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Organic Chemistry Phenomena (2):
Recent article
Organic Chemistry Phenomena
Abstract
We proposed some new topological indices (Sh indices) based on the distance sum and connectivity of a molecular graph that derived directly from two-dimensional molecular topology for use in QSAR/QSPR studies. In this study, the ability of these indices to predict the liquid densities (rho) of a lar...
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PMID: 18948045
PDF is available here.
PDF is available here.
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Organic Letters (10)20 2008
Abstract
A facile stereoselective synthesis of multifunctionalized tetrahydro-1,2-oxazines (THOs) has been achieved by the organocatalyzed asymmetric tandem alpha-aminoxylation/aza-Michael reaction for the C-O/C-N bond formations in moderate to good yields with excellent diastereo- (>99:1 dr) and enantiosele...
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PMID: 18788743
PDF is available here.
PDF is available here.
Abstract
A series of binuclear NiNi complexes supported by a single thiolate bridge and containing a methylnickel moiety have been prepared and fully characterized. The complexes represent structural analogues for the proposed organonickel intermediate in the acetyl coenzyme A synthase catalytic cycle. Varia...
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PMID: 18800791
PDF is available here.
PDF is available here.
Abstract
A new catalyst is designed, synthesized, and evaluated for the asymmetric Michael addition of nitroalkanes to nitroalkenes. The obdurate nature of this reaction has made this a formidable challenge to subdue by asymmetric catalysis. The catalyst design includes a thiourea function to activate the ni...
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PMID: 18808117
PDF is available here.
PDF is available here.
Abstract
Our synthetic route provided a range of key analogues with partial structures to define the pharmacophore. Simplification of the caprazamycins was further pursued to develop diketopiperazine analogs....
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PMID: 18670104
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (128)8 2008
Abstract
N-Heterocyclic carbenes have been studied for their ability to catalyze C-C bond formations and asymmetric reactions. The fluoro groups of fluorobenzenes are nucleophilically substituted with aroyl groups derived from aromatic aldehydes due to the catalytic action of imidazolidenyl carbenes to affor...
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PMID: 18670183
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (128)8 2008
Abstract
We have developed a novel and practical synthetic method for functionalized benzofurans via the route involving [3,3]-sigmatropic rearrangement of N-trifluoroacetyl enehydroxylamines, which was triggered by acylation of oxime ethers. Treatment of oxime ethers with trifluoroacetic anhydride (TFAA) ga...
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PMID: 18670179
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (128)8 2008
Abstract
We named this rearrangement epoxysilane rearrangement. Based on results of mechanistic studies involving competitive experiments using diastereomeric cyanohydrins, we propose a reaction pathway involving a silicate intermediate formed by a concerted process via an anti-opening of the epoxide followe...
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PMID: 18670182
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (128)3 2008
Abstract
We discuss 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM), which serves as an exceptionally convenient reagent for dehydrocondensation. In particular, formation of carboxamide by DMT-MM was found to take place even if water or alcohol were used as a reaction medium. Thus...
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PMID: 18311063
PDF is available here.
PDF is available here.
Abstract
A new route to bottom-up organic nanotechnology is presented. Molecular building blocks with specific optoelectronic properties are designed and grown via directed self-assembly arrays of morphologically controlled light-emitting organic nanofibers on template surfaces. The fibers can be easily tran...
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PMID: 18203230
PDF is available here.
PDF is available here.
Abstract
We investigated a suspected cluster of lymphohaematopoietic cancer in departments of biology and chemistry at a Norwegian university. A historical cohort of students and employees (n = 7,189) were followed for cancer for 96,936 person-years in the Cancer Registry of Norway. Overall, 12 cases of lymp...
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PMID: 17985198
PDF is available here.
PDF is available here.
Abstract
We have prepared soluble melanins via the synthesis of monomeric precursors containing lipophilic substituents. Two such monomers derived from 5,6-dihydroxyindole-2-carboxylic acid (DHICA) were prepared, namely the benzyl and octyl ester derivatives. Both benzyl and octyl ester monomers were oxidati...
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PMID: 18282186
PDF is available here.
PDF is available here.
Abstract
Transmission electron microscopy (TEM), soft X-ray scanning transmission X-ray microscopy (STXM), and mu-FTIR spectromicroscopy were used to map colloidal/ particulate material in an ultra-oligotrophic lake, Lake Brienz, Switzerland, with a special focus on organic functionality. Within the statisti...
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PMID: 18075100
PDF is available here.
PDF is available here.
Abstract
Abstract
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Abstract
For understanding the origin(s) of life on Earth it is essential to search for and study extraterrestrial environments where some of the processes which participated in the emergence of Life on our planet are still occurring. This is one of the goals of astrobiology. In that frame, the study of extr...
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PMID: 17592756
PDF is available here.
PDF is available here.
