2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]-2-(5-nitro-1H-benzimidazol-2(3H)-ylidene)acetonitrile → 2-(5-amino-1H-benzimidazol-2(3H)-ylidene)-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]acetonitrile

Participants

Reaction Steps

4-Nitro-1,2-phenylenediamine (50 mg; 0.32 mmol) and ethyl 2-cyano-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]acetate hydrochloride salt (101 mg; 0.32 mmol) were heated at 198° C. in a microwave for 3 min. Acetic acid (1.5 mL) was added to the crude material and the mixture heated at 100° C. for 6 hr. The solid was collected by filtration, washed with acetonitrile, and dried under high vacuum to give 2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]-2-(5-nitro-1H-benzimidazol-2(3H)-ylidene)acetonitrile (59 mg) as a yellow solid. 2-[4-Methyl-6-(trifluoromethyl)pyrimidin-2-yl]-2-(5-nitro-1H-benzimidazol-2(3H)-ylidene)acetonitrile (55 mg; 0.15 mmol) in DMF (3 mL) was hydrogenated over 10% palladium on carbon (11 mg). The mixture was filtered through diatomaceous earth, washing with methanol, and the filtrate was concentrated to give 2-(5-amino-1H-benzimidazol-2(3H)-ylidene)-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]acetonitrile, which was dissolved in DMF (1 mL) and added to a solution of N-methyl-L-proline (19.3 mg; 0.16 mmol), HBTU (56.8 mg; 0.15 mmol), and DIPEA (104.5 μL; 0.60 mmol) in DMF (1 mL). The mixture was stirred for 5 hr and then partitioned between EA and water. The EA phase was dried and concentrated to give 2-{5-[(S)-(1-methylpyrrolidin-2-yl)carbonylamino]-1H-benzimidazol-2 (3H)-ylidene}-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]acetonitrile (65 mg) as a brown oil. 2-{5-[(S)-(1-Methylpyrrolidin-2-yl)-carbonylamino]-1H-benzimidazol-2(3H)-ylidene}-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]-acetonitrile (65 mg) was dissolved in concentrated sulfuric acid and stirred at room temperature overnight. The mixture was diluted with ice-water and acetonitrile and, after coming to room temperature, was purified by reverse phase preparative HPLC using a Peeke Ultro 120, 7 μm, C18Q, 250×30 mm column at a flow rate of 42 mL/min and mobile phases of 95% water, 5% acetonitrile (with 0.01% hydrochloric acid) and 5% water, 95% acetonitrile (with 0.01% hydrochloric acid) to give 2-{5-[(S)-(1-methylpyrrolidin-2-yl)carbonylamino]-1H-benzimidazol-2 (3H)-ylidene}-2-[4-methyl-6-(trifluoromethyl)pyrimidin-2-yl]acetamide hydrochloride salt (18 mg) as a yellow solid.

Provenance & Evidence