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Usled stalne potrebe za novim antitumorskim lekovima, počevši od androstanskog bis(semikarbazona), sintetisan je novi bis(karbazatni) estar (bisKBZ) za koji je određena antimikrobna aktivnost, citotoksična aktivnost na tri maligne ćelijske linije, i urađen je brine shrimp test toksičnosti. Novo jedinjenje se nije pokazalo kao dobar antimikrobni agens, ispoljilo je umerenu citotoksičnost prema testiranim ćelijskim linijama i pokazalo se kao pet puta manje toksično od cisplatina za račiće Artemia salina što je u dobroj korelaciji sa citotoksičnošću prema HeLa ćelijskoj liniji., Due to the constant need for new antitumor drugs, starting from androstane bis(semicarbazone), a new bis(carbazate) ester (bis-KBZ) was synthesized; antimicrobial activity and cytotoxicity against three malignant cell lines were determined, and the brine shrimp toxicity test was performed. The new compound did not prove to be a good antimicrobial agent, it showed moderate cytotoxicity to the tested cell lines, and proved to be five times less toxic than cisplatin to Artemia salina, which correlates well with the cytotoxicity to HeLa cell line.

In this work, Pt(II) complexes of previously synthesized steroidal thiosemicarbazones were synthesized and characterized. The ligands and their metal complexes were studied by analytical and spectroscopic data (elemental analysis, IR, 1D NMR and 2D NMR, HSQC, HMBC, NOESY, COSY), the analysis of which enabled complete 1H and 13C assignments of each compound including E and Z isomers. All the synthesized ligands and complexes were screened for their cytotoxic and antimicrobial activity. The results demonstrate that new steroidal thiosemicarbazone complexes were significantly less cytotoxic than corresponding steroidal thiosemicarbazones. Also, complexes show lower antimicrobial activity than the standard drugs, similar to the activity of the starting thiosemicarbazones., Почевши од претходно синтетисаних стероидних тиосемикарбазона, у овом раду су синтетисани и окарактерисани комплекси платине(II). Лиганди и њихови метални комплекси проучавани су аналитичким и спектроскопским методама (елементална анализа, ИЦ, 1D NMR и 2D NMR, HSQC, HMBC, NOESY, COSY). Анализом добијених података омогућена је потпуна 1H и 13C асигнација свих једињења укључујући Е и Z изомере. За синтетисане лиганде, као и њихове комплексе испитивана је цитотоксична и антимикробна активност. Резултати указују на то да нови стероидни тиосемикарбазонски комплекси испољавају значајно нижу цитотоксичност од одговарајућих стероидних тиосемикарбазона. Поред тога, комплекси поседују антимикробну активност сличну активности полазних тиосемикарбазона, a нижу од стандардних лекова

Eleven new steroidal mono- and bis(semicarbazones)2a–e, 4d and 3a–e have been prepared starting from various 3-oxo-α,β-unsaturated steroids. Mono-semicarbazones 2a–e were further subjected to ethyl chloroacetate in boiling absolute ethanol but, instead of expected intramolecular cyclocondensation reaction products, the new carbazate esters 5a-e were obtained. The structures of all synthesized compounds and identification of each E/Z isomer were deduced by elemental analysis, HRMS, NMR, and IR spectroscopy. Preliminary screening for the cytotoxic activity in vitro of the new compounds has been conducted against three cancer cell lines, K562, Jurkat and HeLa cells. HeLa cells were the most sensitive while K562 cells were the least sensitive to the cytotoxic action of the novel steroid derivatives. Compounds 2e, 3c and 5e were found to have the best but still moderate cytotoxic effects. All tested compounds showed very weak antimicrobial activities. These results demonstrate that the replacement of thioxo group with carbonyl group in steroidal hydrazone derivatives resulted in decrease in their biological activity.