Abstract
A cyclic ethylene linked triphenylamine dimer formed highly crystalline thin film via vapor deposition. Meanwhile, the corresponding linear molecule only resulted in amorphous films under the same condition. The performance as FET semiconductor also improved significantly when the molecular structur...
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PMID: 17165699
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
Abstract
A sequence involving dihydroxylation and acid induced fragmentation of silene generated silacyclohexenes represents the key step in a concise synthetic route to beta-hydroxy-delta-lactones.
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PMID: 17036108
PDF is available here.
PDF is available here.
Abstract
A mathematical model is presented for predicting the flash point of miscible mixtures. This model is reducible and adequate for some specified systems as proposed previously. Except for multiple aqueous-organic solutions, the predictive capability of the reduced form for other miscible mixtures, inc...
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PMID: 16621255
PDF is available here.
PDF is available here.
Abstract
The carbon-bearing adsorbents were prepared from biochemical and surplus sludges by physical activation and chemical activation. The results indicated that the adsorbents made by way of chemical activation were better, with the optimum activator being complex of ZnCl(2) and H(2)SO(4). Moreover, the...
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PMID: 16563615
PDF is available here.
PDF is available here.
Biodegradation (17)4 2006
Abstract
Experiments were conducted to determine the effects of composting or simple addition of compost to the mineralization of n-hexadecane, pyrene and benzo(a)pyrene in soil. Soil (contaminated or clean) was composted with maple leaves and alfalfa. Samples from different composting phases were spiked wit...
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PMID: 16284924
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
Diols are desymmetrized by a tandem oxidation/Wittig olefination to give alpha,beta-unsaturated hydroxy esters without the requirement for protecting group strategies; the alpha,beta-unsaturated hydroxy esters are transformed into dienyl diesters using a second oxidation/Wittig olefination sequence...
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PMID: 16718329
PDF is available here.
PDF is available here.
Abstract
For many years, our research group has been interested in the new developments of cobalt-mediated cyclizations. In this article, our recent achievements in the field of inter- and intramolecular [2 + 2 + 2] cyclizations are compiled.
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PMID: 16718307
PDF is available here.
PDF is available here.
Abstract
Polymer-supported dicyanoketene acetal (poly-DCKA-1), synthesized by copolymerization of a DCKA bearing a 4-vinylbenzyl group with ethyleneglycol dimethacrylate, was found to be an excellent recyclable catalyst for the three-component Mannich-type reaction of aldehydes, aromatic amines, and TMS enol...
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PMID: 16595974
PDF is available here.
PDF is available here.
Abstract
Natural Product Reports (23)1 2006
Abstract
YAKUGAKU ZASSHI (126)2 2006
Abstract
The reactions of 2- or 4-cyanopyridinium salts with active methylene compounds such as dimethyl malonate, malononitrile, and cyclohexane-1,3-dione affording 2- or 4-(substituted methylene) pyridines are described. Similar reactions of 4-cyano-2-methylthiopyridinium and 4-cyano-2-methylthioquinoliniu...
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PMID: 16462099
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (126)2 2006
Abstract
The carbon-carbon bond-forming reactions of 1-methyl-2-methylthiophenylpyridinium iodides with active methylene compounds (such as dimethyl malonate, malononitrile) using NaH as a base gave the 2-substituted methylene-1,2-dihydropyridine derivatives.
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PMID: 16462100
PDF is available here.
PDF is available here.
Abstract
The use of engineered phenylalanine dehydrogenase N145A supported on Celite for the reductive amination of phenylpyruvic acid in homogeneous and biphasic aqueous-organic solvents is reported. The results indicate that the immobilised biocatalyst is remarkably robust, even in the presence of high con...
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PMID: 16327891
PDF is available here.
PDF is available here.
Abstract
An overview is provided of the capabilities for the current versions of the BOSS and MCPRO programs for molecular modeling of organic and biomolecular systems. Recent applications are noted, particularly for QM/MM studies of organic and enzymatic reactions and for protein-ligand binding.
(c) 2005 Wi...
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PMID: 16200637
PDF is available here.
PDF is available here.
Abstract
We studied the influence of intermolecular interactions on the first combination band between the OH-stretching and -deformation vibrations of the water that is dissolved in organic and polymeric materials. The water has two types. The first type occurs in the matrix in which water-interactive funct...
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PMID: 16150636
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (125)12 2005
Abstract
This review highlights a recent study on allenic compounds by the author's group. In the first section, the organocopper-mediated ring-opening reaction of ethynylaziridines and palladium-catalyzed reductive synthesis of allenes are described. In the second section, palladium-catalyzed stereoselectiv...
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PMID: 16327237
PDF is available here.
PDF is available here.
Abstract
A sensitive method based on the principle of photothermal phenomena to study the energy transfer processes in organic dye mixtures is presented. A dual beam thermal lens method can be very effectively used as an alternate technique to determine the molecular distance between donor and acceptor in fl...
