Factorial study to assess an ultrasonic methodology for the allylation of 4-chloroaniline

• Published in: Green processing and synthesis Vol. 6; no. 2; pp. 203 - 209
• Main Authors: Nascimento, Lillian Ferreira Santos, Fernandes, João Paulo Santos
• Format: Journal Article
• Language: English
• Published: Berlin De Gruyter 01.04.2017; Walter de Gruyter GmbH
• Subjects: Allyl compounds; Bioactive compounds; By products; Chemical reactions; Chromatography; Experiments; factorial design; Indoles; Methodology; Methods; N-allyl-4-chloroaniline; N-allylation; Nuclei; Reaction time; Reagents; Solvents; Temperature effects; ultrasonic bath; Ultrasonic imaging; Ultrasonic methods; Ultrasonic testing; Ultrasound; ultrasound-assisted synthesis
• ISSN: 2191-9542; 2191-9550
• DOI: 10.1515/gps-2016-0122

allylanilines are important compounds that are used to access several bioactive compounds containing indole and dihydroindole nucleus. However, their preparation through allylation can lead to the undesirable -diallyl byproduct. In this work, the -allylation of 4-chloroaniline was studied. In order to accelerate the process and maximize the monoallylated:diallylated ratio, we reported two full factorial studies to transpose the conventional synthetic procedure to an ultrasound (US) methodology. The evaluated factors were temperature, quantity of reagents (allyl bromide and K CO ), reaction time, and methodology (conventional or US). The results showed that US did not change the monoallylated:diallylated ratio, but significantly improved the reaction rate, giving increased average monoallylated and total yields of 11.4% and 18.1%, respectively (p<0.05). The proposed US methodology gave the same yields and product ratio in a 4-h reaction time than the conventional 24-h procedure, without heating and using only an inexpensive US bath to conduct the reactions.