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Updated: May 12, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
Synthesis and tyrosinase inhibitory properties of novel isoquinoline urea/thiourea derivatives
Hayriye Genç1, Mustafa Zengin, Emre Yavuz
1Faculty of Arts and Sciences, Department of Chemistry, Sakarya University , Sakarya , Turkey.
Abstract:
A new series of isoquinoline urea/thiourea derivatives (1-11) were synthesized, and their inhibitory effects on tyrosinase were evaluated. Isoquinoline urea/thiourea derivatives were obtained as a result of the reaction of 5-aminoisoquinoline with isocyanates or isothiocyanates. The result showed that all the synthesized compounds inhibited the tyrosinase enzyme activity. Among the compounds synthesized, 1-(4-chlorophenyl)-3-(isoquinolin-5-yl)thiourea (3) was found to be the most active one (Ki = 119.22 μM), and the inhibition kinetics analyzed using Lineweaver-Burk double reciprocal plots revealed that compound 3 was a competitive inhibitor. We also calculated HOMO-LUMO energy levels, some selected the synthesized compounds (1, 4, 11, 3, 6, 2) using Gaussian software.
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