U potrazi za biološki aktivnim jedinjenjima, počev od progesterona i 3-okso-α,β-nezasićenih androstenskih steroida, u okviru ove disertacije sintetisano je i potpunookarakterisano pedeset novih derivata steroidnih hidrazona, od kojih po jedanaesttiosemikarbazona, tijadiazolina i semikarbazona, dvanaest tiazolidin-4-ona i petkarbazatnih estara.Po prvi put je urađena detaljna analiza stereohemije steroidnih hidrazona u položajimaC-3/17 androstenskih, odnosno C-3/20 progesteronskih derivata. Struktura istereohemija potvrđene su rezultatima rendgenske strukturne analize za tijadiazolin 7a,prvo okarakterisano steroidno jedinjenje koje sadrži šestočlani ugljenični prstenkondenzovan sa spiro-tijadiazolinskim prstenom, i tiazolidinon 9b-E, prvi steroidniderivat sa poznatom konfiguracijom dvostruke veze u položaju C-3 hidrazonotiazolidin-4-onskog fragmenta.Sintetisana jedinjenja su ispoljila najjaču citotoksičnost prema HeLa ćelijamaadenokarcinoma cerviksa i prema K562 ćelijama hronične mijeloidne leukemije, a posvojoj aktivnosti istakli su se tiosemikarbazoni 2a, 2b, 2c i 2f, tijadiazolini 8a i 8e itiazolidin-4-oni 9a i 10a. Pritom su koeficijenti selektivnosti u antikancerskom dejstvuprema malignim ćelijama u odnosu na normalne humane PBMC, kako na nestimulisanetako i na mitogenom stimulisane, bili daleko veći od vrednosti 2,5 što ova jedinjenjasvrstava u potencijalne kandidate za in vivo ispitivanja. Sumporni derivati bili su dalekoaktivniji od kiseoničnih. Najaktivniji derivati indukovali su apoptozu posredstvomkaspaza-3, -8 i -9 i inhibirali angiogezu in vitro zbog čega se smatra da posedujuznačajan antikancerski potencijal., Searching for biologically active compounds, within this doctoraldissertation fifty new steroidal hydrazone derivatives, of which 11 thiosemicarbazones,11 thiadiazolines, 12 thiazolidin-4-ones, 11 semicarbazones and 5 carbazate esters, weresynthesized starting with progesterone and 3-oxo-α,β-unsaturated androstene steroids,and fully characterized.For the first time, detailed stereochemistry analyses of steroidal hydrazones in the C-3/17 positions of androstene derivatives, or C-3/20 positions of progesterone derivativeswas done. Structure and stereochemistry were confirmed by the results of X-rayanalyses for thiadiazoline 7a, the first characterized steroid compound that contains sixmemberedcarbon ring condensed with the spiro-thiadiazoline ring, and thiazolidinone9b-E, the first steroidal derivative with known configuration of double bond in C-3position of the hydrazono-thiazolidin-4-one fragment.Synthesised compounds manifested the best cytotoxicity towards HeLa cervixadenocarcinoma cells, and K562 cells of chronic myeloide leukemia, the best activitybeing showed by thiosemicarbazones 2a, 2b, 2c and 2f, thiadiazolines 8a and 8e, andthiazolidin-4-ones 9a and 10a. All of these compounds exhibited considerably higherintensities of cytotoxic action against malignant cells when compared with normalhuman PBMC, both resting and mitogen-stimulated, with coefficient of selectivityhigher than 2.5, which makes these compounds potential candidates for in vivoexperiments. Sulfur derivatives were much more active than oxygen derivatives. Themost active derivatives induced apoptosis mediated by caspase-3, -8 and -9, and theyinhibited angiogenesis in vitro, because of what they are considered to have significantanticancer potential.

