以六硝基联卞(HNBB)为原料,4-羟基-2,2,6,6-四甲基哌啶-N-氧自由基(4-OH-TEMPO)和氯化亚铁(FeCl2)为催化剂,在二甲亚砜(DMSO)中通过氧气氧化HNBB脱氢制备了六硝基茋(HNS),收率为81%。确定了最佳反应条件:溶剂为DMSO,催化剂组合及其比例...以六硝基联卞(HNBB)为原料,4-羟基-2,2,6,6-四甲基哌啶-N-氧自由基(4-OH-TEMPO)和氯化亚铁(FeCl2)为催化剂,在二甲亚砜(DMSO)中通过氧气氧化HNBB脱氢制备了六硝基茋(HNS),收率为81%。确定了最佳反应条件:溶剂为DMSO,催化剂组合及其比例为n(4-OH-TEMPO)∶n(FeCl2)=4∶6时,在55℃下以25 m L·h-1的速率通入氧气反应8 h。推测了可能的反应机理:亚铁离子结合氧气直接氧化底物HNBB脱氢得到HNS,4-OH-TEMPO在这个过程中起到一个促进FeCl2循环加速氧化脱氢的助催化作用。展开更多
Six novel rod-like magnetic liquid crystals have been prepared, in which trans-bicyclohexyl or trans-cyclohexylphenyl and biphenylcarboxylic acid phenyl ester mesogenic cores with n-propyl and n-pentyl substituents we...Six novel rod-like magnetic liquid crystals have been prepared, in which trans-bicyclohexyl or trans-cyclohexylphenyl and biphenylcarboxylic acid phenyl ester mesogenic cores with n-propyl and n-pentyl substituents were terminated by 4-hydroxyl- TEMPO （TEMPO = 2,2,6,6-tetramethylpiperidine-l-oxy）. Their structures were confirmed by elemental analysis, IR and MS. Determined by SQUID, EPR, DSC and HS-POM （heat stage polarizing optical microscope）, the six compounds all have both magnetic and liquid crystalline properties; their temperature ranges of mesophase were from 16.0 to 24.8 ℃, and the magnetic liquid crystal molecules could obviously improve the response sensitivity of liquid crystal materials.展开更多
A mild and efficient methodology for the direct oxidative synthesis of nitriles from easily available alcohols and aqueous ammonia by employing CuCI/DABCO/4-HO-TEMPO as the catalysts is described. This protocol uses t...A mild and efficient methodology for the direct oxidative synthesis of nitriles from easily available alcohols and aqueous ammonia by employing CuCI/DABCO/4-HO-TEMPO as the catalysts is described. This protocol uses the air as a green oxidant and aqueous ammonia as the nitrogen source at room temperature, A variety of aryl, heterocyclic and allylic alcohols are smoothly converted into the corresponding nitriles in good to excellent yields.展开更多
4 novel rod-like Schiff base magnetic liquid crystals have been prepared in which trans-bicyclohexyl or trans-cyclohexyl phenyl and biphenyl carboxylic acid phenol ester mesogenic cores with n-propyl and n-pentyl subs...4 novel rod-like Schiff base magnetic liquid crystals have been prepared in which trans-bicyclohexyl or trans-cyclohexyl phenyl and biphenyl carboxylic acid phenol ester mesogenic cores with n-propyl and n-pentyl subsfituents were terminated by 4-amino-TEMPO （TEMPO=2,2,6,6-tetramethylpiperidine-l-oxyl）. Of these compounds the silk-like and schlieren textures were found from 4e and 4d by POM （Polarizing Optical Microscope）. DSC （Differential Scanning Calorimeter） measurements show that the mesophase exists from 4-6℃. EPR spectra reveal their paramagnetic properties.展开更多
文摘以六硝基联卞(HNBB)为原料,4-羟基-2,2,6,6-四甲基哌啶-N-氧自由基(4-OH-TEMPO)和氯化亚铁(FeCl2)为催化剂,在二甲亚砜(DMSO)中通过氧气氧化HNBB脱氢制备了六硝基茋(HNS),收率为81%。确定了最佳反应条件:溶剂为DMSO,催化剂组合及其比例为n(4-OH-TEMPO)∶n(FeCl2)=4∶6时,在55℃下以25 m L·h-1的速率通入氧气反应8 h。推测了可能的反应机理:亚铁离子结合氧气直接氧化底物HNBB脱氢得到HNS,4-OH-TEMPO在这个过程中起到一个促进FeCl2循环加速氧化脱氢的助催化作用。
基金supported by Natural Science Foundation of Shaanxi Province Educational Department(No.07JK426)Science Foundation of Xianyang Normal University(No.07XSYK219).
