Regioselective synthesis of 1-alkyl- or 1-aryl-1H-indazoles via copper-catalyzed cyclizations of 2-haloarylcarbonylic compounds.
[reaction: see text] A general method for the one-step regioselective synthesis of 1-alkyl- or 1-aryl-1H-indazoles from ortho-halogenated alkanoylphenones, benzophenones, and arylcarboxylic acids, via copper-catalyzed amination, was developed by using 0.2% mol of CuO in the presence of K(2)CO(3). The reaction involves amination followed by intramolecular dehydration. Different functionalized alkyl aryl ketones, diaryl ketones, and benzoic acid derivatives were efficiently coupled with several hydrazines. Ligands commonly employed as catalysts for intermolecular amination were shown to be ineffective for this cyclization.
Viña
Dolores
D
Department of Pharmaceutical Chemistry, Faculty of Pharmacy, CIETUS, Campus Unamuno, 37007 Salamanca, Spain.
del Olmo
Esther
E
López-Pérez
José L
JL
San Feliciano
Arturo
A
D000447:Aldehydes / Q000737:chemistry*; D000478:Alkylation; D000586:Amination; D001555:Benzene Derivatives / Q000138:chemical synthesis; D001565:Benzoates / Q000737:chemistry; D002254:Carbonates / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D003500:Cyclization; D006834:Hydrazines / Q000737:chemistry; D006841:Hydrocarbons, Aromatic; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D007191:Indazoles / Q000138:chemical synthesis*; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D011188:Potassium / Q000737:chemistry
D000447:Aldehydes; D001555:Benzene Derivatives; D001565:Benzoates; D002254:Carbonates; D002264:Carboxylic Acids; D006834:Hydrazines; D006841:Hydrocarbons, Aromatic; D006846:Hydrocarbons, Halogenated; D007191:Indazoles; D007659:Ketones; D008024:Ligands; D003300:Copper; C037593:potassium carbonate; D011188:Potassium; C000520:cuprous oxide