HCID 19610455, compound → HCID 67652043, compound

Participants

Reaction Conditions

Reaction Steps

To a cooled (-15° C.) and stirred suspension of 4-(imidazol-1-yl)aniline dihydrochloride (20 g, 86.16 mmol) in concentrated hydrochloric acid (100 ml) was added dropwise, over 1 hour, a solution of sodium nitrite (6.25 g, 9.05 mmol) in water (40 ml). After a further 10 minutes of stirring at -12° C., the mixture was quickly filtered to remove a solid, and the filtrate was added portionwise to a cooled (-20° C.) and stirred solution of tin (II) chloride dihydrate (100 g) in concentrated hydrochloric acid (50 ml) at such a rate as to maintain the internal temperature below -10° C. (15 minutes). The mixture was allowed to warm to 5° C. over 30 minutes, and the solid was collected and washed with diethyl ether (4×100 ml). The above solid was suspended in water (200 ml) and basified with 4N sodium hydroxide solution and extracted with ethyl acetate (5×500 ml). The combined organic solutions were dried (Na2SO4) and filtered. The filtrate was vigorously stirred while hydrogen chloride was being bubbled through the solution until a deep red mixture was obtained. Stirring was continued for a further 20 minutes to give a cream solid which was collected by filtration and dried over phosphorus pentoxide-potassium hydroxide under high vacuum to leave 12.7 g (60%) of the title compound: δH (360 MHz, DMSO-d6) 7.20 (2H, d, J=9.0 Hz), 7.73 (2H, d, J=9.0 Hz), 7.91 (1H, t, J=1.5 Hz), 8.23 (1H, t, J=1.7 Hz), 9.71 (1H, t, J=1.3 Hz).

Provenance & Evidence