- Synthesis and evaluation of new 6-hydroximinosteroid analogs as cytotoxic agents
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Taking into account the structural requirements for cytotoxicity, several new hydroximinosteroid derivatives have been prepared and evaluated for their cytotoxic activity against A-549, H116, PSN1, and T98G cultured tumor cell lines in order to obtain further information on the potential pharmacophoric core of this type of compound. The influence of the oxygenated position in the A ring, the presence of an additional oxygenated position at C-7 and C-16, and a fluorinated position at C-5 were considered in order to study the structure-activity relationships. The results reveal the importance of oxygenated positions in the A ring (e.g., 4,5-epoxide showed an IC50 value against HCT-116 under micromolar level) for an increase in cytotoxic activity in this type of compound. Furthermore, they showed an important selectivity toward colon tumor line (HCT-116).
- Poza, Javier,Rega, Miriam,Paz, Vanessa,Alonso, Beatriz,Rodriguez, Jaime,Salvador, Nelida,Fernandez, Antonio,Jimenez, Carlos
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p. 4722 - 4740
(2008/03/13)
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- Synthesis of oxygenated cholesterols as structural mimics of phorbol ester-type tumor promoters
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We designed several oxygenated steroids in which functional groups including a hydrophobic group are arranged analogously to those of phorbol ester (12-O-tetradecanoylphorbol-13-acetate, TPA), with the aim of finding compounds with TPA-like activity, but having a different skeleton and a rigid conformation. The designed steroids, 1β,5α-dihydroxy-3β- hydroxymethylcholestan-6-one (4), 3β,5α-dihydroxycholestan-6-one (5), 3β- hydroxymethylcholestan-5α-ol-6-one (6) and 1β,3β,5α-trihydroxycholestan- 6-one (7), were synthesized. A related oxygenated steroid isolated from soft coral, cholestane-1β,3β,5α,6β-tetrol (8), was also synthesized. Among these analogs, compound 7 showed weak TPA-like activities in three biological tests: inhibition of [3H]TPA binding to protein kinase C and to cytosolic- nuclear tumor promoter-binding protein (CN-TPBP), and induction of differentiation of human promyelocytic leukemia cells (HL-60) to monocyte- like cells. On the other hand, compound 5 was found to be a specific ligand for CN-TPBP, but lacked the other TPA-like activities.
- Endo,Fukasawa,Hashimoto,Shudo
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p. 462 - 469
(2007/10/02)
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- Sterols in Marine Invertebrates. 49. Isolation and Structure Elucidation of Eight New Polyhydroxylated Sterols from the Soft Coral Sinularia dissecta
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A new group of polyhydroxylated sterols - all of them possessing an 11α-hydroxy substituents of potential utility as corticosteroid intermediates - has been isolated from the soft coral Sinularia dissecta.Their general structure was deduced from spectral data (500-MHz and 360-MHz 1H and 13C NMR and MS) and their stereochemistry was determined by correlating the respective spectral data (1H and 13C NMR) with those of synthetic sterols with similar structure and known configuration.
- Jagodzinska, Barbara M.,Trimmer, James S.,Fenical, William,Djerassi, Carl
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p. 1435 - 1439
(2007/10/02)
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- An Efficient Procedure for Preparing 1α,3β-Dihydroxy-Δ5-sterois by Reduction of 1α,2α-Epoxy-4,6-dien-3-ones with Lithium in Ammonia
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A number of 1α,3β-dihydroxy-Δ5-steroids of the cholestane, (20S)-20-methylpregnane (23,24-dinorcholane), pregnane and androstane series were synthesized from common steroidal precursors.A process originally reported by Barton et aI., based on 1,4,6-trien-3-ones as intermediates, was used for the introduction of the lα-hydroxyl function.The last step of this process, consisting of lithium/ammonia reduction of 1α,2α-epoxy-4,6-dien-3-ones, was found to be crucial and therefore subjected to particular study.A reproducible procedure permitting high-yield conversion was developed. lt consists of first reducing the epoxydienone with an approximately stoichiometric amount of lithium in ammonia to give, after protonation with ammonium chloride, a 1α-hydroxy-5-en-3-one.This intermediate is then further reduced by repeated alternating treatment with ammonium chloride and an equivalent amount of lithium.
- Fuerst, Andor,Labler, Ludvik,Meier, Werner
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p. 1870 - 1892
(2007/10/02)
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