- A novel cis-selective cyclohexanone annulation as the key step of a total synthesis of the sesquiterpene lsoacanthodoral
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Isoacanthodoral (1) Is a structurally unique sesquiterpene in that it is a bicyclo[4.4.0]dec-1-ene with a cis- rather than the common transjunction between the constituting rings. An efficient construction of this motif has been accomplished by a novel ci
- Hampel, Thomas,Brueckner, Reinhard
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supporting information; experimental part
p. 4842 - 4845
(2010/03/03)
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- Ruthenium-lewis acid catalyzed asymmetric diels-alder reactions between dienes and α,β-unsaturated ketones
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The complex [Ru(Cp)(R,R-BIPHOP-F)(acetone)][SbF6],(R,R)-1a. was used as catalyst for asymmetric Diels-Alder reactions between dienes (cyclopentadiene, methylcyclopentadienc, isoprene, 2,3-dimethylbutadiene) and α,β-unsaturated ketones (methyl vinyl ketone (MVK). ethyl vinyl ketone, divinyl ketone, α-bromovinyl methyl ketone and α-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50-_90% and with enantioselectivities up to 96% ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90% ee. α-Chlorovinyl methyl ketone performed better than α-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95% ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)]-[SbF6], (S,S)-1b, and [Ru(Cp)((R,R)-Me4BIPHOP-F)(acrolein)][SbF6], (R,R)-2b, provided the basis for a rationalization of the asymmetric induction.
- Rickerby, Jenny,Vallet, Martial,Bernardinelli, Gerald,Viton, Florian,Kuendig, E. Peter
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p. 3354 - 3368
(2008/03/27)
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- 2,3-BENZOXAZIN DERIVATIVES AS NON-STEROIDAL GLUCOCORTICOID RECEPTOR MODULATORS
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The present invention provides compounds of formula (I), wherein R1 represents 1-ethylpropyl, 1-methylethyl or 2-methylpropyl; or a physiologically functional derivative thereof; pharmaceutical compositions comprising the compounds, the use of
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Page/Page column 36
(2010/02/15)
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- Dissociated nonsteroidal glucocorticoid receptor modulators; discovery of the agonist trigger in a tetrahydronaphthalene-benzoxazine series
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The tetrahydronaphthalene-benzoxazine glucocorticoid receptor (GR) partial agonist 4b was optimized to produce potent full agonists of GR. Aromatic ring substitution of the tetrahydronaphthalene leads to weak GR antagonists. Discovery of an "agonist trigger" substituent on the saturated ring of the tetrahydronaphthalene leads to increased potency and efficacious GR agonism. These compounds are efficacy selective in an NFkB GR agonist assay (representing transrepression effects) over an MMTV GR agonist assay (representing transactivation effects). 52 and 60 have NFkB pIC50 = 8.92 (105%) and 8.69 (92%) and MMTV pEC50 = 8.20 (47%) and 7.75 (39%), respectively. The impact of the trigger substituent on agonism is modeled within GR and discussed. 36, 52, and 60 have anti-inflammatory activity in a mouse model of inflammation after topical dosing with 52 and 60, having an effect similar to that of dexamethasone. The original lead was discovered by a manual agreement docking method, and automation of this method is also described.
- Barker, Mike,Clackers, Margaret,Copley, Royston,Demaine, Derek A.,Humphreys, Davina,Inglis, Graham G. A.,Johnston, Michael J.,Jones, Haydn T.,Haase, Michael V.,House, David,Loiseau, Richard,Nisbet, Lesley,Pacquet, Francois,Skone, Philip A.,Shanahan, Stephen E.,Tape, Dan,Vinader, Victoria M.,Washington, Melanie,Uings, Iain,Upton, Richard,McLay, Iain M.,Macdonald, Simon J. F.
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p. 4216 - 4231
(2007/10/03)
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- Chemoenzymatic route to both enantiomers of a 1-isopropyl-3a- methyloctahydroinden-4-one derivative: A synthetic intermediate for sesqui- and diterpenoids
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On the way to a chemoenzymatic synthesis of a key intermediate for sesquiterpenoids and diterpenoids, 2-methyl-2-(4-methyl-3-oxopentyl)-1,3- cyclohexanedione was reduced with the whole cells of yeast biocatalysts. Torulaspora delbrueckii NBRC10921 reduced
- Fujieda, Shigeo,Tomita, Mina,Fuhshuku, Ken-Ichi,Ohba, Shigeru,Nishiyama, Shigeru,Sugai, Takeshi
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p. 1099 - 1109
(2007/10/03)
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- β-Trichlorostannyl Ketones and Aldehydes. Preparation and Facile Amine-Induced Dehydrostannation Leading to α-Methylene Ketones and Aldehydes
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Ring-opening reactions of siloxycyclopropanes 1 with SnCl4 take place under mild reaction conditions and site-selectively to give β-trichlorostannyl ketones and aldehydes 3 in high yields.The β-trichlorostannyl ketones and aldehydes thus obtained readily undergo base-induced dehydrotrichlorostannation at room temperature to give the corresponding α-methylene ketones and aldehydes 4.The reactions are quite general for amines, such as pyridine, triethylamine, N,N,N',N',-tetramethylethylenediamine (TMEDA), and 1,4-diazabicyclooctane (DABCO), and the yields are good to high.One-pot conversion from siloxycyclopropanes 1 to α-methylene ketones or aldehydes 4 by consecutive treatment of 1 with SnCl4 and TMEDA is also successful.The 1H NMR, 13C NMR, 119Sn NMR, and IR spectral properties of β-stannyl ketones and aldehydes are also reported.
- Nakahira, Hiroyuki,Ryu, Ilhyong,Ikebe, Masanobu,Oku, Yoshiaki,Ogawa, Akiya,et al.
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- Preparation of alpha-alkylacroleins
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α-Alkylacroleins are prepared by reacting an alkanal with formaldehyde and a secondary amine in the presence of a carboxylic, dicarboxylic or polycarboxylic acid in certain molar ratios within a pH range of from 2.5 to 7 and at from 0° to 150° C. The α-alkylacroleins which can be prepared by the process described are valuable starting materials for dyes, drugs and pest control agents.
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- β-Silylcarbonyl Compounds as Masked Enones
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β-Trimethylsilylketones and lactones can be brominated (3)->(4) and desilylbrominated (4)->(5) specifically to place a double bond between the carbonyl group and the β-carbon atom to which the silicon had originally been bound.The silyl group therefore is a base- and acid stable group masking the α,β-unsaturation of enones.Several α-methylene-ketones and -lactones have been prepared in this way.With ketones, the bromination step seems always to introduce bromine mainly or exclusively at the α-position on that side of the ketone on which the β-silyl group is placed, regardless of whether it is more or the less substituted α-position.
- Fleming, Ian,Goldhill, Jon
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p. 1493 - 1498
(2007/10/02)
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