- Novel stereoids from cetyltrimethylammonium permanganate-initiated oxidative rearrangements of 16-dehydroprogesterone
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Cetyltrimethylammonium permanganate initiates oxidative opening of the D-ring of 16-dehydroprogesterone in CH2Cl2. The novel steroids 3 and 4 have been isolated and characterized as the major products obtained from oxidative rearrangement of the steroid backbone. The X-ray crystal structure of the D-homosteroid 3 is provided, and a putative mechanism that invokes a benzilic acid rearrangement for formation of 3 is presented.
- Kym, Philip R.,Wilson, Scott R.,Gritton, William H.,Katzenellenbogen, John A.
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- Inherent steroid 17α,20-lyase activity in defunct cytochrome P450 17A enzymes
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Cytochrome P450 (P450) 17A1 catalyzes the oxidations of progesterone and pregnenolone and is the major source of androgens. The enzyme catalyzes both 17α-hydroxylation and a subsequent 17α,20-lyase reaction, and several mechanisms have been proposed for the latter step. Zebrafish P450 17A2 catalyzes only the 17α-hydroxylations. We previously reported high similarity of the crystal structures of zebrafish P450 17A1 and 17A2 and human P450 17A1. Five residues near the heme, which differed, were changed. We also crystallized this five-residue zebrafish P450 17A1 mutant, and the active site still resembled the structure in the other proteins, with some important differences. These P450 17A1 and 17A2 mutants had catalytic profiles more similar to each other than did the wildtype proteins. Docking with these structures can explain several minor products, which require multiple enzyme conformations. The 17α-hydroperoxy (OOH) derivatives of the steroids were used as oxygen surrogates. Human P450 17A1 and zebrafish P450s 17A1 and P450 17A2 readily converted these to the lyase products in the absence of other proteins or cofactors (with catalytically competent kinetics) plus hydroxylated 17α-hydroxysteroids. The 17α-OOH results indicate that a "Compound I" (FeO3+) intermediate is capable of formation and can be used to rationalize the products. We conclude that zebrafish P450 17A2 is capable of lyase activity with the 17α-OOH steroids because it can achieve an appropriate conformation for lyase catalysis in this system that is precluded in the conventional reaction.
- Gonzalez, Eric,Johnson, Kevin M.,Pallan, Pradeep S.,Phan, Thanh T.N.,Zhang, Wei,Lei, Li,Wawrzak, Zdzislaw,Yoshimoto, Francis K.,Egli, Martin,Peter Guengerich
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p. 541 - 556
(2018/02/14)
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- Preparation method of algestone acetophenide
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The invention discloses a preparation method of algestone acetophenide. The preparation method comprises the following steps: (1) performing reaction among androstenedione cyanohydrin ketal, 1 to 1.5 times amount of substance of phosphorus oxychloride and 1 to 10 times amount of substance of an alkaline medium for 1 to 5h at the reaction temperature of -10 to 80 DEG C to obtain a suppressor; (2) performing reaction between the suppressor and 1 to 10 times amount of substance of methyl magnesium chloride for 1 to 5h at the reaction temperature of -10 to 70 DEG C to obtain a Grignard's product; (3) performing reaction between the Grignard's product and 1 to 5 times amount of substance of potassium permanganate for 10 to 60m at the reaction temperature of -10 to 30 DEG C, and then performing reaction between the Grignard's product and 1 to 5 times amount of substance of acid for 1 to 10h at the reaction temperature of -10 to 30 DEG C to obtain a hydroxy compound; (5) performing reaction among the hydroxy compound, 0.025 to 0.1 time amount of substance of a catalyst and 2 to 10 times amount of substance of acetyl benzene for 1 to 10h at the reaction temperature of -10 to30 DEG C to obtain the algestone acetophenide. Not only the quality and yield of a product are improved, but also the production cost is reduced and the process time is shortened.
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Paragraph 0023; 0032; 0037; 0042; 0047; 0052; 0054; 0055
(2017/07/21)
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- Method for reducing or preventing transplant rejection in the eye and intraocular implants for use therefor
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Methods for reducing or preventing transplant rejection in the eye of an individual are described, comprising: a) performing an ocular transplant procedure; and b) implanting in the eye a bioerodible drug delivery system comprising an immunosuppressive agent and a bioerodible polymer.
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- Progestin 16α,17α-dioxolane ketals as molecular probes for the progesterone receptor: Synthesis, binding affinity, and photochemical evaluation
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Chemical probes for steroid receptors have proven useful in providing molecular details about important hormone-receptor interactions. A series of progestin 16α,17α-dioxolane ketals of acetophenone or substituted acetophenones that bind to the progesterone receptor (PgR) with comparable or higher affinities than the natural ligand, progesterone, have been prepared and evaluated as potential in vitro and in vivo probes for the progesterone receptor. p-Azidoacetophenone ketal 6, the tetrafluoro analog 8, and the p- (benzoyl)acetophenone ketal 9 demonstrate the required combination of high relative binding affinity (RBA) (6 = 15%, 8 = 14%, 9 = 6.6%, progesterone = 13%, R5020 = 100%) and photoinactivation efficiency (6 = 80%, 8 = 77%, 9 = 29% at 30 min) required for potential photoaffinity labeling reagents for the PgR. The synthesis of azide 6 has been modified to accommodate a palladium- catalyzed tritium gas hydrogenolysis of an iodoaryl precursor in the final stage of the synthetic sequence; this procedure has been verified by hydrogenation. In addition, the progestin p-fluoroacetophenone ketal 10 was selected for preparation in fluorine-18-labeled form, on the basis of its high affinity for the PgR (RBA = 53%). Fluorine-18-labeled progestins may be evaluated as potential diagnostic imaging agents for PgR-positive breast tumors. The radiochemical syntheses and further biochemical results with the fluorine-18-labeled ketal 10 and the tritium-labeled aryl azide 6 will be presented in an accompanying paper and elsewhere.
- Kym,Carlson,Katzenellenbogen
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p. 1111 - 1119
(2007/10/02)
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