Studia Litteraria

CSENGEI ILDIKÓ: A Bildungsroman mint a Bildungsroman elolvashatatlansága p. 7-26. ASZTALOS ÉVA: Az identitás dinamikus lehetõségei a nyelvi reprezentációban (Kölcsey korai lírájáról és a Katona-versekrõl) p. 26-39. CSOPÁK ZSUZSANNA: A Csongor és Tünde genetikus kapcsolata az Árgirus-széphistóriával p. 39-55. BÉNYEI PÉTER: A történelmi regény mûfajkonstituáló tényezõinek meghatározási kísérlete p. 55-90. KOVÁCS BÉLA LÓRÁNT: A múltban szóródó szubjektum poémája (Kassák Lajos: A ló meghal, a madarak kirepülnek) p. 90-98. JÁSZBERÉNYI-KAMRÁS ORSOLYA: A polgár nyomában (Márai Sándor: Egy polgár vallomásai) p. 98-115. TAKÁCS JUDIT: Vágy és hiány, a vágy hiánya, a hiány vágya (Ottlik Géza: Iskola a határon) p. 115-124. FODOR PÉTER: Elbeszélés és emlékezet (Mészöly Miklós: Az atléta halála) p. 124-138. KÁLAI SÁNDOR: A kalandos utazás (Tar Sándor: Minden messze van) p. 138-149. MAKSA GYULA: A diskurzuskeveredés módosulásai a Garaczi-olvasásban p. 149-169. A kiadvány szerzõirõl p. 169-170

Synthesis and stereochemistry of 3-acetyl-5-amino-spiro[1,3,4-thiadiazoline-2,4'-thioflavans]

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Synthesis and dynamic NMR studies of novel hydantoin and thiohydantoin derivatives. Crystal structure of diethyl 2-(4,4-diaryl-2,5-dioxoimidazolidin-1-yl) fumarate and diethyl 2-(4,4-diaryl-2-mercapto-5-oxo-4,5-dihydro-1H-imidazol-1-yl)fumarate

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Plasma progesterone, metabolic hormones and beta-hydroxybutyrate in Holstein-Friesian cows after superovulation

Metabolic hormones [insulin, leptin, insulin-like growth factor-I (IGF-I), thyroxine (T4) and triiodothyronine (T3)], progesterone (P4) and beta-hydroxybutyrate (BHB) serum concentrations were evaluated and their effect on the superovulation results of donor cows was investigated in a semi-arid environment. Body weight, body condition score (BCS) and lactation stage were also included in the analysis. Twenty-three Holstein-Friesian cows were superovulated with 600 IU FSHp following the routine procedure and flushed on day 7 in a Multiple Ovulation and Embryo Transfer Centre in the semi-arid area of Brazil. The corpora lutea (CL) were counted and blood samples were collected for assays. All of the hormones investigated and BHB serum concentrations were within the physiological ranges. There was a positive correlation between hormones, except between BHB and all the others. The leptin level was influenced by feeding status, as indicated by the BCS. Insulin, T4, T3 and BHB levels were affected by milking status. Dry cows had higher levels of all hormones except BHB. An optimum level of leptin resulted in the highest number of CL, while the linear increase of P4, T4 and IGF significantly increased the number of CL

[Tl(dota)](-): An Extraordinarily Robust Macrocyclic Complex.

