Synthesis Of N-Heterocycles And S-Heterocycles Via Arylation

N-Heterocycles and S-heterocycles are widely found in natural products,biologically and pharmacologically active molecules. N-Heterocycles have become amainstream for development of drugs, because they are similar with nucleotide basesand show a high degree of selectivity and suitability to drug receptors. Recently, greatprogress on synthesis of N-heterocycles and S-heterocycles via ayrlation has beenachieved. In this dissertation, we have investigated synthesis ofH-pyrazolo[5,1-a]isoquinolines, pyrazolo[1,5-c]quinazolines and thiochromen-4-oneson the base of arylation, and some results were obtained as follows:A new, concise and efficient one-pot copper-catalyzed method for synthesis ofH-pyrazolo[5,1-a]isoquinolines has been developed. The protocol uses readily availablesubstituted1-(2-bromophenyl)-3-alkylprop-2-yn-1-one, hydrazine hydrochloride, alkyl2-cyanoacetates，malononitrile, pentane-2,4-dione and ethyl3-oxobutanoate as thestarting materials, inexpensive CuI as the catalyst, K3PO4as the base, DMF as thesolvent, and the corresponding H-pyrazolo[5,1-a]isoquinolines were obtained undermild conditins. The three-component reactions underwent sequential coupling ofsubstituted1-(2-bromophenyl)-3-phenylprop-2-yn-1-one with hydrazine leading tosubstituted5-(2-bromophenyl)-1H-pyrazole, copper-catalyzed intermolecularC-arylation and intramolecular cyclization. The synthesizedH-pyrazolo[5,1-a]isoquinolines own various key functinoal groups including amino,ester, cyano and carbonyl, which provided opportunity for construction of diversebiologically active molecules.An easy and efficient method has been developed for synthesis ofpyrazolo[1,5-c]quinazolines. The protocol uses readily available substituted1-(2-halophenyl)-3-akylprop-2-yn-1-ones, hydrazine hydrochloride, amidinehydrochlorides as the starting materials, and the correspondingpyrazolo[1,5-c]quinazolines were obtained in good to excellent yields. The one-potmethod underwent sequential copper-catalyzed intermolecular N-arylation andintramolecular cyclization. And the second-stepped copper-catalyzed reactionsproceeded very well under mild conditions (at room temperature for most of thereactions).A simple, practical and highly efficient transition metal-free method has been developed for synthesis of thiochromen-4-one derivatives. The protocol uses readilyavailable substituted1-(2-alkoxyaryl)-3-akylprop-2-yn-1-ones and sodium sulfidenonahydrate as the starting materials, ethanol or DMF as the solvent, and the reactionswere performed well at80℃under nitrogen atmosphere. The reactions underwentsequential addition of substituted1-(2-alkoxyaryl)-3-akylprop-2-yn-1-ones with Na2S,isomerization, cycloaddition and aromatization. The method avoided contaminate oftoxic metals to the products, so the inexpensive and environmentally benign approach tothiochromen-4-one derivatives will find wide application in academic and industrialresearches.