Liquid-Phase Organic Synthesis Of Heterocyclic Compounds Based On Poly (Ethylene Glycol)-Supported Acetoacetate

In this dissertation, the progress of liquid-phase organic synthesis (LPOS) of heterocyclic compounds on poly (ethylene glycol) (PEG) support in recent years was first introduced. Then the LPOS of heterocyclic compounds based on PEG- supported acetoacetate reagent was further investigated.Firstly, polyethylene glycol (average MW4000) and tert-butyl acetoacetate in anhydrous toluene was refluxed for 10 h gave rise to PEG-supported acetoacetate, which was reacted with 1,3-cyclohexanedione, aldehydes and ammonium acetate in the presence of catalytic amount of polyphosphoric acid by solvent-free microwave irradiation to afford PEG-3-oxycarbonyl-1,4-dihydropyridines, which were treated with 0.1 N EtONa in ethanol to gave 4-substituted-1,4-dihydropyridine derivatives in good yields (87-96 %).Secondly, reaction of PEG-supported acetoacetate with Meldrum's acid, ammonium acetate and the appropriate aldehyde in the presence of catalytic amount of polyphosphoric acid by solvent-free microwave irradiation formed the corresponding PEG-supported 3,4-dihydropyridone intermediates, followed by treatment with 0.1 N MeONa in methanol to afford 4-substituted-5-methoxycarbonyl-6-methyl-3,4-dihydropyridones with good yields (84-92 %). Finally, Friedl?nder reaction of PEG-supported acetoacetate with 2-aminoaryl methyl ketones in the presence of concentrated hydrochloric acid under microwave irradiation formed the corresponding PEG-supported 3-oxycarbonyl-2-methyl-4-arylquinoline intermediates, which were treated with MeONa, EtONa or NaOH solution to yield 2-methyl-4-arylquinoline-3-carboxylic acids and their methyl or ethyl esters in 88 %-93 % yields, respectively.The present methods for the preparation of the above heterocyclic compounds have the advantages of mild reaction conditions, simple manipulation and excellent yields.