Huffman Rearrangement-based Approaches To 6H-Pyrido[1,2-c]Quinazolin-6-Ones

Huffman rearrangement is a classic organic reaction,which is not only a very effective way to synthesize compounds such as primary amines,ureas and carbamates,etc.,but also importantly applied in the synthesis of intermediates of medicines and pesticides.The traditional Huffman rearrangement reaction is completed through the oxidation of hypochlorite.In recent years,the high-valent iodine reagentsmediated Huffman rearrangement reactions have been widely used in various organic synthetic routes.Iodine compounds with similar reactivity to transition metals are more environmentally friendly and relatively inexpensive.Therefore,trivalent and pentavalent iodine-based high-valent organic iodine reagents have received widespread attention.Bis(trifluoroacetoxy)iodinebenzene(PIFA),a trivalent iodine reagent,is commercially available and often used as an oxidant to promote some reaction to build a variety of different chemical bonds such as C-C,C-N and C-O bonds.6H-Pyridino[1,2-c]quinazolin-6-one derivatives possessing certain anti-inflammatory activities and potential for scavenging superoxides have great potential applications in photovoltaic materials,fluorescent probes,and photocatalysts due to there large ?-plane conjugate structures.To date,there are few effective methods for synthesis of these compounds,due to the structural complexity and big synthetic challenges.Therefore,we hope to develop a new and concise method for the synthesis of 6H-pyrido[1,2-c]quinazoline-6-ones.After extensive literature research,we designed a novel synthetic strategy of 6H-pyrido[1,2-c]quinazolin-6-ones from o-(pyridin-2-yl)arylformamide via intramolecular Huffman rearrangement reactions.Finally,we developed a novel synthetic method of 6H-pyrido[1,2-c]quinazoline-6-ones from o-(2-pyridyl)arylformamide via intramolecular Huffman rearrangement in the presence of high-valent iodine(III)reagent(PIFA).This method has the advantages of mild reaction conditions,broad substrate scopes,short reaction times,and excellent yields.In addition,these kinds of molecules have good fluorescence characteristics due tothere conjugate system and good coplanarity.If the structures can be further modified to improve there fluorescence and other properties,it may be expected to find new photovoltaic materials,fluorescent probes and photocatalysts.