4,5-Dichloro-1,2-phenylenediamine → 5,6-dichloro-2-(2,2,2-trifluoro-ethyl)-1H-benzimidazole

Participants

Reaction Conditions

Reaction Steps

To 4,5-dichloro-1,2-phenylenediamine (25 g) was added 3,3,3-trifluoropropionic acid (25 mls) and 4N HCl (90 mL). The resulting mixture was heated to 10° C. overnight. The reaction mixture was quenched with water, basicified with concentrated NH4OH, extracted with EtOAc, and dried over Na2SO4. The crude product was filtered through a plug of silica gel, eluting with 30% EtOAc/hexanes, and collecting the red band. The fractions were concentrated to yield a mixture of the desired title compound and 4,5-dichloro-1,2-phenylenediamine. The crude material was dissolved in small amount of CH2Cl2 and triturated with hexanes to yield the title compound as a tan solid.

Provenance & Evidence