Studies On The Synthesis Of Nitrogen-containing Heterocyclic Derivatives Without Transition Metal Catalysis

In organic synthesis,nitrogen-containing heterocyclic compounds have become the research object because of their biological activity,which can be used in medicine and natural products.Therefore,the development of a new synthetic method of nitrogen heterocyclic derivatives without transition metal participation has very important application value.The goal of this thesis is to study the synthesis of novel nitrogen-containing heterocyclic compounds through 2-fluoropyridine derivatives and the cyclization reaction of ?-methylstyrene derivatives with transition-metals-free involved in catalysis.The main contents of this thesis are as follows:(1)Synthesis of pyridylpyridones and oxybipyridines from 2-fluoropyridine under transition-metal-free conditions.This reaction does not require transition metal as catalyst.It can promote the selective hydroxylation and arylation of 2-fluoropyridine derivatives with bases to synthesize various pyridone and oxopyridine derivatives.After optimization of reaction conditions,the optimal reaction conditions for the synthesis of pyridyl pyridone and oxybipyridine compounds are 0.2 mmol 2-fluoropyridine derivatives,1 equiv.cesium carbonate,1 mmol water,1 mL dimethyl sulfoxide,and reacted at 110 ? for 12 h.Then,the 2-fluoropyridine derivatives were expanded under the optimal reaction conditions.And the products of pyridone and oxybipyridine were obtained,respectively,from 2-fluoropyridine derivatives which were not 6-substituted and 2-fluoropyridine derivatives which were 6-substituted.Then,in order to explore the reaction mechanism,relevant control experiments and substrate expansion experiments for mechanism verification were carried out.The reaction has the characteristics of low toxicity solvent,no transition metal participation and water as oxygen source.(2)The synthesis of nitrogen heterocyclic compounds by metal-free catalyzed cyclization of ?-methylstyrene compounds with ammonium iodide.Through optimization of the reaction conditions using ?-methylstyrene as the raw material,the best conditions for synthesis of 5-phenylpyrimidine is 0.5 mmol ?-methylstyrene,10 equivalents of ammonium iodide,and 1 mL of dimethyl sulfoxide and reacted at 130 ? for 48 h;the best condition for synthesis of 3-phenyl-4-methyl is 0.5 mmol ?-methylstyrene,4 equivalents of ammonium iodide,0.5 mL formaldehyde,and reacted at 130 ? for 24 h.Next,several representative compounds were selected for substrate expansion which showed fairly good yields.The preliminary mechanism of the reaction of synthesizing pyrimidine compounds was investigated.