Slobodanka Stanković
University of Novi Sad
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Featured researches published by Slobodanka Stanković.
Steroids | 2001
Katarina M. Penov Gaši; Slobodanka Stanković; János Csanádi; Evgenija A. Djurendić; Marija N. Sakač; Ljubica Medić Mijačević; Otto N. Arcson; Srdjan Z. Stojanović; Silvana A. Andric; Dora Molnar Gabor; Radmila Kovacevic
Starting from a 16-oximino derivative of 5-androstene the newly-synthesized 16-oximino-17-hydroxy-17-substituted derivatives 2-4 gave by the Beckmann fragmentation reaction the corresponding D-seco derivatives 6-9. Besides, in the case of the 17-hydroxy-17-methyl-16-oximino derivative 2, as a result of the rearrangement, the hydrolysis product 5 of the 16-oximino group with the opposite configuration at the C-17 was obtained. By the Oppenauer oxidation and/or by dehydration of 7 with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ), the corresponding derivatives 12, 13, and 14 were obtained. The structures of 6 and 12 were unambiguously proved by the appropriate X-ray structural analysis. Kinetic analysis for anti-aromatase activity showed that compound 12 expressed the highest inhibition in the denucleated rat ovarian fraction in comparison to other androstene derivatives (IC(50) was 0.42 microM). In comparison to aminoglutethimide (AG) activity, it was 3.5 times lower. The inhibition was competitive, with K(i) of 0.27 microM. Introduction of additional units of unsaturation (compounds 13 and 14) in D-seco derivatives did not increase anti-aromatase activity.
Steroids | 2003
Katarina M. Penov Gaši; Dušan Miljković; Ljubica Medić Mijačević; Evgenija A. Djurendić; Srdjan Z. Stojanović; Marija N. Sakač; Maja Djurendic; Slobodanka Stanković; Dušan Lazar; Silvana A. Andric; Radmila Kovacevic
D-Homo derivatives in the androstane and estrane series, 12-19, were synthesized by a fragmentation-cyclization reaction of 16-oximino-17-hydroxy-17-substituted derivatives 3-9, or by cyclization of the corresponding D-seco derivatives 20-26. The structures were confirmed by X-ray analysis of compounds 12 and 16. Preliminary assessment of inhibitory effects of D-homo derivatives from androstane series towards aromatase, 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), 17 alpha-hydroxylase/C17-20 lyase (P450c17) and 17 beta-HSD indicated much lower inhibitory potential compared to previously tested activity of another type of D-modified steroids, namely D-seco derivatives. Also, assessment of potential antiestrogenic activity of derivatives from estrane series showed absence of such an activity.
Bioorganic Chemistry | 2003
Suzana S. Jovanović-Šanta; Julijana Petrovic; Silvana A. Andric; Radmila Kovacevic; Evgenija Đurendić; Marija N. Sakač; Dušan Lazar; Slobodanka Stanković
The starting compound for synthesis of new 16,17-seco-estratriene derivatives was 3-benzyloxy-17-hydroxy-16,17-secoestra-1,3,5(10)-triene-16-nitrile (1b), obtained from estrone in several synthetic steps. 17-Tosyl, -chloro-, bromo-, and -iodo- derivatives 2b, 4b, 5b, and 6b were prepared directly from secocyanoalcohol 1b, while the 17-fluoro-derivative 3b was obtained from tosylate 2b in the reaction with tetrabutyl ammonium fluoride. The corresponding 3-hydroxy derivatives of these compounds were produced by action of hydrogen in presence of Pd/C, except the 3-hydroxy-17-iodo derivative 6a, which was obtained from 3-hydroxy-17-tosyloxy derivative 2a. All the newly synthesized compounds in biological tests on experimental animals exhibited an almost total loss of estrogenic activity, while most of them even prevented the action of endogenous estrogens. On the other hand, most of them, except compounds 3a and 6b, partially hindered the action of estradiol benzoate, behaving as moderate antagonists.
Steroids | 2005
Katarina M. Penov Gaši; Srdjan Z. Stojanović; Marija N. Sakač; Mirjana Popsavin; Suzana Jovanović Šanta; Slobodanka Stanković; Olivera R. Klisurić; Nebojsa Andric; Radmila Kovacevic
Starting from D-seco derivatives of 5-androstene 1-3, the D-homo lactones, 4 and 5, were synthesized. By the Oppenauer oxidation and/or by dehydration of 4 and 5 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) or 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil), the corresponding D-lactones 6-12 were obtained. The structures of 6 and 10 were unambiguously proved by the appropriate X-ray structural analysis. Anti-aromatase assay showed that tested compounds possess inhibition potency, however, two to four times smaller (IC50 from 0.2 to 0.7 microM, respectively) in comparison to aminoglutethimide (AG).
