- Molybdenum-mediated diastereoselective synthesis of 2-heterobicyclo[4.4.0]decene derivatives
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The addition of a variety of functionalized zinc-copper reagents RCu(CN)ZnI 2 to (η5-cyclopentadienyl)(η 4-cyclohexa-1,3-diene)dicarbonylmolybdenum cation 1 proceeds in a highly regio- and stereo-specific fashion to generate (η5
- Yeh, Ming-Chang P.,Chaung, Chong-Nan
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Read Online
- Enantioselective allylic hydroxylation of w-alkenoic acids and esters by P450 BM3 monooxygenase
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Chiral allylic alcohols of w-alkenoic acids and derivatives thereof are highly important building blocks for the synthesis of biologically active compounds. The direct enantioselective C-H oxidation of linear terminal olefins offers the shortest route toward these compounds, but known synthetic methods are limited and suffer from low selectivities. Described herein is an enzymatic approach using the P450 BM3 monooxygenase mutant A74G/L188Q, which catalyzes allylic hydroxylation with high to excellent chemo- and enantioselectivities providing the desirable secondary alcohols.
- Neufeld, Katharina,Henssen, Birgit,Pietruszka, J?rg
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supporting information
p. 13253 - 13257
(2015/02/19)
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- Antimicrobial poly(2-methyloxazoline)s with bioswitchable activity through satellite group modification
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Biocides are widely used for preventing the spread of microbial infections and fouling of materials. Since their use can build up microbial resistance and cause unpredictable long-term environmental problems, new biocidal agents are required. In this study, we demonstrate a concept in which an antimicrobial polymer is deactivated by the cleavage of a single group. Following the satellite group approach, a biocidal quaternary ammonium group was linked through a poly(2-methyloxazoline) to an ester satellite group. The polymer with an octyl-3-propionoate satellite group shows very good antimicrobial activity against Gram-positive bacterial strains. The biocidal polymer was also found to have low hemotoxicity, resulting in a high HC50/MIC value of 120 for S. aureus. Cleaving the ester satellite group resulted in a 30-fold decrease in antimicrobial activity, proving the concept valid. The satellite group could also be cleaved by lipase showing that the antimicrobial activity of the new biocidal polymers is indeed bioswitchable. Biocides are widely used for preventing the spread of microbial infections and the fouling of materials. Since their application can build up microbial resistance and cause unpredictable long-term environmental problems, new biocidal agents are required. In a novel approach an antimicrobial polymer is deactivated by hydrolysis of an ester group through the action of a lipase. The crucial feature is the mutual interaction of the two endgroups of the polymer.
- Krumm, Christian,Harmuth, Simon,Hijazi, Montasser,Neugebauer, Britta,Kampmann, Anne-Larissa,Geltenpoth, Helma,Sickmann, Albert,Tiller, Joerg C.
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supporting information
p. 3830 - 3834
(2014/05/06)
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- PDE 10a Inhibitors for the Treatment of Type II Diabetes
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Disclosed are compounds, compositions and methods for treating Type II diabetes. Such compounds are represented by Formula (I) as follows: wherein R1, R2, L, and Q are defined herein.
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Paragraph 0865; 0866
(2015/01/06)
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- Photoinduced radical hydroperfluoroalkylation and the synthesis of fluorinated amino acids and peptides
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The photoinduced radical hydroperfluoroalkylation of unsaturated carboxylic acids using TTMSS as a H-donor was successfully developed. The stereoselective reaction using Oppolzer's camphorsultum was also achieved to give high stereoselectivity. The reaction was also effective for N-phthalimide- dehydroamino acid and the product was easily converted to the corresponding amino acid and a peptide derivative.
