1
|
Zhou S, Zheng Y, Yang B, Zhong J, Shi H. Study on synthesis of key squalamine intermediate 7α, 24R-dihydroxy-5α-cholestan-3-one. Steroids 2019; 151:108472. [PMID: 31400392 DOI: 10.1016/j.steroids.2019.108472] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 07/30/2019] [Accepted: 08/02/2019] [Indexed: 12/01/2022]
Abstract
A facile novel strategy has been developed to obtain a key intermediate of squalamine, 7α, 24R -dihydroxy-5α-cholestan-3-one, starting from methyl Δ5-3β-hydroxycholanate. The pure product was successfully synthesized and separated from the C-24 position epimers in good purity, d.e.% and yield.
Collapse
Affiliation(s)
- Shuai Zhou
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China
| | - Yang Zheng
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China
| | - Beibei Yang
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China
| | - Jiawei Zhong
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China
| | - Haijian Shi
- College of Chemical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, PR China.
| |
Collapse
|
2
|
Phutdhawong WS, Ruensamran W, Phutdhawong W. Synthesis and preliminary evaluation of dimeric-28-homobrassinosteroids for plant growth regulators. Steroids 2016; 116:38-44. [PMID: 27567032 DOI: 10.1016/j.steroids.2016.08.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/15/2016] [Accepted: 08/13/2016] [Indexed: 11/30/2022]
Abstract
Preparation of synthetic analogues of 28-homobrassinosteroids is reported. Also, the addition of the 28-homocastasterone at the C6 carbonyl group via allyl Gringard reagent followed by olefin cross metathesis resulted in dimeric analogues. Rice lamina inclination assay showed that the replacement of the C6 carbonyl group by 6α-allyl and 6β hydroxyl groups led to a decrease in bioactivity, whereas the dimeric analogues showed a reduced but significant bioactivity when compared to the 28-homocastasterone.
Collapse
Affiliation(s)
- Waya S Phutdhawong
- Department of Chemistry, Faculty of Science, Silpakorn University, Nakorn Pathom 73000, Thailand
| | - Wanwikar Ruensamran
- Bioproduct Science Program, Department of Science, Faculty of Liberal Arts and Science, Kasetsart University, Kampang Saen Campus, Nakhon Pathom 73140, Thailand
| | - Weerachai Phutdhawong
- Bioproduct Science Program, Department of Science, Faculty of Liberal Arts and Science, Kasetsart University, Kampang Saen Campus, Nakhon Pathom 73140, Thailand; Department of Chemistry, Faculty of Liberal Arts and Science, Kasetsart University Kampang Saen Campus, Nakhon Pathom 73140, Thailand.
| |
Collapse
|
3
|
Fujimoto Y, Maeda I, Ohyama K, Hikiba J, Kataoka H. Biosynthesis of 20-hydroxyecdysone in plants: 3β-hydroxy-5β-cholestan-6-one as an intermediate immediately after cholesterol in Ajuga hairy roots. Phytochemistry 2015; 111:59-64. [PMID: 25593010 DOI: 10.1016/j.phytochem.2014.12.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 10/24/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
3β-Hydroxy-5β-cholestan-6-one was identified in the EtOAc extract of Ajuga hairy roots by micro-analysis using LC-MS/MS in the multiple reaction mode (MRM). Furthermore, administration of (2,2,4,4,7,7-(2)H6)- and (2,2,4,4,6,7,7-(2)H7)-cholesterols to the hairy roots followed by LC-MS/MS analysis of the EtOAc extract of the hairy roots indicated that cholesterol was converted to the 5β-ketone with hydrogen migration from the C-6 to the C-5 position. These findings, in conjunction with the previous observation that the ketone was efficiently converted to 20-hydroxyecdysone, strongly suggest that the 5β-ketone is an intermediate immediately formed after cholesterol during 20-hydroxyecdysone biosynthesis in Ajuga sp. In addition, the mechanism of the 5β-ketone formation from cholesterol is discussed.
Collapse
Affiliation(s)
- Yoshinori Fujimoto
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
| | - Izumi Maeda
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - Kiyoshi Ohyama
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - Juri Hikiba
- Department of Integrated Bioscience, Graduate School of Frontier Science, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| | - Hiroshi Kataoka
- Department of Integrated Bioscience, Graduate School of Frontier Science, The University of Tokyo, Kashiwa, Chiba 277-8562, Japan
| |
Collapse
|
4
|
Joo SH, Jang MS, Kim MK, Lee JE, Kim SK. Biosynthetic relationship between C₂₈-brassinosteroids and C₂₉-brassinosteroids in rice (Oryza sativa) seedlings. Phytochemistry 2015; 111:84-90. [PMID: 25433632 DOI: 10.1016/j.phytochem.2014.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Revised: 10/24/2014] [Accepted: 10/28/2014] [Indexed: 05/18/2023]
Abstract
A crude enzyme solution was prepared from young rice seedlings, and the metabolism of C29-brassinosteroids identified from the seedlings was examined. When 28-homoteasterone was added as a substrate, 28-homotyphasterol, teasterone, and 26-nor-28-homoteasterone were characterized as enzyme products by GC-MS/SIM analysis. With 28-homotyphasterol, 28-homoteasterone, typhasterol, 28-homocastasterone, and 26-nor-28-homotyphasterol were formed and identified as products. When 28-homocastasterone was used, castasterone and 26-nor-28-homocastasterone were identified as products. Together with the reduced biological activity of C29-brassinosteroids and their metabolites in the rice lamina inclination assay, these metabolic studies suggest a biosynthetic sequence, 28-homoteasterone↔28-homotyphasterol→28-homocastasterone for C29-brassinosteroid biosynthesis is connected to the biosynthetic sequence teasterone↔typhasterol→castasterone for C28-brassinosteroids by C-28 demethylation, i.e., in order to increase biological activity in the rice plant. Additionally, the C29-brassinosteroids seem to bio-degrade their C-26 demethylated C28-brassinosteroid analogs to reduce brassinosteroid activity in planta. In conclusion, the biosynthesis of C29-brassinosteroids is a likely alternative route to the biologically-active brassinosteroid, castasterone, in rice.
