Deep Eutectic Solvent Participated In The Multicomponent Reaction

In the past few decades,although the global economy has been rapid development,environmental problems have become more and more serious.sustainable development is gradually being attention.Similarly,the development of green chemistry has become a top priority of many chemists,especially in organic synthesis field.However,most organic solvents,which is used in the synthesis process,have many restrictions,such as volatile,flammable,highly toxic,non-biodegradable and so on.They do not meet the conditions of green chemistry requirements.Deep eutectic solvent(DES)as a new solvent,which is non-toxic,biodegradable,non-flammable,low vapor pressure,good stability,recyclable and low-cost,easy to get attention.A simple and convenient strategy is described for the synthesis of dihydropyrimidine-5-carboxamides derivatives by using low melting mixture of betaine hydrochloride/urea as a novel reaction medium.An arry of dihydropyrimidine-5-carboxamide were obtained in good to excellent yields.In this procedure,low melting mixture of betaine hydrochloride/urea plays a triple role: as a solvent,as a catalyst and as a reactant.I use deep eutectic solvents based on L-proline/oxalic acid deep eutectic solvent to synthesize chromeno[4,3-d]pyrimidinones derivatives was accomplished in excellent yields.The use of DES increased the yields and shorten the reaction time.And they are non-toxic,readily available and inexpensive,recyclable and so on.More important,some advantages of DES are in line with the requirements of green chemistry.A simple synthesis of novel benzothiazolo [2,3-b]quinazoline-5,14-diones via the reaction of 2-aminobenzothiazole,aromatic aldehydes and2-hydroxy-1,4-naphthalenedione in the presence of L-proline/oxalic acid deep eutectic solvent.The catalytic activity of the DES was not significantly reduced after repeated use,and the reaction time was shortened by microwave heating.I also uses 3-oxo-3-phenylpropanenitrile and 5-amino-1,3-diphenyl-1H-pyrazole,aromatic aldehyde as raw material in the presence of L-proline/oxalic acid deep eutectic solvent to synthesis a series of pyrazolo [3,4-b] pyridine-5-carbonitrile derivatives.The DES is non-toxic and less volatile,and it can still catalyze the reaction to obtain high yield products after repeated use.Moreover,the post-treatment of the method is simple and the target product is easy to be purified.In this paper,the applications of DES in organic synthesis were reviewed.And I also carried out this task with a series of DESs,found that DESs have many advantages,such as greatly reducing the response time and environmental pollution,easy to separated and recycled many times and so on.