Sodium Hydroxide → 4,5-Dibromobenzene-1,2-diamine

Temperature

75 °C

To a solution of 4,5-dibromo-2-nitroaniline (3.35 g, 11.32 mmol) in EtOAc (150 mL) was added stannous chloride dihydrate (12.8 g, 56.74 mmol), the mixture was stirred at 75° C. for 16 h, then allowed to cool to room temperature and poured into ice-water (about 150 mL). To the mixture was added 1N aq NaOH with vigorous stirring to take the pH to 9 (pH paper). The resulting thick yellow white emulsion was extracted with EtOAc (3×100 mL). The organic extracts were combined, washed with brine (2×50 mL), dried (over Na2SO4) and evaporated to dryness. The residual solid was dried under 1 mmHg at 40° C. for 14 h giving 2.92 g (97%) of 4,5-dibromo-1,2-phenylenediamine as a yellowish powder. Mp 149°-50° C. IR (KBr) 3400, 1623, 1489, 1394, 1271, 868 cm-1. 1H NMR (DMSO-d6) 6.754 (s, 2H), 4.867 (s, 4H).

1. temperatureto cool to room temperature
2. stirringwith vigorous stirring
3. extractionThe resulting thick yellow white emulsion was extracted with EtOAc (3×100 mL)
4. washwashed with brine (2×50 mL)
5. dry with materialdried (over Na2SO4)
6. customevaporated to dryness
7. customThe residual solid was dried under 1 mmHg at 40° C. for 14 h

ORD record

ord-e54506b6560d4f8d968bf1cd4a3365e0

Source dataset

uspto-grants-1997_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05620979