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  2. IUPAC nomenclature of organic chemistry - Wikipedia

    en.wikipedia.org/wiki/IUPAC_nomenclature_of...

    Prefixed substituents are ordered alphabetically (excluding any modifiers such as di-, tri-, etc.), e.g. chlorofluoromethane, not fluorochloromethane. If there are multiple functional groups of the same type, either prefixed or suffixed, the position numbers are ordered numerically (thus ethane-1,2-diol, not ethane-2,1-diol.)

  3. Arene substitution pattern - Wikipedia

    en.wikipedia.org/wiki/Arene_substitution_pattern

    Ipso-substitution describes two substituents sharing the same ring position in an intermediate compound in an electrophilic aromatic substitution. Trimethylsilyl, tert-butyl, and isopropyl groups can form stable carbocations, hence are ipso directing groups. Meso-substitution refers to the substituents occupying a benzylic position.

  4. Substituent - Wikipedia

    en.wikipedia.org/wiki/Substituent

    In organic chemistry, a substituent is one or a group of atoms that replaces (one or more) atoms, thereby becoming a moiety in the resultant (new) molecule. [1] ( In organic chemistry and biochemistry, the terms substituent and functional group, as well as side chain and pendant group, are used almost interchangeably to describe those branches from the parent structure, [2] though certain ...

  5. Descriptor (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Descriptor_(Chemistry)

    Pseudoasymmetry occurs when four different substituents are attached to one carbon atom, two of which differ only by their absolute stereochemical configuration. Examples of such are meso compounds such the tropane alkaloids; the parent compound is tropine , whose systematic name is (1 R , 3 r , 5 S )-8-methyl-8-azabicyclo[3.2.1]octane-3-ol.

  6. Functional group - Wikipedia

    en.wikipedia.org/wiki/Functional_group

    In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions.The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition.

  7. Federal employees told to remove pronouns from email ...

    www.aol.com/federal-employees-told-remove...

    Employees at multiple federal agencies were ordered to remove pronouns from their email signatures by Friday afternoon, according to internal memos obtained by ABC News that cited two executive ...

  8. Trump directs Pentagon and DHS to prepare migrant housing at ...

    www.aol.com/trump-says-hell-sign-order-205858322...

    President Donald Trump signed a memo Wednesday that sets in motion preparations for a facility to house thousands of migrants at the U.S. military camp at Guantánamo Bay, Cuba, which he said was ...

  9. Locant - Wikipedia

    en.wikipedia.org/wiki/Locant

    The International Union of Pure and Applied Chemistry (IUPAC) recommends the use of numeric prefixes to indicate the position of substituents, generally by identifying the parent hydrocarbon chain and assigning the carbon atoms based on their substituents in order of precedence.