RESUMO
A series of ruthenium complexes (Ru1-Ru4) bearing new NNN-pincer ligands were synthesized in 58-78% yields. All of the complexes are air and moisture stable and were characterized by IR, NMR, and high-resolution mass spectra (HRMS). In addition, the structures of Ru1-Ru3 were confirmed by X-ray crystallographic analysis. These Ru(II) complexes exhibited high catalytic efficiency and broad functional group tolerance in the N-methylation reaction of amines using CH3OH as both the C1 source and solvent. Experimental results indicated that the electronic effect of the substituents on the ligands considerably affects the catalytic reactivity of the complexes in which Ru3 bearing an electron-donating OMe group showed the highest activity. Deuterium labeling and control experiments suggested that the dehydrogenation of methanol to generate ruthenium hydride species was the rate-determining step in the reaction. Furthermore, this protocol also provided a ready approach to versatile trideuterated N-methylamines under mild conditions using CD3OD as a deuterated methylating agent.
RESUMO
OBJECTIVE: To explore the clinical effect of percutaneous pedicle screw anchored vertebral augmentation(PPSAVA) in the treatment of asymptomatic Kümmell disease without neurological symptoms. METHODS: The clinical data of 20 patients with Kümmell disease without neurological symptoms treated with PPSAVA in our hospital from January 2019 to December 2021 were analyzed retrospectively, including 5 males and 15 females, aged 56 to 88 (74.95±9.93) years old. and the course of disease was 7 to 60 days with an average of (21.35±14.46) days. All patients were treated with PPSAVA. The time of operation, the amount of bone cement injected and the leakage of bone cement were recorded. The visual analogue scale(VAS), Oswestry disability index(ODI), vertebral body angle(VBA), anterior edge height and midline height of vertebral body were compared among the before operation, 3 days after operation and during the final follow-up. The loosening and displacement of bone cement were observed during the final follow-up. RESULTS: All the 20 patients completed the operation successfully. The operation time was 30 to 56 min with an average of (41.15±7.65) min, and the amount of bone cement injection was 6.0 to 12.0 ml with an average of (9.30±1.49) ml. Bone cement leakage occurred in 6 cases and there were no obvious clinical symptoms. The follow-up time was 6 to 12 months with an average of (8.43±2.82) months. The VBA, anterior edge height and midline height of of injured vertebral body were significantly improved 3 days after operation and the final follow-up(P<0.05), and the VBA, anterior edge height and midline height of of injured vertebral body were lost in different degrees at the final follow-up (P<0.05). The VAS and ODI at 3 days after operation and at the final follow-up were significantly lower than those at preoperatively(P<0.05), but the VAS score and ODI at the final follow-up were not significantly different from those at 3 d after operation(P>0.05). At the last follow-up, no patients showed loosening or displacement of bone cement. CONCLUSION: PPSAVA is highly effective in treating Kümmell disease without neurological symptoms, improving patients' pain and functional impairment, and reducing the risk of cement loosening and displacement postoperatively.