Sodium Dithionite → 6-Amino-2-iodo-3,4-dimethoxybenzonitrile

Participants

Reaction Conditions

Reaction Steps

In a reactor vessel, a suspension of 6-nitro-2-iodo-3,4-dimethoxybenzonitrile (see Example 1(d) of WO 98/30560, 10 kg) in ethanol (60 l) at room temperature was charged with a solution of sodium dithionite (15.6 kg of technical grade material) in water (67.5 l) over 45 mins maintaining the temperature below 35° C. The addition vessel was washed with water (10 l). The resulting mixture was warmed to reflux (ca. 85° C.) for ca. 90 mins and then the temperature adjusted to 65° C. A solution of 6M aqueous hydrochloric acid (12.5 l) was added over ca. 10 mins and the resulting mixture stirred at 65° C. for ca. 5 hours before being cooled to room temperature. The pH was adjusted to the range 7–8 using 40% sodium hydroxide (2 l), the resulting mixture left to stir for 3 hours, filtered and washed with water (50 l). The damp cake was slurried in water (90 l) overnight at room temperature, filtered, washed with water (100 l) and dried in vacuo to give 8.35 kg (92%) of the title compound.

Provenance & Evidence