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Antiproliferative activity of 27 phenyl-substituted 4-aryl-4-oxo-2-butenoic acids (aroylacrylic acids) toward Human cervix carcinoma (HeLa), Human chronic myelogenous leukemia (K562) and Human colon tumor (LS174) cell lines in vitro are reported. Compounds are active toward all examined cell lines. The most active compounds bear two or three branched alkyl or cycloalkyl substituents on phenyl moiety having potencies in low micromolar ranges. One of most potent derivatives arrests the cell cycle at S phase in HeLa cells. The 3D QSAR study, using molecular interaction fields (MIF) and derived alignment independent descriptors (GRIND-2), rationalize the structural characteristics correlated with potency of compounds. Covalent chemistry, most possibly involved in the mode of action of reported compounds, was quantitatively accounted using frontier molecular orbitals. Pharmacophoric pattern of most potent compounds are used as a template for virtual screening, to find similar ones in database of compounds screened against DTP-NCI 60 tumor cell lines. Potency of obtained hits is well predicted. © 2011 Elsevier Masson SAS. All rights reserved.

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.

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.

In the present paper, the preparation of 3β-hydroxy-17β-dimethyl- tert-butylsilyloxy-5-azaandrostane (15) in fourteen steps is described. B-nor-17-oxoandrost-5-en-3β-yl acetate (1) 1,2 was used as the starting material, which was transformed to the key intermediate of the synthesis, B-nor-17β-dimethyl-tert-butylsilyloxyandrost-4-en-3β-yl acetate (7).

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.

The acid-catalyzed reaction of (Z)- and (E)-B-nor-5,10-seco-ketones 2 and 3 resulted in an intramolecular cyclization to give the 5-hydroxy-A-nor-1β,5β-10(19)-methylidene derivative 8, the 5β-hydroxy-A-nor-1(10)-unsaturated compound 9 and the 5β,10β-dihydroxy A-nor-product 10, from the (Z)-isomer and the 5-hydroxy-A-nor-1β,5β-10(19)-methylidene product 11, from the (E)-isomer. Upon UV-irradiation, the (Z)- and (E)-seco-ketones 2 and 3 underwent a reversible (Z)/(E) and (E)/(Z)-isomerization and in addition to a transannular photocyclization to afford the 10(19)-methylidene derivatives 8 and 11, respectively, while photolysis of the 10(19)-methylidene-B-nor-5,10-seco-ketone 4 gave the oxetane derivative 12., Kiselo-katalizovana reakcija (Z)- i (E)-B-nor-5,10-seko-ketona 2 i 3 rezultuje u intramolekulskoj ciklizaciji dajući 5-hidroksi-A-nor-1β,5β-10(19)-metilidenski derivat 8, 5β-hidroksi A-nor-1(10)-nezasićeno jedinjenje 9 i 5β,10β-dihidroksi-A-nor-proizvod 10, iz Z-izomera, i 5-hidroksi-A-nor-1β,5β-10(19)-metilidenski proizvod 11, iz E-izomera. (Z)- i (E)-Seko- ketoni 2 i 3 UV-ozračivanjem podležu reverzibilnoj (Z)/(E) odnosno (E)/(Z) izomerizaciji, kao i transanularnoj fotociklizaciji dajući 10(19)-metilidenske derivate 8 odnosno 11, dok se fotolizom 10(19)-metilidenskog-5,10-seko-ketona 4 gradi oksetanski derivat 12.

Expoxidation of cholesta-5,8-dien-3β-yl acetate (1) with peracids takes place preferentially at the more highly substituted Δ8-olefinic double bond to give: (a) with monoperphthalic acid, 8α,9α-epoxycholest-5-en-3β-yl acetate (2) (in 39 % yield) and 9α-hydroxy-5α,6α-epoxycholest-8(14)-en-3β-yl acetate (3) (in 30 % yield); and (b) with m-chloroperbenzoic acid, the 8α,9α-epoxide 2 (64 %) and 5α,6α-epoxy derivative 3 (20 %). Some chemical transformations of the obtained epoxides are described., Epoksidacija holesta-5,8-dien-3β-il acetata (1) sa perkiselinama prvenstveno se odvija na više supstituisanoj Δ8-olefinskoj dvoguboj vezi pri čemu se dobija: (a) sa monoperftalnom kiselinom, 8α,9α-epoksiholest-5-en-3β-il acetat (2) (u prenosu od 39 %) i 9α-hidroksi-5α,6α-epoksiholest-8(14)-en-3β-il acetat (3) (u prenosu od 30 %); i (b) sa m-hlorperbenzoevom kiselinom, 8α,9α-epoksid 2 (u prenosu od 64 %) i 5α,6α-epoksi derivat 3 (u prenosu od 20 %). Opisane su i neke hemijske transformacije dobijenih epoksida.

The thermal and acid-catalyzed intramolecular rearrangement of the (Z)- and (E)-cyclodecene-1,4-dione compounds deriving from steroids, 2a,b and 3a,b, respectively, proceeds stereoselectively to give the corresponding configurationally different spiro-γ-lactone derivatives, the (5R,9R)-isomers 4a,b (from the (Z)-cyclodecenediones 2a,b) and the (5R,9S)-isomers 5a,b (from the (E)-cyclodecenediones 3a,b). The semiempirical MNDOAM1 and PM3 molecular orbital methods were applied to elucidate the possible mechanistic pathway of the observed intramolecular process leading to the spiro-γ-lactone structures.