- Yajima, Tomoko,Yamaguchi, Kanako,Hirokane, Rie,Nogami, Emiko
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- METHOD FOR INCREASING SPECIFIC SURFACE AREA OF SLIGHTLY SOLUBLE DRUG
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The preparation method of the powder of which dissolution rate improves is characterized by including of the process that slightly soluble drug having acidic group (e.g., 3-(5-{2-[5-methyl-2-(4-methylphenyl)-1,3-oxazol-4-yl]ethoxy}-3,4-dihydronaphthalen-1
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Page/Page column 7
(2010/11/25)
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- Thiophene backbone amide linkers, a new class of easily prepared and highly acid-labile linkers for solid-phase synthesis
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Solid-phase synthesis is of tremendous importance for small-molecule and biopolymer synthesis. Linkers (handles) that release amide-containing products after completion of solid-phase synthesis are widely used. Here we present a new class of highly acid-labile backbone amide linkers (BAL handles) based on 3,4-ethylenedioxythiophene (EDOT), which we have termed T-BAL. These thiophene linkers are synthesized in three convenient steps from commercially available EDOT. In the linker design, the spacer was introduced to the EDOT core either via a carbon-carbon bond or via a thioether linkage. Introduction of the spacer via a C-C bond was performed by a chemoselective Negishi coupling without transient protection of the aldehyde group to provide the T-BAL1 handle. Introduction via a thioether linkage was performed by a facile nucleophilic aromatic substitution between the brominated EDOT aldehyde and unprotected mercapto acids to provide T-BAL2 and T-BAL3 handles. The minimal use of protecting groups gave the corresponding linker molecules in few synthetic steps and in good yields. After anchoring of the linker to a polymeric support, introduction of the first amino acid was achieved by reductive amination, giving a secondary amine. A following acylation of the secondary amine with a symmetrical amino acid anhydride resulted in a backbone amide linkage between the handle and the growing substrate (e.g., peptide chain). After solid-phase synthesis, the substrates could be released from the resin by either low acid conditions using 1% TFA in CH2Cl2 or high acid conditions such as 50% TFA in CH2Cl2. Peptide thioesters could be released from the T-BAL1 handle under very mild conditions using aqueous acetic acid. Tert-butyl based protecting groups, tert-butyl esters, tert-butyl ethers, and Boc groups, as well as dimethyl acetals were relatively stable to these mild conditions for release of the peptides.
- Jessing, Mikkel,Brandt, Malene,Jensen, Knud J.,Christensen, Jorn B.,Boas, Ulrik
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p. 6734 - 6741
(2007/10/03)
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- A facile method for synthesis of (R)-(-)- and (S)-(+)-homocitric acid lactones and related α-hydroxy dicarboxylic acids from D- or L-malic acid
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We report here a simple and convenient route for the stereoselective synthesis of (R)-(-)- and (S)-(+)-homocitric acid lactones, which play very important roles in biochemistry. The method involves only three steps, starting from the readily available met
- Xu, Peng-Fei,Matsumoto, Tsuyoshi,Ohki, Yasuhiro,Tatsumi, Kazuyuki
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p. 3815 - 3818
(2007/10/03)
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- Dual function catalysts. Dehydrogenation and asymmetric intramolecular Diels-Alder cycloaddition of N-hydroxy formate esters and hydroxamic acids: Evidence for a ruthenium-acylnitroso intermediate
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The chiral ruthenium salen complex, 13b, functions as an efficient catalyst for the sequential oxidation and asymmetric Diels-Alder cycloaddition of hydroxamic acids and N-hydroxy formate esters. This result provides evidence for the formation of a ruthen
- Chow, Chun P.,Shea, Kenneth J.
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p. 3678 - 3679
(2007/10/03)
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- Synthesis of 13C and 15N multilabeled 5-aminolevulinic acid
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5-[4-13C,15N]- and 5-[5- 13C,15N]Aminolevulinic acid (ALA) were simply synthesized in four steps by the condensation of [1-13C,15N]- or [2-13C,15N]glycine, respectively, with phthalic anhydride, followed by conversion to the chloride, coupling reaction with a three-carbon unit and hydrolysis. Copyright
- Iida, Katsumi,Kajiwara, Masahiro
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p. 139 - 143
(2007/10/03)
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- A simple and versatile method for the hydroiodination of alkenes and alkynes using I2 and Et3SiH in the presence of copper(II)
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The reagent system CuO·HBF4/I2/Et3SiH generates in situ hydrogen iodide which regioselectively adds to alkenes and alkynes. The mild nature of this system tolerates the presence of different groups on the unsaturated compound.
