Synthesis of 1, 2, 3, 4-tetrabromobenzene

Regioselectivity of reductive debromination of substituted pentabromobenzenes with sodium tert-butoxide in DMSO

“…Isomeric tetrabromotoluenes, 5 tetrabromoanisoles, 12 1,2,3,4 tetrabromobenzene, 13 1,2,4,5 tetrabromobenzene, 14 19 pentabromochlorobenzene, 20 pentabromo nitrobenzene, 21 pentabromoaniline, 22 and 2,4,6 tribromo 3 methylaniline 23 were prepared according to described proce dures.…”

A unique approach to the synthesis of 2,3,4,5-substituted polybrominated biphenyls: quantitation in FireMaster FF-1 and FireMaster BP-6

“…Finely divided iron (Merck) was added, and the reaction was monitored by silica gel TLC (methanol-chloroform, 1:9, v/v). The crude reaction mixture was poured onto ice, from which the product was filtered, washed, and dried: mp 260 °C (methanol-water; 241-242 °C; Furuyama and Fukushi, 1971); yield 97%; purity >98% by GC. Structure was confirmed by MS, molecular ion at m/e 369, and NMR in deuterated methylene chloride: 2.12 (s, CH3), 2.14 (s, CH3), 7.23 (s, NH), 7.85 ppm (s, H2, H6).…”

“…The crude reaction mixture was filtered, and the filtrate was evaporated to dryness. The product was obtained by recrystallization: mp 138 °C (methanol-water; 130-137 °C; Furuyama and Fukushi, 1971); yield 86%; purity >99% by GC. The structure was confirmed by MS, molecular ion at m/e 409, and lH NMR in deuterated methylene chloride: 4.45 (s, NH2), 7.11 ppm (s, H6).…”

“…The reaction mixture was poured onto ice, filtered, and dried. The product was purified by alumina chromatography with n-hexane and recrystallized: mp 60-61 °C (n-hexane; 58-59 °C; Furuyama and Fukushi, 1971); yield 90%; purity >99% by GC. The structure was confirmed by MS, molecular ion at m/e 394, and 1H NMR in deuterated methylene chloride: 7.49 ppm (s, H5, H6).…”