Synthesis of Some Nitrogen Heterocycles under Solvent-free Conditions

Soltanzadeh, Zahra (2017) Synthesis of Some Nitrogen Heterocycles under Solvent-free Conditions. Doctoral thesis, University of Mohaghegh Ardabili.

Text (سنتز برخی هتروسیکل های نیتروژن¬دار تحت شرایط بدون حلال) Zahra Soltanzadeh.pdf Download (1MB)

Abstract

Recently, protection of the environment and waste prevention have been increasingly emphasized by researchers. A good way to achieve it is remove or reduce the use of organic solvents in synthetic chemistry. Due to increasing population growth, the development of human societies and the incidence of various diseases resulting from population growth, the need to discover new and more effective medications is essential. Therefore, due to the importance and role of pharmacological compounds such as 4-phenylurazole, phthalazine and pyrazole systems in this work, we decided to synthesis new derivatives of these compounds. Unexpectedly, Michael addition of 4-phenylurazole to fumaric esters led to produce hydantoin derivatives. The formation of this unexpected product was confirmed by x-ray crystallography. According to the above product and with the model reactions of 4-phenylurazole to acrylic and fumaric esters in hands, in next step, we try to Michael addition of phthalhydrazide to these esters to produce N1,N2-disubstituted phthalhydrazides and isoquinoline derivatives respectively. Surprisingly, mentioned Michael reactions only afforded of mono substituted phthalhydrazides. All of above investigations were performed in the presence of base catalyst DABCO and TBAB as a high polar madia at 70-90 oC under solvent-free conditions. Also, in this study we tried to provide a novel and green method for the synthesis of new derivatives of pyrazole systems. Using TBAB at room temperature under solvent-free conditions allowed access to this important demand. The structure of all compounds were confirmed by IR, 1H NMR, 13C NMR, elemental analysis of C, H, N and sometimes mass spectra.

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