ABSTRACT
CuBr-catalyzed coupling reaction of 2-halobenzonitriles with hydrazine carboxylic esters and CuBr/4-hydroxy-l-proline-catalyzed coupling reaction of 2-bromobenzonitriles with N'-arylbenzohydrazides proceed smoothly at 60-90 °C to provide substituted 3-aminoindazoles through a cascade coupling/condensation (or coupling/deacylation/condensation) process. A wide range of 3-aminoindazoles with substituents at both the 1-position and the phenyl ring part can be prepared from the corresponding coupling partners.
Subject(s)
Bromides/chemistry , Copper/chemistry , Indazoles/chemical synthesis , Nitriles/chemistry , Catalysis , Indazoles/chemistry , Molecular StructureABSTRACT
[reaction: see text] L-proline-catalyzed direct aldol reaction of L-amino acid-derived N,N-dibenzyl amino aldehydes with acetone, cyclopentanone, or hydroxyacetone provides gamma-amino-beta-hydroxy- or gamma-amino-alpha,beta-dihydroxy-ketones with moderate to excellent yields and diastereoselectivities.
