To a suspension of LiAlH4 (65.5 mg, 1.724 mmol) in THF (7 mL) cooled to 10° C. was added a solution of 2-cyclopropylmethyl-2-[2-(2-isopropyl-5-methyl-2H-[1,2,4]triazol-3-yl)-4,5-dihydro-6-oxa-1,3a-diazabenzo[e]azulen-8-yloxy]-malonic acid diethyl ester (309 mg, 0.575 mmol) in THF (5 mL). The reaction mixture was stirred at RT for 1.5 h. To the reaction mixture was added EtOAc (1 mL) and stirring was continued for 10 min. An aqueous solution of Rochelle salt was then added and stirring continued for a further 1.5 h. EtOAc was added and the mixture was filtered through a Celite® pad and the aqueous phase was extracted with EtOAc. The combined organic phases were washed with brine, then dried (Na2SO4) and concentrated in vacuo. The resulting residue was purified by column chromatography (Si-PCC, gradient 4-12% MeOH in DCM) affording the title compound as a colourless foam (0.20 g, 77%). LCMS (Method B): RT 2.72 min [M+H]+ 454.
