title: A one-pot-three-step route to triazolotriazepinoindazolones from oxazolino-2H-indazoles.
abstract: A one-pot-three-step method has been developed for the conversion of oxazolino-2H-indazoles into triazolotriazepinoindazolones with three points of diversity. Step one of this process involves a propargyl bromide-initiated ring opening of the oxazolino-2H-indazole (available by the Davis-Beirut reaction) to give an N(1)-(propargyl)-N(2)-(2-bromoethyl)-disubstituted indazolone, which then undergoes -CH(2)Br → -CH(2)N(3) displacement (step two) followed by an uncatalyzed intramolecular azide-alkyne 1,3-dipolar cycloaddition (step three) to form the target heterocycle. Employing 7-bromooxazolino-2H-indazole allows for further diversification through, for example, palladium-catalyzed coupling chemistry, as reported here.
authors: Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616, USA.
authors: Wayne E
authors: WE
authors: Conrad
authors: Kevin X
authors: KX
authors: Rodriguez
authors: Huy H
authors: HH
authors: Nguyen
authors: James C
authors: JC
authors: Fettinger
authors: Makhluf J
authors: MJ
authors: Haddadin
authors: Mark J
authors: MJ
authors: Kurth
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006842:Hydrocarbons, Brominated / Q000737:chemistry; D007191:Indazoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D014230:Triazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D006842:Hydrocarbons, Brominated; D007191:Indazoles; D010080:Oxazoles; D014230:Triazoles; D010165:Palladium