Simple and efficient methods for selective preparation of α-mono or α,α-dichloro ketones and β-ketoesters by using DCDMH

Abstract

New processes that can selectively prepare a-mono or a,a-dichloro ketones and b-ketoesters using 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) are reported. Using silica gel as the catalyst and methanol as the solvent and heating for 1 h under reflux, a-monochlorinated products were selectively obtained in 86-98% yield. However using a deep eutectic solvent (choline chloride: p-TsOH = 1:1) as the solvent and stirring for 45 min at room temperature, a,a-dichlorinated products were selectively obtained in 86-95% yield.

Deep Eutectic Solvents: The Organic Reaction Medium of the Century

“…In contrast, a α,α-dichlorinated product was exclusively obtained, with DCDMH, when the reaction was carried out in a DES formed by an equimolecular mixture of choline chloride and ptoluenesulfonic acid (p-TsOH) and a small amount of acetonitrile (6% w/w). [49] Moreover, if a mixture of TBAF·3H2O and ZnF2 was added to the reaction medium, the formed chlorinated acetophenone underwent nucleophilic substitution giving directly the corresponding α-fluoroacetophenones in a one-pot methodology (Scheme 5). [50] Scheme 5.…”

One-pot α-nucleophilic fluorination of acetophenones in a deep eutectic solvent

“…Deep eutectic solvents (DES) formed between choline chloride and acids are thought to be a new kind of solvents that will be closer to the principles of green chemistry and an efficient method of chlorination in DES that formed between choline chloride and pTsOH has been reported [12]. Based on the nucleophilic fluorination by TBAF, we tried to combine the chlorination in DES with nucleophilic fluorination to develop a one-pot fluorination method that a-fluoroacetophenones can be prepared directly from acetophenones.…”

Deep eutectic liquid organic salt as a new solvent for liquid-phase microextraction and its application in ligandless extraction and preconcentraion of lead and cadmium in edible oils

“…Thus, production of DES is much simpler and cheaper than that of ILs [28]. Deep eutectic solvents based on choline chloride have already been used successfully in various fields such as dissolution of metal oxides [31], synthesis of nanoparticles [32], CO 2 solubility [33], organic synthesis [34], electrocatalytic studies [35], biochemistry [36], purification of biodiesel [37], separation of aromatic hydrocarbons [38], digestion of fish sample [26] and headspace-microextraction of bioactive compounds [39]. However, according to our literature survey, application of DESs in analytical chemistry is still in its infancy, and there is no report on their use as a solvent in extraction.…”