title: Regioselective synthesis of 1,3,5-trisubstituted pyrazoles from N-alkylated tosylhydrazones and terminal alkynes.
abstract: An efficient synthesis of 1,3,5-trisubstituted pyrazoles from N-alkylated tosylhydrazones and terminal alkynes was developed. The protocol was applied to a wide range of substrates and demonstrated excellent tolerance to a variety of substituents, including both electron-donating and -withdrawing groups. In comparison with the common approaches for substituted pyrazole syntheses, this methodology proceeded with complete regioselectivity, especially, in the cases that R(2) and R(3) are similar substituents.
authors.affiliation: School of Pharmacy, Lanzhou University , Lanzhou 730000, P. R. China.
authors.forename: Yuanfang
authors.initials: Y
authors.lastname: Kong
authors.forename: Meng
authors.initials: M
authors.lastname: Tang
authors.forename: Yun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000478:Alkylation; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D006835:Hydrazones / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000480:Alkynes; D006835:Hydrazones; D011720:Pyrazoles