TY  - JOUR
AU  - Krstić, Natalija
AU  - Bjelaković, Mira
AU  - Pavlović, Vladimir D.
AU  - Robeyns, Koen
AU  - Juranić, Zorica
AU  - Matić, Ivana Z.
AU  - Novaković, Irena
AU  - Sladić, Dušan
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/945
AB  - The reactions of 17 alpha-hydroxyprogesterone with Lawesson's reagent (LR) in toluene, CH2Cl2 and/or CCl4 gave, depending on the duration of the reaction, two diastereoisomeric androst-4-en-17-spiro-1,3,2-oxathiaphospholane-2-sulfide pairs 2a,b and 3a,b in approximately 7:3 ratio, differing in configuration at the phosphorus atom. A parallel analysis of heteronuclear 2D H-1-C-13 spectra (HSQC and HMBC) and homo-nuclear 2D spectra (NOESY) enabled complete H-1 and C-13 assignments of each isomer. Also, analysis of NOESY correlations provided evidence for the preferred conformation. X-ray analysis of 3a confirmed the structure and absolute configuration on phosphorus. A pathway for the formation of 1,3,2-oxathiaphospholane ring was proposed. Cytotoxic activity in vitro was tested against three tumor cell lines (human cervix carcinoma HeLa cells and two human breast carcinoma MDA-MB-361 and MDA-MB-453 cells). Compound 3a and mixture 3a,b showed a moderate activity against HeLa and MDA-MB-453 cell lines while against MDA-MB-361 cell line all tested compounds exerted very weak cytotoxic effect. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, toxicity to brine shrimp Artemia sauna, were evaluated. All tested compounds showed strong antifungal activity.
PB  - Elsevier Science Inc, New York
T2  - Steroids
T1  - New androst-4-en-17-spiro-1,3,2-oxathiaphospholanes. Synthesis, assignment of absolute configuration and in vitro cytotoxic and antimicrobial activities
VL  - 77
IS  - 5
SP  - 558
EP  - 565
DO  - 10.1016/j.steroids.2012.01.021
ER  - 

@article{
author = "Krstić, Natalija and Bjelaković, Mira and Pavlović, Vladimir D. and Robeyns, Koen and Juranić, Zorica and Matić, Ivana Z. and Novaković, Irena and Sladić, Dušan",
year = "2012",
abstract = "The reactions of 17 alpha-hydroxyprogesterone with Lawesson's reagent (LR) in toluene, CH2Cl2 and/or CCl4 gave, depending on the duration of the reaction, two diastereoisomeric androst-4-en-17-spiro-1,3,2-oxathiaphospholane-2-sulfide pairs 2a,b and 3a,b in approximately 7:3 ratio, differing in configuration at the phosphorus atom. A parallel analysis of heteronuclear 2D H-1-C-13 spectra (HSQC and HMBC) and homo-nuclear 2D spectra (NOESY) enabled complete H-1 and C-13 assignments of each isomer. Also, analysis of NOESY correlations provided evidence for the preferred conformation. X-ray analysis of 3a confirmed the structure and absolute configuration on phosphorus. A pathway for the formation of 1,3,2-oxathiaphospholane ring was proposed. Cytotoxic activity in vitro was tested against three tumor cell lines (human cervix carcinoma HeLa cells and two human breast carcinoma MDA-MB-361 and MDA-MB-453 cells). Compound 3a and mixture 3a,b showed a moderate activity against HeLa and MDA-MB-453 cell lines while against MDA-MB-361 cell line all tested compounds exerted very weak cytotoxic effect. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, toxicity to brine shrimp Artemia sauna, were evaluated. All tested compounds showed strong antifungal activity.",
publisher = "Elsevier Science Inc, New York",
journal = "Steroids",
title = "New androst-4-en-17-spiro-1,3,2-oxathiaphospholanes. Synthesis, assignment of absolute configuration and in vitro cytotoxic and antimicrobial activities",
volume = "77",
number = "5",
pages = "558-565",
doi = "10.1016/j.steroids.2012.01.021"
}

Krstić, N., Bjelaković, M., Pavlović, V. D., Robeyns, K., Juranić, Z., Matić, I. Z., Novaković, I.,& Sladić, D.. (2012). New androst-4-en-17-spiro-1,3,2-oxathiaphospholanes. Synthesis, assignment of absolute configuration and in vitro cytotoxic and antimicrobial activities. in Steroids
Elsevier Science Inc, New York., 77(5), 558-565.
https://doi.org/10.1016/j.steroids.2012.01.021

Krstić N, Bjelaković M, Pavlović VD, Robeyns K, Juranić Z, Matić IZ, Novaković I, Sladić D. New androst-4-en-17-spiro-1,3,2-oxathiaphospholanes. Synthesis, assignment of absolute configuration and in vitro cytotoxic and antimicrobial activities. in Steroids. 2012;77(5):558-565.
doi:10.1016/j.steroids.2012.01.021 .

