Iminocarbocation intermediates were in situ-generated by treating various oximes with trifluoromethanesulfonic anhydride (Tf2O) in the presence of triethylamine in toluene and nucleophilic trapping with amines or sodium enolates under mild conditions afforded the corresponding amidines and enamines. Some of the thus-obtained enamines were converted to 2-substituted 4-oxo-3-quinolinecarboxylic acid derivatives by subsequent intramolecular Friedel–Crafts acylation.
bdBeckmann rearrangement of OTDP salts of oximes of aromatic ketones and synthetic applications. Reaction between tris(dimethylamino)-phosphine, carbon tetrachloride and oximes of ketones leads to the corresponding Oximoxy-Tris-(Dimethylamino)-Phosphonium salts (OTDP salts), which are isolated in the form of hexafluorophosphates. These salts are solid and stable except if they are completely dehydrated
A convenient one-pot protocol for the synthesis of N,N′-disubstituted and N,N,N′-trisubstituted amidines is reported. In the presence of the Ph3P–I2/Et3N system, a variety of secondary amides were smoothly reacted with primary or secondary amines to afford the corresponding amidines in good to excellent yields under mild conditions.
报道了一种方便的一锅法合成N,N'-二取代的N,N,N,N'-三取代的am。在Ph 3 P–I 2 / Et 3 N体系存在下,多种仲酰胺与伯胺或仲胺平稳反应,在温和条件下以良好或极佳的收率得到相应的am。
Facile One-pot Syntheses of Amidines and Enamines from Oximes via Beckmann Rearrangement Using Trifluoromethansulfonic Anhydride
Facile one-pot syntheses of amidines and enamines were achieved by trapping carbocation intermediates that were formed by Beckmann rearrangement of oximes with amines and carbon nucleophiles, respectively, under mild conditions.