Lithium borohydride → HCID 22224443, compound

Participants

Reaction Steps

To stirred solution of LiBH4 (1.79 g, 82 mmol) in THF at 0° C., ethyl 9-methyl-9H-imidazo[1,2-a]benzimidazole-2-carboxylate (2.5 g, 10.3 mmol) was added drop wise. The reaction mixture was refluxed for 2 hrs and cooled to room temperature. Ti was carefully quenched with ice cold water and acidified with Con. HCl to pH 4. The reaction mixture was stirred at room temperature for 1 hr and basified with K2CO3. The residue was extracted with chloroform:methanol (3:1) and dried over anhydrous MgSO4. It was filtered and concentrated. Yield. 1.3 g (65%). (M+H) 202. The residue (1.3 g, 6.4 mmol) was oxidised with MnO2 (5.0 g) in CH2Cl2 under refluxing condition. After the completion, reaction mixture was filtered and concentrated. It was purified by SiO2 column chromatography by eluting it with 1:1 ethyl acetate:hexane. Brown solid. Yield. 330 mg (25%); (M+H) 200.

Provenance & Evidence