The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Diazo compounds of ferrocene》. Authors are Nesmeyanov, A. N.; Drozd, V. N.; Sazonova, V. A..The article about the compound:Bromoferrocenecas:1273-73-0,SMILESS:Br[C-]12[Fe+2]3456789([C-]%10C6=C7C8=C9%10)C1=C3C4=C25).Reference of Bromoferrocene. Through the article, more information about this compound (cas:1273-73-0) is conveyed.
cf. CA 52, 14579b. Since ferrocenediazonium salts cannot be prepared with HNO2 owing to destruction of the ring by this acid, an indirect method was devised. Diazoaminoferrocene was added at -4(1° to concentrated HCl and the mixture gradually warmed to -20°, when a violet color of the diazonium salt appeared, while at -15°, N evolution commenced and terminated at -5°; crystals of chloroferrocene precipitated After dilution and extraction with Et2O, the organic extract was washed with aqueous KOH and H2O, and evaporated yielding 72% chloroferrocene (I), m. 57-8°. The mother liquor after neutralization and extraction with Et2O gave 62% ferrocenylamine, m. 154-5°. Similar treatment of benzenediazoaminoferrocene gave 76% I and traces of ferrocenylamine; similar decompn, in concentrated HBr or HI gave 70% bromoferrocene, m. 32-3°, or 72% iodoferrocene, m. 42 4°, resp. Similar reaction with 40% H2SO4 in the presence of Et2O gave a solution containing hydroxyferrocene, which was isolated as the benzoyl derivative, m. 108.5-9 5° in 3% yield. Benzenediazoaminoferrocene hydrolyzed as above in concentrated HCl, warmed to -20° to form the diazonium salt solution, and treated with 2-C10H7OH in 10% KOH in the cold gave, after chromatog. purification on Al2O3, 48% 1-ferroceneazo-2-naphthol (II), m. 151-2°, a green solid, along with 28% I; II gave violet solutions in organic solvents and was insoluble in alkalies. 1,1′-Bis(benzenediazoamino)ferrocene treated similarly in the cold with concentrated HCl gave a violet solution of the bis(diazonium salt), which with 2-C10H7OH as above gave a little II, 35% red 1-benzeneazo-2-naphthol, and 24% black ferrocene-1,1′-bis(1-azo-2-naphthol), decompg 212-13°.
After consulting a lot of data, we found that this compound(1273-73-0)Reference of Bromoferrocene can be used in many types of reactions. And in most cases, this compound has more advantages.
Reference:
Thiazolidine – Wikipedia,
Thiazolidine – ScienceDirect.com