Collapse
Affiliation(s)
- Se-Hwan Joo
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Mun-Seok Jang
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Min Kyun Kim
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Ji-Eun Lee
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea
| | - Seong-Ki Kim
- Department of Life Science, Chung-Ang University, Seoul 156-756, Republic of Korea.
| |
Collapse
|
5
|
Abstract
The condensing power of cholesterol and 5α-cholestane has been examined in liposomal membranes made from 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC). Quantitative nearest-neighbor recognition (NNR) analysis and fluorescence measurements using phase-sensitive probe Laurdan have demonstrated that 5α-cholestane exhibits a substantially weaker condensing effect. This fact, in and of itself, provides compelling evidence that cholesterol's condensing effect is critically dependent on having its steroid nucleus at the membrane surface.
Collapse
Affiliation(s)
- Martin R Krause
- Department of Chemistry, Lehigh University, Bethlehem, Pennsylvania 18015, USA
| | | | | |
Collapse
|
6
|
Miyoshi N, Iwasaki N, Tomono S, Higashi T, Ohshima H. Occurrence of cytotoxic 9-oxononanoyl secosterol aldehydes in human low-density lipoprotein. Free Radic Biol Med 2013; 60:73-9. [PMID: 23395781 DOI: 10.1016/j.freeradbiomed.2013.01.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 01/08/2013] [Accepted: 01/29/2013] [Indexed: 11/25/2022]
Abstract
The reaction products of three major cholesteryl esters, cholesteryl palmitate (C16:0-CE), cholesteryl oleate (C18:1-CE), and cholesteryl linoleate (C18:2-CE), present in human low-density lipoprotein (LDL) treated with ozone were isolated and characterized. In vitro ozonization of C16:0-CE was found to form the palmitoyl ester of secosterol-A (3β-hydroxy-5-oxo-5,6-secocholestan-6-al) and its aldolization product secosterol-B (3β-hydroxy-5β-hydroxy-B-norcholestane-6β-carboxaldehyde). On the other hand, when C18:1-CE and C18:2-CE were oxidized by ozone, the aldehyde 9-oxononanoyl cholesterol (9-ONC) was formed as a primary product, which was then further oxidized to form 9-oxononanoyl secosterol-A (9-ON-secoA) and 9-oxononanoyl secosterol-B (9-ON-secoB). The compounds 9-ON-secoA and -B, but not 9-ONC, were found to exhibit strong cytotoxicity against human leukemia HL-60 cells. An LC-ESI-MS/MS method was developed for the detection of these cholesteryl ester ozonolysis products by derivatizing them with dansyl hydrazine. Using this method, we found for the first time that low concentrations of 9-ON-secoA and -B, but not palmitoyl secosterols, were present in human LDL. These novel oxidized cholesterol esters, 9-ON-secoA and -B, probably play important roles in the pathogenesis of several inflammatory disorders such as cancer, diabetes, atherosclerosis, and neurodegenerative diseases.
Collapse
Affiliation(s)
- Noriyuki Miyoshi
- Laboratory of Biochemistry, Graduate School of Integrated Pharmaceutical and Nutritional Sciences, Graduate Program in Food and Nutritional Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
| | | | | | | | | |
Collapse
|
7
|
Abstract
In previous studies on the secondary metabolites of the Taiwanese octocoral Isis hippuris, specimens have always been collected at Green Island. In the course of our studies on bioactive compounds from marine organisms, the acetone-solubles of the Taiwanese octocoral I. hippuris collected at Orchid Island have led to the isolation of five new polyoxygenated steroids: hipposterone M–O (1–3), hipposterol G (4) and hippuristeroketal A (5). The structures of these compounds were determined on the basis of their spectroscopic and physical data. The anti-HCMV (human cytomegalovirus) activity of 1–5 and their cytotoxicity against selected cell lines were evaluated. Compound 2 exhibited inhibitory activity against HCMV, with an EC50 value of 6.0 μg/mL.