- Campos, Pedro J.,García, Bárbara,Rodríguez, Miguel A.
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p. 6111 - 6112
(2007/10/03)
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- Intramolecular palladium(II)-catalyzed 1,2-addition to allenes
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Palladium(II)-catalyzed intramolecular 1,2-additions to allenes substituted with an internal nucleophile have been developed. Carboxylic acids, alcohols, N-substituted amides, and carbamates were used as internal nucleophiles in the palladium-catalyzed re
- Jonasson,Horvath,Backvall
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p. 9600 - 9609
(2007/10/03)
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- Aminoglycoside hybrids as potent RNA antagonists
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Aminoglycosides specifically bind to the A-site decoding region of prokaryotic 16S rRNA with dissociation constants in the 1-2 μM range. The aminoglycoside paromomycin binds to a truncated A-site construct with a K(d) = 1.85 μM. Paromomycin analogs are described here in which the aminoglycoside is linked via spacer groups to either thiazole orange or pyrene. These analogs bind specifically to the truncated A-site construct, but with affinities considerably higher than paromomycin itself. The binding of the hybrid molecules to the A-site is greater the shorter the spacer group.
- Tok, Jeffrey B.-H.,Cho, Junhyeong,Rando, Robert R.
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p. 5741 - 5758
(2007/10/03)
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- Efficient Syntheses of the OPC Homologous Series, OPC-1:0, -3:0, -4:0, -5:0, -6:0, -7:0, and -8:0
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The OPC homologous series was synthesized from 2-[(Z)-2-pentenyl]cyclopenten-1-one in short steps and with high yields. The carbon-carbon bond formation was achieved by the 1,4-conjugate addition approach. This method makes it possible to supply a suffici
- Toshima, Hiroaki,Nara, Shinji,Aramaki, Hisateru,Ichihara, Akitami,Koda, Yasunori,Kikuta, Yoshio
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p. 1724 - 1728
(2007/10/03)
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- A CONVENIENT PREPARATION OF IODOALKYL ESTERS FROM LACTONES
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The reaction of lactones with trimethylsilyl iodide in the presence of an alcohol provides a short and convenient access to iodoalkyl esters, useful intermediates in organic synthesis.
- Kolb, Michael,Barth, Jacqueline
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p. 763 - 768
(2007/10/02)
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- Reactions of the Cyclopropanone Hemiketal Magnesium Salt with Some Nucleophilic Reagents
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Cyclopropanol (5), 1-(arylethynyl)cyclopropanol (7), 1-(3-hydroxypropyl)cyclopropanol derivative 10, 1-(2-propynyl)cyclopropanol (14), cyclopropanone cyanohydrin (19), 1-(aminomethyl)cyclopropanol (21) derivatives, benzylidenecyclopropanes 32, and ethyl cyclopropylideneacetate (38) have been prepared from the magnesium salt of cyclopropanone hemiketal 3. 3-Cyclopropylidene-1-propanol (12) and 3-cyclopropylidene-1-propyne (16) have been obtained from the cyclopropanols 10 and 14, respectively. Some reactions of this new synthon were specific. On the other hand, 3 did not undergo the nucleophilic addition of sulfur and nitrogen ylides; it underwent oxidizing ring opening with BrZnCH2COOEt and induced the decomposition of diazomethane.
- Salauen, Jacques,Bennani, Fatima,Compain, Jean-Claude,Fadel, Antoine,Ollivier, Jean
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p. 4129 - 4135
(2007/10/02)
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