The author of 《Pyrrolecarboxylic acids. VI. 2,3- and 2,4-pyrroledicarboxylic acids》 were Nicolaus, Rodolfo A.; Mangoni, Lorenzo. And the article was published in Gazzetta Chimica Italiana in 1956. SDS of cas: 2818-08-8 The author mentioned the following in the article:
cf. C.A. 52, 351b. 2,4-Pyrroledicarboxylic acid (I) is synthesized by the action of SO2Cl2 on 5-methyl-3-bromo-2,4-dicarbethoxypyrrole (II) to give 5-formyl-3-chloro-2,4-dicarbethoxypyrrole (III), converted by KMnO4 to the 5-carboxy-3-chloro compound (IV), brominated to the 5-bromo intermediate (V). Catalytic reduction of V gave 2,4-dicarbethoxypyrrole (VI), saponified to I. 2,3-Pyrroledicarboxylic acid (VII) is prepared by saponification of 2-carboxy-3-carbethoxypyrrole (VIII) (cf. Rinkes, C.A. 32, 33891, 66481). VII crystallizes from H2O as VII.H2O; m. (anhydrous) 225° (decomposition). 2,5-Pyrroledicarboxylic acid (IX) is prepared by the action of SO2Cl2 on 2,5-dimethylpyrrole to give the 3,4-dichloro compound (X) which, on catalytic reduction, gives IX (cf. Colacicchi, C.A. 5, 1280). The following compounds were prepared (m.p. given): I, 290° (decomposition); III, 151-2°; III phenylhydrazone, 152-3°; III 2,4-dinitrophenylhydrazone, 200-1°; IV, 180-1°; V, 143-4°; VI, 74-5°, VIII, 76-8°; IX, 265° (decomposition); X, 300°; I Me ester, 126-7°; VII Me ester, 72-3°; IX di-Me ester, 129-30°; X Me ester, 147-9°. After reading the article, we found that the author used Dimethyl 1H-pyrrole-2,3-dicarboxylate(cas: 2818-08-8SDS of cas: 2818-08-8)
Dimethyl 1H-pyrrole-2,3-dicarboxylate(cas: 2818-08-8) belongs to pyrroles. Pyrroles are components of more complex macrocycles, including the porphyrinogens and products derived therefrom, including porphyrins of heme, the chlorins, bacteriochlorins, and chlorophylls. Porphobilinogen, a trisubstituted pyrrole, is the biosynthetic precursor to many natural products such as heme.SDS of cas: 2818-08-8
Referemce:
Ester – Wikipedia,
Ester – an overview | ScienceDirect Topics