A new one-pot synthesis of 1,2,3,4-tetrafluoroacridines and some 7-substituted derivatives [1]

Autor: Anthony E. Tipping, A. J. Adamson, Ronald E. Banks
Rok vydání: 1993
Předmět:
Zdroj: Journal of Fluorine Chemistry. 64:5-10
ISSN: 0022-1139
DOI: 10.1016/s0022-1139(00)80058-5
Popis: 1,2,3,4-Tetrafluoroacridine ( 1a ) and a range of 7-substituted analogues can be synthesisedby heating pre-formed Schiff bases ( E )-C 6 F 5 CH  NC 6 H 4 R- p ( 3 ) (fromC 6 F 5 CHO+H 2 NC 6 H 4 R- p ) with the parent aniline H 2 NC 6 H 4 R- p (1:1 molar ratio) or byheating a mixture of the aldehyde C 6 F 5 CHO and the aniline H 2 NC 6 H 4 R- p (R  H, OMe,Me Bu t , F, Cl and Br) (1:2 molar ratio) in toluene or 1,2-dichlorobenzene under reflux.The mechanism has been deduced through the isolation in certain reactions of ortho -substituted Schiff bases 2-( p -RC 6 H 4 NH)C 6 F 4 CH  NC 6 H 4 R- p ( 6 ) (R  Cl or Br), which onacid catalysis (by p -RC 6 H 4 NH 3 + F − ) undergo ring-closure with elimination of the aniline p -RC 6 H 4 NH 2 . Except where R  F, Cl or Br, substantial amounts of the corresponding3-anilino-1,2,4-trifluoroacridines 5 are also formed; these arise via sequential para - and ortho -substitution of fluorine in the pentafluorophenyl moiety of the Schiff bases. Thesynthesis is capable of extension to other fluorinated aromatic aldehydes, e.g. the formationof 1-fluoro-7-methoxyacridine ( 9 ) from 2,6-difluorobenzaldehyde and p -anisidine.
Databáze: OpenAIRE