Synthesis of 1-(N-Benzyloxyformimidoyl)-2-aryl-4,5-dicyanoimidazoles: A New and Efficient Method from Diaminomaleonitrile Derivatives
作者:Brian L. Booth、Flora A. T. Costa、Robin Pritchard、M. Fernanda Proença
DOI:10.1055/s-2000-6420
日期:——
The reaction of (Z)-N-(2-amino-1,2-dicyanovinyl)formamidoxime 3a with aromatic aldehydes led to the isolation of amidoximes 4 in good yield. The structure of these compounds was confirmed by single crystal X-ray analysis. Amidoximes 4 cyclized in the presence of DDQ leading to 1-(N-benzyloxyformimidoyl)-2-aryl-4,5-dicyanoimidazoles 5 in good yields. The structure of these compounds was also confirmed by X-ray crystallography. When the reaction of the formamidoximes 3a and 3b with aromatic aldehydes was carried out in the presence of DBU, a different pathway was followed leading to a γ-lactam structure 8.
Synthesis of (Z )-N-(2-amino-1,2-dicyanovinyl)formamide O-alkyloximes and a study of their cyclization in the presence of base
作者:Brian L. Booth、Flora A. T. Costa、Zahid Mahmood、Robin G. Pritchard、M. Fernanda Proença
DOI:10.1039/a901332f
日期:——
The title compounds (3) have been prepared in high yield by reaction of (Z)-N-(2-amino-1,2-dicyanovinyl)formimidate with an alkoxyamine NH2OR (R = CH2Ph, Me). These compounds cyclize to the corresponding 5-amino-4-cyanoimidazoles 4 by reaction with ethanolic NaOH solution. In ethyl acetate and using DBU as a base, amidoximes 3 follow an unexpected cyclization pathway leading to a pyrimidine structure