Bazı sidnon türevlerinin elektronca yoksun alken ve alkinlerle 1,3-dipolar halka katılma reaksiyonları

One of the most versatile method for the construction of five membered heterocyles is 1,3-dipolar cycloaddition reactions. Sydnones, a well-defined class of mesoionic compounds that can provide an easy access to a variety of heterocyclic systems containing especially pyrazole and pyrazoline ring, They are generally found in the core structure of many drugs and alkaloids. In order to construct new pyrazole (or pyrazoline)-based heterocyles, various electron deficient dipolarophiles have been attempted in the cycloaddition reaction of sydnones throughout this Ph.D. dissertation study. The outcomes of the study were disscussed in four parts; In the first part, N-aryl sydnone derivatives as the precursor of azomethine imine were succesfully synthesized according to reliable literature method and characterized. Then, reactivity of acetylenic dipolarophile, 1-(prop-2-ynyl)-1H-indole, with N-aryl sydnones was investigated and reaction proceeded to give cycloadducts with lack of regioselectivity that is resulted from the nature of electon-withdrawing or donating substituents on the aromatic ring of sydnone. The second section covers the synthesis of new cyclopropyl-(1-substituted phenyl)-(1H-pyrazol-3-yl)methanols as the result of the complete regioselective cycloaddition reaction of acetylenic alcohol, namely 1-cyclopropylprop-2-yn-1-ol with N-aryl sydnone derivatives. The third part of this study involves the synthesis of new fused tricyclic cycloadducts bearing pyrazoline ring, namely, 2-(4-substituted phenyl)-3,3a-dihydro-2H-[1]benzothieno[3,2-c]pyrazole 4,4-dioxides via reaction of benzo[b]thiophene 1,1-dioxide with N-aryl sydnones in moderate yields. The synthesis of corresponding cycloadducts took place in completely regioselective manner. In the last part of the present work, treatment of secondary heterocyclic enamine, 2-nitromethylenethiazolidine, with N-aryl sydnones gave rise to unusual decomposition of sydnone ring by the possible release of acetolactone in intermediate step and underwent diazocoupling reaction instead of 1,3-dipolar cycloaddition. To the best of our knowledge, there is no reported study comprising such kind of decomposition of sydnones leading diazocoupling products.