Methanol → 3-(6-chloro-8-oxo-8,9-dihydro-7H-purin-2-yl)-3H-benzo[d]imidazole-5-carbonitrile

Participants

Reaction Steps

To a solution of crude 4-amino-3-(6-chloro-8-oxo-8,9-dihydro-7H-purin-2-ylamino)benzonitrile (1.23 mmol) in anhydrous DMSO (10 mL) was added methanol (150 mL), followed by anhydrous trimethylorthoformate (5 mL) and p-toluene sulfonic acid (100 mg) and the reaction mixture was stirred under Ar at room temperature for 3 h (LC-MS monitoring). The solvent was removed in vacuo and the residue redissolved in 7 mL of DMSO, then 40 mL of water were added. The pink solid formed was filtered under vacuo using a fine porosity Buchner filter funnel, washed with water, then dried in the vacuum oven at 60° C. to give 0.26 g of the desired product (67% yield on 2 steps). 1H NMR (300 MHz, CDCl3+CD3OD) δ, ppm: 9.24 (s, 1H), 9.00 (s, 1H), 7.91 (d, 1H), 7.69 (d, 1H); MS (EI) m/z 312.2 (MH)+.

Provenance & Evidence