Pyrroles 3- carboxylic acids

It will be noted that pyrrole-3-carboxylic acid (154) is an appreciably weaker acid than benzoic acid and this is attributed to the stabilization of the undissociated acid by electron release from nitrogen. The 2-carboxylic acids of furan, thiophene, selenophene and tel-lurophene are all stronger acids than benzoic acid, tellurophene-2-carboxylic acid (pisTa 4.0) being the weakest acid in this series (77AHC(21)119). [Pg.71]

H-Pyrrole-3-carboxylic acid, ethyl ester C NMR, 4, 172 (74JCS(P2)1004>... [Pg.55]

H-Pyrrole-3-carboxylic acid, methyl ester UV, 4, 14 (71PMH(3)79, 71T245), 178 (71PMH(3)79>... [Pg.55]

Pyrrole-3-carboxylic acid, l-benzoyl-5-bromo-2,4-dimethyl-ethyl ester chlorination, 4, 271... [Pg.818]

Pyrrole-3-carboxylic acid, 2,5-dimethyl-ethyl ester formylation, 4, 217 Pyrrole-3-carboxylic acid, 2-methyl-ethyl ester... [Pg.818]

Grignard reagent from, acylation, 4, 237 nitration, 4, 211 reactivity, 4, 71-72 synthesis, 4, 149, 237, 341, 360 Pyrrole-3-carboxylic acids acidity, 4, 71 decarboxylation, 4, 286 esterification, 4, 287 esters... [Pg.818]

A two-step procedure was required for the preparation of a diverse set of pyrrole-3-carboxylic acid derivatives. The diketone 15 was prepared using a functional homologation of a 6-ketoester 14 with different aldehydes followed by oxidation with PCC. The Paal-Knorr reaction was carried out in AcOH in a sealed tube under microwave irradiation (180 °C, 5-10 min) to give differently substituted pyrroles with a COOMe group in position 3 (Scheme 5). This group was further transformed to expand the diversity of the products prepared with this method [32]. [Pg.218]

Following the discovery of the unique electronic properties of polypyrrole, numerous polymers of pyrrole have been crafted. A copolymer of pyrrole and pyrrole-3-carboxylic acid is used in a glucose biosensor, and a copolymer of pyrrole and A-methylpyrrole operates as a redox switching device. Self-doping, low-band gap, and photorefractive pyrrole polymers have been synthesized, and some examples are illustrated [1,5]. [Pg.35]

With less electron-rich pyrroles, hydrochloric acid can be used in the diazotization. The diazo compounds were isolated after neutralization with aqueous ammonia [84H(22)2269]. 3-Diazo-2,5-diphenylpyrrole, although efficiently prepared by diazotization of the 3-aminopyrrole, can also be prepared by oxidation of the 3-nitrosopyrrole with dinitrogen trioxide (60JCS3270). Pyrrole-3-carboxylic acid, with buffered nitrous acid, gave the 3-diazo derivative 295 by displacement of the carboxyl group, together with the 3-diazo-2-carboxylic acid 296, obtained by further hydrolysis (62JCS1638) (Scheme 90). [Pg.158]

Pyrrole-2-carboxylic acid easily loses the carboxylic group thermally. Pyrrole-3-carboxylic acid and furan-2- and -3-carboxylic acids also readily decarboxylate on heating to about 200°C. Thiophene-carboxylic acids require higher temperatures or a copper-quinoline catalyst. In furans, 2-carboxylic acid groups are lost more readily than 3-carboxylic acid groups (Scheme 64). [Pg.351]

H-Pyrrole-2-carboxylic acid, 5-nitro-, methyl ester 15N NMR, 4, 176 <76OMR(8)208> lH-Pyrrole-3-carboxylic acid, benzyl ester H NMR, 4, 166 <81UP30400>... [Pg.55]

Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...