A New Cascade Cycloaddition Reaction Of Azomethine Ylides To Allenoates:Effectively Construct Pyrrolo[1,2-c]Quinazolinones

A new cascade cycloaddition reaction of azomethine ylides with allenoates to effectively construct potentially biologically active pyrrolo[1,2-c]quinazolinones was estabilished. This reaction had the features of simple materials, mild condition, and simple work-up. Also the method had the advantage of wide substrate scope, which not only could apply to a variety of substituted isatins and allenoates, but also was suitable for various of alkynoates and alkynones. A plausible mechanism has been proposed, which involved 1,3-dipolar cycloaddition/the rearrangement of exocyclic carbon-carbon double bond/intermolecular nucleophilic addition/oxidation. The obtained pyrrolo[1,2-c] quinazolinones could be easily transformed into the pyrrolo[3,2-c]quinoline-4-one derivatives in one-step style. This reaction provided a new method to synthesis the highly functionalized pyrrolo[1,2-c]quinazolinones.This thesis was made up of three charpters. the first charpter was the literature review. Firstly, the important biological activities and synthetic methods of pyrrolo[1,2-c] quinazolinones and pyrrolo[3,2-c]quinoline-4-ones were discussed. Secondly, according to the different types of dienophiles, the 1,3-diplor cycloaddition reaction was briefly reviewed. In addition two examples which the 1,3-diplor cycloaddition was applied to the total synthesis of natural alkaloids were gave. Finally, based on the literature survey and our previous work, the research issue was proposed.The second charpter was the experimental results and discussion. At first, after the investigation of additives, solvents, bases and temperature, the optimized condition was formed. Moreover, with the optimized conditions in hand, the substrate scope of this cascade reaction was explored. Furthermore, based on previous literatures and some control experiments, a plausible mechanism was proposed. In addition, the obtained pyrrolo[1,2-c]quinazolinones which could be easily transformed into diverse potentially biologically active heterocycles were researched. At last, the specific experiments were established.The third charpter was the conclusion of this thesis. After experiment researched, a novel cascade cycloaddition of azomethine ylides with allenoates was found and a new pathway to highly effectively synthesize pyrrolo[1,2-c]quinazolinones was formed.