Experimental Investigation on the Correlation between the Physicochemical Properties and Catalytic Activity of Six DESs in the Kabachnik‐Fields Reaction
M. Shaibuna, K. Sreekumar
Abstract
Abstract Six Type IV Deep Eutectic Solvents (homogeneous mixture of metal chloride hydrate and hydrogen bond donor) were prepared from ZrOCl 2 ⋅ 8H 2 O/CeCl 3 ⋅ 7H 2 O with urea, ethylene glycol and glycerol. A study was performed by correlating the properties of DESs with their activity as catalyst as well as reaction medium in Kabachnik‐Fields reaction. Among the six DESs, lower density, viscosity and higher acidity were observed for DES 1(Deep Eutectic Solvent developed from ZrOCl 2. 8H 2 O and urea at 1 : 5 ratio) and is reported as an excellent catalyst and reaction medium for the productive synthesis of α‐aminophosphonates within a short period of time. The wide substrate applicability was checked by synthesising 21 different α‐aminophosphonate derivatives and analysed by TLC, GCMS, 1 HNMR, 13 CNMR, and melting point measurements. One pot reaction of an aldehyde, dimethyl phosphite and amine (Kabachnik‐Fields/ Phospha‐Mannich reaction) took place at room temperature to give the corresponding α‐aminophosphonates in good yield and the precipitation of these products in to water avoided the regular work up process. Catalyst was recycled up to five times without any loss in its activity.