Collapse
Affiliation(s)
- Wei-Hua Chen
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan; E-Mail:
| | - Shang-Kwei Wang
- Department of Microbiology, Kaohsiung Medical University, Kaohsiung 807, Taiwan
- Authors to whom correspondence should be addressed; E-Mails: (C.-Y.D.); (S.-K.W.); Tel.: +886-7-525-2000 (ext. 5036) (C.-Y.D.); +886-7-312-1101 (ext. 2150) (S.-K.W.); Fax: +886-7-525-5020 (C.-Y.D.)
| | - Chang-Yih Duh
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan; E-Mail:
- Centers for Asia-Pacific Ocean Research and Translational Biopharmaceuticals, National Sun Yat-sen University, Kaohsiung 804, Taiwan
- Authors to whom correspondence should be addressed; E-Mails: (C.-Y.D.); (S.-K.W.); Tel.: +886-7-525-2000 (ext. 5036) (C.-Y.D.); +886-7-312-1101 (ext. 2150) (S.-K.W.); Fax: +886-7-525-5020 (C.-Y.D.)
| |
Collapse
|
8
|
Misharin AY, Mehtiev AR, Zhabinskii VN, Khripach VA, Timofeev VP, Tkachev YV. Toxicity of (22R,23R)-22,23-dihydroxystigmastane derivatives to cultured cancer cells. Steroids 2010; 75:287-94. [PMID: 20096295 DOI: 10.1016/j.steroids.2010.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 01/07/2010] [Accepted: 01/11/2010] [Indexed: 11/30/2022]
Abstract
Toxicity of eight 22,23-dihydroxystigmastane derivatives (four pairs of (22R,23R)- and (22S,23S)-isomers differing in steroid backbone structure) to human breast carcinoma MCF-7 cells was compared. For every pair of structurally related compounds, (22R,23R) isomer was found to be significantly more toxic than (22S,23S) isomer. Computational analysis showed that side chain of (22R,23R)-22,23-dihydroxystigmastane derivatives is rigid, whereas that of (22S,23S)-isomers is rather flexible. Structure of steroid backbone significantly affects cytotoxicity of (22R,23R)-22,23-dihydroxystigmastane derivatives to human breast carcinoma MCF-7 cells, human ovary carcinoma CaOv cells, and human prostate carcinoma LnCaP cells. (22R,23R)-3beta,22,23-trihydroxystigmast-5-ene and (22R,23R)-3beta,22,23-trihydroxystigmast-5-en-7-one, both comprising equatorial 3beta-hydroxyl group, exhibited the highest cytotoxicity, while the most polar 28-homobrassinolide and 28-homocastasterone, both comprising 2alpha,3alpha-dihydroxy groups, exhibited the lowest toxicity. Binding of (22R,23R)-22,23-dihydroxystigmastane derivatives to plasmatic membrane was suggested to be important for cytotoxicity.
Collapse
|
9
|
Sathishkumar K, Raghavamenon AC, Ganeshkumar K, Telaprolu R, Parinandi NL, Uppu RM. Simultaneous analysis of expression of multiple redox-sensitive and apoptotic genes in hypothalamic neurons exposed to cholesterol secoaldehyde. Methods Mol Biol 2010; 610:263-284. [PMID: 20013184 DOI: 10.1007/978-1-60327-029-8_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Oxidative stress and apoptotic cell death are two important processes that occur under several disease states and in conditions of toxicant insult. Traditionally, investigators have chosen a variety of analytical methods to detect and/or quantify oxidative stress and apoptosis. The approach has proven less satisfying, however, when applied to complex systems with many unknown influences. Such areas of study could benefit from the development and application of new and more powerful analytical tools. Microarray-based approach has been developed for analyzing various cellular phenomena at the level of gene expression. These gene arrays are hybridization chips that are capable of simultaneous analysis of the expression of thousands of genes. Often, this approach warrants examining a multitude of unrelated genes which can greatly impede the interpretation of results. The real-time RT-PCR-based methodology presented here allows simultaneous detection and analysis of as many as 84 well-characterized genes associated with either oxidative stress or apoptosis in hypothalamic neuronal cells exposed to cholesterol secoaldehyde, an "ozone-/singlet oxygen-specific" oxidation product of cholesterol that has been shown to be present at the inflammatory sites including the arterial plaque and the brain specimens of patients with Alzheimer's disease. This pathway-specific analysis of the expression of the well-defined chosen set of genes offers ways of convenient and reliable interpretation of results that often corroborate well with the results obtained from other standard biochemical analytical approaches.
Collapse
Affiliation(s)
- K Sathishkumar
- Department of Environmental Toxicology and the Health Research Center, Southern University and A&M College, Baton Rouge, LA, USA
| | | | | | | | | | | |
Collapse
|
10
|
Sysa AG, Kiselev PA, Zhabinskiĭ VN, Khripach VA. [Effect of the structure of the brassinosteroid side chain on monooxygenase activity of liver microsomes]. Prikl Biokhim Mikrobiol 2010; 46:29-34. [PMID: 20198913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Possible pathways by which brassinosteroids affect the monooxygenase enzymatic system of mammalian liver microsomes, which is involved in the transformation of a broad spectrum of xenobiotics, were studied. The role of the structure of the side chain of brassinosteroids in the regulation of monooxygenase activity was studied using two natural compounds (24-epibrassinolide and 28-homobrassinolide) and two synthetic analogues, (22S, 23S-dihydroxy) stereoisomers. The results of this study show that brassinosteroids can directly influence the functioning of the microsomal enzymatic system. It was found that the degree of this influence depends on the side chain structure. This suggests the possibility of targeted modification of natural compounds to ensure the desired physiological effects.
