To a suspension of 2-(2-isopropyl-5-methyl-2H-[1,2,4]triazol-3-yl)-4,5-dihydro-6-oxa-1,3a-diazabenzo[e]azulen-8-ol from Example 4 (267 mg, 0.82 mmol), 4-(1-hydroxyethyl)azepane-1-carboxylic acid tertbutyl ester (300 mg, 1.23 mmol) and triphenylphosphine (365 mg, 1.39 mmol) in dioxane (3 mL) was added dropwise DIAD (273 ul, 1.39 mmol) and the reaction mixture was stirred at RT for 2 h. The mixture was then diluted with EtOAc and washed with aq. NaOH (1N). The aqueous phase was extracted with EtOAc (×3) and the combined organic layers were then washed with brine, dried over MgSO4 and concentrated in vacuo. The resulting residue was purified by column chromatography (Si-PCC, gradient 0-10% MeOH in DCM followed by Si-PCC, gradient 0-10% MeOH in EtOAc) affording the title compound as a colorless oil (60 mg, 15%). LCMS: RT 4.08 min [M+H]+ 551.2