文摘Six novel rod-like magnetic liquid crystals have been prepared, in which trans-bicyclohexyl or trans-cyclohexylphenyl and biphenylcarboxylic acid phenyl ester mesogenic cores with n-propyl and n-pentyl substituents were terminated by 4-hydroxyl- TEMPO （TEMPO = 2,2,6,6-tetramethylpiperidine-l-oxy）. Their structures were confirmed by elemental analysis, IR and MS. Determined by SQUID, EPR, DSC and HS-POM （heat stage polarizing optical microscope）, the six compounds all have both magnetic and liquid crystalline properties; their temperature ranges of mesophase were from 16.0 to 24.8 ℃, and the magnetic liquid crystal molecules could obviously improve the response sensitivity of liquid crystal materials.
文摘A mild and efficient methodology for the direct oxidative synthesis of nitriles from easily available alcohols and aqueous ammonia by employing CuCI/DABCO/4-HO-TEMPO as the catalysts is described. This protocol uses the air as a green oxidant and aqueous ammonia as the nitrogen source at room temperature, A variety of aryl, heterocyclic and allylic alcohols are smoothly converted into the corresponding nitriles in good to excellent yields.
文摘目的探讨eNOS和NADPH氧化酶在慢性缺氧条件下小鼠肺组织中表达的关系。方法将野生型及e NOS基因敲除的C57BL/6雄性小鼠各30只随机分为常氧组、低氧7 d组、低氧21 d组、治疗7 d组和治疗21 d组,每种每组小鼠各6只。低氧和治疗组小鼠在10%氧浓度条件下进行饲养,治疗组小鼠饮水中加入10 mmol/L 4-羟基-2,2,6,6-四甲基哌啶(TEMPOL)进行干预。比较各组小鼠肺小动脉重塑(MT%)及右心室肥厚指标的变化;ELISA法检测各组肺组织ROS浓度的变化;RT-PCR法检测各组肺组织NOX2、4及e NOS基因表达的变化。结果野生型及基因敲除低氧组小鼠肺血管重塑及右心室肥厚指标较常氧组和治疗组均明显上升(P<0.05),而治疗组和常氧组间比较差异无统计学意义(P>0.05)。野生型低氧及治疗组小鼠肺组织ROS浓度均低于常氧组(P<0.05),而低氧组和治疗组间比较差异无统计学意义(P>0.05)。野生型低氧组小鼠e NOS、NOX2和NOX4的m RNA表达较常氧组均显著上升(P<0.05),TEMPOL干预可逆转上述指标的过度表达。基因敲除常氧组小鼠NOX2和NOX4 m RNA表达高于同组野生型小鼠(P<0.05);慢性缺氧后NOX4 m RNA表达较常氧组差异无统计学意义(P>0.05),NOX2 m RNA表达较常氧组显著下降(P<0.05);治疗组NOX2m RNA表达较低氧组进一步下降,而NOX4 m RNA表达较低氧组明显上升(P<0.05)。结论 e NOS是低氧条件下NOX2、4表达的重要调控因素,e NOS和NOX在低氧性肺血管重塑过程中可能有着重要的联系。
文摘4 novel rod-like Schiff base magnetic liquid crystals have been prepared in which trans-bicyclohexyl or trans-cyclohexyl phenyl and biphenyl carboxylic acid phenol ester mesogenic cores with n-propyl and n-pentyl subsfituents were terminated by 4-amino-TEMPO （TEMPO=2,2,6,6-tetramethylpiperidine-l-oxyl）. Of these compounds the silk-like and schlieren textures were found from 4e and 4d by POM （Polarizing Optical Microscope）. DSC （Differential Scanning Calorimeter） measurements show that the mesophase exists from 4-6℃. EPR spectra reveal their paramagnetic properties.