Collapse
|
11
|
Macías-Alonso M, Flores-Alamo M, Iglesias-Arteaga MA. Beckmann reactions of steroidal spirocyclic oximes derived from the 16beta,23:23,26-diepoxy-22-oxo moiety. Steroids 2009; 74:112-20. [PMID: 18996137 DOI: 10.1016/j.steroids.2008.09.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 09/20/2008] [Accepted: 09/26/2008] [Indexed: 10/21/2022]
Abstract
The Beckmann rearrangement of the syn and anti isomers of the spirocyclic oxime derived from a 16beta,23:23,26-diepoxy-5beta-cholestan-22-one was studied. Whereas the anti isomer always follows the Beckmann fragmentation course, the syn isomer, depending on the reaction conditions, follows the normal Beckmann rearrangement course and/or the isomerization to the anti isomer followed by the fragmentation course.
Collapse
Affiliation(s)
- Mariana Macías-Alonso
- Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 México D.F., Mexico
| | | | | |
Collapse
|
12
|
Abstract
The reaction of 3beta-chloro-5alpha-cholestan-6-one semicarbazone 1 with hydrogen peroxide at 0 degrees C gives 3beta-chloro-5alpha-cholestan-6-spiro-1',2',4'-triazolidine-3'-one 2 as a product. The structural assignment of the product was confirmed on the basis of its elemental, analytical and spectral data. The ab initio calculations were performed by using density functional theory (DFT) at B3LYP/6-31G* basis set in order to describe a free radical reaction mechanism. The reaction proceeds through two radical intermediates formation. The mechanism of the reaction was explained by using frontier molecular orbital (FMO), spin electronic density map, encoded electrostatic potential map and atomic charges. It was found that the localization of frontier orbitals and the flow of atomic charges of all the calculated structures support the present reaction mechanism. The molecular properties like total energy, dipole moment and hardness of each optimized structure, were also explained. Stability of all the optimized structures in this study was supported by their respective fundamental frequencies and energy minima.
Collapse
Affiliation(s)
- Kamlesh Sharma
- Department of Chemistry, University of Pretoria, Pretoria 0002, South Africa.
| | | |
Collapse
|
13
|
Sugandhi EW, Slebodnick C, Falkinham JO, Gandour RD. Synthesis and antimicrobial evaluation of water-soluble, dendritic derivatives of epimeric 5alpha-cholestan-3-amines and 5alpha-cholestan-3-yl aminoethanoates. Steroids 2007; 72:615-26. [PMID: 17532019 DOI: 10.1016/j.steroids.2007.04.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 04/02/2007] [Accepted: 04/05/2007] [Indexed: 11/20/2022]
Abstract
To examine the effect of negatively charged steroidal amphiphiles on antimicrobial activity, two pairs of epimeric, dendritic tricarboxylato amphiphiles--4-(2-carboxyethyl)-4-[3-(5alpha-cholestan-3-yl)ureido]heptanedioic acid (1) and 4-(2-carboxyethyl)-4-[3-(5alpha-cholestan-3-yloxycarbonylmethyl)ureido]heptanedioic acid (2)--were synthesized. A broad antimicrobial screen of 11 microbes revealed that these amphiphiles only showed good activity against a methicillin-resistant isolate of Staphylococcus aureus (MRSA) and modest activity against an unrelated strain of S. aureus. The best activity, a minimal inhibitory concentration (MIC) of 27 microM, was found for the 3beta epimer of 1 against MRSA.
Collapse
Affiliation(s)
- Eko W Sugandhi
- Department of Chemistry MC 0212, Virginia Tech, Blacksburg, VA 24061, United States
| | | | | | | |
Collapse
|
14
|
Denancé M, Guyot M, Samadi M. Short synthesis of 16beta-hydroxy-5alpha-cholestane-3,6-dione a novel cytotoxic marine oxysterol. Steroids 2006; 71:599-602. [PMID: 16620894 DOI: 10.1016/j.steroids.2006.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2006] [Revised: 03/02/2006] [Accepted: 03/07/2006] [Indexed: 11/17/2022]
Abstract
The first and short synthesis of 16beta-hydroxy-5alpha-cholestane-3,6-dione 1 a metabolite from marine algae, has been achieved in six steps from readily available diosgenin 5. Selective deoxygenation of primary alcohol of triol 6 has been accomplished in one step using Et(3)SiH and catalytic amount of B(C(6)F(5))(3) to produce compound 9 in high yield. Oxidation of 11 with PCC, allowed the introduction of 3,6-ene-dione functionality, and further catalytic hydrogenation and deprotection furnished the 3,6-diketo steroid 1.
Collapse
Affiliation(s)
- Mickaël Denancé
- Département de Chimie, LIMBP, IPEM, Université Paul Verlaine de Metz, 1 Bd Arago, Metz Technopôle, 57078 Metz, France
| | | | | |
Collapse
|
15
|
Wachtel E, Bach D, Epand RF, Tishbee A, Epand RM. A product of ozonolysis of cholesterol alters the biophysical properties of phosphatidylethanolamine membranes. Biochemistry 2006; 45:1345-51. [PMID: 16430232 DOI: 10.1021/bi0516778] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is evidence that some products of the reaction of ozone with cholesterol contribute to atherosclerosis. One of these compounds is 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al. We have synthesized this compound and have demonstrated that it reacts with phosphatidylethanolamine to form a Schiff base. The 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al also affects the physical properties of phosphatidylethanolamines. We show by both DSC and X-ray diffraction that it increases the negative curvature of the membrane. In addition, 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al causes the lamellar phase to become disorganized, resulting in the loss of lamellar periodicity. The chemical and physical interactions of 3beta-hydroxy-5-oxo-5,6-secocholestan-6-al with phosphatidylethanolamines may contribute to damaging effects of this lipid on cell membranes, resulting in pathology.
