Phosphorous Acid Applied To Synthesis Of Quinazolinones And Cinnamaldehyde Compounds

Phosphorous acid,a medium-strong solid inorganic acid,is a reducing agent,and is usually used as the materal of pesticide,nylon whitening agent,plastic stabilizers,and synthetic fiber.However,the use of H3PO3 as a catalyst in organic synthesis is seldomly reported.Quinazolinones and cinnamaldehyde possess comprehensive pharmacological and biological activities,which are significant in the field of medicine and organic synthesis.Over the past decades,the efficient synthesis of quinazolinones and cinnamaldehyde have becomed one of the hot topics in medicine,pesticide and fine chemicals.Thereover,the environment friendly and high-atom economy new catalytic system has wide application prospects.This thesis attempts H3PO3 to apply to the synthesis of quinazolinones compounds and cinnamaldehyde compounds as following two sections:1.A general and efficient cyclocondensation of o-aminobenzamides and ?-ketoesters(or?-diketones)in the prensence of 50 wt%H3PO3 solution via selective C-C bond cleavage leading to quinazolinones was developed.Through the study of reaction conditions(reaction temperature and time,solvent,kind and amount of catalyst,substrate molar ratio)influence on quinazolinones yield,the optimum reaction conditions were confirmed:under N2,substrate molar ratio o-aminobenzamides and ?-ketoesters(or ?-diketones)= 1:1.3,catalyst 10 mol%50 wt%phosphorous acid solution,solvent 0.5 mL ethanol,reaction temperature 50?,reaction time 15 h?24 h.Based on the optimum reaction conditions,twenty-nine kinds of substituted substrate were examined for this system,and the isolated yields were 80%?95%.On the basis of GC-MS and GC monitor reaction,this possible mechanism via H3PO3 catalyzed the reaction of C-C bond cleavage and cyclization addition reaction was proposed.The reaction system for quinazolinones synthesis provides an efficient,green environmental and high atom economical method.2.The second part of this paper reported the efficient synthesis of a series of cinnamaldehyde compounds with propargyl alcohol compounds by 50 wt%H3PO3 solution catalyze and intramolecular rearrangement.The best reaction conditions as follows:under N2,catalyst 150 mol%50 wt%phosphorous acid solution,solvent 0.5 mL CH2Cl2,reaction temperature 120?,reaction time 2 h.On this basis,further expanding the scope of the substrate,19 kinds of cinnamaldehyde compounds were synthesized in the isolated yields of 30%?95%.this reaction probably mechanism in the synthesis of cinnamicaldehyde was reported with propargyl alcohol compounds as substrates via a typical Br(?)nsted acid-catalyzed and molecular rearrangement.The reaction via H3PO3-catalyzed provides a simple and efficient method for the synthesis of cinnamaldehyde,which has potential application in the synthesis useful compounds.