- A biocatalytic route to enantioenriched, sulfanyl aldol products
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The aldol products derived from sulfur- or selenium containing acceptors were prepared by kinetic resolution in the presence of antibody 84G3 with enantiomeric excesses ranging from 56 to 70%. Much higher level of enantioselectivity was obtained (enantiomeric excesses all superior to 96%) for sulfanyl aldol products derived from thiomethoxyacetone with three different acceptors.
- Baker-Glenn,Ancliff,Gouverneur
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p. 7607 - 7619
(2007/10/03)
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- Unusual reversal of regioselectivity in antibody-mediated aldol additions with unsymmetrical methyl ketones
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A catalytic regio- and enantioselective aldol reaction of various unsymmetrical methyl ketones with para-nitrobenzaldehyde has been developed using aldolase antibodies as the catalysts. It has been found that the sense and level of regioselectivity for the reactions catalysed by antibody 38C2 and 33F12 are highly dependent on the structure of both the donor and the acceptor but in contrast, antibodies 84G3 and 93F3 catalyse the exclusive formation of the linear regioisomer independent of the structure of the reactants examined. The level of enantiocontrol is very high for most reactions. Both linear aldol enantiomers could be accessed through aldol or retro-aldol reactions using the same antibody. Theoretical studies on regioisomeric α- and β-heteroatom substituted enamines derived from unsymmetrical ketones suggest that most of the linear aldol products formed in the presence of antibodies 84G3 and 93F3 must be formed from intermediate enamines which are not the thermodynamically most favourable.
- Maggiotti,Bahmanyar,Reiter,Resmini,Houk,Gouverneur
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p. 619 - 632
(2007/10/03)
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- Substituted indoles as alpha-1 agonists
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This invention relates to compounds which are alpha-1 receptor agonists, preferably alpha-1A/L receptor agonists, and which are represented by Formula I: wherein X is —S(O)n— or —C(O)—, A is C1-6alkyl, aryl, heteroaryl, hydroxyalkyl,
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- New hypoxia-selective cytotoxines derived from quinoxaline 1,4-dioxides
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A new series of quinoxaline 1,4-dioxides, structurally related to the benzotriazine tirapazamine 1 have been prepared starting from 5,6-dichlorobenzofuroxane 2. The Beirut reaction between 2 and alkyl or aryl thiopropanones afforded the 2-methyl-3-alkyl(a
- Monge,Palop,Gonzalez,Martinez-Crespo,Lopez De Cerain,Sainz,Narro,Barker,Hamilton
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p. 1213 - 1217
(2007/10/02)
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- A CONVENIENT GENERAL ACCESS TO α-SULFENYLATED ACETOPHENONES AND ALKANONES
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Friedel-Crafts acylation of arenes with methylthio- (1) or phenylthio-acetyl chloride (2) provides ready access to α-methylthio- or α-phenylthio-substituted acetophenones.The acyl chlorides 1 and 2 reacted also with organoaluminium reagents to give α-sulfenylated alkanones.
- Ishibashi, Hiroyuki,Takamuro, Iwao,Mizukami, Yo-ichi,Irie, Maki,Ikeda, Masazumi
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p. 443 - 452
(2007/10/02)
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- Identification of Volatile Flavor Components of the Oil from Roasted Sesame Seeds
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The volatile extract obtained by steam distillation of the oil from roasted sesame seeds was seperated into its neutral, weakly acidic, acidic and basic fractions.The neutral fraction was further seperated by preparative TLC.All fractions were analyzed by means of a gas chromatograph (GC) equipped with FID and FPD, and by gas chromatography/mass spectrometry (GC/MS) and/or gas chromatograhy/Fourier transform-infrared (GC/FT-IR) spectrometry.Two hundred and twenty one constituents were identified.One hundred and forty six of these compounds are being reported for the first time in the aroma of roasted sesame seeds, 7 of which were newly identified as naturally occurring flavor components.Two dithioketones, 1-methyldithio-2-propanone and 1-methyldithio-2-butanone, are new compounds.
- Nakamura, Shuichi,Nishimura, Osamu,Masuda, Hideki,Mihara, Satoru
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p. 1891 - 1900
(2007/10/02)
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- Nonsteroidal antiandrogens. Synthesis and structure-activity relationship of 3-substituted derivatives of 2-hydroxypropionanilides
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A series of 3-(substituted thio)-2-hydroxypropionanilides and some corresponding sulfones and sulfoxides of general structure 7, in which R' is methyl or trifluoromethyl, were prepared and tested for antiandrogen activity. Members of the trifluoromethyl series (7,R' = CF3) generally exhibited partial androgen agonist activity whereas the members of the methyl series (7,R' = CH3) were pure antagonists. Lead optimization in the methyl series has led to the discovery of novel, potent antiandrogens, which are peripherally selective. One of these, (RS)-4'-cyano-3-[(4-fluorophenyl)sulfonyl]-2-hydroxy-2-methyl-3'-(trifd luoromethyl)propionanilide, 40 (ICI 176334), is being developed currently for the treatment of androgen-responsive benign and malignant disease.
- Tucker,Crook,Chesterson
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p. 954 - 959
(2007/10/02)
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- Regiochemistry and reactivity in the chlorination of sulfides
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Huheey's original method for the calculation of substituent electronegativities is modified so that isomeric groups have different electronegativities.The modified form of Huheey's method is then employed to show that our previously published method for anticipating regiochemistry in asymmetric sulfide chlorination, i.e., ΔXP calculations for the α and α' substituents in the sulfide substrates, is successful in all fifty known cases.A new reactivity function (RP) is defined, for the sulfenium ion intermediates, which permits one to anticipate when substrates become inert to chlorine in exhaustive chlorinations conducted in aprotic media.
- Hancock, James Reid,Hardstaff, William Rayne,Johns, Paul Alan,Langler, Richard Francis,Mantle, William Stanley
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p. 1472 - 1480
(2007/10/02)
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- Azide
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Carbamate derivatives of ketoximes are useful in combatting pests such as insects, mites, and nematodes.
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