Collapse
Affiliation(s)
- Ellen Wachtel
- Chemical Research Infrastructure Unit, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | | |
Collapse
|
16
|
Talarico LB, Castilla V, Ramirez JA, Galagovsky LR, Wachsman MB. Synergistic in vitro interactions between (22S,23S)-3beta-bromo-5alpha,22,23-trihydroxystigmastan-6-one and acyclovir or foscarnet against herpes simplex virus type 1. Chemotherapy 2005; 52:38-42. [PMID: 16340198 DOI: 10.1159/000090242] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Accepted: 06/20/2005] [Indexed: 11/19/2022]
Abstract
The replication of herpes simplex virus (HSV) type 1 in Vero cells is inhibited in the presence of (22S,23S)-3beta-bromo-5alpha,22,23-trihydroxystigmastan-6-one (6b), a synthetic brassinosteroid derivative. Since a late step of virus multiplication is hindered by 6b, we performed studies of drug-drug combination with acyclovir (ACV) and foscarnet (FOS). It was determined that 6b would act synergistically with low concentrations of ACV and moderate concentrations of FOS against HSV. The best drug combination tested in this study resulted in an increase of 29.3 and 47.2% in antiviral activity for ACV (0.036 microM) and FOS (37.5 microM) in the presence of 14.8 and 6.9 microM of 6b, respectively.
Collapse
Affiliation(s)
- Laura B Talarico
- Laboratorio de Virología, Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | | | | | | | | |
Collapse
|
17
|
Wo LQ, Luo GM, Wang BX, Zhu WF. [Studies on triterpenes chemical constituents in rhizome of Alisma gramineum]. Zhongguo Zhong Yao Za Zhi 2005; 30:1263-5. [PMID: 16245905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
OBJECTIVE To investigate the triterpenoids chemical constituents in rhizome of Alisma gramineum. METHOD Silicon gel chromatography and HPLC techniques were employed for isolation and purification of the constituents, and the structures were elucidated by various spectral analyses such as NMR, MS and IR. RESULT 5 protostane-type tetracyclic triterpenoids were isolated and identified as 16,23-oxidoalisol B(1), 11-deoxyalisol C(2), alisol F(3), 16beta-methoxyalisol B acetate (4), 16beta-hydroxyalisol B acetate (5). CONCLUSION All of these compounds were found from A. gramineum for the first time.
Collapse
Affiliation(s)
- Lian-qun Wo
- Zhejiang pharmaceatical College, Ningbo 315100, China
| | | | | | | |
Collapse
|
18
|
Khripach VA, Zhabinskii VN, Konstantinova OV, Khripach NB, Antonchick AV, Antonchick AP, Schneider B. Preparation of (25R)- and (25S)-26-functionalized steroids as tools for biosynthetic studies of cholic acids. Steroids 2005; 70:551-62. [PMID: 15894040 DOI: 10.1016/j.steroids.2005.02.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2004] [Revised: 01/31/2005] [Accepted: 02/09/2005] [Indexed: 10/25/2022]
Abstract
A new synthesis of both epimeric forms of 26-cholestanoic acids and 26-alcohols containing a 3beta-hydroxy-Delta(5)- or a Delta(4)-3-keto-functionality in ring A is described starting from stigmasterol or (20S)-3beta-acetoxy-pregn-5-en-20-carboxylic acid. The obtained compounds are useful as standards for studies of cholic acids. Construction of the side chain was achieved by linkage of steroidal 23-iodides to sulfones prepared from (2R)- and (2S)-3-hydroxy-2-methylpropanoates. Oxidation of intermediate 26-alcohols into the corresponding carboxylic acids ensuring preservation of stereochemistry at C-25 and functional groups in the cyclic part was achieved with sodium chlorite catalyzed by TEMPO and bleach.
Collapse
Affiliation(s)
- Vladimir A Khripach
- Laboratory of Chemistry of Steroids, Institute of Bioorganic Chemistry, National Academy of Sciences of Belarus, Kuprevich Str. 5/2, 220141 Minsk, Belarus.
| | | | | | | | | | | | | |
Collapse
|
19
|
Ramírez JA, Brosa C, Galagovsky LR. Synthesis and bioactivity of C-29 brassinosteroid analogues with different functional groups at C-6. Phytochemistry 2005; 66:581-7. [PMID: 15721951 DOI: 10.1016/j.phytochem.2004.12.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2004] [Revised: 11/23/2004] [Indexed: 05/08/2023]
Abstract
In this paper, we report the synthesis and bioactivity of four synthetic analogues of 28-homobrassinosteroids, in order to evaluate the influence in bioactivity when the C-6 keto group is replaced by different functional groups. The synthetic analogues are 6-deoxo-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,22,23-tetraol], 6alpha-hydroxy-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,6alpha,22,23-pentaol], 6beta-hydroxy-28-homocastasterone [(22R,23R)-stigmasta-2alpha,3alpha,6beta,22,23-pentaol], and [(22R,23R)-6alpha-fluorostigmasta-2alpha,3alpha,22,23-tetraol]. Results indicate that replacement of the 6-keto moiety by an beta or alpha hydroxyl group led to a decrease in activity, whereas the 6-deoxo analogue showed a very low activity, confirming the importance of an electronegative moiety at C-6 to observe hormonal potency. The 6alpha-fluorinated analogue elicited a low activity, similar to that of the 6-deoxo analogue.
