To 0.023 g (0.10 mmol) (S)—N-{1-[4-(3-hydroxy-azetidin-1-yl)-phenyl]-ethyl}-acetamide (V.1) in 5 mL THF are added 0.017 mL (0.12 mmol) TEA and the mixture is cooled to 0° C. 0.008 mL (0.10 mmol) methanesulfonyl chloride are added dropwise and the mixture is stirred for 2 h at 0° C. Water is added and the aq. phase is extracted with ethyl acetate (2×). The combined organic layers are dried (MgSO4) and concentrated. The residue is taken up in 1.0 mL DMA and is added to a mixture of 0.014 g (0.12 mmol) 2,3-difluoro-4-methylphenol and 0.039 g (0.12 mmol) Cs2CO3 in 1.0 mL DMA. The resulting mixture is stirred for 12 h at 100° C. After cooling the mixture is directly purified by HPLC (MeOH/water (+0.1% NH4OH)) to yield the desired product.
