- Photocatalysis with Quantum Dots and Visible Light: Selective and Efficient Oxidation of Alcohols to Carbonyl Compounds through a Radical Relay Process in Water
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Selective oxidation of alcohols to aldehydes/ketones has been achieved with the help of 3-mercaptopropionic acid (MPA)-capped CdSe quantum dot (MPA-CdSe QD) and visible light. Visible-light-prompted electron-transfer reaction initiates the oxidation. The thiyl radical generated from the thiolate anion adsorbed on a CdSe QD plays a key role by abstracting the hydrogen atom from the C?H bond of the alcohol (R1CH(OH)R2). The reaction shows high efficiency, good functional group tolerance, and high site-selectivity in polyhydroxy compounds. The generality and selectivity reported here offer a new opportunity for further applications of QDs in organic transformations.
- Zhao, Lei-Min,Meng, Qing-Yuan,Fan, Xiang-Bing,Ye, Chen,Li, Xu-Bing,Chen, Bin,Ramamurthy, Vaidhyanathan,Tung, Chen-Ho,Wu, Li-Zhu
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p. 3020 - 3024
(2017/03/13)
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- Modification of estrone at the 6, 16, and 17 positions: Novel potent inhibitors of 17β-hydroxysteroid dehydrogenase type 1
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The 17β-hydroxysteroid dehydrogenases (17β-HSDs) catalyze the interconversion between the oxidized and reduced forms of androgens and estrogens at the 17 position. The 17β-HSD type 1 enzyme (17β-HSD1) catalyzes the reduction of estrone to estradiol and is
- Allan, Gillian M.,Lawrence, Harshani R.,Cornet, Josephine,Bubert, Christian,Fischer, Delphine S.,Vicker, Nigel,Smith, Andrew,Tutill, Helena J.,Purohit, Atul,Day, Joanna M.,Mahon, Mary F.,Reed, Michael J.,Potter, Barry V. L.
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p. 1325 - 1345
(2007/10/03)
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- C(10)-C(19) bond cleavage reaction of 19-oxygenated androst-4-ene-3,6-dione steroids under various conditions
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C(10)-C(19) bond cleavage reaction of 19-hydroxy- and 19-oxoandrost-4-ene- 3,6,17-triones (5, 6) was explored under various conditions. Treatment of steroids 5 and 6 with KOH in MeOH gave the A-ring aromatized product 6-oxoestrone (11) in a fair yield, respectively, in contrast, the treatment with a weak base yielded 4-methyl steroid 17 (20%) in the case of 19-alcohol 5 or 19-nor- Δ5(10)-steroid 9 (12-67%) along with compound 11 (6-27%) in the case of 19-aldehyde 6. Reaction of compound 6 with HCl in MeOH produced 3-methyl ethers of 6-oxoestrone and Δ6-estrone, compounds 12 and 14 (ca. 20% each). Thus, 6-oxosteroids 5 and 6 showed unique C(10)-C(19) bond cleavage reactions with a base or acid.
