A new and convenient one-potsynthesis of a variety of N-aryl lactam analogues 4 of pentalene has been developed. Pulvinic acid dilactams 4 are of interest due to their electronic and optical features and as synthetic pigments.
A novel cobalt(II)-mediated domino reaction of carbon nucleophiles with 1a-d has been developed. The resulting cyclization regioselectively yields functionalized α-tetramic acidamides.
Vinylogous Tetraazafulvalenes: New Deeply Coloured Compounds Derived from Simple Amidines
作者:J. Brandenburg、C. Käpplinger、R. Beckert
DOI:10.1055/s-1996-4386
日期:1996.11
A one-step synthesis of vinylogous tetraazafulvalenes by simple cycloacylation of acetamidine 2 with bisimidoyl chlorides of oxalic acid 1 is described. The deeply coloured products 4a-i constitute a new class of stable neutrocyanines as well as compounds with indigoid properties.
The reaction between bis-imidoylchlorides 2 derived from oxalic acid and several aromatic and aliphatic amines was investigated. While primary aromatic amines need a thermical activation by refluxing, primary aliphatic amines give mainly at room temperature the amidines 3 in moderatly up to good yields.Proceeding from enantiomeric pure amines e.g. (R)- or (S)-1-phenethylamine the new homochiral oxalic amidines 3y and 3z with C-2-symmetry were obtained. Several secondary amines react with the bis-imidoylchloride 2a to give via intramolecular cycloacylation derivatives of isatine. The new synthesized amidines 3 perform systems with a strong molecular dynamic like prototropie and E/Z-interconversion. All new compounds described were characterized by elemental analysis and spectroscopic methods.