1. Synthesis of acetonine nitroxide radical and 1-hydroxy-2,2,4,6,6-pentamethyl-1,2,5,6-tetrahydropyrimidine
2. Volodarsky, L., Kosover, V. US Patent 5 847 035; Dec. 8, 1998.
3. 2,2,4,4,6-Pentamethyl-7-oxa-1,3-diaza-bicyclo[4.1.0]heptan-3-oxyl, 4: Mp=52–53°C (heptane); IR: absence of νCN at 1670 cm−1; anal. calcd for C9Hl7N202 (185.24): C, 58.35; H, 15.12; N, 9.25; O, 17.27. Found: C, 58.60; H, 9.36; N, 15.24; O, 17.54; esr (H2O, LiCl): aN=15.8 G (ΔHpp=1.8 G); UV: (ethanol) 410 nm (ε=10 mol−1 cm−1), 235 nm (ε=3490 mol−1 cm−1). In ethanol solution, both the esr signal and the UV absorption at 410 nm decay with a half life of ca. 17 h at room temperature.
4. 2,2,4,4,6-Pentamethyl-7-oxa-1,3-diaza-bicyclo[4.1.0]heptan-3-ol, 6: Mp=98.5–99°C; 1H NMR (250 MHz, CDCl3) δ 1.16 (s, 3H), 1.25 (s, 3H), 1.41 (s, 3H), 1.53 (s, 6H), 2.06–2.28 (d, J=16 Hz, 1H); 13C NMR (250 MHz, CDC13) δ: 24.5, 24.9, 25.26, 27.4, 29.2, 40.6, 54.9, 77.4, 80.2.