O-Phenylenediamine → Benzimidazole, 2-butyl-

To a solution of o-phenylenediamine (0.171 g, 1.58 mmol) in absolute ethanol (8 ml), ethyl valerylimidate (0.313 g, 1.9 mmol) was added, and the mixture was refluxed overnight. The reaction was cooled to room temperature and concentrated in vacuo. The residue was partitioned between ethyl acetate and saturated NaHCO3. The organic phase was separated and the aqueous layer was extracted with ethyl acetate (3×20 ml). The organic layers were combined and washed with brine, dried (MgSO4), and then concentrated in vacuo. The crude product, thus obtained, was purified by medium pressure liquid chromatography (MPLC) on silica-gel using ethyl acetate-hexane (1:1) to give cream colored crystalline solid (0.19 g, 69%). NMR (CDCl3): δ0.92 (t, J=7 Hz, 3H), 1.42(m, 2H), 1.86(m, 2H), 2.95(t, J=7Hz, 2H), 7.22(m, 2H), 7.58(m, 2H); FAB-MS: m/e 174 (M+H).

1. temperaturethe mixture was refluxed overnight
2. concentrationconcentrated in vacuo
3. customThe residue was partitioned between ethyl acetate and saturated NaHCO3
4. customThe organic phase was separated
5. extractionthe aqueous layer was extracted with ethyl acetate (3×20 ml)
6. washwashed with brine
7. dry with materialdried (MgSO4)
8. concentrationconcentrated in vacuo
9. customThe crude product, thus obtained
10. customwas purified by medium pressure liquid chromatography (MPLC) on silica-gel

ORD record

ord-0e7a0d730cdd453bb19d6914bb6f1cbb

Source dataset

uspto-grants-1993_01

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05177074