Phosphoramides, XV. Phosphorus pentoxide amine mixtures as reagents in the synthesis of 2-(dialkylamino)quinolines

✍ Scribed by Hansen, Bo W. ;Pedersen, Erik B.

• Publisher: John Wiley and Sons
• Year: 1981
• Tongue: English
• Weight: 358 KB
• Volume: 1981
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.198119810820

✦ Synopsis

Abstract

2‐(Dialkylamino)quinolines were prepared by treating acetanilides and N,N‐dialkylformamides with a mixture of phosphorus pentoxide and a dialkylamine at 250°C. A mechanism which is related to HMPT induced ring closure reactions is proposed. Proper choice of amine and formamide is important, because transacylation reactions take place. The cleanest reaction was obtained if the amine used and the amine, which could be liberated from the formamide, were identical, or if the former amine has the greater nucleophilicity. Sterical hindrance in the ring closing step may occur. Formates, instead of formamides, can also be used.