The synthesis and cytotoxic activities determination of new steroidal mono- and bis(thiazolidin-4-ones) 4a-f and 5a-f have been performed. Their anticancer action was also evaluated in comparison to previously synthesized and reported corresponding steroidal thiosemicarbazones. All compounds were obtained as stereoisomeric mixtures with different configuration (E or Z) in the hydrazone moiety at the C-3 position. After several consecutive crystallizations diastereomerically pure major (5)-isomers of mono-thiazolidin-4-ones were isolated. The structure and stereochemistry of 2,4-thiazolidinedione,2-[(17-oxoandrost-4-en-3-ylidene)hydrazone] were confirmed by X-ray analysis. A pathway for the formation of thiazolidin-4-one ring was proposed. The steroid thiazolidinone derivatives examined in this study exerted selective concentration-dependent cytotoxic activities on six tested malignant cell lines. Ten out of twelve examined compounds exhibited strong cytotoxic effects on K562 cells (IC50 values from 8.5 mu M to 14.9 mu M), eight on HeLa cells (IC50 values ranging from 8.9 mu M to 15.1 mu M) while against MDA-MB-361 cells six compouds exerted similar or even higher cytotoxic action (IC50 values from 12.7 mu M to 25.6 mu M) than cisplatin (21.5 mu M) which served as a positive control. Eight of these ten compounds showed high selectivity in the cytotoxic action against HeLa and K562 cancer cell lines when compared with normal human fibroblasts MRC-5 and normal human PBMC. The study of mechanisms of the anticancer activity of the two selected compounds, mono- and bis(thiazolidin-4-one) derivatives of 19-norandrost-4-ene-3,17-dione 4a and 5a, revealed that both of these compounds induced apoptosis in HeLa cells through extrinsic and intrinsic signalling pathways. Treatment of EA.hy926 cells with sub-toxic concentrations of these compounds led to the inhibition of cell connecting and sprouting, and tube formation. The synthesized compounds exhibited poor antioxidant activ

The synthesis and cytotoxic activities determination of new steroidal mono- and bis(thiazolidin-4-ones) 4a-f and 5a-f have been performed. Their anticancer action was also evaluated in comparison to previously synthesized and reported corresponding steroidal thiosemicarbazones. All compounds were obtained as stereoisomeric mixtures with different configuration (E or Z) in the hydrazone moiety at the C-3 position. After several consecutive crystallizations diastereomerically pure major (5)-isomers of mono-thiazolidin-4-ones were isolated. The structure and stereochemistry of 2,4-thiazolidinedione,2-[(17-oxoandrost-4-en-3-ylidene)hydrazone] were confirmed by X-ray analysis. A pathway for the formation of thiazolidin-4-one ring was proposed. The steroid thiazolidinone derivatives examined in this study exerted selective concentration-dependent cytotoxic activities on six tested malignant cell lines. Ten out of twelve examined compounds exhibited strong cytotoxic effects on K562 cells (IC50 values from 8.5 mu M to 14.9 mu M), eight on HeLa cells (IC50 values ranging from 8.9 mu M to 15.1 mu M) while against MDA-MB-361 cells six compouds exerted similar or even higher cytotoxic action (IC50 values from 12.7 mu M to 25.6 mu M) than cisplatin (21.5 mu M) which served as a positive control. Eight of these ten compounds showed high selectivity in the cytotoxic action against HeLa and K562 cancer cell lines when compared with normal human fibroblasts MRC-5 and normal human PBMC. The study of mechanisms of the anticancer activity of the two selected compounds, mono- and bis(thiazolidin-4-one) derivatives of 19-norandrost-4-ene-3,17-dione 4a and 5a, revealed that both of these compounds induced apoptosis in HeLa cells through extrinsic and intrinsic signalling pathways. Treatment of EA.hy926 cells with sub-toxic concentrations of these compounds led to the inhibition of cell connecting and sprouting, and tube formation. The synthesized compounds exhibited poor antioxidant activ

A series of new steroidal mono- and bis(thiosemicarbazones) (2a-e and 3a-e) and corresponding mono- and bis(1,3,4-thiadiazolines) (4a-e and 5a-e) was synthesized, characterized and evaluated for their anticancer activity. Detailed NMR analysis of the mono-and bis(thiosemicarbazones) revealed the presence of two stereoisomers (Z and E) with different configurations in the hydrazone moiety at the C-3 position, where the substituents on the C(3)]=N double bond in the main isomers adopted the E configuration. The configurations at C-3 and C-17 in thiadiazolines 4a-e and 5a-e were deduced by detailed NMR analysis as well as by the examination of Dreiding molecular models and X-ray analysis of 3-thiadiazoline 4a, which confirmed the structure and absolute configuration at C-3. The synthesized compounds were tested against six cancer cell lines (HeLa, K562, MDA-MB-361, MDA-MB-453, LS174 and A549), the normal human cell line MRC-5 and peripheral blood mononuclear cells (PBMC) isolated from healthy donors. The best activity was exhibited by 3-thiosemicarbazones 2a, 2b, 2c and 2e and 3,17-bis(thiadiazolines) 5a and 5d. Examination of the mechanisms of cytotoxicity on cervical adenocarcinoma HeLa cells revealed the pro-apoptotic action of these compounds, which triggered both extrinsic and intrinsic apoptotic pathways. These compounds also showed the ability to decrease angiogenesis in vitro. In addition, 3,17-bis(thiadiazolines) 5a and 5d showed high selectivity in anticancer activity against all the examined malignant cell lines. Compound 5a displayed prominent anticancer potential. The tested compounds showed poor antimicrobial activity.

