77746-99-7Relevant articles and documents
VILSMEIER-HAACK REACTION OF 5-AMINO- AND 5-ACYLAMINO-PYRAZOLES
Simay, A.,Takacs, K.,Horvath, K.,Dvortsak, P.
, p. 127 - 140 (2007/10/02)
The Vilsmeier-Haack reaction of 5-aminopyrazole derivatives 1 was investigated in view of contradictory literature reports.Structure 2 of the products was proved both chemically and spectroscopically.The mechanism of the reaction was postulated on the basis of isolated intermediates 7 and 8. 5-Acylaminopyrazoles 9, 10 and 11 were found to give also 2 (and 7) under the Vilsmeier conditions by an acyl splitting reaction, proceeding probably via diacylamino derivatives 12.Compounds 2 provided a simple route to pyrazolopyrimidine derivatives 13 and 14 as well as to azomethine compounds 15-18.