between 1-methyl-2-vinylpyrrole and seven dienophiles, with maleic anhydride being 4800 to 50,000 times more reactive than the other dienophiles (DMAD, maleonitrile, fumaronitrile, dimethyl maleate, methyl acrylate, and acrylonitrile) [8], In a clever tactic to thwart the formation of dihydroindoles, Jones used an excess of methyl propio-late to convert the initial adduct to a second Diels-Alder cycloadduct that subsequently loses ethene by a retro-Diels-Alder reaction to afford the dimethyl 1-methyl (phenyl)-4,7-dicarboxylates (equation 4). The reactions are concerted and were consistent with FMO calculations (HOMO[vinylpyrrole]-LUMO[alkene]). The yields are 54% to 81%, but attempts to dehydrogenate the tetrahydroindole products to indoles were unsuccessful. 2-Vinylpyrrole itself undergoes Michael additions and polymerization with these dienophiles. Domingo, Jones, and coworkers subsequently... 

The formation of 1,3-oxathiolane with chloral and 1,3-dithio-lanes with cycloaliphatic thioketones occurs regioselectively to yield the sterically less hindered products. On the other hand, aromatic thioketones, e.g., thiobenzophenone or 9/ fluorene-9-thione, intercept 8 to give comparable amounts of both regio-isomeric adducts. Usually, stereoisomeric dipolarophiles such as fumaronitrile and maleonitrile as well as dimethyl fumarate and maleate form 18 in a stereoselective manner. However, in the case of extremely electron-poor dipolarophiles, e.g., dimethyl 1,2-dicyanofumarate or ( )-l,2-bis(trifluoromethyl)ethylene-l,2-dicarbonitrile, non-stereospecific formations of the corresponding tetrahydrothiophenes are described. i- s This result is interpreted in terms of a stepwise reaction mechanism with a zwitterion as the key intermediate. Alternatively, this intermediate can cyclize to form seven-membered ketenimines of type 20. With R = Cp3, this product can be isolated in a crystalline form, whereas in the case of R = CN, stable lactam 21 is obtained only after addition of water (eq 10). 

The influence of the reaction conditions upon the stereochemistry of polymerization has been examined for a number of systems. The presence of a small amount of water increased the isotacticity of the polymerization of ethyl methacrylate in toluene at -78 °C. A new type of cyclic structure for polybutadiene-a substituted cyclopentane - was identified in polymer prepared using an organo-lithium initiator in the presence of tetramethylethylene diamine. The polymerization of 1-phenylbutadiene initiated by alkyl-lithium in hydrocarbon solvents results in 50—60% trans-, A, some 25% c/r-1,4, and 10— 25% 3,4 enchainment. When THF is employed as solvent, the corresponding values are about 80, 10, and 10%, respectively. The anionically-prepared polymers have structures very different from those formed cationically, which comprise lately 3,4 addition accompanied by extensive cyclization. The distribution of cis-and trans-1,4 structures in polyisoprene prepared using Bu Li in non-polar media has been shown by C n.ra.r. spectroscopy to be nearly random. The polymerization of fumaronitrile is initiated in benzene solution by the addition of butyl-lithium across one C N group in THF solution initiation is by transfer of an electron from BuLi. ... 

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