Hydrochloric Acid → 2-Amino-o-cresol

Participants

Reaction Conditions

Reaction Steps

To a 500 mL erlenmeyer flask was added sulfanilic acid (14.38 g, 83 mmol), sodium carbonate (4.29 g, 40.5 mmol) and distilled H2O (83 mL), when all of the sulfanilic acid dissolved, the solution was cooled in an ice bath to 0° C. and a solution of sodium nitrite (6.16 g, 89.3 mmol) in H2O (15 mL) was added in one portion. The ice bath was allowed to warm to +15° C. and the mixture was stirred at this temperature 1 h. The reaction mixture was poured onto a mixture of ice (100 g) and 12N HCl (17.4 mL). The ice was allowed to melt and the solid diazonium salt was collected by suction filtration on a scintered glass frit. O-cresol (9.10 g, 84.1 mmol) was dissolved in a solution of NaOH (1.21 g, 30.25 mmol) in H2O (100 mL). This solution was cooled to 0° C. and the solid diazonium salt was added in one portion. This well stirred mixture was maintained at +15° C. for 4 h. The temperature of the mixture was raised to +60° C. and sodium dithionite (35 g, 1.03 mol) was added portionwise. The reaction was allowed to proceed at +60° C. for 15 min. The mixture was cooled to room temperature, diluted with saturated aqueous NaHCO3 and extracted with EtOAc. The EtOAc extract was dried (MgSO4), filtered, concentrated in vacuo and chromatographed on 100 g of silica gel using 1:3 EtOAc-hexane as eluant. There was obtained 2-methyl-3-amino-phenol as a tan solid.

Provenance & Evidence