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In chemistry, a reaction intermediate, or intermediate, is a molecular entity arising within the sequence of a stepwise chemical reaction. It is formed as the reaction product of an elementary step, from the reactants and/or preceding intermediates, but is consumed in a later step. It does not appear in the chemical equation for the overall ...
In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical reaction occurs. [ 1 ] A chemical mechanism is a theoretical conjecture that tries to describe in detail what takes place at each stage of an overall chemical reaction.
Reactive intermediates have several features in common: low concentration with respect to reaction substrate and final reaction product; with the exception of carbanions, these intermediates do not obey the lewis octet rule, hence the high reactivity; often generated on chemical decomposition of a chemical compound
A Meisenheimer complex or Jackson–Meisenheimer complex in organic chemistry is a 1:1 reaction adduct between an arene carrying electron withdrawing groups and a nucleophile. These complexes are found as reactive intermediates in nucleophilic aromatic substitution but stable and isolated Meisenheimer salts are also known. [1] [2] [3]
The concept of a transition state has been important in many theories of the rates at which chemical reactions occur. This started with the transition state theory (also referred to as the activated complex theory), developed independently in 1935 by Eyring, Evans and Polanyi, and introduced basic concepts in chemical kinetics that are still used today.
The Curtin–Hammett principle is a principle in chemical kinetics proposed by David Yarrow Curtin and Louis Plack Hammett.It states that, for a reaction that has a pair of reactive intermediates or reactants that interconvert rapidly (as is usually the case for conformational isomers), each going irreversibly to a different product, the product ratio will depend both on the difference in ...
Hydrazones are intermediates in the Wolff–Kishner reduction. Hydrazones are reactants in hydrazone iodination , the Shapiro reaction , and the Bamford–Stevens reaction to vinyl compounds. Hydrazones can also be synthesized by the Japp–Klingemann reaction via β-keto acids or β-keto-esters and aryl diazonium salts.
Schiff bases are common enzymatic intermediates where an amine, such as the terminal group of a lysine residue, reversibly reacts with an aldehyde or ketone of a cofactor or substrate. The common enzyme cofactor pyridoxal phosphate (PLP) forms a Schiff base with a lysine residue and is transaldiminated to the substrate(s). [7]