Search Results

You are looking at 1 - 10 of 116 items :

  • "Electrophilic Substitution Reactions" x
Clear All

Phosphonyl- und Phosphinyl-triazene [1, 2] Elektrophile Substitutionsreaktionen mit Benzol Phosphonyl- and Phosphinyl-triazenes [1, 2] Electrophilic Substitution Reactions with Benzene Richard Kreher* und Reinhard Halpaap Institut für Chemie, Medizinische Hochschule Lübeck, Ratzeburger Allee 160, D-2400 Lübeck Z. Naturforsch. 87b, 1178-1183 (1982); eingegangen am 24. Mai 1982 Phosphonyl- and Phosphinyl-triazenes, ^-Elimination, Electrophilic Substitution Reactions with Benzene The reaction of phosphonyltriazenes with benzene in the presence of

ANOMALOUS ELECTROPHILIC SUBSTITUTION REACTIONS IN 3,3'-LINKED DIPYRROMETHANES Sam Η. Leung, Liem Τ. Nguyen and Kevin M. Smith* Department of Chemistry, University of California, Davis, CA 95616, U.S.A. Abstract: The 3,3'-linked dipyrromethane 5 was synthesized by the self-condensation of hydroxymethylpyrrole 4; along with 5, a minor by-product was the novel tripyrrane 7. Vilsmeier formylation of 5 unexpectedly afforded the formylpyrrole 6 instead of the diformyldipyrromethane 8. Likewise, acylation of 5 gave acetylpyrrole 9 as the major product. A

Radiochimica 132 DANIEL-ACHE: Electrophilic Substitution Reactions of Bromine Ions with Halomethanes in the Gasphase Acta Electrophilic Substitution Reactions of Bromine Ions with Halomethanes in the Gasphase [1] By S A M U E L H . D A N I E L and H A N S J. A C H E , D e p a r t m e n t o f Chemis t ry , Virginia Polytechnic Inst i tute and Sta te University, Blacksburg, Virginia 24061 With 2 figures. (Received January 9, 1973) Abstract The electrophilic substitution reactions of 8 0Br+ , generated in the 8 0 mBr —LJL—>. 8 0ßr nuclear process, were

THE IMPORTANCE OF COORDINATION IN ELECTROPHILIC SUBSTITUTION REACTIONS OF ORGANOMET ALLIC COMPOUNDS 0. A. REUTOV Department of Chemistry, Moscow M. V. Lomonosov State Universiry, Moscow, U.S.S.R. The mechanism of electrophilic substitution at a saturated carbon atom ""' l ""' } -C-lX + z+------* -c-z + x+ sE / : / has been clarified by recent work on organametallic compoundsl-3. This is 6- B+ largely because of the polarization of the metal-carbon bond C-Me, which favours SE reactions. Organomercury compounds are most convenient for such studies

SOME ELECTROPHILIC SUBSTITUTION REACTIONS OF DITHIENO [2,3-b : 3* 4'-d]PYRIDINE Ecalerina Temciuc, Anna-Britta Hörnfeldt and Salo Gronowitz* Division of Organic Chemistry 1, Chemical Center, University of Lund, P.O. Box 124, S-22100 Lund , Sweden. Abstract;Nitration, bromination and iodination of dithieno[2,3-b:3,4-c/]pyridine have been studied and the results compared with those obtained for other isomeric systems. Nitration with concentrated nitric acid in trifluoroacetic acid gave selectively the 8-nitro isomer. The 8-bromo isomer was best obtained in 61

Untersuchungen zur Chemie von Isoindolen und Isoindoleninen, XXXII [1] Elektrophile Substitutionsreaktionen von 2-Aryl-2H-isoindolen mit Trifluoressigsäureanhydrid Studies on the Chemistry of Isoindoles and Isoindolenines, XXXII [1] Electrophilic Substitution Reactions of 2-Aryl-2H-isoindoles with Trifluoroacetic Anhydride Richard P. Kreher*, Udo Feldhoff und Frank Jelitto Fachbereich Chemie, Lehrstuhl für Organische Chemie II der Universität Dor tmund, Postfach 500500, D-4600 Dortmund 50 Z. Naturforsch. 43b, 1332-1340 (1988); eingegangen am 17. Mai 1988

Reaktionen von l-Phenyl-3-alkoxycarbonyl-triazenen mit Lewis-Säuren in Benzol* Reactions of 1-Phenyl-3-alkoxycarbonyl-triazenes with Lewis Acids in Benzene R I C H A R D K R E H E R u n d K U R T G O T H Institut für Organische Chemie der Technischen Hochschule Darmstadt (Z. Naturforsch. 31 b, 131-134 [1976]; eingegangen am 11. August 1975) l-Phenyl-3-alkoxycarbonyl-triazenes, No-Fragmentation Reactions, Electrophilic Substitution Reactions 1-Phenyl-3-alkoxycarbonyl-triazenes react with aluminiumchloride in benzene by elimination of nitrogen, especially

semiempirischer MO-Methoden H . STERK * u n d W . HOPELS Institut für Organische Chemie der Universität Graz (Z. Naturforsch. 27 a, 319—324 [1972] ; eingegangen am 15. Dezember 1971) Estimations of Reactivity on Substituted Phenols by Semiempirical MO-methods The electron density distributions for a series of phenol derivatives in the ground state are calculated by HMO, EHT, CNDO, and MINDO/2 methods. The values thus obtained provide an explanation for the point of attack in electrophilic substitution reactions, a feature of particular interest being the displacement of

-thiophenyl) tellurium) oxide (3). Polyhedron 2013 , 62 , 227–233. . 10.1016/j.poly.2013.06.044 Singh P. Chauhan A. K. Butcher R. J. Duthie A. Synthesis and structural aspects of 1-naphthyltellurium (IV) trichloride (1), bis (mesityl) tellurium (IV) dichloride (2) and bis (chlorobis (2-thiophenyl) tellurium) oxide (3) Polyhedron 2013 62 227 233 Singh, P.; Chauhan, A. K.; Butcher, R. J.; Duthie, A. Electrophilic substitution reactions of 2-acetylpyridine, 2-acetylpyrrole & cyclohexanone

. Figure 2: Variation of radiochemical yield of [ 125 I] H4 as a function of substrate concentration (x mM H3 , 200 μg iodogen, 100 μL of citrate buffer pH 3 and 10 μL Na 125 I) at room temperature within 40 min in a total volume of 0.5 mL. The pH of the reaction medium was a critical factor affecting the radiochemical yield as illustrated in Figure 3 . The pH-range 2–8 was selected to achieve the radioiodination through the electrophilic substitution reaction. The maximum yield is obtained at pH 3. When the pH of the reaction medium was shifted toward alkaline pH