Collapse
Affiliation(s)
- Javier A Ramírez
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria (C1428EGA), Buenos Aires 1428, Argentina
| | | | | |
Collapse
|
20
|
Antonchick AP, Schneider B, Zhabinskii VN, Khripach VA. Synthesis of [26,27-2H6]brassinosteroids from 23,24-bisnorcholenic acid methyl ester. Steroids 2004; 69:617-28. [PMID: 15465106 DOI: 10.1016/j.steroids.2004.05.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2003] [Revised: 04/20/2004] [Accepted: 05/04/2004] [Indexed: 11/28/2022]
Abstract
A number of hexadeuterated brassinosteroids (BS) containing a hydroxy group at C-22 or a 22R,23R-diol function were prepared starting from 23,24-bisnorcholenic acid methyl ester for biosynthetic studies. Synthesis of the cyclic part was accomplished via the initial hydroboration-oxidation of Delta(5)-double bond. The key step in the synthesis of the side chain involved addition of (2S)-[3,4-(2)H(6)]2,3-dimethylbutylphenyl sulfone to the corresponding C-22 aldehydes.
Collapse
Affiliation(s)
- Andrey P Antonchick
- Max-Planck-Institute for Chemical Ecology, Beutenberg Campus Winzerlaer Str. 10, D-07745 Jena, Germany
| | | | | | | |
Collapse
|
21
|
Cyrański MK, Frelek J, Jastrzebska I, Morzycki JW. Rearrangement of 23-oxospirostanes to the 22-oxo-23-spiroketal isomers promoted by Lewis acids--X-ray crystal structure of (23R,25S)-3beta-acetoxy-16beta,23:23,26-diepoxy-5beta-cholestan-22-one. Steroids 2004; 69:395-400. [PMID: 15219789 DOI: 10.1016/j.steroids.2004.03.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2003] [Revised: 03/11/2004] [Accepted: 03/18/2004] [Indexed: 10/26/2022]
Abstract
Both 25R and 25S 23-oxospirostanes undergo rearrangement to the 22-oxo-23-spiroketal isomers promoted by Lewis acids. An X-ray crystal structure analysis of the rearranged product of 23-oxosarsasapogenin acetate confirmed the R configuration at the new spiro carbon atom.
Collapse
Affiliation(s)
- Michał K Cyrański
- Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02-093 Warsaw, Poland
| | | | | | | |
Collapse
|
22
|
Abstract
A novel steroid, 1alpha,3beta,5beta-trihydroxy-24-methylenecholestan-6-one (gibberoketosterol) (1), along with four known steroids, was isolated from the lipophilic extracts of a Taiwanese soft coral Sinularia gibberosa. The structure of the new metabolite was determined on the basis of extensive spectral analyses and chemical reaction. The relative stereochemistry of gibberoketosterol was established by the NOESY experiments and analysis of the pyridine-induced deshielding effect of the axial hydroxy groups. Gibberoketosterol is the first example of 1alpha,3beta,5beta-trihydroxy-6-oxosteroids isolated from natural sources and was found to exhibit a moderate cytotoxicity against the growth of Hepa59T/VGH cancer cells.
Collapse
Affiliation(s)
- Atallah F Ahmed
- Department of Marine Resources, National Sun Yat-Sen University, Kaohsiung 804, Taiwan, ROC
| | | | | | | |
Collapse
|
23
|
Szendi Z, Forgó P, Tasi G, Böcskei Z, Nyerges L, Sweet F. 1,5-Hydride shift in Wolff-Kishner reduction of (20R)-3beta,20, 26-trihydroxy-27-norcholest-5-en-22-one: synthetic, quantum chemical, and NMR studies. Steroids 2002; 67:31-8. [PMID: 11728519 DOI: 10.1016/s0039-128x(01)00130-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Heating (20R)-3beta,20,26-trihydroxy-27-norcholest-5-en-22-one (1) with hydrazine and KOH at 160 degrees C completely converted the steroid to a diastereoisomeric mixture of the new (20R,22RS)-27-norcholest-5-ene-3beta,20,22-triols (2). Exclusive formation of 2 suggests that the expected Wolff-Kishner reduction to a methylene group at the C-22 ketone in 1 was diverted to the C-26 position by a 1,5-hydride shift. All attempts under acid conditions failed to produce a C-22 phenyl hydrazone from 1. However, reaction of 1 was reacted with phenylhydrazine in hot KOH, gave the C-26 phenylhydrazone 4 as the sole product. Evidently, under alkaline conditions, first a hydride ion undergoes an intramolecular transfer from the C-26 CH(2)OH group to the C-22 ketone in 1, and then the phenylhydrazine traps the newly formed aldehyde. To examine this hypothesis, we constructed computer-simulated transition state models from quantum chemical calculations and then compared data from these models with NMR measurements of the reaction mixtures containing 2. The NMR data showed that the C-22 diastereoisomers of 2 are formed in a nearly 1:1 ratio exactly as predicted from the energy-optimized transition states, which were calculated for intramolecular 1,5-hydride shifts that produced each of the two C-22 diastereoisomers. Accordingly, these results support the hypothesis that an intramolecular 1,5-hydride shift mechanism promotes complete conversion of 1 to 2 under classical Wolff-Kishner reduction conditions.
