Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral...Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.展开更多
The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by prote...The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by protein engineering for the asymmetric reductive amination of ketones,they all display(R)‐stereoselectivity.To date,there is no report of an(S)‐stereoselective biocatalyst for this reaction.Herein,a microorganism named Brevibacterium epidermidis ECU1015 that catalyzes the(S)‐selective reductive amination of ketones with ammonium has been successfully isolated from soil.Using B.epidermidis ECU1015 as the catalyst,the asymmetric reductive amination of a set of phenylacetone derivatives was successfully carried out,yielding the corresponding(S)‐chiral amines with moderate conversion and>99%enantiomeric excess.展开更多
Objective：To investigate the clinical characteristics, treatment options and causes of misdiagnosis of ipsilateral femoral neck and shaft fractures. Methods： Among 20 patients with ipsilateral femoral neck and shaf...Objective：To investigate the clinical characteristics, treatment options and causes of misdiagnosis of ipsilateral femoral neck and shaft fractures. Methods： Among 20 patients with ipsilateral femoral neck and shaft fractures, 19 were treated operatively and 1 was treated conservatively. Sixteen cases of femoral shaft fractures were treated by open reduction and internal fixation with compressive plate, and 2 cases were treated with interlocking intramedullary nailing. Eighteen femoral neck fractures were treated with cannulated screws. Another patient was treated with proximal femoral nail to fix both the neck and shaft. Delayed diagnosis for femoral neck frac-tures occurred in 2 cases preoperatively. Results： A total of 19 patients were followed up. The follow up period ranged from 5 to 48 months with an average of 15 months. All the fractures were healed. Conclusion： For case of femoral shaft fracture caused by high energy injury, an AP pelvic film should be routinely taken. Once the femoral neck fracture is recognized, operative reduction and fixation should be performed in time. Femoral neck and shaft fractures should be fixed separately.展开更多
Fractures of the paediatric talus are in- frequent injuries, most complicated by posttraumatic arthro- sis and avascular necrosis in the course of treatment. Non- union in children has not been reported before in lite...Fractures of the paediatric talus are in- frequent injuries, most complicated by posttraumatic arthro- sis and avascular necrosis in the course of treatment. Non- union in children has not been reported before in literature. We report a case of a 12-year-old boy who had a nonunion of Hawkins type II fracture of talar neck. The nonunion was treated surgically with a good clinical outcome. The goalsof management in nonunion of paediatric talar neck fracture are different from those in fresh fractures. A suboptimal re- duction should be acceptable without trying a radical sur- gery which may cause further impairment.展开更多
基金Supported by the Natural Science Foundation of Hubei Province（2008CDB354） Wuhan Youth Scientist Dawn Foundation（200750731288）
文摘Chiral aromatic alcohols are the key chiral building block for many important enantiopure pharmaceu-ticals. In this work,we studied asymmetric reduction of prochiral aromatic ketone to produce the corresponding chiral alcohol using vegetables as the biocatalyst. Acetophenone was chosen as the model substrate. The results in-dicate that acetophenone can be reduced to the corresponding chiral alcohols with high enantioselectivity by the chosen vegetables,i.e. apple(Malus pumila),carrot(Daucus carota),cucumber(Cucumis sativus),onion(Allium cepa),potato(Soanum tuberosum),radish(Raphanus sativus),and sweet potato(Ipomoea batatas) . In the reaction,R-1-phenylethanol is produced with apple,sweet potato and potato as the catalyst,while S-1-phenylethanol is the product with the other vegetables as the catalyst. In term of the enantioselectivity and reaction yield,carrot(D. ca-rota) is the best catalyst for this reaction. Furthermore,the reaction characteristics were studied in detail using car-rot(D. carota) as the biocatalyst. The effects of various factors on the reaction were investigated and the optimal reaction conditions were determined. Under the optimal reaction conditions(reaction time 50 h,substrate concen-tration 20 mmol·L-1,reaction temperature 35 °C and pH 7),95% of e.e.(to S-1-phenylethanol) and 85% chemical yield can be obtained. This work extends the biocatalyst for the asymmetric reduction reaction of prochiral aromatic ketones,and provides a novel potential route to produce enantiopure aromatic alcohols.
基金supported by the National Natural Science Foundation of China(21472045,21536004)the National Defense Scientific and Technological Innovation Special Zone(17-163-12-ZT-003-055-01)~~
文摘The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by protein engineering for the asymmetric reductive amination of ketones,they all display(R)‐stereoselectivity.To date,there is no report of an(S)‐stereoselective biocatalyst for this reaction.Herein,a microorganism named Brevibacterium epidermidis ECU1015 that catalyzes the(S)‐selective reductive amination of ketones with ammonium has been successfully isolated from soil.Using B.epidermidis ECU1015 as the catalyst,the asymmetric reductive amination of a set of phenylacetone derivatives was successfully carried out,yielding the corresponding(S)‐chiral amines with moderate conversion and>99%enantiomeric excess.
文摘Objective：To investigate the clinical characteristics, treatment options and causes of misdiagnosis of ipsilateral femoral neck and shaft fractures. Methods： Among 20 patients with ipsilateral femoral neck and shaft fractures, 19 were treated operatively and 1 was treated conservatively. Sixteen cases of femoral shaft fractures were treated by open reduction and internal fixation with compressive plate, and 2 cases were treated with interlocking intramedullary nailing. Eighteen femoral neck fractures were treated with cannulated screws. Another patient was treated with proximal femoral nail to fix both the neck and shaft. Delayed diagnosis for femoral neck frac-tures occurred in 2 cases preoperatively. Results： A total of 19 patients were followed up. The follow up period ranged from 5 to 48 months with an average of 15 months. All the fractures were healed. Conclusion： For case of femoral shaft fracture caused by high energy injury, an AP pelvic film should be routinely taken. Once the femoral neck fracture is recognized, operative reduction and fixation should be performed in time. Femoral neck and shaft fractures should be fixed separately.
文摘Fractures of the paediatric talus are in- frequent injuries, most complicated by posttraumatic arthro- sis and avascular necrosis in the course of treatment. Non- union in children has not been reported before in literature. We report a case of a 12-year-old boy who had a nonunion of Hawkins type II fracture of talar neck. The nonunion was treated surgically with a good clinical outcome. The goalsof management in nonunion of paediatric talar neck fracture are different from those in fresh fractures. A suboptimal re- duction should be acceptable without trying a radical sur- gery which may cause further impairment.
