New practical synthesis of indazoles via condensation of o-fluorobenzaldehydes and their O-methyloximes with hydrazine.
The reaction of o-fluorobenzaldehydes and their O-methyloximes with hydrazine has been developed as a new practical synthesis of indazoles. Utilization of the methyloxime derivatives of benzaldehydes (in the form of the major E-isomers) in this condensation effectively eliminated a competitive Wolf-Kishner reduction to fluorotoluenes, which was observed in the direct preparations of indazoles from aldehydes. Reaction of Z-isomers of methyloximes with hydrazine resulted in the formation of 3-aminoindazoles via a benzonitrile intermediate.
Lukin
Kirill
K
GPRD Process Research and Development, Abbott Laboratories, North Chicago, Illinois 60064, USA. kirill.lukin@abbott.com
Hsu
Margaret C
MC
Fernando
Dilinie
D
Leanna
M Robert
MR
D007191:Indazoles / Q000138:chemical synthesis*
D007191:Indazoles