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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.
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base.It can be used to determine pH via titration.Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
Natural bond orbital (NBO) analysis of C 4 H 4 BH has been performed in order to understand the bonding of borole in the familiar Lewis picture. [5] According to the computational results, the occupancy of the two C−C π orbitals is about 1.9, with a tiny amount of electronic charge (an occupancy of 0.13) delocalised on the out-of-plane boron p orbital, illustrated below.
Pyrrole-2-carboxylic acid is an organic compound with the formula HNC 4 H 3 CO 2 H. It is one of two monocarboxylic acids of pyrrole. It is a white solid. It arises in nature by dehydrogenation of the amino acid proline. [1] It also arises by carboxylation of pyrrole. [2] The ethyl ester of this acid is readily prepared from pyrrole. [3]
1-Pyrroline-5-carboxylic acid (systematic name 3,4-dihydro-2H-pyrrole-2-carboxylic acid [2]) is a cyclic imino acid. Its conjugate base and anion is 1-pyrroline-5-carboxylate (P5C). In solution, P5C is in spontaneous equilibrium with glutamate-5-semialdhyde (GSA).
Dissolving Knorr's pyrrole in concentrated sulfuric acid, and then pouring the resulting solution into water will hydrolyze the 4-ester group selectively. The 5-methyl group can be variously oxidized to chloromethyl, aldehyde, or carboxylic acid functionality by the use of stoichiometric sulfuryl chloride in glacial acetic acid. [7]
If the aqueous solution is saturated with a given salt solute, any additional such salt precipitates out of the solution. In the more general Brønsted–Lowry acid–base theory (1923), a base is a substance that can accept hydrogen cations (H +)—otherwise known as protons.
Tetrapyrroles are a class of chemical compounds that contain four pyrrole or pyrrole-like rings. The pyrrole/pyrrole derivatives are linked by (= (CH)-or -CH 2-units), in either a linear or a cyclic fashion. Pyrroles are a five-atom ring with four carbon atoms and one nitrogen atom.