两亲刚性三嵌段聚多肽的合成及其自组装行为

通过胱胺三甲基硅氮烷(N-TMS)引发N-羧基内酸苷(NCA)开环聚合,合成了2种两亲刚性三嵌段聚多肽聚(L-赖氨酸-ε-端甲基二缩乙二醇酰胺)-b-聚(L-谷氨酸-γ-苄酯)-b-聚(L-赖氨酸-ε-端甲基二缩乙二醇酰胺)(P[Lys-(EG)_2]-b-PBLG-b-P[Lys-(EG)_2])和聚(L-谷氨酸-γ-苄酯)-b-聚(L-赖氨酸-端甲基二缩乙二醇酰胺)-b-聚(L-谷氨酸-γ-苄酯)(PBLG-b-P[Lys-(EG)_2]-bPBLG),并用其在N,N-二甲基甲酰胺(DMF)-水的混合溶液中制备了三嵌段聚多肽的自组装体。采用核磁共振氢谱(1 H-NMR)和凝胶渗透色谱(GPC)表征了三嵌段聚多肽的结构,通过透射电子显微镜(TEM)研究了三嵌段聚多肽在混合溶液中的自组装行为。结果表明:通过N-TMS引发NCA开环聚合得到的三嵌段聚多肽的分子量与其理论值基本一致,且分子量分布窄;聚多肽在DMF-水的混合溶液中分别形成了球状胶束、大复合胶束、棒状大复合胶束等组装体;其自组装行为与特殊的全刚性嵌段结构有关。     

基于葡萄糖和苯硼酸基元之间的可逆共价键构筑多重响应性高分子复合物胶束

通过可逆加成-断裂链转移(RAFT)的聚合方法,合成了分别含有苯硼酸基元和葡萄糖基元的聚(N-异丙基丙烯酰胺)-b-聚(丙烯酰胺基苯硼酸)(PNIPAM-b-PAPBA)和聚(N-异丙基丙烯酰胺)-b-聚(丙烯酰葡萄糖胺)(PNIPAM-b-PAGA)二嵌段聚合物.由于苯硼酸和葡萄糖基元之间在弱碱性条件下(pH9.3)形成硼酸酯共价键,两种二嵌段聚合物的水溶液混合后能自发形成以PAPBA/PAGA络合物为核,PNIPAM为壳层的高分子复合物胶束.由于硼酸酯共价键在pH值和葡萄糖浓度改变时能可逆形成和断裂,以及胶束PNIPAM壳层的温敏性,所制备的基于苯硼酸/葡萄糖可逆共价键的高分子复合物胶束对pH、葡萄糖和温度具有多重响应性.     

聚丙烯酰胺/聚L-谷氨酸苄酯接枝共聚物的合成及其胶束制备

以聚丙烯酰胺(PAM)为大分子引发剂, 采用开环聚合方法, 在N,N-二甲基甲酰胺(DMF)中引发L-谷氨酸苄酯环内酸酐(BLG-NCA)聚合合成了两亲性聚丙烯酰胺/聚L-谷氨酸苄酯接枝共聚物(PAM-g-BLG), 采用IR, 1H NMR和GPC方法对共聚物结构进行了表征; 用芘作荧光探针, 研究了共聚物胶束的形成及其临界胶束浓度(cmc), 利用动态光散射(DLS)和透射电镜(TEM)研究了胶束的粒径分布和形态. 结果表明, PAM能够引发BLG-NCA开环聚合得到接枝共聚物, 在一定条件下接枝共聚物能够形成球形的稳定胶束, cmc值和胶束粒径随着共聚物中疏水性聚L-谷氨酸苄酯(PBLG)链段含量的增加而减小.     

具有pH-响应性的聚天冬氨酸类载药胶束的制备和释放能力研究

通过大分子引发剂ω-氨基-α-甲氧基聚乙二醇引发N-羧基-α-氨基环内酸酐开环聚合和水合肼侧基改性,制备了一系列聚乙二醇-聚氨基酸类三嵌段共聚物.其中聚氨基酸链段包括具有酰肼基的聚天冬氨酸衍生物(PAHy),以及疏水性的聚丙氨酸链段.引入具有pH响应性的腙键键合阿霉素,利用键合阿霉素与游离阿霉素之间的π-π叠合作用,在聚合物自组装形成胶束过程中通过化学键合+物理包埋的方式充分负载药物.该胶束以聚丙氨酸链段为核心,以PEG链段为冠层,以PAHy链段为包裹药物的壳层.载药胶束的粒径在170 nm左右.研究不同pH值条件下载药胶束的药物释放能力,随环境pH值的降低药物的释放速率显著增加.     

聚L-谷氨酸γ-苄酯的合成及其结晶结构的研究

利用L-谷氨酸苄酯与三光气反应制备了N-羧基-L-谷氨酸γ-苄酯-环内酸酐(NCA),以正已胺为引发剂,引发NCA开环聚合,合成了分子量为6700的聚L-谷氨酸γ-苄酯(PBLG).利用核磁共振仪(1 H-NMR)、凝胶渗透色谱(GPC)、傅里叶变换红外光谱(FTIR)以及一维大角X射线衍射仪(1D-WAXD)等表征手...     

