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Unexpected Reaction (unexpected + reaction)
Selected AbstractsChemInform Abstract: NHC-Catalyzed Transformation of Aromatic Aldehydes to Acids by Carbon Dioxide: An Unexpected Reaction.CHEMINFORM, Issue 41 2010Vijay Nair Abstract The reaction affords the corresponding carboxylic acids instead of the expected glyoxylic acids (III) (mechanism). [source] ChemInform Abstract: An Unexpected Reaction of Phosphorous Tribromide on Chromanone, Thiochromanone, 3,4-Dihydro-2H-benzo[b]thiepin-5-one, 3,4-Dihydro-2H-benzo[b]oxepin-5-one and Tetralone Derived Allylic Alcohols: A Case Study.CHEMINFORM, Issue 7 2009Maloy K. Parai Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: An Unexpected Reaction of Cyanothioacetamide: Novel Preparation of Pyrazolo[3,4-b]pyridine Derivatives under MWI.CHEMINFORM, Issue 46 2008Xue Sen Fan Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] New Three-Component Reaction: Novel Formation of a Seven-Membered Ring by the Unexpected Reaction at the ,-Position of the ,-Keto Ester.CHEMINFORM, Issue 36 2007Hiromichi Fujioka Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] An Unexpected Reaction of Trimethylsilyl Fluorosulfonyldifluoroacetate (TFDA) with Imidazoles.CHEMINFORM, Issue 14 2007Formation of N-Difluoromethylthioureas. Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Thin Layer Chromatography for the Detection of Unexpected Reactions in Organometallic Combinatorial CatalysisADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 8 2003Olivier Lavastre Abstract Thin layer chromatography (TLC) represents a fast and inexpensive alternative to NMR spectroscopy or analytical methods based on chromatography for the detection of unexpected products in organometallic combinatorial catalysis. This screening test led to the detection of the catalytic system [Ir(COD)Cl]2/PPh3 for isomerisation of diolefinic substrates instead the expected ring closing metathesis (RCM) reaction. [source] Unexpected reactions associated with the xanthate-mediated polymerization of N -vinylpyrrolidoneJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 19 2008Gwenaelle Pound Abstract The monomer N -vinylpyrrolidone (NVP) undergoes side reactions in the presence of R group functional xanthates and impurities. The fate of the monomer NVP and a selection of six O -ethyl xanthates during xanthate-mediated polymerization were studied via NMR spectroscopy. A high number of by-products were identified. Significant side reactions affecting NVP include the formation of an unsaturated dimer and hydration products in bulk or in solution in C6D6. In addition, the xanthate adjacent to a NVP unit was found to undergo elimination at moderate temperature (60,70 °C), resulting in unsaturated species and the formation of new xanthate species. The presence of the chlorinated compound ,-chlorophenyl acetic acid, ethyl ester, a precursor in the synthesis of the xanthate S -(2-ethyl phenylacetate) O -ethyl xanthate, resulted in a dramatic increase in the rate of side reactions such as unsaturated dimer formation and a high ratio of unsaturated chain ends. The conditions for the occurrence of such side reactions are discussed in this article, with relevance to increasing the control over the polymerization kinetics, endgroup functionality, and control over the molar mass distribution. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6575,6593, 2008 [source] Dimerization of ionized 4-(methyl mercapto)-phenol during ESI, APCI and APPI mass spectrometryJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 9 2009Lianming Wu Abstract A novel ion/molecule reaction was observed to occur under electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo ionization (APPI) conditions, leading to dimerization of ionized 4-(methyl mercapto)-phenol followed by fast H· loss. The reaction is particularly favored during ESI, which suggests that this ion/molecule reaction can occur both in the solution inside the ESI-charged droplets and in the gas-phase environment of most other atmospheric pressure ionization techniques. The dimerization reaction is inherent to the electrolytic process during ESI, whereas it is more by ion/molecule chemistry in nature during APCI and APPI. From the tandem mass spectrometry (MS/MS) data, accurate mass measurements, hydrogen/deuterium (H/D) exchange experiments and density functional theory (DFT) calculations, two methyl sulfonium ions appear to be the most likely products of this electrophilic aromatic substitution reaction. The possible occurrence of this unexpected reaction complicates mass spectral data interpretation and can be misleading in terms of structural assignment as reported herein for 4-(methyl mercapto)-phenol. Copyright © 2009 John Wiley & Sons, Ltd. [source] Sodium tris(glycinium) bis(hexafluorosilicate) glycine trisolvateACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007Moolya B. Narayana The title compound, Na+·3C2H6NO2+·2SiF62,·3C2H5NO2, arose from an unexpected reaction of glycine and HF with the glass container. It is an unusual hybrid organic,inorganic network built up from chains of vertex-sharing NaF4O2 and SiF6 octahedra. A pair of glycinium/glycine molecules bridges the chains into a sheet via a centrosymmetric O...H...O link. The other organic species interact with the network by an extensive N,H...F hydrogen-bond network, including bifurcated and trifurcated bonds. Finally, an extremely short C,H...O interaction (H...O = 2.25,Å) is seen in the crystal structure. The Na atom has site symmetry . [source] Synthesis and Biological Evaluation of Phorbol-Resiniferatoxin (RTX) HybridsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 16 2004Giovanni Appendino Abstract Phorboid 20-homovanillates modified on ring C to mimic the constitution and conformation of the ultrapotent vanilloid resiniferatoxin (RTX) and on the AB ring system to suppress the tumour-promoting potential of the terpenoid core were prepared. Several unexpected reactions were discovered, and the structure-activity relationships for this class of vanilloid ligands were expanded. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] | ||||||||||