Dimethylformamide → 1-Isopropylsulfonyl-2-amino-6-formylbenzimidazole

Participants

Reaction Conditions

Reaction Steps

Add phenyllithium (750 mL, 1.8 M in cyclohexane/ether, 70/30) over 1 hour to a solution of 1-isopropylsulfonyl-2-amino-6-iodobenzimidazole (150 g, 0.41 mol) in tetra-hydrofuran (5.6 L) at −76° C. Stir for 15 minutes and then add tert-butyllithium (750 ml, 1.7 M in pentane). After 1 hour add dimethylformamide (250 mL) slowly over one hour and then warm to 0° C. Quench by pouring the reaction mixture into a mixture of cold saturated aqueous ammonium chloride (500 g, 5 L) and concentrated hydrochloric acid (300 mL). Separate the layers, wash the organic phase with water and then concentrate under reduced pressure. Slurry the residue in methanol (500 mL), filter the yellow precipitate, and dry to provide 85 g (76%) of the title compound.

Provenance & Evidence