Related Experiment Video
Updated: May 12, 2026

Facile Preparation of 4-Substituted Quinazoline Derivatives
Published on: February 15, 2016
Novel isoquinoline derivatives as antimicrobial agents
Abraham Galán1, Laura Moreno, Javier Párraga
1Departamento de Farmacología, Laboratorio de Farmacoquímica, Facultad de Farmacia, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
Abstract:
The wide variety of potent biological activities of natural and synthetic isoquinoline alkaloids encouraged us to develop novel antimicrobial isoquinoline compounds. We synthesized a variety of differently functionalized 1-pentyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolines (THIQs), including dihydroisoquinolinium salts (2 and 5), methyl pentanoate-THIQ (6), 1-pentanol-THIQ (7), ester derivatives (8-15) and carbamate derivatives (16-23). We employed classic intramolecular Bischler-Napieralski cyclodehydration to generate the isoquinoline core. All the structures were characterized by nuclear magnetic resonance and mass spectrometry. The bactericide and fungicide activities were evaluated for all the synthesized compounds and structure-activity relationships were established. Many compounds exhibited high and broad-range bactericidal activity. Fluorophenylpropanoate ester 13 and the halogenated phenyl- (17, 18) and phenethyl carbamates (21, 22) exerted the most remarkable bactericidal activity. However, few compounds displayed antifungal activity against most of the fungi tested. Among them, chlorinated derivatives like chlorobenzoate and chlorophenylpropanoate esters (10 and 14, respectively) and chlorophenethyl carbamate 22, exhibited the greatest antifungal activity.
Related Concept Videos
Inhibitors of Bacterial DNA Synthesis
Aryldiazonium Salts to Azo Dyes: Diazo Coupling
Anthelminthic Agents
Inhibitors of Bacterial Protein Synthesis
Inhibitors of Gram-positive Cell Wall Synthesis
Antifungal Agents

