CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料在SBF中的性能研究

利用溶胶-凝胶生物活性材料粉末二次烧结工艺,制备了CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料,并利用体外实验(in vitro)方法和XRD,SEM及FTIR技术研究了此烧结材料的显微形貌、晶相、生物活性和可降解性能.结果表明,经800℃烧结5 min后,有少量硅磷酸钙[Ca5(PO4)2SiO4,5CPS]析出,在模拟体液(SBF)中浸泡,随着时间的增长,材料表面最初形成的无定形钙磷化合物矿化成碳酸羟基磷灰石(HCA)纳米团簇,并逐渐相互融合形成HCA覆盖层;HCA只在烧结体的玻璃相(SG相)表面生成,在5CPS微晶相表面未发现HCA,该材料在37℃恒温的SBF溶液中具有较高的生物活性和可降解性能.     

碱和酸碱处理对钛生物活性的影响

利用碱处理和酸碱处理钛表面,获得不同形貌和不同晶型的Ti O2薄膜。利用SEM对材料的表面形貌进行了分析,利用XRD测试了材料的晶型。将样品浸泡于模拟人体体液(SBF)中,观察材料表面羟基磷灰石(HA)的沉积情况,并进行体外细胞毒性实验,探讨其生物活性。结果表明:相同的热处理温度下,碱处理和酸碱处理的钛表面具有相同的晶型,但是表面形貌不同的Ti O2薄膜。对比了其生物活性的差异发现:450℃的酸碱处理钛具有较好的生物活性,归于其表面有尺寸较小的花蕊状纳米丝形貌,700℃的碱处理钛具有优异的生物活性,归因于其表面具有较小微观尺寸的纳米颗粒形貌。     

含硅磷酸钙骨水泥的理化性质及体外细胞毒性

用共沉淀反应法制备硅酸三钙(C3S),将所制备的硅酸三钙(C3S)加入到磷酸钙系骨水泥(CPC)中,制备了一种新型的硅磷酸钙骨水泥(CPSC).研究了该复合骨水泥的理化性质和体外细胞毒性.与CPC骨水泥相比,硅磷酸钙骨水泥(CPSC)的固化时间延长,添加适量的C3S可提高CPC的抗压强度;在模拟体液(SBF)浸泡设定时间后,硅磷酸钙骨水泥(CPSC)降解率增加,并且在浸泡初期,SBF的pH增加.体外细胞毒性实验结果显示:复合C3S骨水泥浸提液能促进成纤维细胞的增殖,表明硅磷酸钙骨水泥有良好的生物相容性.含C3S的磷酸钙骨水泥可作为骨组织再生的生物材料使用.     

CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料在SBF中的性能研究

利用溶胶-凝胶生物活性材料粉末二次烧结工艺,制备了CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料,并利用体外实验（in vitro）方法和XRD,SEM及FTIR技术研究了此烧结材料的显微形貌、晶相、生物活性和可降解性能.结果表明,经800℃烧结5 min后,有少量硅磷酸钙[Ca5（PO4）2SiO4,5CPS]析出,在模拟体液（SBF）中浸泡,随着时间的增长,材料表面最初形成的无定形钙磷化合物矿化成碳酸羟基磷灰石（HCA）纳米团簇,并逐渐相互融合形成HCA覆盖层;HCA只在烧结体的玻璃相（SG相）表面生成,在5CPS微晶相表面未发现HCA,该材料在37℃恒温的SBF溶液中具有较高的生物活性和可降解性能.     

钛表面钠氢氧钛纳米线的结构、生物活性和MC3T3-E1细胞响应

采用化学方法处理微弧氧化(MAO)制备的含Si、Ca元素的Ti O2涂层(SC),获得钛氢氧钠(Na0.8H1.2Ti3O7)生物活性纳米线结构。化学处理过程中,SC涂料表面出现了Ca、Na元素溶解,Si元素沉积的现象。化学处理后的SC涂层比SC涂料具有更好的吸水性和诱导磷灰石形成能力。这与处理后涂层(SHTO)特殊的纳米结构有关,在模拟体液浸泡过程中更容易形成Ti-OH。同时,钠氢氧钛纳米线的表面形貌、相组成、OH基团以及良好的湿润能力使其更加适合于MC3T3-E1细胞的粘附和增值。     

介孔生物活性玻璃材料在模拟体液中的用量对考察其体外生物活性的影响

制备了具有骨修复性能的新型介孔生物玻璃(mesoporous bioactive glass, MBG)材料. 在其它条件相同时改变MBG在模拟生理体液(simulated body fluid, SBF)中的用量比(0.0001～0.002 g/mL), 考察了材料的体外生物活性. 用等离子体原子发射光谱测定了不同反应时间SBF中钙、磷、硅物种的浓度; 用傅立叶红外光谱和电子扫描显微镜对材料进行了表征. 结果表明: MBG材料表面羟基磷灰石的形成速度和材料在SBF中的用量比直接相关, 其中用量比在0.001 g/mL时表现出最佳的体外生物活性. 最佳用量比的确定, 对于深入理解MBG材料的结构与体外活性的关联, 筛选具有更佳生物活性的MBG材料有着重要的意义.     

