74873-84-0Relevant articles and documents
Catalytic Staudinger/aza-Wittig sequence by in situ phosphane oxide reduction
Van Kalkeren, Henri A.,Te Grotenhuis, Colet,Haasjes, Frank S.,Hommersom,Rutjes, Floris P. J. T.,Van Delft, Floris L.
, p. 7059 - 7066 (2013)
A Staudinger/aza-Wittig reaction sequence is described that is catalytic in phosphorus. Towards this end, the phosphane oxide is reduced in situ by diphenylsilane, which allows for substoichiometric amounts of the catalyst 5-phenyldibenzophosphole to be used. The substrate scope is investigated and benzoxazoles, benzodiazepine imidates and a 2-methoxypyrrole were successfully synthesized. These investigations show that a fast aza-Wittig reaction is required to obtain high yields. A catalytic Staudinger/aza-Wittig reaction sequence, involving in situ phosphane oxide reduction, was successfully developed. Benzoxazoles, benzodiazepine imidates and 2-methoxypyrrole were synthesized without phosphane oxide waste products. Copyright
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.
