To a solution of 7-[(2,6-dichlorophenyl)amino]-2-methyl-8H-imidazo[4,5-e][1,3]benzoxazole-4-carboxylic acid (Intermediate-55, 0.100 g, 0.276 mmol) in benzene (4 mL), thionyl chloride (5.0 mL) was added at 5-10° C. The reaction mass was refluxed for 3 h. Thionyl chloride was removed under vacuum and stripped out with benzene. The solution of 4-fluoroaniline (0.091 g, 0.828 mmol) in THF (5.0 mL) was added 60% NaH (0.033 g, 0.825 mmol) under N2-atmosphere at 0-5° C. The solution was stirred for 30 minutes at same temperature and above prepared solution was added to reaction mixture. The reaction mass was stirred at RT for 1 h. The reaction mass was quenched in ice water and extracted with ethyl acetate. The obtained product was further purified by column chromatography on neutral alumina eluting with 1.5-2.0% MeOH:DCM to afford 0.020 g of the desired product. 1HNMR (DMSO-d6): δ 2.65 (s, 3H), 7.17-7.20 (m, 4H), 7.38-7.50 (m, 1H), 7.61 (s, 2H), 7.79 (s, 1H), 8.96-9.04 (m, 1H), 9.40-9.60 (s, 1H), 11-12 (s, 1H); MS [M+H]+: 470.23.
