The Study On The Glycerol Or PEG Promoting Organic Reaction For Synthesis Of Heterocyclic Compounds

With growing concern over the green and sustainable chemistry,development of environmentally benign chemical processes in synthetic chemistry has been advocated.At the heart of green chemistry are alternative reaction media.They are the basis of many cleaner chemical technologies.So,in the last couple of decades employing environment-friendly solvents instead of traditional organic solvents for chemical synthesis has attracted increasing attention especially without the use of catalyst.Both polyethylene glycol and glycerol are non-toxicity media and compatible with most organic and inorganic compounds.They have been proposed as the popular green reaction medium and efficient promoter in modern organic synthesis.In this dissertation,the green methods for the preparation ?-substituted indole,coumarin-3-carboxylic acid,4H-pyran compounds and their derivatives which promoted by PEG or glycerol under catalyst free condition were described,the main contents and contributions are listed as follows:1.The applications of glycerol and PEG as environment-friendly medium in organic synthesis in recent years are briefly summarized.2.The synthesis of ?-substituted indole derivatives.An efficient and facile procedure for the synthesis of 5-[(indol-3-yl)-arylmet hyl]-2,2-dimethyl-1,3-dioxane-4,6-dione derivatives has been developed by condensation of Meldrum's acid with aldehyde and indole in mixture solvent from H2 O and glycerol at room temperature without catalyst under the ultrasonic radiation.The structures of products were characterized by 1H NMR,13 C NMR and IR.This strategy can tolerate the diverse functional groups such as 4-methylbenzaldehyde and4-methoxybenzaldehyde and provides an alternative approach for easy access to the usefull synthetic inter mediate ?-indole derivatives in the yields of 36%~96%.3.The synthesis of coumarin-3-carboxylic acid.A catalyst-free procedure for the synthesis of coumarin-3-carboxylic acids via Knoevenagel-intramolecular cyclization cascade reaction of Meldrum's acid with various 2-hydroxyarylaldehydes has been established.This study has the merits ofusing aqueous glycerol as green solvent and in the absence of a catalyst.All compounds were prepared smoothly with up to 99% yield.The structure was characterized by IR and NMR.4.The synthesis of 4H-pyran compoundsThe convenient one-pot three component strategy for the synthesis of2-amino-3-cyano-4H-pyran annulated derivatives was conducted successfully employing water and PEG-400 as the efficient and cheap promoting medium.A wide range of aromatic aldehydes were condensed with malononitrile and different1,3-dicarbonyl compounds smoothly to give the corresponding products in good to excellent yields.The compounds were characterized by 1H NMR,13 C NMR,IR and HRMS.