Search results
Results from the WOW.Com Content Network
Levi and Zanetti extended the Knorr synthesis in 1894 to the use of acetylacetone (2,4-pentanedione) in reaction with ethyl 2-oximinoacetoacetate. The result was ethyl 4-acetyl-3,5-dimethylpyrrole-2-carboxylate, where "OEt" = R 1 = R 3 = Me, and R 2 = COOEt. [9] The 4-acetyl group could easily be converted to a 4-ethyl group by Wolff-Kishner ...
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]
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.
Naphthoylpyrroles: Any compound containing a 3-(1-naphthoyl)pyrrole structure with substitution at the nitrogen atom of the pyrrole ring by an alkyl, haloalkyl, alkenyl, cycloalkylmethyl, cycloalkylethyl, 1-(N-methyl-2-piperidinyl)methyl, or 2-(4-morpholinyl)ethyl group whether or not further substituted in the pyrrole ring to any extent and ...
Pyrrolysine ball and stick model spinning. Pyrrolysine (symbol Pyl or O; [2] encoded by the 'amber' stop codon UAG) is an α-amino acid that is used in the biosynthesis of proteins in some methanogenic archaea and bacteria; [3] [4] it is not present in humans.
Pyrrole-2-carboxylate decarboxylase (EC 4.1.1.93) is an enzyme with systematic name pyrrole-2-carboxylate carboxy-lyase. [ 1 ] [ 2 ] [ 3 ] This enzyme catalyses the following chemical reaction (1) pyrrole-2-carboxylate ⇌ {\displaystyle \rightleftharpoons } pyrrole + CO 2
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).
Heating the 1,4-diketone with ammonium acetate in methanol with camphor sulfonic acid and 4 angstrom molecular sieves gave the pyrrole with no N-substitution. This pyrrole was found to be unstable, and as such was treated with trimethylsilyl ethoxy methoxy chloride (SEM-Cl) to protect the pyrrole prior to isolation. Roseophillin Paal-Knorr