- A NEW SYNTHETIC ROUTE TO PYROGALLOLESTROGEN DIMETHYL ETHERS BY NUCLEOPHILIC SUBSTITUTION OF 2,4-DIBROMOESTROGENS
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A novel synthetic route to pyrogallolestrogen dimethyl ethers was developed.Benzo-15-crown-5 with CuI catalyses the specific nucleophilic substitution of bromo atoms by methoxide ions.
- Zheng, Xu-hua,Wang, Wen-long,Zhong, Zhi-zheng,Xu, Zhen-bon,Zhao, Hua-ming
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- Electrochemical A-ring bromination of estrogens
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A-ring bromination of estrogens has been achieved by constant current electrolysis of the solutions of these substrates and Et4NBr in appropriate solvents. Thus, electrolysis consuming 2 F mol-1 charge gave mixtures of 2- and 4-estrogens (1:1.1-2.5; up to 97%), whereas 4 F mol -1 charge experiments yielded 2,4-dibromoestrogens as the sole products.
- Damljanovic, Ivan,Vukicevic, Mirjana,Vukicevic, Rastko D.
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p. 407 - 409
(2008/02/11)
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- Chemical synthesis of two novel diaryl ether dimers of estradiol-17β
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We recently detected the formation of estradiol-17β (estradiol) dimers, linked together through a diaryl ether bond between the C-3 phenolic oxygen of one estradiol molecule and the 2- or 4-position aromatic carbon of another estradiol, following incubations of [3H]estradiol with human liver microsomes or cytochrome P450 enzymes in the presence of NADPH. Using estradiol as the starting material, we designed a four-step method for the chemical synthesis of these two estrogen dimers with the Ullmann condensation reaction as a key step. Step 1: Synthesis of 2- or 4-bromoestradiol from estradiol. Step 2: Protection of the C-3 phenolic hydroxyl group of the 2- or 4-bromoestradiol. Step 3: The Ullmann condensation reaction between the phenol-protected bromoestradiol and the estradiol potassium salt under our modified reaction conditions (with a 41% product yield). Step 4: Removal of the C-3 benzyl group by catalytic hydrogenation. The chromatographic and various spectrometric properties of the two synthesized compounds were identical to those metabolically formed by human cytochrome P450 3A4.
- Lee, Anthony J.,Sowell, J. Walter,Cotham, William E.,Zhu, Bao Ting
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- Synthesis of analogs of 2-methoxyestradiol with enhanced inhibitory effects on tubulin polymerization and cancer cell growth
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A new series of estradiol analogs was synthesized in an attempt to improve on the anticancer activity of 2-methoxyestradiol, a naturally occurring mammalian tubulin polymerization inhibitor. The compounds were evaluated as inhibitors of tubulin polymeriza
- Cushman, Mark,He, Hu-Ming,Katzenellenbogen, John A.,Varma, Ravi K.,Hamel, Ernest,Lin, Chii M.,Ram, Siya,Sachdeva, Yesh P.
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p. 2323 - 2334
(2007/10/03)
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- Reaction of Benzeneselenyl Halides with Estrogens
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The reaction of estradiol and estrone with benzeneselenyl chloride affords mainly 2-phenylselenyl adducts which are readily converted into the corresponding 2-halogenated estrogens upon treatment with a variety of reagents.
- Ali, Hasrat,Lier, Johan E. van
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p. 269 - 271
(2007/10/02)
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- A NEW SYNTHETIC ROUTE TO 2- AND 4-METHOXYESTRADIOLS BY NUCLEOPHILIC SUBSTITUTION
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A new synthetic route to 2- and 4-methoxyestradiols is described.Benzo-15-crown-5 with CuI catalyzes the specific nucleophilic substitution at the carbon atom carrying a non-activated halogen on ring A of the estradiol.
- Chen, Shu-hua,Luo, Guan-rong,Wu, Xu-sen,Chen, Min,Zhao, Hua-ming
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- Synthesis of 2-Methoxy- and 4-Methoxy-Estrogens with Halogen-Methoxy Exchange Reaction
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Synthesis of 2-methoxy- and 4-methoxy-estrone (6) and (9), 2-methoxy- and 4-methoxy-estradiol (15) and (18), and 2-methoxy- and 4-methoxy-estratriol (24) and (27) are described.Catalytic hydrogenation over Pd/C of 2,4-dibromo or 2,4-diiodo estrogens gave regioselectively the corresponding 4-halogeno derivatives in excellent yields.Reaction of 2-iodo or 4-iodo estradiol and 2-iodo or 4-iodo estriol with NaOCH3 in MeOH and dimethylformamide (DMF) in the presence of CuCl2 gave in an excellent yield and in a good yield, while (6) and (9) were also similarly obtained by the reaction with pyridine instead of DMF.
- Numazawa, Mitsuteri,Ogura, Yuko,Kimura, Katsuhiko,Nagaoka, Masao
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p. 3701 - 3715
(2007/10/02)
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- Novel and Efficient Synthesis of Estriol and its 16-Glucuronide via 2,4,16α-Tribromoestrone
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A novel synthesis of estra-1,3,5(10)-triene-3,16α,17β-triol (5), sodium 3,17β-dihydroxyestra-1,3,5(10)-trien-16α-yl-β-D-glucopyranosuronate (12b) aand sodium 3-hydroxyestra-1,3,5(10)-trien-17β-yl-β-D-glucopyranosuronate (10b) is described. 2,4,16α-Tribromo-3-hydroxyestra-1,3,5(10)-trien-17-one (2a) was efficiently synthesized in one step with quantitative yield by bromination of 3-hydroxyestra-1,3,5(10)-trien-17-one (1) with cupric bromide.Treatment of (2a) with NaOH in aqueous pyridine under the controlled conditions gave the 16α-hydroxy-17-ketone (4a) without ketol rearrangement.The ketol (4a) was converted in quantitative yield into the triol (5) via a sodium borohydride reduction in the presence of palladium chloride.Reaction of (4a) with methyl 1-bromo-1-deoxy-2,3,4-tri-O-acetyl-α-D-glucopyranosuronate using silver carbonate as a catalyst yielded the 16-monoglucuronide acetate methyl ester (11).The reductive removal of the bromines of (11) with sodium borohydride followed by NaOH hydrolysis gave the glucuronide (12b).A direct glucuronidation of 2,4-dibromoestra-1,3,5(10)-triene-3,17β-diol (8) and a subsequent hydrolysis of the 17-glucuronide (9) gave the glucuronide (10b).
- Numazawa, Mitsuteru,Nagaoka, Masao,Tsuji, Masachika,Osawa, Yoshio
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p. 121 - 125
(2007/10/02)
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