Choline Chloride Based Deep Eutectic Solvents as a Tuneable Medium for Synthesis of Coumarinyl 1,2,4‐Triazoles: Effect of Solvent Type and Temperature

Abstract

A study of 1,2,4‐triazole synthesis from 2‐((4‐methyl‐2‐oxo‐2H‐chromen‐7‐yl)oxy)acetohydrazide (1) or 2‐(7‐hydroxy‐2‐oxo‐2H‐chromen‐4‐yl)acetohydrazide (2) and various isothiocyanates, in deep eutectic solvents, was performed. In order to find the best conditions for 1,2,4‐triazole formation, a model reaction on 1 and phenylisothiocyanate was performed in 14 different choline chloride based deep eutectic solvents, at two different temperatures (40 °C and 80 °C). Pure 1,2,4‐triazoles were obtained in choline chloride/urea (1:2) and choline chloride/N‐methyl urea (1:3) deep eutectic solvents at 80 °C. Pure thiosemicarbazides were obtained in choline chloride/ethane‐1,2‐diol (1:2), choline chloride/malic acid (1:1), choline chloride/malonic acid (1:1), choline chloride/butane‐1,4‐diol (1:3) and choline chloride/glycerole (1:2) at 40 °C. The ratio of 1,2,4‐triazoles and thiosemicarbazides in reaction mixtures was determined by HPLC and 1H NMR. After the best conditions for 1,2,4‐triazole synthesis were found, some coumarinyl 1,2,4‐triazoles were synthesized from two different coumarinyl hydrazides (1 and 2) and various alkyl and aryl isothiocyanates in one step reaction.

Application of Deep Eutectic Solvents in the Synthesis of Substituted 2-Mercaptoquinazolin-4(3H)-Ones: A Comparison of Selected Green Chemistry Methods

“…Choline chloride-based DESs have been in focus of our investigation for some time, and we found them to be suitable for different chemical processes, both heterocyclic compounds synthesis [17,25,33,43] and extraction [44]. In this regard, the objectives of this research were focused on the investigation on finding an appropriate Type III [36], choline chloride-based deep eutectic (ChCl-based DES) solvent for the synthesis of 3-substituted 2-mercaptoquinazolin-4(3H)-one derivatives, as well as on the influence of some reaction parameters such as temperature and reaction time.…”

“…The procedure was repeated four times. The Sheldon's E-factor was calculated according to the following formula as described in our previous work [43]:…”

Facile synthesis of quinazoline, oxazine and triazole derivatives as potential antimi-crobial agents based on isothiocyanate moiety

“…Meltingpointsweredeterminedbythecapillarytube method and were uncorrected.IR spectra in KBr were recorded using (Perkin -Elmer 298) spectrophotometer. 1 H NMR spectra were recorded on a variam-Gemini 400 MHZ instrument. CDCl 3 and DMSO-d 6 were used as solvents, chemical shifts (δ) were reported in ppm relative to internal TMS.…”

“…Yield, 74 %; mp 157°C-159 °C; IR (Cm -1 ): ʋmax: 3380 (NH) , 3030(CH aromatic), 1692-1670(C=O), 1315( C=S); Ms: m/z 477 (M ˑ+ ); 1…”

“…Heteroallenesisothiocyanatesareaninterestinggroupoforganiccompounds that are used asreactivekeyprecursors in the synthesis of heterocyclic molecules due to theirdiversereactionsandalsoto the ireasyavailability. [1][2][3][4] Isothiocyanatesare often prepared from thereactionofaminederivativeswithcarbondisulfide [5][6][7][8]orthiophosgene, [9][10][11] as well as treatmentofthecarboxylicacidderivativeswithammoniumthiocyantes [12][13][14][15][16][17].…”