简介：Methetraxate(MTX),aclassicaldihydrofolatereductaseinhibitor,wasasuccessfulclinicalantitumoragent,havingpotentinhibitoryactivitiestoseveralkindsoftumors.Unfortunately,thecancercellkswereeasiertoproduceresistancetoMTXwhichendedinthefailureofchemotherapy.Inordertoovercometheresistanceoftumorcells,anewkindofdihydrofolatereductaseinhibitorscallednonclassicalantifolateincludingtriazines,pyrimidinesandquinazolinesweredesignedandsynthesized.Becauseofthedifferentantitumormechanismsbetweenthetwokindsofcompunds,thecancercellsresistanttoMTXmaystillbesensitivetothenonclassicalantifolate.Accordingtothistheory,somenonclassicalantifolate2,4-diamino-5-methyl-6-(substitutedbenzylamino)quinazolineswiththegeneralstructureshowninFIg.1weresynthesizedandtheirantitumoractivitiesweredeterminedinthisthesis.