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  • 1
    ISSN: 0947-3440
    Schlagwort(e): Trifluoromethyl-substituted alkenes ; anti-Michael addition ; Acceptor-substituted double bond ; Steric demand of a CF3 group ; Charge-shift correlation ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Several bis(trifluoromethyl)- and trifluoromethyl-substituted alkenes, dienes, arylalkenes, and α,β-unsaturated derivatives of carbonyl compounds such as tosylhydrazone 5b and diazomethane 5c were prepared. Their reactivity towards a variety of nucleophiles, resulting from the electron-withdrawing effect of the trifluoromethyl group, was investigated. Depending on the trifluoromethyl- and a bis(trifluoromethyl)-substituted double bond, different regioselectivities were observed in the reaction with morpholinocyclohexene as a nucleophile. An explanation is given on the basis of the 13C-NMR data.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 121 (1988), S. 1329-1340 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Syntheses of New Aromatic Compounds with Fluorimated Side Chains and their Chemical ReactivityThe syntheses of a wide range of aromatic compounds of the type p-Y-C6H4CF2X (4-13) are described, and the chemical behavior of these compounds as a function of substituent Y is investigated [Y = both electron-releasing and -withdrawing substituents such as NO2, CF3, Cl, H, C(CH3)3, OCH3, and N(CH3)2 (a-g), X = -H, -Br, -SPh, -OPh, -N3, -NCO, -NCS, -SCN, -NCSe, or -SeCN]. Analogously the pyridine derivatives 15, 17, and 18 were synthesized and characterized. From a correlation of the 19F-NMR data of these compounds with the Hammett constant of Y, participation of C-F π-back-donation is seen as the cause for an observed shift of the 19F signals to lower field.
    Notizen: Die Synthese zahlreicher Verbindungen des Typs p-Y-C6H4CF2X (4-13) wird beschrieben und ihr chemisches Verhalten in Abhängigkeit vom Substituenten Y untersucht [Y = Donor- und Akzeptorsubstituenten NO2, CF3, Cl, H, C(CH3)3, OCH3 und N(CH3)2 (a-g), X = -H, -Br, -SPh, -OPh, -N3, -NCO, -NCS, -SCN, -NCSe oder -SeCN]. Analog sind die Pyridinderivate 15, 17 und 18 dargestellt und charakterisiert worden. Durch Korrelation der 19F-NMR-Daten dieser Verbindungen gegen die Hammettkonstante des Y-Substituenten kann die Beteiligung von C-F-π-Rückbindungen als Ursache für eine Tieffeld-Signalverschiebung abgeleitet werden.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 145-149 
    ISSN: 0009-2940
    Schlagwort(e): Bis(trifluormethyl)butenal ; Retinoids ; β-Ionol ; Fluoro compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Preparation of Suitable Precursors for the Synthesis of 16,16,16,17,17,17-HexafluororetinalsCycloaddition reactions of (CF3)2C = CHCHO with butadiene or 1,3-pentadiene provide the corresponding cyclohexane derivatives 2, 3 and 4. Condensation of 3 with (C2H5O)2P-(O)CH2C(O)CH3 or of 2 with acetone in the presence of bases yields 5 and 7. While 5 reacts with CH2 = CHMgBr to give 6, treatment of 7 with diluted HCI provides 8. Compounds 7 and 8 proved to be not suitable as starting materials for the preparation of 16,16,16,17,17,17-hexafluororetinals. A better synthon is the diene 11. This is obtained in a threestep reaction starting from hexafluoroacetone and (C6H5)3P=CHC(O)CH3 to give 9 which on treatment with CH3MgI provides 10. Dehydration of 10 with 50% H2SO4 forms 11. In this reaction sequence byproduct 12 is formed presumably by addition of CF3C(O)CF3 to 9. At elevated temperatures under pressure 11 adds ethylene to form 13. Functionalization of 13 in 2-position is achieved by hydroboration/oxidation yielding 14 which is oxidized with pyridinium dichromate to 15. Oxidation and bromination reaction of 13 are described.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 449-455 
