Deep eutectic solvent (ChCl/Urea) as a green catalyst for reductiveamination of aldehydes and ketones

Using the non-toxic and environmentally friendly reagents is one of the goals of green chemistry. One of the main components of mostorganic reactions is catalyst. The use of green and non-toxic catalyst is an important issue in a chemical reaction and of particular interested to researchers.Employment of heterogeneous or heterogenized homogeneous catalytic systems, utilization of organic compounds, organocatalysts, and designing the catalytic systems based on environmentally friendly compounds such as ionic liquids are among the attempts that have beenmade in recent years to bring the catalysts closer to the aims of green chemistry. Recently, deep eutectic solvents (DESs) have emerged. DESs are peers of the conventional ionic liquids (ILs)and as they have low vapor pressure and low flammability [1]. Themain difference between these two families of compounds is that ILsare neither biodegradable nor cost-effective but DESs are biodegradable,non-toxic, inexpensive, and easily prepared. Due to their presence in natural products, pharmaceutical, and many biologically active molecules, as well as their role as intermediates in the synthesis of fine chemicals and dyes, amine structure has become an important component in chemistry[2] Despite the development of several synthetic methods for the preparing of these compounds in recent years[3] the direct reductive amination of carbonyl compounds is still the powerful tool for this purpose. In this study, we are going to report the synthesis of secondary amines by reductive amination of aldehydes/ketones in the presence of DES (ChCl/Urea) as catalyst and NaBH4 as a reducing agent in MeOH (Figure 1).