Lithium Hydroxide → Ethyl 2-(7-oxo-4-tosyl-1,4-diazepan-5-yl)acetate

A solution of the product of step A (1.34 g, 5.44 mmol) was stirred in THF (30 ml) at 0*C. Bu3SnOTf (90%, 2.73 g, 5.60 mmol) in THF 8.0 ml was added dropwise over 6 min, and the mixture was heated to reflux for 22 h. The reaction was cooled to 0° C., and triethylamine (1.52 ml, 10.9 mmol) and dimethylaminopyridine (0.135 g, 1.11 mmol) were added followed by p-toluenesulfonyl chloride (2.09 g, 11.0 mmol) in THF 4.0 ml. The reaction was allowed to r.t. and after 4 h concentrated under reduced pressure. AcOEt (100 ml) was added to the residue and washed with 0.1 N HCl aq. (100 ml×2), sat'd NaHCO3 aq. (100 ml×2) and sat'd NaCl aq. (100 ml×2), dried over Na2SO4 and concentrated under reduced pressure. The crude product was chromatographed on silica (AcOEt→AcOEt/-MeOH=80/1) to yield the title compound. MS:355.2 C. 2-(7-Oxo-4-tosyl-1,4-diazepan-5-yl)acetic acid (3) To a solution of the product of step B (0.416 g, 1.17 mmol) in 1,4-dioxane (24 ml) and MeOH (24 ml), 0.13 N LiOH (28 ml, 3.6 mmol) was added, and the mixture was heated to reflux for overnight. The reaction was cooled to r.t. and AcOEt (400 ml) was added and washed with sat'd NaCl (400 ml×5), dried over Na2SO4 and concentrated under reduced pressure to yield the title compound. MS: 327.1 D. (R)-2-(7-Oxo-4-tosyl-1,4-diazepan-5-yl)-N-(6-(piperidin-1-ylmethyl)-1,2,3,4-tetrahydronaphthalen-1-yl)acetamide. To a mixture of 2-(7-oxo-4-tosyl-1,4-diazepan-5-yl)acetic acid (0.115 g, 0.352 mmol), (R)-6-(piperidin-1-ylmethyl)-1,2,3,4-tetrahydronaphthalen-1-amine (0.0945 g, 0.387 mmol) and HOBt (<5% H2O, ˜0.398 mmol) in DMF (3.0 ml) was added EDCI*HCl (0.0805 g, 0.420 mmol), and stirred overnight under N2. AcOEt (60 ml) was added and washed with sat'd NaHCO3 aq. (60 ml×3) and sat'd NaCl aq. (60 ml×3), dried over Na2SO4 and concentrated under reduced pressure. The crude product was chromatographed on silica (CH2Cl2/MeOH with 2N NH3=10/1) to yield the title compound. MS: 553.1