The Experts below are selected from a list of 66 Experts worldwide ranked by ideXlab platform

Muhammad A. Hasan - One of the best experts on this subject based on the ideXlab platform.

Ananda S. Amarasekara - One of the best experts on this subject based on the ideXlab platform.

Marshall Kulka - One of the best experts on this subject based on the ideXlab platform.

  • the Skraup Synthesis of quinolines
    Organic Reactions, 2011
    Co-Authors: R H F Manske, Marshall Kulka
    Abstract:

    Konigs first synthesized quinoline in 1879 by passing allylaniline over heated litharge. Shortly after he prepared quinoline by heating the condensation product of aniline and acrolein, thus anticipating the classical Skraup Synthesis. This Synthesis involves a series of reactions brought about by heating a primary aromatic amine, in which at least one position ortho to the amino group is unsubstituted, with glycerol, sulfuric acid, and an oxidizing agent. The product is a quinoline containing only those substituents that were originally present in the aromatic amine. Quinolines substituted in the hetero ring may be obtained by a modified Skraup Synthesis in which a substituted acrolein or a vinyl ketone is used in place of glycerol. Keywords: Skraup Synthesis; quinolines; aroquinolines; orientation; nitroquinolines; dimethylquinolines; oxidizing agents; experimental conditions

  • Organic Reactions - The Skraup Synthesis of Quinolines
    Organic Reactions, 2011
    Co-Authors: R H F Manske, Marshall Kulka
    Abstract:

    Konigs first synthesized quinoline in 1879 by passing allylaniline over heated litharge. Shortly after he prepared quinoline by heating the condensation product of aniline and acrolein, thus anticipating the classical Skraup Synthesis. This Synthesis involves a series of reactions brought about by heating a primary aromatic amine, in which at least one position ortho to the amino group is unsubstituted, with glycerol, sulfuric acid, and an oxidizing agent. The product is a quinoline containing only those substituents that were originally present in the aromatic amine. Quinolines substituted in the hetero ring may be obtained by a modified Skraup Synthesis in which a substituted acrolein or a vinyl ketone is used in place of glycerol. Keywords: Skraup Synthesis; quinolines; aroquinolines; orientation; nitroquinolines; dimethylquinolines; oxidizing agents; experimental conditions

R H F Manske - One of the best experts on this subject based on the ideXlab platform.

  • the Skraup Synthesis of quinolines
    Organic Reactions, 2011
    Co-Authors: R H F Manske, Marshall Kulka
    Abstract:

    Konigs first synthesized quinoline in 1879 by passing allylaniline over heated litharge. Shortly after he prepared quinoline by heating the condensation product of aniline and acrolein, thus anticipating the classical Skraup Synthesis. This Synthesis involves a series of reactions brought about by heating a primary aromatic amine, in which at least one position ortho to the amino group is unsubstituted, with glycerol, sulfuric acid, and an oxidizing agent. The product is a quinoline containing only those substituents that were originally present in the aromatic amine. Quinolines substituted in the hetero ring may be obtained by a modified Skraup Synthesis in which a substituted acrolein or a vinyl ketone is used in place of glycerol. Keywords: Skraup Synthesis; quinolines; aroquinolines; orientation; nitroquinolines; dimethylquinolines; oxidizing agents; experimental conditions

  • Organic Reactions - The Skraup Synthesis of Quinolines
    Organic Reactions, 2011
    Co-Authors: R H F Manske, Marshall Kulka
    Abstract:

    Konigs first synthesized quinoline in 1879 by passing allylaniline over heated litharge. Shortly after he prepared quinoline by heating the condensation product of aniline and acrolein, thus anticipating the classical Skraup Synthesis. This Synthesis involves a series of reactions brought about by heating a primary aromatic amine, in which at least one position ortho to the amino group is unsubstituted, with glycerol, sulfuric acid, and an oxidizing agent. The product is a quinoline containing only those substituents that were originally present in the aromatic amine. Quinolines substituted in the hetero ring may be obtained by a modified Skraup Synthesis in which a substituted acrolein or a vinyl ketone is used in place of glycerol. Keywords: Skraup Synthesis; quinolines; aroquinolines; orientation; nitroquinolines; dimethylquinolines; oxidizing agents; experimental conditions

Vitalij D. Shteingarts - One of the best experts on this subject based on the ideXlab platform.

  • N-acetylation as a means to activate polyfluoroarylamines for selective ortho -hydrodefluorination by zinc in aqueous ammonia : A concise route to polyfluorobenzo azaheterocycles
    European Journal of Organic Chemistry, 2007
    Co-Authors: Sergey S. Laev, Larisa Yu. Gurskaya, Galina A. Selivanova, Irina V. Beregovaya, L. N. Shchegoleva, Nadezhda V. Vasil’eva, Makhmut M. Shakirov, Vitalij D. Shteingarts
    Abstract:

    N-Acetylation of polyfluoroarylamines is proposed as a meansto remove the amino group blocking effect of their hydrodefluorination by zinc in aqueous ammonia. With pentafluoroacetanilide, the Zn ion specific effect has been demonstrated to be responsible for ortho hydrodefluorination. This regiochemistry is accompanied by the removal of a fluorine atom from the para position, which occurs predominantly in the initial phase of the process in the absence of deliberately added zinc salt. The CuCl2 additive has been found to accelerate the reaction and to propel it to double defluorination. Quantum chemical calculations suggest a diminished electron affinity of pentafluoroaniline, which is responsible for its inertness in relation to the hydrodefluorination reaction. The pentafluoroaniline radical anion, which essentially has a nonplanar structure, is prone to easy fragmentation to give an aminotetrafluorophenyl radical. For pentafluoroacetanilide, CVA experiments and quantum chemical calculations predict that the pentafluorophenyl moiety serves as the electron receptor and that the acetamido group is twisted out of coplanarity with the benzene ring; thus, together with the electron-withdrawing effect of the acetyl group, the amino group blocking effect is suppressed. On this ground, the selective ortho hydrodefluorination of polyfluoroacetanilides is developed as an important protocol for the expeditious and general Synthesis of polyfluorobenzo azaheterocycles via readily accessible polyfluoroarylamines from base polyfluoroarenes. Its applicability has been illustrated by preparing quinolines that possess a polyfluorinated benzene moiety by the Skraup Synthesis utilizing crude polyfluoroacetanilide hydrodefluorination products as starting materials. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)