Middleton, Richard W. et al. published their research in Synthesis in 1984 |CAS: 5709-67-1

On September 30, 1984, Middleton, Richard W.; Monney, Hugh; Parrick, John published an article.Electric Literature of 5709-67-1 The title of the article was N-Methylation of heterocycles with dimethylformamide dimethyl acetal. And the article contained the following:

Benzimidazoles I (R = H, CF3), II (R1 = H, Me), and III (R2 = H, Me) were prepared 4,7-Dimethoxybenzimidazole was heated with HC(OMe)2NMe2 in PhMe to give I (R = H). 4,7-Dimethoxybenzimidazoline-2-thione gave III (R2 = H) and III (R2 = Me). The experimental process involved the reaction of 2-Nitro-1H-benzo[d]imidazole(cas: 5709-67-1).Electric Literature of 5709-67-1

The Article related to methylbenzimidazole, methylation benzimidazole dmf methyl acetal, benzimidazolinone methylation dmf methyl acetal, Heterocyclic Compounds (More Than One Hetero Atom): Imidazoles and other aspects.Electric Literature of 5709-67-1

Referemce:
Imidazole – Wikipedia,
Imidazole | C3H4N2 – PubChem