P. Machado, Glauber R. Lima, M. Rotta
2011
Citations
0
Influential Citations
27
Citations
Journal
Ultrasonics sonochemistry
Abstract
A series of 14 ethyl 1-(2,4-dichlorophenyl)-1H-pyrazole-3-carboxylates has been synthesized from the cyclocondensation reaction of ethyl 4-methoxy-2-oxoalk[cycloalk]-3-enoates [EtO(2)CC(O)C(R(2))=C(R(1))OR, where R=H, Me; R(1)=Pr, Ph, 4-MeOC(6)H(4), 4-MeC(6)H(4), 4-FC(6)H(4), 4-ClC(6)H(4), 4-BrC(6)H(4), 4-NO(2)C(6)H(4), fur-2-yl; R(2)=H; R(1), R(2)=-(CH(2))(3)-, -(CH(2))(4)-, -(CH(2))(5)-, -(CH(2))(6)-, 3,4-dihydronaphth-2-yl] with 2,4-dichlorophenyl hydrazine hydrochloride under ultrasound irradiation with high regioselectivity and in 71-92% yields. The main goal of this methodology was the significant reduction of reaction times. The compounds were obtained after irradiation for 10-12 min. In addition, the structure of the ethyl 1H-pyrazole-3-carboxylates was supported by crystallographic data.