- Nagaoka, Masao,Numazawa, Mitsuteru
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p. 983 - 985
(2007/10/03)
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- COMPOUND
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There is provided a compound of Formula (I) wherein (I) R is a selected from (i) an alkyloxyalkyl group (ii) a nitrile group, and wherein R is capable of forming a hydrogen bond (iii) alkylaryl group, wherein the aryl group is substituted by other than a C1-10 group (iv) alkenylaryl group wherein the aryl group is substituted (v) alkyiheteroaryl group, wherein when heteroaryl group comprises only C and N in the ring, the aryl group is substituted by other than a methyl group (vi) alkenylheteroaryl group, (vii) =N-O-alkyl or =N-O-H group (viii) branched alkenyl (ix) alkyl-alcohol group (x) amide or alkylamide wherein (a) the alkyl of the alkylamide is - CH2- or -CH2CH2-, (b) the amide is di-substituted and/or (c) the amide is substituted with at least one of a I kyl heterocycle group, al ke nyl heterocycle group, alkylheteroaryl group, alkenylheteroaryl group, heteroaryl group, alkylamine group, alkyloxyalkyl group, alkylaryl group, straight or branched alkyl group, (xi) -CHO so that R, together with R3 provide the enol tautomer (a); OR R1 together with R form (xii) a pyrazole wherein (a) R is =N-0-alkyl or =N-0-H group, (b) the pyrazole is substituted with one of alkyl-OH group, alkyl ester group, alkyloxyalkyl. group, branched alkyl group, and an amide and/or (c) the 2 position is substituted with a group selected from -OH and -0-hydrocarbyl (xiii) a heteroaryl ring to provide a compound of the formula (b); (II) Ris selected from groups capable of forming a hydrogen bond, a sulphamate group, a phosphonate group, a thiophosphonate group, a sulphonate group and a sulphonamide group; and (III) Ris selected from -OH, =O, or a -C(=O)- mimetic.
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Page 168-169
(2010/02/08)
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- Aromatization of 19-Oxygenated Androst-4-ene-3,6,17-triones with Human Placental Microsomes
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To gain insight into the aromatization sequence of androst-4-ene-3,6,17-trione (1), a suicide substrate of aromatase, the aromatization of its 19-hydroxy and 19-oxo analogs 2 and 3 with human placental microsomes, was studied using GC-MS. Steroids 2 and 3 were separately incubated with the microsomes in the presence of NADPH in air. The GC-MS analysis of the trimethylsilyl derivative of the aromatization product indicated that both the 19-oxygenated steroids 2 and 3 were aromatized to yield 6-oxoestrogens, 6-oxoestrone (4) and 6-oxoestradiol (5), in each experiment. The aromatization rates of substrates 2 and 3 were 605+/-48 and 1794+/-75 pmol/mg protein/10 min, respectively. These relatively higher rates, compared to that of the parent steroid 1 (73.2+/-6.6 pmol/mg protein/10 min), indicates that the suicide substrate 1 is aromatized through the 19-oxygenated intermediates 2 and 3.
- Numazawa, Mitsuteru,Sugiyama, Takanori,Nagaoka, Masao
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p. 289 - 292
(2007/10/03)
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- Biochemical studies of estr-4-ene-3,6,17-trione and 5α-androstan-17-ones with or without a carbonyl function at C-3 and/or C-6 as aromatase inhibitors
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19-Nor (2) and 5α-reduced (3) derivatives of androst-4-ene-3,6,17-trione (1) as well as 5α-androstan-17-ones 4-6 were tested for their abilities to inhibit aromatase in human placental microsomes. All the steroids except 5α-6-one 4 were fair to good competitive inhibitors of the enzyme, with apparent K(i)'s ranging from 50 to 820 nM in which 5α-3-one 5 was the most potent among them. The inhibitory activities of the 19-nor and 5α-reduced derivatives (2 and 3) were less potent than that of the parent compound 1. Inhibitor 2 caused a time-dependent, pseudo-first-order inactivation of aromatase activity with a rate constant for inactivation of 0.148 min-1 in the presence of NADPH in air. The substrate androstenedione prevented the inactivation and L-cysteine did not protect aromatase from the inactivation.
- Numazawa,Mutsumi,Tachibana,Nagaoka
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p. 555 - 558
(2007/10/03)
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- A Novel Efficient Approach to the Synthesis of 6-Oxo Ethinylestradiol and its 3-Isopropanesulfonate
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Ethinylestradiol (1) was converted into the corresponding 6-oxo derivative 7 by a short and simple procedure involving acetate 10 and ketone 11.Phase transfer catalyzed esterification of compound 7 with propane-2-sulfonyl chloride gave sulfonate 12.
- Weber, Gisela,Schaumann, J.,Carl, Constanze,Schwarz, S.,Leisner, Rosemarie
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p. 223 - 230
(2007/10/02)
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