Substituted aryl acrylamides

P-Arylated acrylamides also react to give a-substituted succinimides. Thus a-phenylsuccinimide is obtained from cinnamamide. 

Substituted alkenyl and aryl acrylamides 308 and 310 undergo electro-cyclic ring closure at 800 °C to produce the dihydropyridone derivatives 309 and 311, respectively, in moderate yields (Scheme 62 2002SC875). The unsaturated ester 312 also imdergoes electrocyclization followed by in situ aromatization to give the tricyclic product 313 (20060BC407). 

Radical carbonylation reaction serves as a powerful tool for the synthesis of a range of carbonyl compounds. Radical carbonylation has been successfully applied to the synthesis of functionalized ketones from alkyl, aryl, and alkenyl halides.The radical aminocarbonylation reaction of alkynes and azaenynes provided efficient routes to 2-substituted acrylamides, lactams, and pyrrolidinones. For example, the aminocarbonylation of 4-pentyn-l-yl acetate 318 initiated by tributyltin hydride (Bu"3SnH) (30mol%) with AIBN (20mol%) gave acrylamide 325 in 92% yield (Scheme 43).A proposed mechanism starts from the addition of tributyltin radical 319 to alkyne... 

Rhodium(I) or polymer supported rhodium(I) compounds catalyzed the formation ofFefCO - CNR L (x = 1 - 3 R = Bu, xylyl L = MA, citra-conic anhydride, acrylamide) (29, 30), and the dimer [CpFe(CO)2]2 catalyzed the stepwise substitution of carbonyl groups in CpFeI(CO)2 to give CpFeKCO - CNR) (x = 1,2 R = Bu, xylyl) in 60-80% yields. A nonchain free-radical mechanism was proposed for the latter reaction (28). The compounds CpFeX(CO)2 x(CNR)x (x = 1,2 X = halide, SiMe3) are known for a range of alkyl and aryl isocyanides (169-171). 

Supercritical carbon dioxide with a minute co-solvent addition is an effective medium for the 1,3-dipolar cycloaddition of azomethine ylides with DMAD to produce substituted pyrroles.67 The 1,3-dipolar cycloaddition of nitrile ylides [e.g. benzonitrile (4-nitrobenzylide) and 4-nitrobenzonitrile(benzylide)] with acrylamides provided a synthesis of 3,4-dihydro-2//-pyrroles with moderate to good yields.68 The Pt(II)-or Au(III)-catalysed 3 + 2-cycloaddition of the transition metal-containing azomethine ylide (63) with electron-rich alkenes provided a carbene complex (64), which yields tricyclic indoles (65) having a substituent at 3-position (Scheme 17).69 The 1,3-dipolar cycloadditions of azomethine ylides with aryl vinyl sulfones are catalysed by Cu(MeCN)4C104-Taniaphos with nearly complete exo- selectivity and enantioselec-tivities up to 85% ee.10 The 3 + 2-cycloaddition of benzol/>]thiophene 1,1-dioxide... 

Regioselective aza-annulation reactions have been achieved through the use of aryl substituted keto enamine substrates. Aryl substitution at the a-position of the enamine provides for regioselective imine-enamine tautomerization at the non aryl (i carbon. Early studies in this area compared the utility of pyrrolidine enamine versus benzyl imine derivatives of a-tetralone.8 In the absence of solvent, aza-annulation of 75 with acrylamide led to the formation of 76, but use of imine derivative 77 resulted in significantly higher yield of 76 (eq. 19).8 Similar reactions were observed between an aryl ethyl ketone and acrylamide (72% yield, dioxane, 70 °C) or acrylonitrile when catalyzed by AICI3 at 25 °C.33... 

The inverse temperature-dependent solubility in aqueous media of polymer-bound palladium(0)-phosphine catalysts, based on the water-soluble polymer poly(Wisopropyl)acrylamide (PNIPAM) 28, was also used to recycle and reuse these catalysts in nucleophilic allylic substitutions (Equation (8)) and cross-coupling reactions between aryl iodides and terminal alkynes (Equation (9)). The catalyst was highly active in both reactions, and it was recycled 10 times with an average yield of 93% in the allylic nucleophilic substitution by precipitation with hexane. ... 

Novel polymerization techniques were used to synthesize new macro-molecules that consisted of a water-soluble backbone unth small amounts of hydrophobic functionality. Micellar polymerization is based on the capability of surfactant micelles to solubilize hydro-phobic molecules into an aqueous medium it was used to copolymerize acrylamide and hydrophohically substituted acrylamide monomers. A critical aspect of these polymerizations was the incorporation of the hydrophobic monomer into the water-soluble polymers. A method that used the UV chromophore of newly synthesized N-aryl substituted acrylamides was developed to quantify incorporation at the low levels of hydrophobe normally used about 1 mol %). The synthesis of the substituted acrylamides, the UV technique, and results obtained with it are discussed. 

A critical aspect of the micellar polymerization of hydrophobically substituted acrylamides and water-soluble monomers is the incorporation of the hydro-phobic monomer into the resultant water-soluble polymers. Because of the low levels of hydrophobic monomer (<1 mol %), previous analyses were unsuccessful in measuring hydrophobe incorporation into the polymer. By using the UV chromophore of newly synthesized N-aryl-substituted acrylamides, a method was developed to quantify incorporation at the low levels of hydrophobe normally used. In all the cases examined, the hydrophobic monomer was incorporated at close to feed levels with complete conversion to polymer. Incorporation varied as a function of conversion therefore, the resultant polymers were compositionally heterogeneous. Research is continuing to gain a better understanding of hydrophobe incorporation. 

Cu(OAc)2-oxidized annulations of (di)aryl- and (di)alkyl-substituted alkynes by various electron-rich and electron-deficient acrylamides using [RuCl2(p-cymeme)]2 as the catalyst in the presence of f-AmOH as a solvent result in the formation of 2-pyridones. The catalyst displayed a notable chemo- and regio-selectivity. °... 

On the other hand, UV is a probe that is sensitive enough to measure low levels of hydrophobes, provided that there is a UV active chromophore in the hydrophobic segment. Incorporation levels of N-aryl substituted acrylamide (2) and nonyl phenoxy (etheroxy) acrylates (3) into polyacrylamide backbones have been determined using such UV methods [14,17]. The absorbtivity of 2 has been measured by comparison of the absorptivity of the hydrophobic unit in the polymer to that of the model compound (4). Assuming the absorptivity of the hydrophobe in the polymer is similar to that of the model, polymer absorptivity to the model gives the weight fraction of the hydrophobe in the polymer. 

Song, Li, and coworkers reported a Rh-catalyzed oxidative coupling of acrylamides with allcynes to generate 2-pyridones 100 (Eq. (5.97)) [50a]. Both diaryl-or aryl- and alkyl-substituted alkynes were suitable coupling partners for this reaction. The nature of the substituents plays a vital role in this reaction. When the steric hindrance around the olefin or Af-substituent was increased, the reaction afforded N-acyl-indoles as the annulation products. Similarly, Hyster and Rovis reported an improved method for Rh-catalyzed highly regioselective synthesis of pyridones from the annulation of acrylamides and unsymmetrical alkynes [50b]. 

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