Collapse
Affiliation(s)
- Zsuzsanna Szendi
- Department of Organic Chemistry, University of Szeged, H-6720 Szeged Dóm tér 8, Hungary.
| | | | | | | | | | | |
Collapse
|
24
|
Galagovsky LR, Gros EG, Ramírez JA. Synthesis and bioactivity of natural and C-3 fluorinated biosynthetic precursors of 28-homobrassinolide. Phytochemistry 2001; 58:973-980. [PMID: 11684198 DOI: 10.1016/s0031-9422(01)00379-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this paper we describe the synthesis of two new fluorinated brassinosteroids: (22R,23R)-22,23-dihydroxy-3alpha-fluorostigmastan-6-one and (22R,23R)-22,23-dihydroxy-3beta-fluorostigmastan-6-one. Their bioactivities were evaluated in the rice lamina inclination test and compared with that of 28-homocastasterone, 28-homotyphasterol and 28-homoteasterone, possible biosynthetic precursors of 28-homobrassinolide. Results confirmed expected similarities between the biosynthesis of 24-ethylbrassinosteroids (named as the 28-homo series) and that described for 24-methylbrassinosteroids, and also indicated that these precursors might exhibit per se activities.
Collapse
Affiliation(s)
- L R Galagovsky
- Departamento de Química Orgánica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Pabellón 2, Ciudad Universitaria, 1428, Buenos Aires, Argentina.
| | | | | |
Collapse
|
25
|
Abstract
A new cytotoxic oxysterol, 16beta-hydroxy-5alpha-cholestane-3,6-dione was isolated from the red alga Jania rubens. Its structure was established by spectroscopic method. The ID50 value was 0.5 microg/mL.
Collapse
Affiliation(s)
- L Ktari
- Laboratoire de Chimie des Substances Naturelles, associé au CNRS, Muséum National d'Histoire Naturelle, Paris, France
| | | | | |
Collapse
|
26
|
Abstract
3-Epi-6,7-dideoxyxestobergsterol A (2), an analogue of xestobergsterol A, has been synthesized from dehydroepiandrosterone (3) in 15 steps. The key synthetic intermediate, 15beta,16alpha-dioxypregn-17(20)E-ene derivative 8, was prepared from the corresponding 15beta,16beta-epoxide 6 by treating with acetic acid and titanium tetraisopropoxide. The 23-oxo side chain was constructed stereoselectively by orthoester Claisen rearrangement of 8 followed by introduction of an isobutyl group. Basic treatment of the 15,23-diketone 12 followed by deprotection gave the title compound 2.
Collapse
Affiliation(s)
- Y Kaji
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Meguro, Japan
| | | | | | | |
Collapse
|
27
|
Abstract
The gorgonian Leptogorgia sarmentosa contains three new steroids, (20S)-20-hydroxycholestane-3,16-dione (1), (16S, 20S)-16,20-dihydroxycholestan-3-one (2), and (20S)-20-hydroxycholest-1-ene-3,16-dione (3) together with a known related compound (4). Their structures were defined by spectroscopic analysis. The new steroids exhibited significant cytotoxicity against four tumor cell lines (ED50 = 1 microg/ml).
Collapse
Affiliation(s)
- L Garrido
- Departamento de Química Orgánica, Facultad de Ciencias del Mar, Universidad de Cádiz, Spain
| | | | | | | |
Collapse
|
28
|
Abstract
[formula: see text] A novel pentacyclic polyhydroxylated sterol, xestobergsterol A (1a), has been synthesized in 24 steps and in good overall yield from stigmasterol 17. The key steps of the synthesis are the Breslow remote functionalization of the polyoxygenated steroid derived from 25 and the base-catalyzed epimerization-aldol condensation of the dione derived from 27.
Collapse
Affiliation(s)
- M E Jung
- Department of Chemistry and Biochemistry, University of California, Los Angeles 90095-1569, USA.
| | | |
Collapse
|
29
|
Abstract
Two novel sesterterpenoids, 12 alpha-acetoxy-19 beta-hydroxyscalara-15,17- dien-20,19-olide (3) and 12 alpha,-16 beta-diacetoxyscalarolbutenolide (5), and a new 9,11-secosterol, 3 beta-hydroxy-5 alpha,6 alpha-epoxy-9-oxo-9,11-seco-5 alpha-cholest-7-en-11-al (6), were isolated from the marine sponge Spongia matamata from Palau together with the known compounds scalarin (1) and 12 alpha-acetoxy-16 beta-hydroxyscalarolbutenolide (4). The structures were determined by interpretation of spectroscopic data.
