Study On Organic Reaction With A Aid Of Low-valent Titanium Reagent

Low-valent titanium reagent is an important reducing agent, as well as a goodcatalyst. It shows high reactivity and selectivity and many reactions can be carried outunder mild conditions. In the thesis, selective reductive reactions and reductive couplingreaction of the multi-functional compounds induced by low-valent titanium reagenthave been investigated and a series of heterocyclic compounds containing nitrogen atomhave been synthesized. The first part involves the organic reactions and researchprogress in organic synthesis induced by low-valent titanium reagent.In the second chapter, a series of indolin-2-one derivatives have been obtained ingood yield under mild reaction conditions and in short reaction times by a novelselective reduction of isatin derivatives induced by low-valent titanium reagent. Thestructures of the products were charactered by IR,1H NMR,13C NMR and HRMS. Thismethod provides a simple, fast and effective way to indolin-2-one derivatives.In the third chapter, the selective reductive reactions of2-oxo-2-arylethane-thioamide induced by low-valent titanium have been investigated. A series of2-hydroxyl-2-arylethanethioamides and2-arylethanethioamides were obtained at roomtemperature and refluxing temperature, respectively. The structures of the products werecharactered by IR,1H NMR,13C NMR and HRMS. The structures of compounds7a and8b were further determined by crystal X-ray diffraction analysis.In the fourth chapter, a mild, efficient and improved synthesis of2H-indazolederivatives via cyclization of N-(2-nitrobenzyl)aniline promoted by low-valent titaniumreagent has been described. A series of indazoles were synthesized in good yields. Thestructures of the products were determined by IR,1H NMR,13C NMR, HRMS andX-ray analysis. The remarkable advantages of this method are mild, neutral, simpleoperation, good yields and atomic economy.