Suchergebnisse

The interactions between four native and modified beta-cyclodextrins and a benzimidazolium bromide salt were analyzed through UV-Vis and NMR Spectroscopy. The new benzimidazolium salt was obtained by simple and efficient conversion of N-1 substituted 5,6-dimethylbenzimidazole with phenacyl bromide in acetone. In all cases, the complexes stoichiometry was 1:1, as determined from UV-Vis titrations. Based on the values for association constants, the strength of the interactions with benzimidazolium bromide was weakest with the methyl substituted beta-cyclodextrin and strongest with the sulfobutylether substituted beta-cyclodextrin. Through-space NOE experiments were used to investigate the structural aspects of inclusion process. The obtained NOE correlations indicate coexistence of two inclusion modes: one with the phenacyl group inside the cyclodextrin cavity and the second one with dimethyl-substituted benzene ring inside the cavity. The imidazole ring and the ethyl substituent have been proven to remain outside the cyclodextrin cavity in both inclusion modes.

Novel indolizines and pyrrolo[1,2-c]pyrimidines bearing a 3-carbonylchromen-2-one moiety on the pyrrole rings were synthesized and spectroscopic properties of some of synthesized compounds were investigated. Synthetic procedures started from 4-substituted pyrimidines, 3-(2-bromoacetyl)-2H-chromen-2-one and electron-deficient alkynes via 3+2 dipolar cycloaddition of cycloimmonium-ylides, generated in situ from their corresponding quaternary salts, in the presence of an epoxide playing the role of acid scavenger and reaction solvent. The structures of novel compounds were confirmed by chemical analyses, IR and NMR spectroscopy. Spectroscopic properties of some of the synthesized compounds were investigated.