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PMID: 16112890
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (125)10 2005
Abstract
Using a unique character of the chiral palladium complexes 1 and 2, several types of novel catalytic asymmetric reactions have been developed. In contrast to the conventional Pd(0)-catalyzed reactions, these complexes function as an acid-base catalyst. Thus active methine compounds were activated to...
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PMID: 16205036
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (125)10 2005
Abstract
Highly active and reusable polymeric catalysts were produced by a self-assembly process of non-cross-linked amphiphilic polymeric ligands with inorganic species. Thus a new insoluble tungsten polymeric catalyst PWAA 1 was prepared from H(3)PW(12)O(40) and poly[(N-isopropylacrylamide)-co-(acrylamide...
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PMID: 16205034
PDF is available here.
PDF is available here.
Abstract
Methoxyamine (MX) is a potential new anti-cancer drug. In this paper, a quantitative HPLC-UV method for MX using 4-(diethylamino)benzaldehyde (DEAB) as a derivatizing agent has been developed and validated. The studies showed that MX reacts with DEAB under acidic conditions to form protonated 4-(die...
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PMID: 15951147
PDF is available here.
PDF is available here.
Abstract
We present real-time quantitative monitoring of the catalyzed Heck reaction by using the solvent as internal standard. In this way, all multiplicative distortions, e.g., laser intensity variations or absorbance of the laser light, can be corrected for. We also show that a limited amount of fluoresce...
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PMID: 15732901
PDF is available here.
PDF is available here.
Abstract
In 1971 Kenner et al. introduced the safety-catch principle into solid phase peptide synthesis. Thus two contradicting needs were addressed. On the one hand, sufficient stability of the linker substrate bond to impede hydrolysis or similar side reactions, on the other hand mild chemical conditions a...
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PMID: 15653327
PDF is available here.
PDF is available here.
Abstract
A synthesis of the C9-C16 segment of ambruticin is described which relies on organoiron methodology to establish the 1,2,3-trisubstituted cyclopropane ring.
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PMID: 15614389
PDF is available here.
PDF is available here.
Molecular Diversity (9)4 2005
Abstract
We present soluble dendritic polyglycerol (PG) supported reagents PG-DEAD, PG-PPh3, and PG-DCC as well as scavengers PG-carbonate, PG-carbazate, and PG-amine, which all have been synthesized in high overall conversions and yields using simple purification techniques. The supported reagents have been...
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PMID: 16311807
PDF is available here.
PDF is available here.
Abstract
Some new substituted dihydrothieno[2',3':4,5]thieno[2,3-c]quinolin-6-ones 9- 12 and tetrahydrodithieno[2,3-b: 2',3'-d]thieno[2'',3''-c:2'',3''-c']diquinolin-6,14-dione (17) were prepared from the corresponding new anilides 5-8 and from the corresponding dianilide 15, respectively, by a multistep com...
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PMID: 18007297
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (124)11 2004
Abstract
This paper covers recent publications from our laboratory on the synthesis of a variety of phosphonate and phosphinate derivatives. New methods for the enantioselective synthesis of alpha-hydroxyphosphonates were established by Lewis acid-mediated cleavage of homochiral 1,3-dioxaneacetals with P(OEt...
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PMID: 15516802
PDF is available here.
PDF is available here.
Abstract
Abstract
Abstract
Due to their extraordinary properties, such as the ionic composition, good thermal stability, low vapor pressure, and solution interactions, ionic liquids can be used as solvents, reagents, and heating aids in conjunction with microwave chemistry. Synthesis of diverse molecules can be improved with...
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PMID: 15320715
PDF is available here.
PDF is available here.
Abstract
We showed, by FTIR spectroscopy, that cyanamide can be isomerized in carbodiimide (HNCNH), another interstellar relevant molecule, by a reaction involving the amorphous water-ice surface as catalyst. This isomerization occurs at low temperature (T < 100 K) which agrees quite well with that expected...
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PMID: 15212513
PDF is available here.
PDF is available here.
Abstract
Hyperolactone C is prepared from furan 4. The key transformation is a tandem Claisen rearrangement/lactonization.
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PMID: 15217291
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (124)6 2004
Abstract
The aqueous medium radical reactions of a variety of imine derivatives such as oxime ether, oxime, hydrazone, nitrone, and N-sulfonylimine were investigated. Triethylborane-mediated intermolecular alkyl radical addition to glyoxylic oxime ether, oxime, and nitrone in water proceeded smoothly to give...
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PMID: 15170066
PDF is available here.
PDF is available here.
YAKUGAKU ZASSHI (124)5 2004
Abstract
A structure-activity relationship study was performed on cyclic RGD peptides using a combination of multisubstituted alkene dipeptide isosteres. To clarify the effects on bioactivity of a valine N-methyl group in the cyclo(-Arg-Gly-Asp-D-Phe-MeVal-) peptide developed by Kessler's group, novel D-Phe-...
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PMID: 15118239
PDF is available here.
PDF is available here.