Ostapchuk E. Trimethylsilylchloride in Biginelli reactions

The thesis is devoted to the study of Biginelli reactions in the presence trimethylsilylchloride as a condensing agent (promoter). It was shown that trimethylsilylchloride is an effective condensing agent for such reactions. The effective methodology of Biginelli reaction in the presence of trimethylsilylchloride was developed. The new types of substrates for the Biginelli reaction were found and the limits of its application were expanded. The role of trimethylsilylchloride in Biginelli condensations was investigated. An efficient solution-phase procedure for the combinatorial synthesis of libraries of N1-substituted 3,4-dihydropyrimidin-2(1H)-ones was developed. For the first time, a simple convenient procedure for synthesis of N1-aryl-3,4-dihydropyrimidin-2(1H)-(thi)ones in solution was presented. The chemical behavior of various trifluoromethyl-1,3-diones in classical Biginelli reaction using DMF/TMSCl was investigated. In the case of 1,1,1-trifluoropentane-2,4-dione and substituted (thio)ureas unexpected cyclization route was disclosed. The derivatives of dihydropyrimid(thi)ones containing COCF3-group at 5-position were obtained for the first time. The TMSCl-mediated Biginelli type reaction of cyanoketones with thiourea and benzaldehydes furnishes dihydropyrimidinenitriles in high preparative yield and excellent purity. Serendipitously, a similar reaction of cyanoacetamides with benzaldehyde and thioureas leads to the first representatives of thiazinopyrimidine heterocyclic system.