To a solution of 7-[(2,6-dichlorophenyl)amino]-2-methyl-8H-imidazo[4,5-e][1,3]benzoxazole-4-carboxylic acid (Intermediate-55, 0.050 g, 0.132 mmol) in benzene (2 mL) was added thionyl chloride (1.5 mL) at 5-10° C. The reaction mass was refluxed for 3 h. To a solution of hexan-1-amine (0.020 g, 0.198 mmol) in THF (5.0 mL), DIPEA (0.086 g, 0.663 mmol) was added under N2-atmosphere at RT. The solution was stirred for 1 h at RT and above prepared solution was added to reaction mixture. The whole reaction mass was stirred at RT for 1 h. Thionyl chloride was removed under vacuum and stripped out with THF. The reaction mass was quenched in ice water and extracted with ethyl acetate. The organic layer was concentrated. 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 0.83-0.85 (s, 3H), 1.26 (s, 6H), 1.51-1.54 (m, 2H), 2.61 (s, 3H), 3.30 (m, 2H), 7.30 (s, 1H), 7.57 (s, 3H), 7.90 (s, 1H), 9.30 (s, 1H), 11.40-11.50 (s, 1H); MS [M+H]+: 460.41
