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Main arene substitution patterns. In ortho-substitution, two substituents occupy positions next to each other, which may be numbered 1 and 2. In the diagram, these positions are marked R and ortho. In meta-substitution the substituents occupy positions 1 and 3 (corresponding to R and meta in the diagram). In para-substitution, the substituents ...
Ortho effect is an organic chemistry phenomenon where the presence of a chemical group at the at ortho position or the 1 and 2 position of a phenyl ring, relative to the carboxylic compound changes the chemical properties of the compound. This is caused by steric effects and bonding interactions along with polar effects caused by the various ...
The R 1 group can only be a secondary substitution and branched is the optimal choice; Alkyl (—CH 3) substituents on the α, β or γ carbon (if X = —OCH 2 —) lower beta blockade, especially at the α carbon; The general rule for aromatic substitution is: ortho > meta > para. This gives non-selective β-blockers.
Infobox references. Terphenyls are a group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. There are three substitution patterns: ortho -terphenyl, meta -terphenyl, and para -terphenyl. Commercial grade terphenyl is generally a ...
Electrophilic aromatic substitution (SEAr) is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile. Some of the most important electrophilic aromatic substitutions are aromatic nitration, aromatic halogenation, aromatic sulfonation, alkylation Friedel–Crafts reaction and ...
Electrophilic aromatic directing groups. In electrophilic aromatic substitution reactions, existing substituent groups on the aromatic ring influence the overall reaction rate or have a directing effect on positional isomer of the products that are formed. An electron donating group (EDG) or electron releasing group (ERG, Z in structural ...
Phenyl radical group. In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula C6H5, and is often represented by the symbol Ph (archaically φ). The phenyl group is closely related to benzene and can be viewed as a benzene ring, minus a hydrogen, which may be replaced by some other element or compound ...
Directed ortho metalation. Directed ortho metalation is an important tool in the synthesis of regiospecific substituted aromatic compounds. This approach to lithiation and subsequent quenching of the intermediate lithium species with electrophile is often better than the electrophilic aromatic substitution due to its high regioselectivity.