Synthesis Of4-Hydroxy-2-Pyridones

4-hydroxy-2-pyridones are embedded as common structural units of many natural products. They exhibited good or excellent biological activities such as antifungal, antibacterial, and cytototoxic activity and so on. Since1970s’,4-hydroxy-2-pyridones have been isolated, such as Ilicilolin H and Tenellin, some novel and effective synthesis methodologies have been developed to obtain4-hydroxy-2-pyridones. This article introduce the research progress and synthesis progress of4-hydroxy-2-pyridones, on the basis of the research, many4-hydroxy-2-pyridones have been synthesized. The main contents of this paper are as follows:1、Malonyl chloride was synthesized from malonic acid and thionyl chloride as starting materials by chlorination reaction. It was cyclized with phenylacetonitrile to give4-hydroxyl-5-phenyl-6-chloride-2-pyridone, which was reduced with10%Pd/C under a hydrogen atmosphere to provide4-hydroxy-5-phenyl-2-pyridone, which N-methylaion by selectively to obtain N-methyl-4-hydroxy-5-phenyl-2-pyridone.then4-hydroxy-5-phenyl-2-pyridone cyclized with Ethyl3-aminocrotonate to give4-methyl-8-phenyl-6H-pyrano[3,2-c]pyridine-2.5-dione. which N-methylaion by selectively to obtain4,6-dimethyl-8-phenyl-6H-pyrano [3,2-c]pyridine-2.5-dione. Then, Their ultraviolet and fluorescence properties have been studied. The results suggested that the target compounds showed two maximum absorption peaks at240-300and320～400nm in UV spectrum. The maximum emision wavelength was around400to520nm in fluorescence spectrum. The effect of structure of the compounds on fluorescence properties was also discussed. Using rhodamine B as a reference, the fluorescence quantum yields for all compounds were detected. The results showed that these compounds have good fluorescence with strong fluorescence intensity, different substituent and NH-methylation make fluorescence wavelength red shift.2、In order to increase the water-solubility. Four1-methyl-5-phenyl-4-(2-aminoethoxy)pyridin-2(1H)-one was designed and synthesized from4-hydroxy-5-phenyl-2-pyridone and1-(2- chloroethyl)amino hydrochloride as starting materials. Methyl iodide was used to react with4-hydroxy-2-pyridines in NaOH aqueous solution, NH-methylation production was given as a main product. And then, it was treated with NaH and1-(2-chlorine ethyl) amino hydrochloride in DMF solution to provide1-methyl-5-phenyl-4-(2-aminoethoxy)pyridin-2(1H)-one. The after-processing is simple, and has a high yield.3、4-Hydroxy-2-pyridone was synthesized from ethyl cyanoacetate and trimethyl orthoacetate as starting materials. The condensation of ethyl cyanoacetate with trimethyl orthoacetate provided ethyl2-cyano-3-methoxybut-2-enoate. And then, it was treated with N,N-dimethylformamide dimethyl acetal to give the ethyl2-cyano-5-(dimethylamino)-3-methoxypenta-2,4-dienoate. It was subjected to cyclization in80%acetic acid to provide ethyl4-methoxy-2-oxo-1,2-dihydropyridine-3-carboxylate.Finally.4-hydroxy-2-pyridone was obtained by demethylation and decarboxylic reaction of ethyl4-methoxy-2-oxo-1,2-dihydropyridine-3-carboxylate in48%HBr solution. The total yield is around31%. The structure was confirmed by IR,1H NMR. and MS analysis.4、Twenty two4-hydroxy-2-pyridones were synthesized. four of them are belong to pyrano[3,2-c]pyridine derivatives. Eight of them are novel compounds which have not been reported before. Their structures were identified with IR、1H-NMR、MS and HRMS analysis.