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Öğe (3aR,6aR)-1-Phenyl-5-[(R)-1-phenylethyl]-3-[4-(trifluoromethyl)phenyl]-1,6a-dihydropyrrolo[3,4-c]pyrazole-4,6(3aH,5H)-dione(Int Union Crystallography, 2009) Fronczek, Chris F.; Dürüst, Yaşar; Yıldırım, Muhammet; Fronczek, Frank R.In the title molecule, C26H20F3N3O2, the two central five-membered rings form a dihedral angle of 62.94 (8)degrees. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = -0.05 (11). Notable intra-and intermolecular contacts include C-H center dot center dot center dot O and C-H center dot center dot center dot pi (arene) hydrogen bonds.Öğe Bis(3-phenyl-1,2,4-thiadiazole-5-thiolato)mercury(II)(Int Union Crystallography, 2005) Dürüst, Yaşar; Altuğ, Cevher; Bozkurt, Çetin; Fronczek, Frank R.The title compound, [Hg(C8H5N2S2)(2)], has crystallographic C-2 symmetry. The Hg-S distance is 2.353 (2) and the coordination geometry is linear, with an S-Hg-S angle of 179.77 (18)degrees. The exocyclic C-S single-bond distance is 1.749 (6) angstrom, and intramolecular Hg center dot center dot center dot N distances of 2.857 (4) angstrom exist, as well as secondary Hg center dot center dot C and S center dot center dot center dot S contacts.Öğe A cycloaddition product of a chiral maleimide: 4-{(3aS*,6aS*)-4,6-dioxo-1-phenyl-5-[(1R)-1-phenylethyl]-1,3a,4,5,6,6a-hexahydropyrrolo[3,4-c]pyrazol-3-yl}phenyl acetate(Int Union Crystallography, 2009) Fronczek, Chris F.; Dürüst, Yaşar; Yıldırım, Muhammet; Fronczek, Frank R.In the title molecule, C27H23N3O4, the two central five-membered rings form a dihedral angle of 63.66 (4)degrees. The absolute configuration was determined by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y = -0.10 (7).Öğe (Phenyl) (3-phenylsulfonyl-1,2-dihydropyrrolo [1,2-a]quinoxalin-1-yl) methanone(Int Union Crystallography, 2011) Dürüst, Yaşar; Sağırlı, Akın; Fronczek, Frank R.In the title molecule, C24H18N2O3S, the 13-atom ring system comprising the quinoxaline and fused five-membered ring exhibits an r.m.s. deviation from coplanarity of 0.039 angstrom, with a maximum deviation of 0.0710 (10) angstrom for the PhCO-bearing C atom of the five-membered ring. The 10-membered C8N2 quinoxaline ring system has an r.m.s. deviation from coplanarity of 0.022 angstrom, with a maximum deviation of 0.0403 (9) angstrom for the C atom involved in the C=C bond in the five-membered ring. The three atoms of the five-membered ring fused to the quinoxaline ring system show deviations of up to 0.118 (2) angstrom for the PhCO-bearing C atom. C-N bond distances in the quinoxaline ring system of the title molecule deviate from those in unsubstituted quinoxaline. In particular, the two C-N distances to the N atom involved in the five-membered ring are essentially equal, with values of 1.3786 (17) and 1.3773 (16) angstrom, unlike the difference of nearly 0.06 angstrom in quinoxaline.Öğe Regioselective 1,3-dipolar cycloaddition of phenanthrolinium N-ylides to substituted arylidene oxazolones(Springer, 2011) Dürüst, Yaşar; Sağırlı, Akın; Fronczek, Frank R.The 1,3-dipolar cycloaddition reactions of phenanthrolinium ylides have been investigated. Thus 15 novel aryl substituted spiro[oxazole-4,10'-pyrrolo[1,2-a][1,10] phenanthrolin]-5-ones were prepared in a regioselective manner, by the treatment of phenanthrolinium ylides with (Z)-arylidene oxazolones.Öğe Synthesis and crystal structure of new heterocycles containing 1,2,4-oxadiazole, 1,2,4-oxadiazolone (thione), hydantoin, and mercaptobenzimidazole units(Springer, 2014) Dürüst, Yaşar; Gözlükaya, Özge; Özer, Gülsün; Fronczek, Frank R.A number of 1,2,4-oxadiazolone and mercapto nitro benzimidazole derivatives containing 1,2,4-oxadiazole and hydantoin moieties have been prepared, and their structures were identified by means of spectral/physical characteristics including X-ray diffraction data.Öğe Synthesis and stereochemistry of some novel dihydropyrrolo[3,4-c]pyrazoles(Springer Wien, 2012) Dürüst, Yaşar; Yıldırım, Muhammet; Fronczek, Chris F.; Fronczek, Frank R.Eleven novel dihydropyrrolo[3,4-c]pyrazole derivatives were obtained by the reaction of chiral (1R)-N-(1-phenylethyl)maleimide and C,N-aryl-substituted nitrilimines. The reaction afforded the cycloadducts as a regioisomeric mixture which can be separable in some cases. The structure and stereochemistry of cycloadducts were assigned on the basis of infrared (IR), H-1 and C-13 nuclear magnetic resonance (NMR), mass and X-ray spectra, optical rotation measurements, and CHN analyses.Öğe Synthesis, crystal structure, and in vitro antiprotozoal activity of some 5-phenyl(methyl)sulfonyl-substituted dihydroisoxazoles(Springer Wien, 2013) Dürüst, Yaşar; Altuğ, Cevher; Kaiser, Marcel; Fronczek, Frank R.; Taşdemir, Deniz4,5-Dihydroisoxazole derivatives are interesting synthetic targets that exhibit various biological activities, including anti-infective. Taking account of the principle of bioisosterism, a number of 4,5-dihydroisoxazoles carrying a phenyl- (or methyl-)sulfonyl group at position 5 were designed and synthesized by 1,3-dipolar cycloaddition of nitrolic acid-generated nitrile oxides with electron-deficient phenyl (or methyl) vinyl sulfones. The structures of all the cycloadducts were elucidated by means of spectroscopic methods (NMR, MS), X-ray diffraction, and physical characteristics. The in vitro antiprotozoal and cytotoxic activities of these heterocyclic compounds were investigated.
