54012-99-6Relevant academic research and scientific papers
1H- and 2H-Indazoles by Thermal and Photolytic Decomposition of o-Azidobenzoic Acid and o-Azidobenzaldehyde Derivatives
Ardakani, Manouchehr Azadi,Smalley, Robert K.,Smith, Richard H.
, p. 2501 - 2506 (2007/10/02)
Ethyl o-azidobenzimidate (6) and o-azidobenzamidine (7) on thermolysis yield 3-ethoxy- (9; X=OEt) and 3-amino-1H-indazole (9; X=NH2), respectively.The former product is also obtained on irradiation of the imidate in methanol-tetrahydrofuran solution. 2-Aryl- and 2-heteroaryl-3-chloro-2H-indazoles have been prepared by the action of hot thionyl chloride on o-azidoanilides.The trichloro-2H-indazoles obtained by the action of phosphorus pentachloride on o-azidobenzanilide (12) and by the action of thionyl chloride on N-(o-azidobenzoyl)-2-aminopyridine have been identified as the 3,5,7-trichloro derivatives.The reductive dehalogenation, nitration, and reactivity of the halogen towards nucleophiles, of 3-chloro-2-phenyl-2H-indazole (19) are reported.A new practicable synthesis of o-azidobenzaldehyde (31; X=O) is described.Thermolysis of its phenylhydrazone and semicarbazone derivatives yields 2H-indazoles.
