- Synthesis of Cyclic α-Diazo-β-keto Sulfoxides in Batch and Continuous Flow
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Diazo transfer to β-keto sulfoxides to form stable isolable α-diazo-β-keto sulfoxides has been achieved for the first time. Both monocyclic and benzofused ketone derived β-keto sulfoxides were successfully explored as substrates for diazo transfer. Use of continuous flow leads to isolation of the desired compounds in enhanced yields relative to standard batch conditions, with short reaction times, increased safety profile, and potential to scale up.
- McCaw, Patrick G.,Buckley, Naomi M.,Eccles, Kevin S.,Lawrence, Simon E.,Maguire, Anita R.,Collins, Stuart G.
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p. 3666 - 3679
(2017/04/11)
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- Development of Chiral Spiro P-N-S Ligands for Iridium-Catalyzed Asymmetric Hydrogenation of β-Alkyl-β-Ketoesters
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The chiral tridentate spiro P-N-S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3-dithiane moiety into the ligand resulted in a highly efficient chiral iridium catalyst for asymmetric hydrogenation of β-alkyl-β-ketoesters, producing chiral β-alkyl-β-hydroxyesters with excellent enantioselectivities (95-99.9 % ee) and turnover numbers of up to 355 000. Bulkyness is the key: New chiral tridentate spiro P-N-S ligands (SpiroSAP) bearing a conformationally constrained 1,3-dithiane moiety were developed. Their iridium catalysts showed excellent enantioselectivities and activity (TON up to 355 000) for asymmetric hydrogenation of β-alkyl-β-ketoesters.
- Bao, Deng-Hui,Wu, Hui-Ling,Liu, Chao-Lun,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 8791 - 8794
(2015/11/27)
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- Crystal Structure of 3-(4-Methoxy-benzylidene)-isothiochroman-4-one
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The title compound, 3-(4-methoxy-benzylidene)-isothiochroman-4-one (C 17H14O2S) was prepared from the reaction of isothiochroman-4-one with benzaldehyde in the presence of small amount of HCl. The structure of the synthesised compound was determined by IR, 1H NMR and X-ray crystallography. The structure was solved in monoclinic, space group P21/n with a = 3.9773 (7) A, b = 10.918 (2) A, c = 30.609 (6) A, β = 90.615 (3)°, V = 1329.1 (4) A3, Z = 4 and with R int = 0.047. The bicyclic ring of isothiochroman-4-one moiety does not adopt a planar geometry. The molecular conformation is stable via C10-H???O1 and C16- H???S1 intramolecular hydrogen-bonding interactions. These contacts involve molecules in an extended two-dimensional sheet to the bc plane.
- Akkurt,YIldIrIm,Kerbal,Bennani,Hadda, T. Ben,Chohan,McKee, Vickie
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experimental part
p. 165 - 168
(2011/07/30)
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- Extractants for palladium and method of rapidly separating and recovering palladium using the same
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Provided is a novel extractant for palladium capable of improving an extraction rate compared to the conventional extractant, DHS, and also capable of back-extracting palladium using an ammonia solution, and a method of separating and recovering palladium
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Page/Page column 3
(2009/07/25)
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- SUBSTITUTED CYCLOHEXYL-1,4-DIAMINE DERIVATIVES WITH A CHAIN EXTENSION
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The invention relates to substituted cyclohexyl-1,4-diamine derivatives, to a method for their production, to medicaments containing said compounds and to the use of substituted cyclohexyl-1,4-diamine derivatives for producing medicaments.
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Page/Page column 25
(2008/06/13)
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- Non-thiol farnesyltransferase inhibitors: Structure-activity relationships of aralkylsubsituted benzophenones
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We describe a novel class of benzophenone-based farnesyltransferase inhibitors exploiting a novel aryl binding region in the farnesyltransferase's active site. The present study was mainly focussed on structural modifications of the trimethylene spacer of the 4-phenyl butyroyl residue of our lead structure (IC50 = 530 nM). These modifications turned out to have little effect on activity as had the replacement of the terminal aryl by cyclohexyl (IC50 = 440 nM vs. IC50 = 530 nM).
- Mitsch, Andreas,Wi, Pia,Sattler, Isabel,Schlitzer, Martin
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- Comparison of the labelling characteristics of mercaptoacetyltriglycine (MAG3) with different S-protective groups
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A number of different thiol protective groups have been synthesized and attached to mercaptoacetyltriglycine (MAG3) ligand. The newly made MAG3 analogues were labelled with 99mTc by direct labelling under alkaline condition and by stannous tartrate exchange labelling method. In the latter method, the amount of the ligand, reaction temperature and pH varied and their effects on the labelling efficiencies were studied. Radiochemical purities of 51% to 70%, 58% to 75% and 46% to 81% respectively, were obtained by radio-HPLC analysis for the studied MAG3 precursors when, 0.1 mg, 0.4 mg and 1.6 mg of the ligand was used and labelling was performed at both low temperature (70°C) and pH (pH 3). All the studied ligands were efficiently labelled with 99mTc (up to 99%) when heated for 10 min at pH 9 and 100°C. The labelling efficiency obtained by the direct labelling method for MAG3 analogues varied from 32% to 94% and was in all cases lower than after the exchange labelling at pH 9 and at 100°C. It was observed that the radiochemical purities can be improved significantly by heating the 'direct labelling mixture' at elevated temperature.
- Okarvi, Subhani M.,Adriaens, Paul,Verbruggen
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p. 853 - 874
(2007/10/03)
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- Mass Spectrometry of 2-Alkylthio-2-methylpropanoic Acids and Their Esters and Amides. Structural and Steric Effects on the McLafferty Rearrangement
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The electron ionization mass spectra (MS) of S-methylated derivatives of N-(2-mercapto-2-methylpropanoyl)-L-cysteine and 2-alkylthio-2-methylpropanoic acids, as well as their esters and amides, were examined.Use of the deuterium labeling technique and accurate mass measurement supported the proposed fragmentation pathways.Extensive loss of CH2S from a molecular ion by the McLafferty rearrangementof a primary hydrogen is important in the MS of S-methyl compounds of amide derivatives.It was demonstrated that the intensity of the rearrangement ion decreases in the order of amide, ester, and acid, and in the case if amides the reaarangement is suppressed by the nonbonded interaction between methyl groups on the α carbon and the amide nitrogen.Keywords-N-(2-mercapto-2-methylpropanoyl)-L-cysteine; 2-alkylthio-2-methylpropanoic acid and methyl ester; 2-alkylthio-2-methylpropanamide; electron impact mass spectrometry; McLafferty rearrangement; steric interaction
- Mori, Yuji,Fujiwara, Shigeru,Miyachi, Toshiko,Kitanishi, Hiroyuki,Oya, Masayuki,et al.
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p. 1505 - 1517
(2007/10/02)
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