Urea-amino acid conjugates

Metal-mediated approaches to the synthesis of imidazoles have been reported. PaUadium(ll)-catalyzed intermolecular 1,2-diamination of conjugated dienes with ureas led to 4-alk enyl-2-imidazolones in good yields rmder mild conditions <05JA7308>. Palladium-catalyzed cyclization of O-pentafluorobenzoylamidoximes 74 furnished l-benzyl-2-substituted-4-methylimidazoles 75 <050L609>. Direct copper(I)-chloride mediated reaction of nitriles 76 with a-amino acetals 77 followed by acidic reaction led to a variety of 2-substituted imidazoles 78 <05TL8369>. 

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