A solution of 1-{[1-(chloroacetyl)azetidin-3-yl]carbonyl}-4-cyclobutyl-1,4-diazepane (40 mg, 0.13 mmol) and piperidine (38 μl, 0.38 mmol) in toluene (2 ml) was heated at 80° C. for 4 hrs in a sealed tube then cooled to RT. The reaction was diluted with DCM (30 ml), washed with a saturated aqueous solution of NaHCO3 (2×15 ml), dried (MgSO4), filtered and concentrated at reduced pressure. The residue was purified by silica FCC (using a gradient of eluents; DCM/MeOH/NH3 99:1:1 to 92:8:1) to give the title compound (25 mg, 53% yield) as a colourless oil.
