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  2. Pyrrole - Wikipedia

    en.wikipedia.org/wiki/Pyrrole

    Pyrrole is an extremely weak base for an amine, with a conjugate acid pK a of −3.8. The most thermodynamically stable pyrrolium cation (C 4 H 6 N +) is formed by protonation at the 2 position. Substitution of pyrrole with alkyl substituents provides a more basic molecule—for example, tetramethylpyrrole has a conjugate acid pK a of +3.7.

  3. Electron-rich - Wikipedia

    en.wikipedia.org/wiki/Electron-rich

    with regards to acid-base reactions, electron-rich species have high pKa's and react with weak Lewis acids. [4] with regards to nucleophilic substitution reactions, electron-rich species are relatively strong nucleophiles, as judged by rates of attack by electrophiles. For example, compared to benzene, pyrrole is more rapidly attacked by ...

  4. Acid strength - Wikipedia

    en.wikipedia.org/wiki/Acid_strength

    For example, acetic acid is a weak acid which has a = 1.75 x 10 −5. Its conjugate base is the acetate ion with K b = 10 −14 /K a = 5.7 x 10 −10 (from the relationship K a × K b = 10 −14), which certainly does not correspond to a strong base. The conjugate of a weak acid is often a weak base and vice versa.

  5. Simple aromatic ring - Wikipedia

    en.wikipedia.org/wiki/Simple_aromatic_ring

    Examples of non-basic nitrogen-containing aromatic rings are pyrrole and indole. In the oxygen- and sulfur-containing aromatic rings, one of the electron pairs of the heteroatoms contributes to the aromatic system (similar to the non-basic nitrogen-containing rings), whereas the second lone pair extends in the plane of the ring (similar to the ...

  6. Rothemund reaction - Wikipedia

    en.wikipedia.org/wiki/Rothemund_reaction

    The reaction employs an organic acidic medium such as acetic acid or propionic acid as typical reaction solvents. Alternatively p-toluenesulfonic acid or various Lewis acids can be used with chlorinated solvents. The aldehyde and pyrrole are heated in this medium to afford modest yields of the meso tetrasubstituted porphyrins [RCC 4 H 2 N] 4 H 2.

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    America’s top investors have achieved double-digit returns for years, sometimes decades. Following these top investors is a great strategy for two reasons.

  8. Weak base - Wikipedia

    en.wikipedia.org/wiki/Weak_base

    A weak base is a base that, upon dissolution in water, does not dissociate completely, so that the resulting aqueous solution contains only a small proportion of hydroxide ions and the concerned basic radical, and a large proportion of undissociated molecules of the base.

  9. AOL Mail - AOL Help

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    Get answers to your AOL Mail, login, Desktop Gold, AOL app, password and subscription questions. Find the support options to contact customer care by email, chat, or phone number.