*4.7. 1,5-Bis (p-Toluenesulfonyl)-1,5-diazacyclooctane (7)*

To a solution of sodium methanolate (8.0 g, 148 mmol) in dry MeOH (100 mL) **5** (5.0 g, 13 mmol) was added, and the mixture was heated under reflux for 4 h. The solvent was removed, the residue was dissolved in dry DMF (100 mL) and 6 (5.0 g, 13 mmol) was added. The mixture was stirred at 80 ◦C for 12 h. The product was precipitated by adding aq. HCl (2 M), filtered off, and **7** (4.7 g, 84%) was obtained as a colorless solid; m.p. 214–216 ◦C (lit. [33]: 214–215 ◦C); Rf = 0.33 (hexane/ethyl acetate, 7:3); UV-Vis (CHCl3): λmax (log ε) = 232 nm (4.32); IR (ATR): *ν* = 2953*w*, 1597*w*, 1456*m*, 1378*m*, 1321*s*, 1182*m*, 1150*s*, 1088*s*, 1017*m*, 1059*s*, 987*s*, 927*m*, 837*m*, 812*s*, 723*s,* 644*s*, 627*m*, 543*s*, 487*m*, 462*m*, 408*m* cm<sup>−</sup>1; 1H NMR (400 MHz, CDCl3): δ = 7.68 (*d*, *J* = 8.3 Hz, 4H, 5-H, 9-H), 7.33–7.30 (*m*, 4H, 6-H, 8-H), 3.31–3.24 (*m*, 8H, 1-H, 3-H), 2.43 (*s*, 6H, 10-H), 2.04 (*p*, *J* = 5.9 Hz, 4H, 2-H) ppm; 13C NMR (101 MHz, CDCl3): δ = 143.4 (C-7), 135.6 (C-4), 129.8 (C-6, C-8), 127.1 (C-5, C-9), 47.0 (C-1, C-3), 30.2 (C-2), 21.5 (C-10) ppm; MS (ESI, MeOH/CHCl3, 4:1): *m*/*z* = 445.2 (100%, [M+Na]+).

#### *4.8. 1,5-Diazacyclooctane Dihydrobromide (8)*

#### 4.8.1. Procedure A

A solution of **7** (2.5 g, 6 mmol) and thioanisole (2.4 mL, 18 mmol) in HBr (33% in glacial acetic acid, 150 mL) was stirred at 80 ◦C for 3 h. The volatiles were removed under diminished pressure, DCM (30 mL) was added, and the solution was washed with water (3 × 100 mL), followed by decolorization (activated charcoal). The solution was filtered, the solvent removed, and **8** (1.5 g, 5.5 mmol, 92%) was obtained as a colorless solid.
