Friedrich, Karlheinz; Oester, Hans published the artcile< The preparation of aromatic polyhydroxy compounds and polyhydroxycarboxylic acids. VII. Bromo derivatives of 4-hydroxybenzoic acid>, Recommanded Product: 2-Bromo-4-nitrobenzoic acid, the main research area is .
Various methods for the preparation of 2,4-Br(HO)C6H3CO2H (I) and 2,3,5,4-Br3(HO)C6HCO2H (II) were investigated. A general method was described for oxidation of aliphatic side chains in the o-position to Br in the aromatic ring. 2,4-Br(O2N)C6H3Me (4 g.) and 50 cc. dilute HNO3 (1 volume HNO3, d. 1.5, and 2.5 volumes H2O) heated 3-4 hrs. with 1 drop Hg in a sealed tube at 130°, the mixture cooled, filtered, the residue dissolved in dilute aqueous NaOH, the solution filtered, and acidified gave 3.5 g. 2,4-Br(O2N)C6H3CO2H (III), needles, m. 162-4° (H2O). 2,6,4-Br2(O2N)C6H2Me (4 g.) oxidized similarly during 4 hrs. at 135-40° gave 1.5 g. 2,6,4-Br2(O2N)C6H2CO2H (IV), m. 195-8°. III (4 g.) in 50 cc. MeOH hydrogenated over Raney Ni yielded 40% 2,4-Br(H2N)C6H3CO2H (V), m. 198-200° (H2O). V (5 g.) in dilute H2SO4 diazotized, heated to boiling until the N evolution ceased, cooled, concentrated, and filtered yielded 2.8 g. I, m. 206-8° (H2O), dark yellow with FeCl3. I (4 g.) in 40 cc. AcOH and a small amount of Fe powder treated at 10° with 7 g. Br in 30 cc. AcOH with stirring, the mixture kept overnight, and filtered gave 3.6 g. II, m. 222-5° (aqueous EtOH). I with the appropriate amount of Br gave 60% 2,5,4-Br2(HO)C6H2CO2H, m. 218-20°. III and IV with CH2N2-Et2O gave 80% Me ester (VI) of III, m. 152°, and Me ester of IV, m. 82-4°, resp. VI (8 g.) in 150 cc. 10% HCl treated at 60-70° with 8 g. powd. Fe, the mixture heated to 90°, filtered hot, treated with a small amount of concentrated HCl, filtered, the residue in dilute EtOH treated with a few cc. 2N NaOH, heated to boiling, filtered, and cooled gave 4 g. Me ester (VII) of V, needles, m. 85-6°. VII (3 g.) diazotized and refluxed gave 2 g. Me ester of I, violet with aqueous FeCl3. I (3 g.) treated with CH2N2-Et2O, the resulting oil saponified with excess 40% KOH, and acidified with dilute HCl gave 2,4-Br(MeO)C6H3CO2H, needles, m. 196-7°. The following compounds were prepared by standard procedures: acetate of I, m. 153-4°; N-Ac derivative of VII, m. 52-3°; 2,6,4-Br2(O2N)-C6H2CO2H (VIII), m. 195-8°; 4-NH2 analog of VIII, m. 233-4°; Me ester of VIII, m. 142-5°; 4-OH analog of VIII, m. 218-20°.
Chemische Berichte published new progress about Acids. 16426-64-5 belongs to class bromides-buliding-blocks, and the molecular formula is C7H4BrNO4, Recommanded Product: 2-Bromo-4-nitrobenzoic acid.
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary