To a solution of 2-[(1-methylethyl)oxy]-5-[3-(2,3,4,5-tetrahydro-1,4-benzoxazepin-9-yl)-1,2,4-oxadiazol-5-yl]benzonitrile hydrochloride (Example 32) (90 mg, 0.218 mmol) in acetonitrile (10 ml) was added N,N-diisopropylethylamine (0.076 ml, 0.436 mmol) followed by ethyl 3-bromopropanoate (0.056 ml, 0.436 mmol). The reaction mixture was heated at 80° C. overnight. A further 1 equivalent of N,N-diisopropylethylamine and ethyl 3-bromopropanoate were added and heating continued overnight. The reaction mixture was cooled and evaporated. Purification of the residue by column chromatography on silica, eluting with 60-70% ethyl acetate in cyclohexane to give the title compound as a brown oil (40 mg).
