In a 8 ml vial 6-[(3-ethyl-1,3-dihydro-2-benzofuran-4-yl)oxy]-3-pyridinamine (Intermediate 108, 10 mg) was dissolved in N,N-dimethylformamide (1 ml) to give a colourless solution. DIPEA (10.22 μl, 0.059 mmol), (2R)-2-({[(1,1-dimethylethyl)oxy]carbonyl}amino)butanoic acid (9.52 mg, 0.047 mmol) and, finally, TBTU (15.03 mg, 0.047 mmol) were added. The reaction mixture was shaken at 60° C. After overnight shaking, the reaction was completed. The reaction mixture was evaporated under vacuum to give the crude product as a yellow oil which was purified via Biotage SP1 (with Cyclohexane/EtOAc as eluents from 2:1 to 1:1 in 10 CV; then 2:1 for 5 CV; 10 g SNAP Silica column). The collected fractions afforded the title compound as a colourless oil (12.7 mg).
