Formic Acid → 6-(methylthio)-1H-benzimidazole

4-(Methylthio)benzene-1,2-diamine (10.7 g, 69.2 mmol) was dissolved in 230 mL of aqueous 4N HCl with stirring. Formic acid (7.85 mL, 208 mmol) was added and the reaction was refluxed for 1 h. The reaction was cooled to rt then concentrated in vacuo to a dark solid. The dark solid was dissolved In 500 mL of MeOH with stirring, NaHCO3 (51.0 g, 607 mmol) was added and the reaction was stirred for 1 h. The reaction was then filtered, and the filtrate concentrated in vacuo to a solid. The solid was stirred in 400 mL of EtOAc and heated to reflux, then filtered. The filtrate was concentrated in vacuo to a solid. The solid dissolved in 400 mL of DCM with stirring, then dried over MgSO4, and filtered. The filtrate was concentrated in vacuo to give 11.3 g (99%) of the crude 6-(methylthio)-1H-benzimidazole as a dark oil. 1H NMR (400 MHz, CD3OD) δ 8.12 (s, 1H), 7.52 (m, 2H), 7.24 (m, 1H), 2.50 (s, 3H). MS m/z 165 (M+1).

1. temperaturethe reaction was refluxed for 1 h
2. concentrationthen concentrated in vacuo to a dark solid
3. dissolutionThe dark solid was dissolved In 500 mL of MeOH
4. stirringwith stirring
5. stirringthe reaction was stirred for 1 h
6. filtrationThe reaction was then filtered
7. concentrationthe filtrate concentrated in vacuo to a solid
8. stirringThe solid was stirred in 400 mL of EtOAc
9. temperatureheated
10. temperatureto reflux
11. filtrationfiltered
12. concentrationThe filtrate was concentrated in vacuo to a solid
13. dissolutionThe solid dissolved in 400 mL of DCM
14. stirringwith stirring
15. dry with materialdried over MgSO4
16. filtrationfiltered
17. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-babbceeecf374d3481ebeca821153e84

Source dataset

uspto-grants-2009_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07615643B2