Krstić, Natalija, Bjelaković, Mira, Pavlović, Vladimir D., Robeyns, Koen, Juranić, Zorica, Matić, Ivana Z., Novaković, Irena, Sladić, Dušan, "New androst-4-en-17-spiro-1,3,2-oxathiaphospholanes. Synthesis, assignment of absolute configuration and in vitro cytotoxic and antimicrobial activities" in Steroids, 77, no. 5 (2012):558-565,
https://doi.org/10.1016/j.steroids.2012.01.021 . .

TY  - JOUR
AU  - Bjelaković, Mira
AU  - Krstić, Natalija
AU  - Milić, Dragana
AU  - Kop, Tatjana
AU  - Robeyns, Koen
AU  - Pavlović, Vladimir D.
PY  - 2012
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/1114
AB  - The present study is concerned with the oxidative behaviour of unsaturated and epoxy 5-oxo-5,10-secosteroids in the presence of m-CPBA or TFAA-UHP as oxidants in order to investigate potential parameters controlling the chemoselectivity and regioselectivity. In the study we discovered a striking difference in the chemical behaviour of stereoisomeric compounds, (Z)- and (E)-3 beta-acetoxy-5,10-secocholest-1(10)-en-5-ones, as well as 1S,10R- and 1R,10R-epoxides. The secoketones were oxidized with exclusively C-6 migration and Baeyer-Villiger rearrangement product formation, whereas their stereoisomers provided the ring-contracted products, without lactone formation. The preferred conformation of expanded and contracted rings was established by NOESY correlations. The structures of two obtained lactones were also confirmed by X-ray analysis. The mechanistic and stereochemical aspects of these transformations are discussed.
PB  - Oxford : Pergamon-Elsevier Science Ltd
T2  - Tetrahedron
T1  - Oxidative 10-membered ring expansion and contraction of stereoisomeric 1(10)-unsaturated and 1,10-epoxy-5-oxo-5,10-secosteroids induced by peracids
VL  - 68
IS  - 36
SP  - 7479
EP  - 7488
DO  - 10.1016/j.tet.2012.06.024
ER  - 

@article{
author = "Bjelaković, Mira and Krstić, Natalija and Milić, Dragana and Kop, Tatjana and Robeyns, Koen and Pavlović, Vladimir D.",
year = "2012",
abstract = "The present study is concerned with the oxidative behaviour of unsaturated and epoxy 5-oxo-5,10-secosteroids in the presence of m-CPBA or TFAA-UHP as oxidants in order to investigate potential parameters controlling the chemoselectivity and regioselectivity. In the study we discovered a striking difference in the chemical behaviour of stereoisomeric compounds, (Z)- and (E)-3 beta-acetoxy-5,10-secocholest-1(10)-en-5-ones, as well as 1S,10R- and 1R,10R-epoxides. The secoketones were oxidized with exclusively C-6 migration and Baeyer-Villiger rearrangement product formation, whereas their stereoisomers provided the ring-contracted products, without lactone formation. The preferred conformation of expanded and contracted rings was established by NOESY correlations. The structures of two obtained lactones were also confirmed by X-ray analysis. The mechanistic and stereochemical aspects of these transformations are discussed.",
publisher = "Oxford : Pergamon-Elsevier Science Ltd",
journal = "Tetrahedron",
title = "Oxidative 10-membered ring expansion and contraction of stereoisomeric 1(10)-unsaturated and 1,10-epoxy-5-oxo-5,10-secosteroids induced by peracids",
volume = "68",
number = "36",
pages = "7479-7488",
doi = "10.1016/j.tet.2012.06.024"
}

Bjelaković, M., Krstić, N., Milić, D., Kop, T., Robeyns, K.,& Pavlović, V. D.. (2012). Oxidative 10-membered ring expansion and contraction of stereoisomeric 1(10)-unsaturated and 1,10-epoxy-5-oxo-5,10-secosteroids induced by peracids. in Tetrahedron
Oxford : Pergamon-Elsevier Science Ltd., 68(36), 7479-7488.
https://doi.org/10.1016/j.tet.2012.06.024

Bjelaković M, Krstić N, Milić D, Kop T, Robeyns K, Pavlović VD. Oxidative 10-membered ring expansion and contraction of stereoisomeric 1(10)-unsaturated and 1,10-epoxy-5-oxo-5,10-secosteroids induced by peracids. in Tetrahedron. 2012;68(36):7479-7488.
doi:10.1016/j.tet.2012.06.024 .

Bjelaković, Mira, Krstić, Natalija, Milić, Dragana, Kop, Tatjana, Robeyns, Koen, Pavlović, Vladimir D., "Oxidative 10-membered ring expansion and contraction of stereoisomeric 1(10)-unsaturated and 1,10-epoxy-5-oxo-5,10-secosteroids induced by peracids" in Tetrahedron, 68, no. 36 (2012):7479-7488,
https://doi.org/10.1016/j.tet.2012.06.024 . .