Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO ...Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.展开更多
2′,4″-O-Bis(trimethylsilyl) 6-O-methylerythromycin A 9-O-(1-methoxycyclohexyl) oxime was regioselectively synthesized and characterized and its crystal structure was determined by the single crystal X-ray structure ...2′,4″-O-Bis(trimethylsilyl) 6-O-methylerythromycin A 9-O-(1-methoxycyclohexyl) oxime was regioselectively synthesized and characterized and its crystal structure was determined by the single crystal X-ray structure analysis. The crystal belonged to tetragonal system with I4 space group and a=b=2.9720(4) nm, c=1.4939(3) nm, V=13.195(4) nm3, Z=8, R=0.0587, wR=0.1263, S=1.004 for 11526 unique reflections. The crystal structure shows that the attack of methylation reagents was blocked by 9-oxime ether as result, a hydrogen bond formed between 11-OH and nitrogen of 9-oxime, and the attack of methylation reagents was blocked by 9-oxime ether, whereas the orientation of 6-OCH3 was located in the cave surrounded by several rings so that 6-OH was unique one to be exposed to methylation reagents. However, the congestion around 11-OH was loosened, which resulted from the orientation of protective group so that much 6,11-O-dimethyl product was yielded. Additionally, the crystal structure of 2′,4″-O-bis(trimethylsilyl) erythromycin A 9-O-(1-methoxy-1-methylethyl) oxime was first disclosed as a comparison.展开更多
文摘Ozone mediated nitration of chlorobenzene with nitrogen dioxide over solid acid catalysts is expected to be a green process. The reaction was carried out at ca . 0 ℃. It was found that the solid acid catalysts of SO 2- 4/TiO 2 and SO 2- 4/ZrO 2 and a series of SO 2- 4/TiO 2 ZrO 2 catalysts exhibited a fairly good activity for the nitration reaction, whereas SO 2- 4/TiO 2 ZrO 2(atomic ratio 1∶1) gives yield of 62 4% and SO 2- 4/TiO 2 ZrO 2(molar ratio 3∶1) shows a good para selectivity in CH 2Cl 2 solvent. The ortho para isomer ratios( ortho/para ) of the nitration products were varied in range from 1 11 to 0 36. This phenomenon is interpreted in terms of acid amount and acid strength of solid acid catalysts.
文摘2′,4″-O-Bis(trimethylsilyl) 6-O-methylerythromycin A 9-O-(1-methoxycyclohexyl) oxime was regioselectively synthesized and characterized and its crystal structure was determined by the single crystal X-ray structure analysis. The crystal belonged to tetragonal system with I4 space group and a=b=2.9720(4) nm, c=1.4939(3) nm, V=13.195(4) nm3, Z=8, R=0.0587, wR=0.1263, S=1.004 for 11526 unique reflections. The crystal structure shows that the attack of methylation reagents was blocked by 9-oxime ether as result, a hydrogen bond formed between 11-OH and nitrogen of 9-oxime, and the attack of methylation reagents was blocked by 9-oxime ether, whereas the orientation of 6-OCH3 was located in the cave surrounded by several rings so that 6-OH was unique one to be exposed to methylation reagents. However, the congestion around 11-OH was loosened, which resulted from the orientation of protective group so that much 6,11-O-dimethyl product was yielded. Additionally, the crystal structure of 2′,4″-O-bis(trimethylsilyl) erythromycin A 9-O-(1-methoxy-1-methylethyl) oxime was first disclosed as a comparison.
基金supported by the National Natural Science Foundation of China(51302156,21302057)Combined with Shandong Provincial Natural Science Foundation,China(ZR2014BL012)~~