A series of new steroidal mono- and bis(thiosemicarbazones) (2a-e and 3a-e) and corresponding mono- and bis(1,3,4-thiadiazolines) (4a-e and 5a-e) was synthesized, characterized and evaluated for their anticancer activity. Detailed NMR analysis of the mono-and bis(thiosemicarbazones) revealed the presence of two stereoisomers (Z and E) with different configurations in the hydrazone moiety at the C-3 position, where the substituents on the C(3)]=N double bond in the main isomers adopted the E configuration. The configurations at C-3 and C-17 in thiadiazolines 4a-e and 5a-e were deduced by detailed NMR analysis as well as by the examination of Dreiding molecular models and X-ray analysis of 3-thiadiazoline 4a, which confirmed the structure and absolute configuration at C-3. The synthesized compounds were tested against six cancer cell lines (HeLa, K562, MDA-MB-361, MDA-MB-453, LS174 and A549), the normal human cell line MRC-5 and peripheral blood mononuclear cells (PBMC) isolated from healthy donors. The best activity was exhibited by 3-thiosemicarbazones 2a, 2b, 2c and 2e and 3,17-bis(thiadiazolines) 5a and 5d. Examination of the mechanisms of cytotoxicity on cervical adenocarcinoma HeLa cells revealed the pro-apoptotic action of these compounds, which triggered both extrinsic and intrinsic apoptotic pathways. These compounds also showed the ability to decrease angiogenesis in vitro. In addition, 3,17-bis(thiadiazolines) 5a and 5d showed high selectivity in anticancer activity against all the examined malignant cell lines. Compound 5a displayed prominent anticancer potential. The tested compounds showed poor antimicrobial activity.

Square-planar isocyanate and chloride Ni(II) complexes with tridentate PNO condensation product of 2-(diphenylphosphino)benzaldehyde and Girard's T reagent have been synthesized and their crystal structures were determined. These Ni(II) complexes with different monodentate ligands, chloride, cyanate, and thiocyanate were tested for their antimicrobial activities against pathogenic microorganisms. The ligand and Ni(II) complexes were active not only against laboratory control strains of bacteria and yeast, but also on clinical isolates of Escherichia coli and Pseudomonas aeruginosa strains resistant to most of the clinically used antibiotics.

Square-planar isocyanate and chloride Ni(II) complexes with tridentate PNO condensation product of 2-(diphenylphosphino)benzaldehyde and Girard's T reagent have been synthesized and their crystal structures were determined. These Ni(II) complexes with different monodentate ligands, chloride, cyanate, and thiocyanate were tested for their antimicrobial activities against pathogenic microorganisms. The ligand and Ni(II) complexes were active not only against laboratory control strains of bacteria and yeast, but also on clinical isolates of Escherichia coli and Pseudomonas aeruginosa strains resistant to most of the clinically used antibiotics.

