Synthesis Of The Novel Heterocycle-fused Pyrido[1,2-a]pyrimidinones

With the gradual development of organic synthesis technology and the deeping of the pyrimidine chemistry research. pyrimidine and its derivatives has been got wideapread concern of chemical workers, because they have a wide range of application in the pharmaceutical, chemical, dyes and other fields.Firstly, this paper describe that the synthesis of novel benzofurano [3”,2”:2’,3’]pyrido[4’,5’:4,5]pyrido[1,2-a]pyrimidine derivatives has been developed using a Pictet-Spengler reaction between 2-(3-aminobenzofuran-2-yl)pyrido[1,2-a]pyrimidin-4- one, which could be obtained from the alkylation of 2-(chloromethyl)-4H-pyrido[1,2-a] pyrimidin-4-one with 2-hydroxybenzonitrile followed by a Thorpe-Ziegler isomerization, and aromatic aldehydes under p-TsOH as catalysis.Secondly, with 2-(3-aminobenzothien-2-yl)-4H-pyrido[1,2-a]pyrimidin-4-one as a star-ting material, which could be obtained from the alkylation of 2-(chloromethyl)-4H-pyrido [1,2-a]pyrimidin-4-one with 2-mercaptobenzonitrile, series of benzothieno [3”,2”:2’,3’] pyrido[4’,5’:4,5]pyrido[1,2-a]pyrimidines has been synthesed throw Picter-Spengler reaction, and aromatic aldehydes in the presence of p-TsOH.Finally, 2-(3-aminopryido[2,3-b]thien-2-yl)-4H-pyrido[1,2-a]pyrimidin-4-one as a starting material, which could be obtained from the alkylation of 2-(chloromethyl)-4H- pyrido[1,2-a]pyrimidin-4-one with 3-cyanopyridine-2-thione, series of pyrido [2”’,3”’:2”,3”]thieno[4”,5”:2’,3’]pyrido[4’,5’:4,5]pyrido[1,2-a]pyrimidines has been synthesed throw Picter-Spengler reaction, and aromatic aldehydes in the presence of p-TsOH.