Suberogorgin（S）, a new reversible anticholinesterase agent, is a tricyclopentapentalane sesquiterpene acid with a rare novel structure. It is important for the exploration of the relationships between its structure ...Suberogorgin（S）, a new reversible anticholinesterase agent, is a tricyclopentapentalane sesquiterpene acid with a rare novel structure. It is important for the exploration of the relationships between its structure and bioactivities and for the development of terpene chemistry to study its structural characteristics. This note is on using 2D NMR techniques to analyse the <sup>1</sup>H and <sup>13</sup>C NMR spectra and the stereochemistry of it.展开更多
The two symmetrical isomers in [Co(amp)2Cl2]2 (amp=2 (Aminomethyl)pyridine) system were synthesized by general oxidation method and were separated by chromatography and recrystallization method. Their configurations w...The two symmetrical isomers in [Co(amp)2Cl2]2 (amp=2 (Aminomethyl)pyridine) system were synthesized by general oxidation method and were separated by chromatography and recrystallization method. Their configurations were assigned by using 2D NMR techniques, particularly the NOESY NMR spectra. Solvent used was Me2SO d6 with the central peak of the CD3 septet as the reference (13C,δ 39.37;1H,δ 2.49 relative to SiMe4). Cation exchange media used was Dowex 50Wx 2(H+ form, 200～400mesh; Biorad).展开更多
A Series of LiCl/γ-Al2O3 samples were prepared by mixing and then heating at 400℃ for 30 hours. 7Li MAS NMR was used to investigated their structures. The 7Li MAS NMR signal of LiCl in the dispersion phase was obser...A Series of LiCl/γ-Al2O3 samples were prepared by mixing and then heating at 400℃ for 30 hours. 7Li MAS NMR was used to investigated their structures. The 7Li MAS NMR signal of LiCl in the dispersion phase was observed for the first time, and its chemical shift was at 0.25ppm.After the dispersion threshold of LiCl on γ-Al2O3 was achieved, the 7Li signal in the crystallme phase LiCl appears at -1.01ppm and its intensity increases with the increasing in LiCl loading.From the 2D nutation NMR spectra, it can be seen that the electric field gradient surrounding the lithium nuclei in the dispersion state is larger and so the quadrupole interaction is stonger than that in the crystalline state. The dispersion threshold indicated by NMR is in agreement with that deduced from XRD, which is about 0.136gLiCl/gγ-Al2O3.展开更多
Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobala...Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘Suberogorgin（S）, a new reversible anticholinesterase agent, is a tricyclopentapentalane sesquiterpene acid with a rare novel structure. It is important for the exploration of the relationships between its structure and bioactivities and for the development of terpene chemistry to study its structural characteristics. This note is on using 2D NMR techniques to analyse the <sup>1</sup>H and <sup>13</sup>C NMR spectra and the stereochemistry of it.
文摘The two symmetrical isomers in [Co(amp)2Cl2]2 (amp=2 (Aminomethyl)pyridine) system were synthesized by general oxidation method and were separated by chromatography and recrystallization method. Their configurations were assigned by using 2D NMR techniques, particularly the NOESY NMR spectra. Solvent used was Me2SO d6 with the central peak of the CD3 septet as the reference (13C,δ 39.37;1H,δ 2.49 relative to SiMe4). Cation exchange media used was Dowex 50Wx 2(H+ form, 200～400mesh; Biorad).
文摘A Series of LiCl/γ-Al2O3 samples were prepared by mixing and then heating at 400℃ for 30 hours. 7Li MAS NMR was used to investigated their structures. The 7Li MAS NMR signal of LiCl in the dispersion phase was observed for the first time, and its chemical shift was at 0.25ppm.After the dispersion threshold of LiCl on γ-Al2O3 was achieved, the 7Li signal in the crystallme phase LiCl appears at -1.01ppm and its intensity increases with the increasing in LiCl loading.From the 2D nutation NMR spectra, it can be seen that the electric field gradient surrounding the lithium nuclei in the dispersion state is larger and so the quadrupole interaction is stonger than that in the crystalline state. The dispersion threshold indicated by NMR is in agreement with that deduced from XRD, which is about 0.136gLiCl/gγ-Al2O3.
基金Project supported by the National Natural Science Foundation of China.
文摘Two new coenzyme B12 analogues, 2',5'-dideoxycytidylcobalamin (2a) and 2',5'-dide-oxyuridinylcobalamin (2b), and two others, 2',5'-dideoxyadenosylcobalamin (2c), and 5'-deoxy-thymidylcobalamin (2d) were prepared by an improved method. All the four analogues were investigated by UV-vis and 2D 1H NMR spectroscopy. The comparisons and discussion about their spectroscopic properties were done.