    ISSN: 0009-2940
    Schlagwort(e): Trifluoromethylsulfanyl compounds ; Pentafluorophenylsulfanyl compounds ; Trifluoromethylselenanyl compounds ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Tris(perfluoroorganochalkogenyl)methyl Compounds: Synthesis, Structures, and PropertiesReaction of (CF3S)2CHC(OC2H5)3 with CF3SCl or CF3SeCl in the presence of NaH in ether provides X(CF3S)2CC(O)OC2H5 (1a, b: X = CF3S, CF3Se). These compounds react with NH3 to form (CF3S)2CHC(O)NH2 (2b) which is also obtained from (CF3S)2CHC(O)OC2H5 and NH3. Dehydration of the amide 2b yields (CF3S)2CHCN (3b), which reacts with NaH and then with CF3SX (X = Cl, SCF3) or with RfCl (Rf = CF3Se, C6F5S) to give Rf (CF3S)2CCN [Rf = CF3S (3c), CF3Se (3d), C6F5S (3e)]. 3c is also obtained from (CF3S)3CBr and AgCN. Hydrolysis of 3c with conc. H2SO4 leads almost quantitatively to (CF3S)3CC(O)NH2 (2c), which on treatment with COCl2 gives only 3c and not the corresponding isocyanate. If phosgene is replaced by oxalyl chloride and treated with 2c in a 1:1 molar ratio, (CF3S)3CC(O)NCO (4a) is formed. The urea derivative (CF3S)3CC(O)NHC(O)NHC(O)C(SCF3)3 (4b) is obtained either by using a 2:1 molar ratio of 2c and [C(O)Cl]2 or from 2c and 4a. Attempts to substitute (CF3S)2CHCO2H - after treatment with NaH in ether - with CF3SCl provides low yields of 2,4-bis[bis(trifluoromethylsulfanyl)methylene]-1,3-dithietane (5). X-ray structure analyses are performed for (CF3S)3CCN (3c) and the 1,3-dithietane 5.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3502-3506 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Efforts in Synthesizing α,β-Unsaturated Trifluoromethyl-substituted AldehydesHexafluoroacetone reacts with ethynylmagnesium bromide to yield (CF3)2C(OH) — C ≡ CH (1). Bromine can be added to the triple bond affording the cis/trans-isomer 2. With PCl5 1 yields the allene (CF3)2C=C=CClH (3). The addition of a metalated Schiff base to hexafluoroacetone leads to 4a which on hydrolysis yields (CF3)2C(OH) — CH2 — CHO (4b). The reaction of (EtO)2P(O)CH2 — R (R=CHO, CO2Et) with hexafluoroacetone gives α,β-unsaturated aldehydes or esters 6. 1,1,1-Trifluoroacetone provides analogous reactions.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 130 (1997), S. 131-134 
    ISSN: 0009-2940
    Schlagwort(e): Trifluoromethyl vinyl sulfide ; Gas-phase structure ; Electron diffraction ; Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The geometric structure of trifluoromethyl vinyl sulfide, CF3SC(H)=CH2, was determined by gas electron diffraction and ab initio calculations (HF/3-21G* and MP2/6-31G*). A single conformer with a dihedral angle φ(C=C-S-C) = 129(4)° is present. The conformational properties are compared to those of the parent compound, CH3SC(H)=CH2, and of the perfluorinated species CF3SC(F)=CF2.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2891-2894 
    ISSN: 0009-2940
    Schlagwort(e): Chemistry ; Inorganic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Preparation and Properties of (Trifluoromethylthio)-substituted Carbonyl CompoundsHalogene exchange reaction of CF3SC(O)F with BBr3 leads to CF3SC(O)Br, a good starting material for synthesizing compounds of the type CF3SC(O)X (X = CN, NCO, NCS, OC(O)CF3, CF3, SeCF3, and NH2).
    Notizen: Durch Halogenaustausch mit BBr3 läßt sich CF3SC(O)F in CF3SC(O)Br überführen. Dieses ist ein gutes Ausgangsreagenz zur Synthese von Verbindungen des Typs CF3SC(O)X (X = CN, NCO, NCS, OC(O)CF3, CF3, SeCF3 und NH2).
    Materialart: Digitale Medien
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