The X-ray structure of {C(NH2)3}[Tl(dota)].H2O shows that the Tl3+ ion is deeply buried in the macrocyclic cavity of the dota4- ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 A, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl3+. A multinuclear 1H, 13C, and 205Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Lambda(lambdalambdalambdalambda)/Delta(deltadeltadeltadelta) enantiomeric pair. 205Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)]- + H+ left arrow over right arrow [Tl(Hdota)] to be determined, which turned out to be pKHTl(dota) = 1.4 +/- 0.1. [Tl(dota)]- does not react with Br-, even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)]- + CN- left arrow over right arrow [Tl(dota)(CN)]2-, with an equilibrium constant of Kmix = 6.0 +/- 0.8. The dissociation of the [Tl(dota)]- complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br-, and it was found to follow proton-assisted kinetics and to take place very slowly ( approximately 10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 109 h range at neutral pH. The solution dynamics of [Tl(dota)]- were investigated using 13C NMR spectroscopy and DFT calculations. The 13C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Lambda(lambdalambdalambdalambda) Delta(deltadeltadeltadelta) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Lambda(lambdalambdalambdalambda) Delta(deltadeltadeltadelta) interconversion

[TlIII(dota)]-: An Extraordinarily Robust Macrocyclic Complex

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Tricyclanos: conformationally constrained nucleoside analogues with a new heterotricycle obtained from a D-ribofuranose unit

A novel type of nucleoside analogue in which the sugar part is replaced by a new tricycle, 3,7,10-trioxa-11-azatricyclo[5.3.1.05,11]undecane has been prepared by substrate-controlled asymmetric synthesis. 1,5-Dialdehydes obtained from properly protected or unprotected uridine, ribothymidine, cytidine, inosine, adenosine and guanosine by metaperiodate oxidation reacted readily with tris(hydroxymethyl)aminomethane to provide the corresponding tricyclic derivatives with three new stereogenic centers. Through a double cyclisation cascade process the tricyclic compounds were obtained in good to high yields, with very high diastereoselectivity. Formation of one stereoisomer, out of the eight possible, was observed in all cases. The absolute configuration of the new stereotriad-containing tricyclic systems was aided by conventional NMR experiments followed by chemical shift calculations using an X-ray crystal structure as reference that was in good agreement with H–H distances obtained from a new ROESY NMR method. The synthesis was compatible with silyl, trityl and dimethoxytrityl protecting groups. A new reagent mixture containing ZnCl2, Et3SiH and hexafluoroisopropanol was developed for detritylation of the acid-sensitive tricyclano nucleosides

Complexation of Ln3+ Ions with Cyclam Dipicolinates: A Small Bridge that Makes Huge Differences in Structure, Equilibrium, and Kinetic Properties

The coordination properties toward the lanthanide ions of two macrocyclic ligands based on a cyclam platform containing picolinate pendant arms have been investigated. The synthesis of the ligands was achieved by using the well-known bis-aminal chemistry. One of the cyclam derivatives (cb-tedpa2−) is reinforced with a cross-bridge unit, which results in exceptionally inert [Ln(cb-tedpa)]+ complexes. The X-ray structures of the [La(cb-tedpa)Cl], [Gd(cbtedpa)]+, and [Lu(Me2tedpa)]+ complexes indicate octadentate binding of the ligands to the metal ions. The analysis of the Yb3+-induced shifts in [Yb(Me2tedpa)]+ indicates that this complex presents a solution structure very similar to that observed in the solid state for the Lu3+ analogue. The X-ray structures of [La(H2Me2tedpa)2]3+ and [Yb(H2Me2tedpa)2]3+ complexes confirm the exocyclic coordination of the metal ions, which gives rise to coordination polymers with the metal coordination environment being fulfilled by oxygen atoms of the picolinate groups and water molecules. The X-ray structure of [Gd(Hcb-tedpa)2]+ also indicates exocyclic coordination that in this case results in a discrete structure with an eight-coordinated metal ion. The nonreinforced complexes [Ln(Me2tedpa)]+ were prepared and isolated as chloride salts in nonaqueous media. However, these complexes were found to undergo dissociation in aqueous solution, except in the case of the complexes with the smallest Ln3+ ions (Ln3+ = Yb3+ and Lu3+). A DFT investigation shows that the increased stability of the [Ln(Me2tedpa)]+ complexes in solution across the lanthanide series is the result of an increased binding energy of the ligand due to the increased charge density of the Ln3+ ion