title: Sulphur promoted C(sp(3))-C(sp(2)) cross dehydrogenative cyclisation of acetophenone hydrazones with aldehydes: efficient synthesis of 3,4,5-trisubstituted 1H-pyrazoles.
abstract: A novel strategy for the cross dehydrogenative coupling (CDC) of acetophenone hydrazones and aldehydes has been developed for the synthesis of highly substituted pyrazoles. This work, for the first time, uses elemental sulfur as a promoter as well as a hydrogen acceptor in effecting the Csp(3)-Csp(2) bond formation via C-H activation.
authors.affiliation: Department of Chemistry (Centre of Advanced Study), Faculty of Science, Banaras Hindu University, Varanasi-221005, India. knsingh@bhu.ac.in knsinghbhu@yahoo.co.in.
authors.forename: Rajeshwer
authors.initials: R
authors.lastname: Vanjari
authors.forename: Tirumaleswararao
authors.initials: T
authors.lastname: Guntreddi
authors.forename: Saurabh
authors.initials: S
authors.lastname: Kumar
authors.forename: Krishna Nand
authors.initials: KN
authors.lastname: Singh
mesh_terms: D000098:Acetophenones / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006835:Hydrazones / Q000737:chemistry*; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry*
chemical_list: D000098:Acetophenones; D000447:Aldehydes; D006835:Hydrazones; D011720:Pyrazoles; D013455:Sulfur; C038699:acetophenone