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  2. Buchner ring expansion - Wikipedia

    en.wikipedia.org/wiki/Buchner_ring_expansion

    The Buchner ring expansion reaction was first used in 1885 by Eduard Buchner and Theodor Curtius [1] [2] who prepared a carbene from ethyl diazoacetate for addition to benzene using both thermal and photochemical pathways in the synthesis of cycloheptatriene derivatives. The resulting product was a mixture of four isomeric carboxylic acids ...

  3. Arene substitution pattern - Wikipedia

    en.wikipedia.org/wiki/Arene_substitution_pattern

    The use of the prefixes ortho, meta and para to distinguish isomers of disubstituted aromatic rings starts with Wilhelm Körner in 1867, although he applied the ortho prefix to a 1,4-isomer and the meta prefix to a 1,2-isomer. [6] [7] It was the German chemist Karl Gräbe who, in 1869, first used the prefixes ortho-, meta-, para- to denote ...

  4. Simple aromatic ring - Wikipedia

    en.wikipedia.org/wiki/Simple_aromatic_ring

    [1] [2] Simple aromatic rings can be heterocyclic if they contain non-carbon ring atoms, for example, oxygen, nitrogen, or sulfur. They can be monocyclic as in benzene, bicyclic as in naphthalene, or polycyclic as in anthracene. Simple monocyclic aromatic rings are usually five-membered rings like pyrrole or six-membered rings like pyridine.

  5. Thermal rearrangement of aromatic hydrocarbons - Wikipedia

    en.wikipedia.org/wiki/Thermal_rearrangement_of...

    Both mechanisms are shown as follows for the ring contraction of biphenylene: The first involves a 1,2-hydrogen shift to a carbene followed by a 1,2-carbon shift on the same C-C bond but in opposite directions. The second differs from the first only by the order of the 1,2-shifts, with the 1,2-carbon shift preceding the 1,2-hydrogen shift.

  6. Hexacene - Wikipedia

    en.wikipedia.org/wiki/Hexacene

    Hexacene is an aromatic compound consisting of six linearly-fused benzene rings. It is a blue-green, air-stable solid with low solubility. [1]Hexacene is one of a series of linear polycyclic molecules created by such aromatic ring fusions, a series termed acenes; the previous in the series is pentacene (with five fused rings) and the next is heptacene (with seven).

  7. Alkyne trimerisation - Wikipedia

    en.wikipedia.org/wiki/Alkyne_trimerisation

    An alkyne trimerisation is a [2+2+2] cycloaddition reaction in which three alkyne units (C≡C) react to form a benzene ring. The reaction requires a metal catalyst. The process is of historic interest as well as being applicable to organic synthesis. [1] Being a cycloaddition reaction, it has high atom economy.

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  9. Triple bond - Wikipedia

    en.wikipedia.org/wiki/Triple_bond

    Structure and AFM image of dehydrobenzo[12]annulene, where benzene rings are held together by triple bonds. A triple bond in chemistry is a chemical bond between two atoms involving six bonding electrons instead of the usual two in a covalent single bond. Triple bonds are stronger than the equivalent single bonds or double bonds, with a bond ...