Study On Selective Formation Of C-N Bond And Microwave-Assisted Intramolecular Oxa-Michael Addition Reaction

The selective formation of C-N bond and microwave-assisted intramolecular oxa-Michael addition reaction were studied in this thesis.Quinazolin-4(3H)-ones(1) were conveniently synthesized from anthranilic acids and amidines,which could be chloridized with POCl₃ to obtain 4-chloroquinazolines (2).The reaction of 2 and 1H-pyrazol-3-amine would give two types of products.In the presence of acid or base,the C-N bond would be formed between the 4-position carbon of 2 and the NH₂ of 1H-pyrazol-3-amine.While the C-N bond between the 4-position carbon of 2 and the NH of 1H-pyrazol-3-amine would be formed when Pd catalyst was utilized.It was confirmed that the C-N bond would be selectively formed under different reaction conditions.The influence factors in the Pd-catalyzed cross-coupling of 2 and 1H-pyrazol-3-amine,such as Pd source,the ratio of the catalyst,ligand,base and reaction temperature,were optimized.The acid-catalyzed intramolecular oxa-Michael addition of (E)-1-aryl-4-hydroxy-4-methylpent-1-en-3-ones under solvent-free and microwave irradiation conditions has been investigated.Experimental results showed Bronsted acids were more efficient than Lewis acids in this reaction.The microwave-assisted reactions could be finished within several minutes to give high conversion and selectivity.Substrates whose aryl groups were substituted phenyl or naphthyl groups were more suitable in this reaction.This method possessed such advantages as short reaction time.environmentally benign procedures and easy purification.