The in vitro cytotoxic activity of previously synthesized steroid dimers with different spacer group (sulfide, trithiolane ring or phosphorotrithioate) and the substituent at C-17 position was tested for their possible effects against following human tumor cell lines: cervical adenocarcinoma (HeLa), chronic myelogenous leukemia (K562) and two human breast cancer cell lines (MDA-MB-361 and MDA-MB-453). These compounds, applied at micromolar concentrations, exhibited cytotoxic activity of different intensity (compared with cisplatin as a control), modality and selectivity in these malignant cell lines. The best activity against all four cell cancer lines was exhibited by dimer-sulfides. All screened compounds exerted concentration-dependent cytotoxic activity against leukemia K562 cells. The compounds which exerted the most pronounced cytotoxic action exhibited notably higher cytotoxic activities against K562, HeLa and MDA-MB-453 cells in comparison to resting and PHA-stimulated PBMC, pointing to a significant selectivity in their antitumor actions. Examination of the mechanisms of cytotoxicity on leukemia K562 cells revealed pro-apoptotic action of each of the investigated compounds applied at concentrations 2IC(50). The most prominent pro-apoptotic action was exhibited by dimer-sulfide of cholest-4-en-3-one. Furthermore, almost all of the tested compounds at IC50 concentrations induced G1 phase cell cycle arrest in K562 cells. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, and toxicity to brine shrimp Artemia sauna, were evaluated. There was no antibacterial activity. The best antifungal activity was exhibited against Saccharomyces cerevisiae by dimers linked with trithiolane ring, indicating a selective activity of investigated compounds. (C) 2014 Elsevier Ltd. All rights reserved.

Complexes of Pd(II) and Fe(III) with the condensation derivative of 2-(diphenylphosphino)benzaldehyde and ethyl carbazate were synthesized, characterized, and their antimicrobial activity was evaluated. The structures of the Pd(II) and Fe(III) complexes in solid state were determined by IR, elemental analysis and X-ray analysis. The structure of Pd(II) complex in solution was determined by NMR spectroscopy. Results of magnetic measurements for Fe(III) complex were reported. In both complexes the ligand is coordinated as tridentate via the phosphorus, the imine nitrogen and the carbonyl oxygen atoms. Results of antimicrobial activity investigation indicate that the activity of the ligand is enhanced upon complexation, and that the MIC values of the iron complex to some bacterial strains are not much higher than those of cefotaxime.

The in vitro cytotoxic activity of previously synthesized steroid dimers with different spacer group (sulfide, trithiolane ring or phosphorotrithioate) and the substituent at C-17 position was tested for their possible effects against following human tumor cell lines: cervical adenocarcinoma (HeLa), chronic myelogenous leukemia (K562) and two human breast cancer cell lines (MDA-MB-361 and MDA-MB-453). These compounds, applied at micromolar concentrations, exhibited cytotoxic activity of different intensity (compared with cisplatin as a control), modality and selectivity in these malignant cell lines. The best activity against all four cell cancer lines was exhibited by dimer-sulfides. All screened compounds exerted concentration-dependent cytotoxic activity against leukemia K562 cells. The compounds which exerted the most pronounced cytotoxic action exhibited notably higher cytotoxic activities against K562, HeLa and MDA-MB-453 cells in comparison to resting and PHA-stimulated PBMC, pointing to a significant selectivity in their antitumor actions. Examination of the mechanisms of cytotoxicity on leukemia K562 cells revealed pro-apoptotic action of each of the investigated compounds applied at concentrations 2IC(50). The most prominent pro-apoptotic action was exhibited by dimer-sulfide of cholest-4-en-3-one. Furthermore, almost all of the tested compounds at IC50 concentrations induced G1 phase cell cycle arrest in K562 cells. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, and toxicity to brine shrimp Artemia sauna, were evaluated. There was no antibacterial activity. The best antifungal activity was exhibited against Saccharomyces cerevisiae by dimers linked with trithiolane ring, indicating a selective activity of investigated compounds.

