Dess-Martin periodinane (0.278 g) was added to a stirred solution of (2-butylthiazol-4-yl)(9-(2-fluoro-3-(2-hydroxyethyl)benzyl)-1-oxa-4,9-diazaspiro[5.5]undecan-4-yl)methanone (example 78, step i) (0.240 g) and trifluoroacetic acid (0.058 mL) in DCM (5 mL). After 1 h, ethyl acetate (30 mL) was added followed by a mixture of saturated sodium thiosulphate solution (5 mL) and saturated sodium bicarbonate solution (5 mL). The reaction mixture was shaken well and separated. The ethyl acetate solution was washed with saturated sodium bicarbonate solution, water and brine. Acetic acid (0.08 mL) was added, the solution was dried over sodium sulphate, filtered and evaporated in vacuo (bath temperature=30° C.) to give the subtitled compound as a gum. Yield 0.24 g. Used directly.
