Arylation 2-aminoacrylates

The spectra of 2-alkoxycarbonyl-3-aminoacrylic esters (73, R1 = H, alkyl, aryl) show that these substances exist in the enamino-ester form with a strong intramolecular hydrogen bond between the amino and COOR2 groups. Conformers 73a (Z, Z, E) and 73b (E,Z,E) predominate in non-polar media conformation 73b is also probably present in polar solvents and is preferred in the solid state109. (The symbols indicate, in the order shown, the alignments of the free C=0, the bonded C=0 and the R1 group with respect to the carbon-carbon double bond.)... 

Cycloaddition of phenyl isothiocyanate (296) to pyridinium salts (295) produced imidazo[l,2-a]pyridine-2(3//)-thiones (297) (77Ml4looi). Reaction of l-aryl-2-chloropyridin-6-ones with mono-A/ -substituted ethylenediamines provided dihy-droimidazo[l,2-a]pyridin-5-ones (79CPB1207). Another procedure involves the polyphos-phoric acid cyclization of 2-(2-hydroxyethyl)aminopyridines (76AJC1039). Treatment of certain /3-aminoacrylic esters (298) with benzenediazonium fluoroborate (299) resulted in... 

The spectra of 2-alkoxycarbonyl-3-aminoacrylic esters (73, = H, alkyl, aryl) show... 

Few Rh-catalyst systems have been shown to reduce mixtures of ( ) and (Z)-isomers of P-aryl- and P-aminoacrylic acid derivatives effectively. To this end, Fu et al. found that a monodentate phosphonite ligand derived from SIPHOS was effective in the asymmetric hydrogenation of p-aryl- and P-aminoacrylic acid derivatives. The authors also found that the electronic properties of the substituents had a significant impact on the reaction rate and enantioselectivities. The reactions of substrates having electron-donating substituents proceeded faster with higher enantioselectivities. ... 

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