Collapse
Affiliation(s)
- Q Lu
- Scripps Institution of Oceanography, University of California at San Diego, La Jolla 92093-0212, USA
| | | |
Collapse
|
30
|
Kobayashi J, Shinonaga H, Shigemori H. Xestobergsterol C, a new pentacyclic steroid from the Okinawan marine sponge Ircinia Sp. and absolute stereochemistry of xestobergsterol A. J Nat Prod 1995; 58:312-318. [PMID: 7769397 DOI: 10.1021/np50116a029] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A new pentacyclic steroid, xestobergsterol C [1], possessing a cis C/D ring junction, has been isolated together with two known compounds, xestobergsterols A [2] and B [3], from the Okinawan marine sponge Ircinia sp., and the structure determined on the basis of spectral data. Reexamination of the nmr data of xestobergsterols A [2] and B [3] resulted in revision of the configuration at C-23 and of the conformation of ring D in 2 and 3. The absolute stereochemistry of xestobergsterol A [2] was established by the cd exciton chirality method.
Collapse
Affiliation(s)
- J Kobayashi
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan
| | | | | |
Collapse
|
31
|
Siddiqui AU, Wilson WK, Parish EJ, Gerst N, Pinkerton FD, Schroepfer GJ. Inhibitors of sterol synthesis. Synthesis and spectral properties of 3 beta-hydroxy-5 alpha-cholestan-15-one and its 17 beta-epimer and their effects on 3-hydroxy-3-methylglutaryl coenzyme A reductase activity. Chem Phys Lipids 1994; 74:1-15. [PMID: 7820900 DOI: 10.1016/0009-3084(94)90106-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
3 beta-Hydroxy-5 alpha-cholestan-15-one (2a) and its 14 beta-epimer 2b were prepared from 3 beta-acetoxy-5 alpha-cholest-8(14)-ene (3). Hydroboration of 3 at 45-50 degrees C gave a mixture of 5 alpha,14 alpha-cholestane-3 beta,15 alpha-diol and 5 alpha,14 beta-cholestane-3 beta,15 beta-diol, which were separated on silica gel as their 3 beta-tert-butyldimethylsilyl ethers 5a and 5b. Oxidation of 5a with pyridinium chlorochromate, followed by desilylation with tetrabutylammonium fluoride gave 2a. Analogous transformations of 5b gave 2b contaminated with 2a. Desilylation of 5b followed by oxidation with pyridinium chlorochromate resulted in a mixture composed mainly of 5 alpha,14 beta-cholestane-3,15-dione and 2b. Successive chromatographic separations on silica gel and reversed phase media gave 2b of high purity. Compound 2a was also prepared by lithium-ammonia reduction of 3 beta-hydroxy-5 alpha-cholest-8(14)-en-15-one (96% yield) and by selective reduction of 5 alpha-cholestane-3,15-dione with lithium tri-tert-butoxyaluminum hydride (90% yield). Isomers 2a and 2b were readily epimerized under acidic or basic conditions or under conditions used for gas chromatographic analysis. The purities of 2a and 2b were measured from nuclear magnetic resonance (NMR) spectra; chromatographic methods gave less reliable estimates of purity. NMR data also showed that ring C of the 14 beta sterols is predominantly in a chair conformation. The effects of 2a and 2b on the levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase have been studied in Chinese hamster ovary cells.
Collapse
Affiliation(s)
- A U Siddiqui
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251-1892
| | | | | | | | | | | |
Collapse
|
32
|
Wang K, Bermúdez E, Pryor WA. The ozonation of cholesterol: separation and identification of 2,4-dinitrophenylhydrazine derivatization products of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al. Steroids 1993; 58:225-9. [PMID: 8356575 DOI: 10.1016/0039-128x(93)90023-g] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The ozonation products of cholesterol, which are of interest as possible biomarkers of O3 exposure, were studied by derivatization with 2,4-dinitrophenylhydrazine (DNPH). The DNPH derivatization of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al (2) produces the expected trans (3b) and cis (3c) derivatives of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al, and the unexpected DNPH derivative of 3,5-dihydroxy-B-norcholestane-6-carboxaldehyde (3a). The structures of 3a, 3b, and 3c were identified with 1H nuclear magnetic resonance (NMR), 13C NMR, DEPT, COSY, and H-C correlation two-dimensional NMR techniques, and by comparison with the spectra of known compounds. A possible mechanism involving an enamine functionality is proposed for the formation of 3a. The ratio of 3a/(3b + 3c) depends on the concentration of acid used and the reaction time.
Collapse
Affiliation(s)
- K Wang
- Biodynamics Institute, Louisiana State University, Baton Rouge 70803-1800
| | | | | |
Collapse
|
33
|
Zhu JL, Zhou WS. Studies on steroidal plant-growth regulators (XVII)--a new synthesis of homobrassinolide and (22S, 23S)-22, 23-epi-homobrassinolide. Sci China B 1991; 34:706-11. [PMID: 1888437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Homobrassinolide (2) and (22S, 23S)-22,23-epi-homobrassinolide (4) were synthesized from stigmasterol in seven steps respectively in 4.7% and 24.1% overall yields. The ratio of 2 to 4 is 1:5. The key step is the highly regioselective formation of the B-homo-7-oxa-lactone ring by oxidation of an enol silyl ether with 3-chloro-peroxybenzoic acid.
Collapse
Affiliation(s)
- J L Zhu
- School of Pharmacy, Shanghai Medical University, PRC
| | | |
Collapse
|