Br(?)nsted Acid Catalyzed Cyclization Of Aminodiazoesters With Aldehydes

Nitrogen-containing heterocyclic molecules,an important class of compounds,play an important role in many fields such as life sciences,materials chemistry,medicine and pesticide chemistry,the synthetic method of which have very important research value and has always been one of the sinificant research contents of organic synthetic chemistry.One of the common methods for the synthesis of nitrogen-containing heterocyclic compounds is to utilize diazo compounds,whereas it often requires a precious metal catalyst,which limits its application to some extent.In this thesis,we have developed a cyclization reaction of amino diazonate with aldehyde compounds,using amino diazonate and aldehyde as raw materials,benzoic acid as a catalyst,which provides a new and efficient method for the synthesis of nitrogen-containing heterocyclic compounds.Initially,we have chosen ethyl benzylaminodiazobutyrate and benzaldehyde as model substrates.After systematic screening,the optimal reaction conditions were finally established:10 mol%benzoic acid as catalyst in methanol under the reaction temperature of 80? for 12 hours.Under the optimized conditions,we have studied the reaction properties of various aromatic and aliphatic aldehydes(a total of 26 aldehyde compounds)with different substituents in this reaction,with the corresponding target products being obtained in a yield up to 85%,showing good reactivity.At the same time,polysubstituted unsaturated nitrogen heterocyclic compounds and benzoazepine heterocyclic compounds with 5-7 membered rings can be obtained when utilizing different aminodiazide esters as substrates.Finally,we make a derivation of the products.The 3-pyrroolidine derivative can be obtained by oxidation of 2-pyrroolidine and next hydrolysis.At the same time,ethyl 3-piperidine formate can be obtained by hydrogenation and debenzylation of 1,2,3,4-tetrahydropyridine.