The reactions of 21-hydroxyprogesterone with Lawesson's reagent in toluene or gave four P-heterocyclic androst-4-ene derivatives (two tautomeric pairs): 4-(3-thioxoandrost-4-en-17-yl)-1,3,2-oxathiaphosphole-2- sulfide (2), 4-(3-thioxoandrost-4-en-17-ylidene)-1,3,2-oxathiaphospholane-2-sulfide (3), 4-(3-oxoandrost-4-en-17-yl)-1,3,2-oxathiaphosphole-2-sulfide (4), and 4-(3-oxoandrost-4-en-17-ylidene)-1,3,2- oxathiaphospholane-2-sulfide (5). The structures of all novel 17-substituted steroids were elucidated from their analytic and spectral data (HRMS, IR, 1D NMR and 2D NMR-HSQC, HMBC, NOESY, COSY). The detailed NMR analysis for all compounds revealed the presence of two pairs of signals in approx. 8:2 ratio indicating the existence of two diastereoisomers (a and b) with different configurations at the phosphorus atom. A parallel analysis of heteronuclear 2D - spectra (HSQC and HMBC) and homonuclear 2D spectra (NOESY and COSY) enabled complete and assignments of each isomer and provided evidence for the preferred configuration on phosphorus atom. Cytotoxic activity in vitro was tested against four tumor cell lines (human cervix carcinoma HeLa cells, chronic myelogenous leukemia K-562 and two human breast carcinoma MDA-MB-361 and MDA-MB-453 cells). Compounds 3a,b and 4a,b showed a poor activity against HeLa and MDA-MB-453 cell lines, while against MDA-MB-361 cell line, all tested compounds exerted very weak cytotoxic effect. All compounds exerted moderate activity against K562 cells. Antimicrobial activity against Gram-positive, Gram-negative bacteria and fungal cells, and toxicity to brine shrimp Artemia salina were evaluated. All tested compounds showed strong antifungal activity.

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.

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.

In this paper a synthetic pathway to the modified 5,10:13,14-bisfragmentation cholestane derivatives 8-14 is described. The synthesis involves introduction of the 5α- and 14α-hydroxyl groups in the cholestane molecule and subsequent cleavage of the C(5)-C(10) bond in 5α,14α-dihydroxycholestan-3β-yl acetate (4) with the HgO/I2 reagent and the C(13)-C(14) bond in the stereoisomeric 14α-hydroxy-5,10-secosteroids 5 and 6 with the Pb(OAc)4/I2 reagent. Complete and unambiguous 1H and 13C NMR resonance assignments of the obtained secosteroids, as well as the solution conformations of their 10- and 9-membered rings were determined by extensive analysis of 1D and 2D NMR spectral data. The structures and the solid-state conformations of 5,10-secosteroids 5-7 were confirmed by X-ray analysis. All diseco-compounds have a novel 5,10:13,14-disecocholestane skeleton.

The antiproliferative activity of previously synthesized (Z)-cholest-4-en-6-one oxime (1), (E)-cholest-4-en-6-one oxime (2), 7-aza-B-homocholest-4-en-6-one (3) and 6-aza-B-homocholest-4-en-7-one (4) and newly synthesized 6-thioxo-7-aza-B-homocholest-4-ene (5) and 6-aza-7-thioxo-B-homocholest-4-ene (6) was tested for their possible effects against two human tumor cell lines, cervical carcinoma (HeLa) and chronic myelogenous leukemia (K-562). Compounds 1-6, exerted a dose-dependent antiproliferative effect toward cell lines used in experimental design, showing high selectivity in their action for tumor cells in comparison to normal immunocompetent cells (non-stimulated PBMC and PHA-stimulated PBMC). Compounds 2, 3 and 4 exhibited a very high but selective antitumor activity, by inducing apoptosis in sensitive, for that purpose targeted tumor cell line (HeLa cells). Low toxic effect upon both non-stimulated, and PHA stimulated PBMCs from control, healthy volunteers, has been detected for compounds 1, 2, 3 and 4. The possible reasons for profound differences in the effects of this spectrum of steroidal compounds between tumor cell lines and normal stimulated and non-stimulated PBMCs are discussed. The molecular mechanisms for apoptotic events in HeLa cell line are suggested. The guidelines for further research are underlined.

We report herein the synthesis of a novel modified steroid with two rigidly positioned amino acids in C- and N-protected forms (Gly-OtBu and N-Fmoc-l-Phe) at the angular positions (C-18 methylamino group and C-19 carboxylic function) of the steroid nucleus via amide bonds, starting from 18-cyanopregnenolone acetate over 10 steps. In an attempt to gain more insight into the structural and conformational features of this novel 18-Phe,19-Gly-containing steroidal compound, we describe the detailed 2D NMR spectral analysis. Despite the large size and the conformational flexibility of the amino acid units in this molecule, conformational analysis by NOESY connectivities showed the existence of mainly one conformation (∼95%) in CDCl3 solution with approximately parallel orientation of the phenylalanine and glycine moieties.