5-Hydroxy-5α-cholest-8-en-3β-yl acetate (8) (prepared in 6 steps starting from 7-dehydrocholesteryl acetate (1) was transformed with ruthenium tetroxide to 5-hydroxy-8,9-dioxo-8,9-seco-5α-cholestan-3β-yl acetate (9). Treatment of the latter 8,9-seco-5-hydroxy derivative with lead tetraacetate (LTA) or mercuric oxide/iodine reagent (HgO/I2) resulted, instead of the expected oxidative β-fragmentation of its C(5)-C(10) bond, in the competing non-regio and non-stereoselective acetoxylation of the α-positions next to the 8- and 9-oxo functions (with LTA), and in the ≈ 82% recovery of the starting material (with HgO/I2). The results are discussed in terms of the strong hydrogen bonding which exists between the 5α-hydroxyl and the 8-oxo group.

In this paper is described a synthetic pathway to the modified 5, 10:8, 14-bisfragmentation cholestene derivatives 10, 11 and 12, which involves introduction of the Δ8(14)-double bond and 5α-hydroxyl group in the cholestane molecule and subsequent cleavage of the olefinic C(8)-C(14) bond (with ruthenium tetroxide) and C(5)-C(10) bond (with mercuric oxide/iodine or lead tetracetate/iodine).

Photochemically induced HgO/I2 oxidation of cholest-5-en-3α-ol (6) and cholest-5-en-3β-ol (7) afforded (Scheme 3) products arising from the corresponding alkoxy radicals (12, 13 and 14a,b) and from attack of the I2O intermediate at the olefinic double bond (epoxides 15a and 16a,b respectively). With cholest-5-ene-1α,3β-diol 3-acetate (8) and cholest-7-ene-3β,5α-diol 3-acetate (9) the HgO/I2 oxidation led to unresolvable complex mixtures (Scheme 5). With the same reagent cholest-5-en-3α-ol acetate (10) and cholest-5-en-3β-ol acetate (11) underwent exclusively attack by I2O, to give epoxides 20a,b, iodohydrin 21, and rearranged products 19 and 22 (Scheme 7), in the case of 10, and predominantly epoxides 23a,b (Scheme 8), in the case of 11. © 1994.

The molecular structure of the title compound, which might be a possible intermediate in the synthesis of 5,10:8,9‐diseco‐steroids (=steroklastanes), was determined by X‐ray analysis. Hydrogen bonding between the 5α‐hydroxyl group and the 9‐oxo function attached to the ten‐membered ring, and the presence of two conformational forms of the side‐chain in the solid state structure of 2 are established. Copyright © 1993 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim

UV irradiation of the steroidal isoxazolidines 2a, 2b, and 2c in various solvents in the presence of molecular oxygen, results in oxidative cleavage of the epoxyimino bridge to give several products; the N-unsubstituted isoxazolidine 2a afforded the nitro products 3, 4, and 5 and the azoxy compounds 6 and 7, while the N-methyl and N-acetyl derivatives 2b and 2c produced only the nitro compounds 3 and 5 as sole identifiable material. An explanation of the observed photooxygenation processes involving exciplex formation followed by proton transfer from isaxazolidine to molecular oxygen is presented. © 1991.

The oxidation of androst-4-ene-3β,9α,17β-triol 3,17-diacetate (2) with lead tetraacetate resulted mainly In β-fragmentation of the C(9)-C(10) bond to give a mixture of 10α- and 10β-acetoxy-Δ4-unsaturated 9,10-seco-steroidal ketones (3a and 3b) as the minor components (in ~7% yield) and the rearranged 4β-acetoxy-Δ5(10) -unsaturated 9,10-seco-9-ketone (4) as the major product (in 61% yield). Unexpectedly, when the same substrate (2) was subjected to the mercuric oxide - iodine oxidation, it underwent predominantly α-epoxidation of the olefinic double bond to produce the 4α,5α-epoxy derivative (5) (in 58% yield). © 1988.

The stereochemistries and conformations of the cyclopropane ring containing compounds derived from (E-3α- and (E)-3β-hydroxy-5,10-seco-1(10)-cholesten-5-one tosylates have been determined by X-ray methods and the results correlated with 13C nmr chemical shift data. © 1979.

The solvolysis of (Z)- and (E)-3β-acyloxy-5,10-seco-1(10)-cholesten-5β-ol p-nitrobenzoates 4 and 5 has been investigated and compared with the solvolytic reactivity of the epimeric (Z)- and (E)-5α-p-nitrobenzoates 1 and 2, as well as of the reference compound, i.e. the 1,10-saturated 5α-p-nitrobenzoate. Kinetic data and product analysis revealed that the relative spatial orientation of the 1(10)-olefinic double bond and the chiral center at C(5) in the 10-membered ring, which these secosteroidal 5-p-nitrobenzoates can adopt in the transition state, is the main factor which determines their solvolytic behaviour, so that the esters 1,2 and 5 solvolyse with transannular double bond participation, while such an interaction is not present in the case of the (Z)-5β-ester 4. © 1979.

Circular dichroism of the rearranged keto steroids 3 and 4, containing a condensed three and nine-membered ring system, shows that the conformation of the nine-membered ring is the same in solution as in the crystal; reduction of the kto group does not change this situation. CD also indicates that epimerization at C(5) in the pair 7 8 and the pair 11 12 leaves the cyclononanone ring conformation unchanged. © 1982.