羟基磷灰石在磺化聚醚苯并咪唑薄膜表面的生长

以聚[2,2′-(对氧基联苯)-5,5′-苯并咪唑](OPBI)及其磺化产物磺化聚[2,2′-(对氧基联苯)-5,5′-苯并咪唑](SOPBI)薄膜作为基体, 采用交替沉积和模拟体液(SBF)浸泡相结合的方法快速在薄膜表面沉积羟基磷灰石层. 采用选区电子衍射(SAED)和衰减全反射傅里叶变换红外光谱(ATR-FTIR)对羟基磷灰石(HA)的晶体结构进行了分析. 用扫描电子显微镜(SEM)对整个沉积过程中羟基磷灰石的形态变化进行了跟踪. 实验结果表明, SOPBI薄膜诱导HA沉积的速率明显快于OPBI薄膜. SOPBI的磺酸基团不但提供了固定Ca²⁺的负电表面, 而且还有助于咪唑基团对Ca²⁺的固定. 而缺失磺酸基团的OPBI在不同pH值的交替沉积溶液中的电离形式阻碍了咪唑基团对Ca²⁺和HPO₄^2-的作用, 且未能在SBF浸泡过程中得到改善.     

不同磺化及碱处理聚醚醚酮的表面化学组成及体外生物活性评价

提出一种酸碱结合改性聚醚醚酮（PEEK）方法,并评价其对PEEK表面类骨磷灰石形成的影响.结果表明,通过磺化处理引入-SO₃H,显著改善了样品的亲水性,且磺化程度与H₂SO₄浓度和磺化反应时间成正比,并影响样品的表面形貌.质量分数为85% H₂SO₄处理30 min的PEEK-S具有较好的改性效果.将PEEK-S进一步用NaOH处理,可继续引入Na元素并提高样品的亲水性,但会受处理时间的影响.模拟体液（SBF）浸泡的生物活性评价结果表明,磺化后碱处理24 h的PEEK-Na具有快速的类骨磷灰石沉积能力,浸泡3 d的样品表面即可完全被沉积的类骨磷灰石覆盖,表现出较佳的生物活性.此酸碱双重改性方法操作简单,可大幅度提升PEEK的生物活性,具有较好的应用前景.     

造孔剂对电泳沉积制备多孔HA涂层及其生物活性的影响

采用水热法制得的羟基磷灰石(HA)纳米粉体,分别与造孔剂葡萄糖(Glu)、壳聚糖(CS)、炭粉(C)3种微粒(＜38.5 μm)配置成质量比1∶1的悬浮液,电泳沉积 烧结制备钛基多孔HA涂层,并对制得的3种多孔HA涂层在模拟体液浸泡前后的表面形貌、化学组成及物相变化进行表征。 结果表明,经700 ℃烧结处理后制得的3种多孔HA涂层在1.5倍人体模拟体液中浸泡5 d后,多孔HA涂层表面均被层状生长的碳磷灰石颗粒完全覆盖,颗粒直径在5~25 μm,说明这些多孔HA涂层均具有良好的生物活性。 其中以CS为造孔剂制得的多孔HA涂层结合强度最高,达19.5 MPa,有望开发成为新型的人骨植入生物陶瓷材料。     

钛表面钠氢氧钛纳米线的结构、生物活性和MC3T3-E1细胞响应

采用化学方法处理微弧氧化(MAO)制备的含Si、Ca元素的TiO₂涂层(SC), 获得钛氢氧钠(Na_0.8H_1.2Ti₃O₇)生物活性纳米线结构。化学处理过程中, SC涂料表面出现了Ca、Na元素溶解, Si元素沉积的现象。化学处理后的SC涂层比SC涂料具有更好的吸水性和诱导磷灰石形成能力。这与处理后涂层(SHTO)特殊的纳米结构有关, 在模拟体液浸泡过程中更容易形成Ti-OH。同时, 钠氢氧钛纳米线的表面形貌、相组成、OH基团以及良好的湿润能力使其更加适合于MC3T3-E1细胞的粘附和增值。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.