- Computational and Experimental Studies of Phthaloyl Peroxide-Mediated Hydroxylation of Arenes Yield a More Reactive Derivative, 4,5-Dichlorophthaloyl Peroxide
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The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel "reverse-rebound" mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.
- Camelio, Andrew M.,Liang, Yong,Eliasen, Anders M.,Johnson, Trevor C.,Yuan, Changxia,Schuppe, Alex W.,Houk,Siegel, Dionicio
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p. 8084 - 8095
(2015/09/01)
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- Total synthesis of synechoxanthin through iterative cross-coupling
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The choice is yours: The first total synthesis of the antioxidant carotenoid synechoxanthin was achieved through a novel iterative cross-coupling approach in which the polarity of the bifunctional building blocks is reversed to match the preferred polarity for C-C bond formation (see scheme). The convergent, stereocontrolled, and flexible nature of this synthesis enables systematic studies of the biological activities of this natural product.
- Fujii, Seiko,Chang, Stephanie Y.,Burke, Martin D.
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p. 7862 - 7864
(2011/10/08)
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- CARBOXYLIC ACID COMPOUNDS AND MEDICINAL COMPOSITIONS CONTAINING THE SAME AS THE ACTIVE INGREDIENT
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A compound represented by formula (I) wherein the symbols in the formula are the same meanings as those in specification, salts thereof, solvates thereof, or prodrugs thereof binds to DP receptor and shows antagonistic activity for DP receptor. Thus, it is useful for prevention and/or treatment of diseases such as allergic disease (e.g., allergic rhinitis, allergic conjunctivitis, atopic dermatitis, bronchial asthma and food allergy), systemic mastocytosis, disorders accompanied by systemic mast cell activation, anaphylaxis shock, bronchoconstriction, urticaria, eczema, diseases accompanied by itch (e.g., atopic dermatitis and urticaria), diseases (e.g., cataract, retinal detachment, inflammation, infection and sleeping disorders) which is generated secondarily as a result of behavior accompanied by itch (e.g., scratching and beating), inflammation, chronic obstructive pulmonary diseases, ischemic reperfusion injury, cerebrovascular accident, chronic rheumatoid arthritis, pleurisy ulcerative colitis, etc. Since it specifically binds to DP receptor and binds weakly to other prostaglandins receptors, they can be pharmaceuticals having little side effect.
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Page/Page column 41
(2008/06/13)
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- Isoxazoles as Latent Siloxybutadienes: An Easy Entry to Polyfunctionalized Benzene Systems via Diels-Alder Reaction with Acetylenes
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Base-induced or reductive cleavage of isoxazole rings followed by silylation of the resulting open-chain products affords bis(siloxy)butadienes in high yields. Their synthetic usefulness in the construction of multifunctionalized aromatic systems, via Diels-Alder reactions, is shown. The ability of bis(siloxy)butadienes to undergo deprotonation and reaction with electrophiles is also studied.
- Barbero, Asuncion,Pulido, Francisco J.
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p. 401 - 404
(2007/10/03)
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- Steroid 5α-reductase: Comparative study of mechanism of inhibition by nonsteroids ONO-3805 and LY191704
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Two nonsteroids, ONO-3805 and LY191704, were evaluated as inhibitors of the human and rat 5α-reductases (5αR). ONO-3805 was prepared in a 12-step convergent synthesis. This compound is a potent inhibitor of the human and rat 5αRs, with more potent inhibition seen against the rat enzymes. The inhibition patterns of this compound were best fit to an uncompetitive model which suggests binding in a ternary complex with enzyme and NADP+. Apparent K(i) values of 27, 31, 1, and 0.5 nM versus testosterone were obtained with human type 1, human type 2, rat type 1, and rat type 2 5αR, respectively. Multiple inhibition studies with ONO-3805 and NADP+ support synergistic binding of these two inhibitors with all isozymes. LY191704 was also evaluated as an inhibitor of the human and rat 5αRs. This compound is a selective, competitive inhibitor of human type 1 5αR. Poor inhibition was observed with human type 2 and rat types 1 and 2 5αR.
- Harris, Georgianna S.,Ellsworth, Kenneth,Witzel, Bruce E.,Tolman, Richard L.
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p. 386 - 400
(2007/10/03)
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- Photochemical and Acid-Catalyzed Dienone-Phenol Rearrangements. The Effect of Substitutents on the Regioselectivity of 1,4-Sigmatropic Rearrangements of the Type A Intermediate
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Birch reduction of isophthalic acid and 3-cyanobenzoic acid followed by (1) methylation of the resulting enolate with methyl iodide and (2) esterification with diazomethane proved 2-carbomethoxy- and 2-cyano-6-methyl-6-carbomethoxy-1,4-cyclohexadienes 9 and 25.Type A photorearrangement of a series of 2-carbomethoxy-, 2-cyano-, 2-methoxy-, and 2-methyl-4-carbomethoxy-4-methyl-2,5-cyclohexadien-1-ones 11, 26, 45a, and 45b gave 4-carbomethoxy-3-methyl-2-substituted-phenols 12, 28, 46, and 31.It has been demonstrated that the regioselectivity of type A photorearrangement of C(2) substituted 2,5-cyclohexadien-1-ones is governed by electronic rather than steric effects to give the intermediate C(1) rather than C(3) substituted bicyclo1,5>hex-3-en-2-ones.Regioselectivities of the acid-catalyzed dienone-phenol rearrangements of C(2) substituted 2,5-cyclohexadienones 11, 45a, and 45b appear to be dependent upon the relative stabilities of carbocations resulting from migration of the C(4) carbomethoxy group.
- Schultz, Arthur G.,Hardinger, Steven A.
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p. 1105 - 1111
(2007/10/02)
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