Study On The Photo-induced Reaction Of Dichloro-quinones With Chlorinated Isocoumarins

As an eco-friendly synthetical chemistry,photochemistry has the unique advantage of high efficiency and cleanness,especially in constructing polycyclic compounds with strain.Quinones have strong absorptions of light which makes them capable of the excitable substrates in photo-reactions.Due to the diverse bioactivities of quinone derivatives,such as antitumor and antifugal acitivities,we developed a method to synthesize novel polycyclic quinone derivatives by means of photoinduced cycloaddition(PCA)in enlarging the access to such compounds.In this thesis,we studied the PCA reactions of dichloro-quinones and chlorinated isocoumarins.The reactions afforded a series of compounds with four-membered ring including both cyclobutanes and oxetanes.This research mainly consists the following sections:1.We studied the photoreactions of 6,7-dichloro-5,8-quinolinequinone(DCQ),6,7-dichloro-2-methyl-5,8-quinolinequinone(DCMQ)with four chlorinated isocoumarins respectively.The PCA reaction of DCQ orDCMQ with chlorinated isocoumarins gave the oxetane as sole products.It indicated the N atom on the quinoline ring with strong electron withdrawing effect enhanced the activity of 8-carbonyl group in of DCQ and DCMQ.2.We implement the PCA reactions of 2,3-dichloronaphthalene-1,4-dione(DCN)with chlorinated isocoumarins,which gave a complicated result.The reaction of DCN and 3-chloro-1H-isochromen-1-one gave the isomers of oxetanes as prodcuts,while the reaction of 4-chloro-3-(cyclohexyloxy)-1 H-isochromen-1-one gave cyclobutanes.The reaction of 4-chloro-3-methoxy-1 H-isochromen-1-one and 3-(benzyloxy)-4-chloro-1H-isochromen-l-one gave both cyclobutanes and oxetanes,but the cyclobutanes are main products in both cases.It implied that the loss of N atom as the directing group in naphthalene ring decrease the selctivities of PC A reactions,the substituent in isocoumarins predominated the regio-and stereo-slectivity of the reaction.The 3-substituent in isocoumarin with electron withdrawing effect will facilitate the formation of oxetanes.3.The PCA reaction of 1,2,4,5-tetrachlorobenzoquinone(TCBQ)with 3-alkoxy-4-chloro isocoumarins gave the only cyclobutanes products and the yields are quite low.But the reaction of 3-chloro-1H-isochromen-1-one gave the oxetanes as products and the yield increased slightly.The Cl atom in the 3-position of isocoumarin showed a considerable impact on the selctivity of the reaction leading to oxetanes other than cyclobutanes.4.We prepared nine chlorinated isocoumarins from some substituted homophthalic acids for the present and future photochemistry study.We investigates the photo-induced reaction of four dichloroquinones with four isocoumarins.As a result,the selectivities of the PCA reactions depend on the structures of both substrates.The photo-reaction of TCBQ and isocoumarins gave the cyclobutanes as products except that the 3-chloro isocoumarin gave oxetane product.The reactions of DCN gave both cyclobutanes and oxetanes as products in which the former is main product except 3-chloro isocoumarin.The photo reactions of DCQ,DCMQ and isocoumarins only gave the oxetanes.