The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Thiocyanopyrrole, thiopyrroles and pyrrole disulfides》. Authors are Pratesi, P..The article about the compound:5-Iodo-2-furaldehydecas:2689-65-8,SMILESS:IC1=CC=C(O1)C=O).Synthetic Route of C5H3IO2. Through the article, more information about this compound (cas:2689-65-8) is conveyed.
Thiocyanopyrroles have been prepared by addition of Br2 to pyrrole and NH4SCN in glacial AcOH, theoretical quantities being used according to the scheme RH + 2NH4SCN + Br2 → RSCN + 2NH4Br + HSCN. With ordinary pyrrole, the reaction mix is cooled with ice and salt. The yields are 90-5%. 2,4-Dimethyl-3-carbethoxy-5-thiocyanopyrrole (I), m. 169.5°. The 5-carbethoxy-3-thiocyano derivative (II), m. 198-9°. A dithiocyanopyrrole, C4H3N(SCN)2, m. 114°, was the only product obtained in an attempt to produce the tetrathiocyanate. Thiocyanopyrroles are very stable compounds, indifferent toward alkalies. They crystallize very readily, usually in needle form, and are readily purified and recrystallized from H2O or EtOH. With Zn and AcOH the corresponding thiopyrrole is formed. Thus, 2,4-dimethyl-5-carbethoxy-3-thiopyrrole (III), m. 140°, is formed by the reduction of II; yield, 50%. These compounds resemble the thiophenols, being soluble in alkali and insoluble in alk. bicarbonates. They react readily with Hg salts, giving compounds of the types: RSHgX, and (RS)2Hg [X = halogen]. The thiopyrroles oxidize readily in air, forming the disulfides. Oxidation of III by boiling in the presence of bone black gave bis[2,4-dimethyl-5-carbethoxy-3-pyrryl disulfide. On cooling the disulfide seps. quantitatively, as a white powder, m. 234°, insoluble in alkali, slightly soluble in EtOH. IV was also obtained directly from the NCS derivative by reduction with Na and EtOH.
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Reference:
1,8-Naphthyridine – Wikipedia,
1,8-Naphthyridine | C8H6N2 – PubChem