New Synthetic Method Of Dihydrooxazole Oxazinoquinazoline And Pyrazinone

N-heterocyclic compounds have become a hot topic in organic synthesis because of their widespread biological activities, which were not only used in pharmaceutical and pesticide field, but also in dyes, multi-functional materials and chemical intermediates. And due to their simple operation and high resource utilization, multi-component reactions have been widely used in the discovery of new drugs and combinatorial chemistry and synthesis of natural products. In this dissertation, we using the Isocyanide based Multicomponent Reactions components combined with the aza-Wittig reaction, which is known for its mild react conditions and high yield, synthesized three series of 34 unreported N-heterocyclic compounds. The cyclization conditions and the spectral properties were also studied, it can be summarized as following:1. By using combined Passerini reaction and aza-Wittig reaction, eight 2-aryl substitut-ed-4,5-dihydrooxazole-5-carboxamide derivatives were synthesized. The reaction conditions and spectral properties of the intermediates and target compounds were also discussed. This new method not only has the advantage of easily accessible starting materials and mild mild react conditions, but also has high yield, which could be an efficient way to synthesis oxazole derivatives.2. Thirteen unreported 11b,13-dihydrobenzo[4,5][1,3]oxazino[3,2-c]quinazoline deriv-derivatives were synthesized by application of aza-Wittig reaction, and the new compounds were characterized using IR,1H NMR,13C NMR, MS and elemental analysis. The cyclization conditions of 2.4-dihydro-1H-benzo[d][1,3]oxazine derivatives were also discussed, when there is a substituent of methyl group in the phenyl ring of (2-aminophenyl)methanol, benzo[d][1,3]oxazine was easily formed through the Schiff base, but when the substituent become to a chloro-group, the reaction was stopped at the stage of Schiff base.3. Thirteen unreported dihydropyrazine-2-carboxamide derivatives were synthesized using sequential Ugi/Staudinger/aza-Wittig reaction from 2-(4-chlorophenyl)-2-oxoacet-aldehyde,and the spectral properties of new compounds were characterized by IR,1H NMR,13C NMR, MS and elemental analysis. Furthermore, the reactant scope research found that the Ugi reaction was only taken place when aliphatic amine was used.