1H-Benzimidazole-5-carbonylchloride(9CI) synthesis

Yield:-

Reaction Conditions:

with thionyl chloride;N,N-dimethyl-formamide in benzene for 6 h;Heating / reflux;

Steps:

12
EXAMPLE 12 1H-Benzimidazole-5-carboxantide To a stirred suspension of benzimidazole-5-carboxylic acid (5.0 g, 30.8 nunol) in benzene (25 mL) was added thionyl chloride (25 mL) dropwise at room temperature. To this mixture was added DMF (0, 1 mL) and it was then heated under reflux for 6h. Benzene and thionyl chloride was evaporated off under reduced pressure and toluene (20 mL) added to the residue. This was removed under reduced pressure and the acid chloride thus obtained suspended in tetrohydrofuran (20 mL). To this was the added 28% aqueous ammonia (20 mL) dropwise at 0°C, and the resultant mixture was then stirred at room temperature overnight. The precipitate was filtered and washed with cold H20 to give the primary amide as a brown solid (3.55 g). 1H-n. m. r. (d6-DMSO) 87. 25 (br e, 1H, NH), 7.6U (d, 1H,/= 8. 4 Hz, ArH), 7. 78 (dd, 1H, J = 8.4 and 1.6 Hz, ArH), 7.97 (br s, 1H, CONH), 8.18 (br s, 1H, ArH), 8.342 (br s, 1H, ArH).

References:

CYTOPIA RESEARCH PTY LTD WO2005/54230, 2005, A1 Location in patent:Page/Page column 31-32