Tetrahedron Letters | 1997
Dušan Miljković; Katarina M. Penov-Gaši; Evgenija A. Djurendić; Marija N. Sakač; Ljubica Medić-Mijačević; Vjera Pejanović; Slobodanka Stanković; Dušan Lazar
Abstract By the action of acidic titanium trichloride upon 16-oximino-17α-benzyl-17β-hydroxy derivatives in the androstane and estrane series the 16-oxo-17β-benzyl-17α-hydroxy derivatives 6 and 7 with inversed configuration at C 17 were obtained. A mechanism for this novel rearrangement is proposed.
Tetrahedron | 1995
Vjera Pejanović; Julijana A. Petrovtć; János Csanádi; Slobodanka Stanković; Dušan Miljković
Abstract Sodium borohydride reduction of anti-3-methoxy-17β-hydroxyestra-1,3,5(10)-trien-6,7-dione 7-oxime (4a) afforded syn-3-methoxy-6α,17β-dihydroxyestra-1,3,5(10)-trien-7-one oxime (5), which in thionyl chloride at −18 °C undenvent Beckmann fragmentation reaction to the unexpected 3-methoxy-6-oxo-17β-hydroxy-6.7-secoestra-1.3.5(10)-trien-7-nitrile (6). A mechanism of this fragmentation process was proposed.
Tetrahedron Letters | 1984
Dušan Miljković; Djerdj Čanadi; Julijana Petrovic; Slobodanka Stanković; B. Ribár; Gyula Argay; Alajos Kálmán
Abstract A selected saturated steroid derivative has been subjected to ozonation in solution. As the main reaction product 14,15-ozonide has been isolated in crystalline form whose structure has been unambiguously confirmed by the X-ray difraction method.
Tetrahedron Letters | 1998
Katarina M. Penov-Gaši; Dušan Miljković; Ljubica Medić-Mijačević; Evgenija Durendić; Julijana Petrovic; Vjera Pejanović; Slobodanka Stanković; Dušan Lazar
Abstract By a novel “one pot” fragmentation-cyclization reaction 17β-hydroxy-17α-substituted-16-oximino derivatives in the androstane and estrane series were converted to a new type of D-homo derivative.
Tetrahedron | 1987
Dušan Miljković; Katarina Gas̆i; Marija Kindjer; Slobodanka Stanković; Gyula Argay
Abstract Three pairs of isomeric 17,20-epoxy-17-picolyl-derivatives of 5-androstene and 5α-androstane ( 3 – 8 ) have been prepared by an oxidation of 3β-acetoxy-17-picolinylidene-androst-5-ene (2) and 3β-acetoxy-17-picolinylidene-5α-androstane (2) with in situ prepared Cr(VI) oxide-pyridine-complex in methylene chloride at room temperature. X-Ray structural analysis of the suitably crystalline epoxides 5 and 6 revealed the structure of 5 being 17α, 20α-epoxide, while structure of 6 corresponded to 17β, 20β-epoxide. It was proved that in both cases E-geometrical isomers were formed. Based on the deduced absolute stereochemistry of 5 and 6 , the structures of other two pairs ( 3 – 4 , 7 – 8 ) were readily worked out by NMR-spectroscopy. A mechanism of the oxidation reaction was proposed, and some other relevant chemical experiments were described. Finally, an explanation was offered for the observed differences of the relevant bond lengths and dihedral angles in 5 and 6 which indicated a slight σ - π conjugation between the epoxide and the pyridine rings, which might be coupled with long range effect of the C-7 carbonyl group.
Acta Crystallographica Section C-crystal Structure Communications | 1995
Slobodanka Stanković; Dušan Lazar; J. Petrovic; D. Miljovic; Vjera Pejanović; C. Courseille
X-ray structure analysis of the title compound, C 19 H 23 NO 4 , showed an unexpected anti orientation for the 6-oxo-7-oximino function. After molecular-mechanics calculations, the H atom of the 17-hydroxy moiety, which participates in a strong hydrogen bond formed in the crystalline state, changed its orientation substantially. Some change in the conformation of ring B was also observed.