Phosphorus oxide (P4O10) → 5,6-Dichloro-2-(4-cyano-2-methoxyphenyl)benzimidazole

Participants

Reaction Steps

A suspension of N-(2-amino-4,5-dichlorophenyl)-2-methoxy-4-cyanobenzamide (2.9 g, 8.6 mmol) and P2O5 (2.9 g, 10 mmol) in xylene (48 ml) was refluxed for 24 h. Additional P2O5 (2.9 g, 10 mmol) was added and the mixture was refluxed for 42 h. Solvent was removed under reduced pressure. The residue was treated with 2N NaOH (50 ml) and extracted with ethyl acetate (100 ml). The organic layer was washed with water and brine, dried over Na2SO4, filtered and evaporated under reduced pressure to give 2 g of the title compound (yield 73%), mp>250° C.

Provenance & Evidence