The conformations of (Z)‐ and (E)‐5‐oxo‐B‐nor‐5,10‐secocholest‐1(10)‐en‐3β‐yl acetates (2 and 3, resp.) were examined by a combination of X‐ray crystallographic analysis and NMR spectroscopy, with emphasis on the geometry of the cyclononenone moiety. The 1H‐ and 13C‐NMR spectra showed that the unsaturated nine‐membered ring of (E)‐isomer 3 in C6D6 and (D6)acetone solution exists in a sole conformation of type B1, which is similar to its solid‐state conformation. The (Z)‐isomer 2 in C6D6, CDCl3, and (D6)acetone solution, however, exists in two conformational forms of different families, with different orientation of the carbonyl group, the predominant form (85%) corresponding to the conformation of type A1 and the minor (15%) to the conformation A2 present also in the crystalline state. In this solid‐state conformations of the nine‐membered ring of both compounds, the 19‐Me and 5‐oxo groups are ‘β’‐oriented. The NMR analysis suggests that the nine‐membered ring of 4 has a conformation of type C1 in CDCl3 solution.

Beckmann rearrangement of (Z)-cholest-4-en-6-one oxime (4) (prepared in 4 steps starting from cholest-5-en-3β-ol ο1)) with thionyl chloride in dioxane solution afforded an enamide-type lactam, i.e. 7-aza-B-homocholest-4-en-6-one (6) as a single product. Photoreaction of the same compound in methanol or benzene-acetic acid solution gave a mixture of products, with the formation of the parent ketone 3 and the occurrence of Z/E isomerization, while the lactam 6 was obtained only when the reaction was performed in methanol and then in very low yield (7%)., Bekmanovo premeštanje (Z)-holest-4-en-6-on oksima (4) (koji je dobijen u 4 faze, polazeći od holest-5-en-3 β-ola (1)) sa tionil-hloridom u dioksanskom rastvoru, kao jedini proizvod daje laktam enamidnog tipa, tj. 7-aza-B-homoholest-4-en-6-on (6). Fotoreakcijom istog jedinjenja u metanolu ili u rastvoru benzen-sirćetna kiselina, nastaje smesa proizvoda koju čine polazni keton 3 i proizvodi Z/E izomerizacije, dok je laktam 6 dobiven u vrlo niskom prinosu (7%) samo u metanolnom rastvoru.

5-hydroxy-1-oxo-5α-cholestan-3β-yl acetate (11) was prepared in 5 steps starting from (E)-3β-acetoxy-5,10-seco-1(10)-cholesten-5-one (6). Treatment of the 1-oxo-5-hydroxy derivative 11 with lead tetraacetate (LTA) (under thermal or hypoiodite conditions) or with mercuric oxide/iodine (HgO/I2) reagent resulted in the oxidative β-fragmentation of the C(5)–C(10) bond affording 1,5-dioxo-5,10-secocholest-10(19)-en-3β-yl acetate (12), in different yields, depending on the reagent. Also the stereochemistry of the 1β,6β-cyclization product 13, formed by transannular cyclization of the 1,5-diketone 12 on silica gel, is discussed in this work., Sintetizovan je 5-hidroksi-1-okso-5α-holestan-3β-il-acetata (11) u 5 faza polazeći od (E)- 3β-acetoksi-5,10-seko-1(10)-holesten-5-ona (6). Dejstvom olovo-tetraacetata (LTA) (pod termičkim ili hipojoditnim uslovima), ili merkuri-oksid/jodnog reagensa (HgO/I2) na 1-okso-5-hidroksi derivat 11, vrši se oksidativna β-fragmentacija njegove C(5)–C(10) veze, pri čemu se dobija 1,5-diokso-5,10-sekoholest-10(19)-en-3β-il-acetat (12), u različitim prinosima u zavisnosti od upotrebljenog reagensa. Takođe, diskutovana je stereohemija 1β,6β-ciklizacionog proizvoda 13, nastalog intramolekulskom ciklizacijom 1,5-diokso-5,10-seko jedinjenja 12 na silika gelu.