接枝树形支化分子双亲性嵌段共聚肽的合成及性能研究

分别以叠氮丙胺和丙炔胺为引发剂,采用氨基酸环内酸酐开环聚合法(NCA-ROP),引发L-谷氨酸-γ-苄酯-N-羧基-环内酸酐和L-谷氨酸-γ-氯乙醇酯-N-羧基-环内酸酐聚合得到链端基为叠氮基的聚(L-谷氨酸-γ-苄酯)(PBLG)和链端基为炔基的聚(L-谷氨酸-γ-氯乙醇酯)(PCELG)均聚物.联合点击化学法(click chemistry)制备了一系列聚(L-谷氨酸-γ-苄酯)-b-聚(L-谷氨酸-γ-氯乙醇酯)(PBLG-b-PCELG),再通过对嵌段共聚物侧基氯进行化学修饰,将二代的甲基烷氧醚类亲水性树形枝化分子(G2)接枝到侧链上,形成一系列树形支化分子接枝聚肽双亲性嵌段共聚物,通过核磁(NMR)、红外光谱(IR)和凝胶渗透色谱(GPC)对其化学结构进行了表征,并采用紫外-可见光谱(UV-Vis)研究了聚合物结构及其溶液浓度对其温敏行为的影响规律.     

聚肽螺旋纳米弯棒的制备与形成机理

通过五元环酸酐（NCA）开环聚合的方法成功合成了聚(γ-苄基-L-谷氨酸酯)（PBLG）聚肽均聚物和聚(γ-苄基-L-谷氨酸酯)-b-聚乙二醇（PBLG-b-PEG）聚肽嵌段共聚物，并通过酸解脱苄基及与肉桂醇的酯化反应对PBLG-b-PEG嵌段共聚物改性，制备了聚(γ-苄基-L-谷氨酸酯-co-肉桂基-L-谷氨酸酯)-b-聚乙二醇（P(BLG/CLG)-b-PEG）改性嵌段共聚物，其聚肽侧链上修饰了可光交联的肉桂酰氧基，其C=C双键在紫外光照射下能发生环加成反应交联聚肽链段。采用四氢呋喃-N,N-二甲基甲酰胺（THF-DMF）有机共溶剂溶解、选择性溶剂（水）沉淀的自组装方法制备了PBLG纳米棒；然后向纳米棒水溶液中加入THF溶剂诱导纳米棒弯曲，制备了纳米弯棒。通过THF的加入量可以调控纳米棒的弯曲程度。利用类似的方法，通过PBLG与PBLG-b-PEG或P(BLG/CLG)-b-PEG共组装制备了螺旋纳米棒（其中PBLG均聚物形成棒状内核、PBLG-b-PEG或P(BLG/CLG)-b-PEG形成表面纳米螺纹），然后向螺旋纳米棒水溶液中加入THF溶剂，但是仅得到了光滑纳米弯棒（表面螺纹...     

聚肽HVLPs的制备与载药性能

通过脱苄基和酯化反应,在聚(γ-苄基L-谷氨酸酯)-b-聚乙二醇(PBLG-b-PEG)嵌段共聚物的PBLG嵌段侧基修饰上可光交联的肉桂酰氧基,得到聚(γ-苄基L-谷氨酸酯-co-肉桂基L-谷氨酸酯)-b-聚乙二醇(P(BLG/CLG)-b-PEG)嵌段共聚物。将P(BLG/CLG)-b-PEG分别与PBLG均聚物、聚苯乙烯(PS)均聚物共混自组装,制备出具有核-壳结构的棒状和球状仿病毒粒子(VLPs),其中,均聚物形成棒状或球状内核,嵌段共聚物构成外壳。利用紫外光照射交联CLG链段固定VLPs壳结构,以N,N′-二甲基甲酰胺(DMF)溶解去除均聚物内核,制备中空仿病毒粒子(HVLPs)。采用扫描电镜、透射电镜表征了组装体的微观形貌。研究表明:DMF可以溶解去除球状VLPs的PS均聚物内核,制备出表面具有条纹的球状HVLPs;而棒状VLPs的PBLG均聚物内核不能被DMF溶解去除。以阿霉素(DOX)为模型药物,研究了球状HVLPs的载药性能,其对DOX的相对载药量可以达到230%,在pH=7.4时72 h药物累计释放量达到80%。     

含半胱氨酸多肽的研究——Ⅲ.牛胰岛素A链带保护基的氨端九肽的合成

本文报告带保护基的牛胰岛素A链氨端九肽酯■和相应的九肽酰肼■与九肽酸■的合成.苄氧羰基甘氨酰-异亮氨酰-缬氨酰-γ-叔丁酯谷氨酸乙酯(III)分别由已知的苄氧羰基缬氨酰-γ-叔丁酯谷氨酸乙酯经催化氢解法脱去N-保护基后与苄氧羰基甘氨酰-异亮氨酰肼(VIII)按迭氮化合物法缩合,以及由已知的苄氧羰基甘氨酰-异亮氨酰-缬氨酸(VIII)与γ-叔丁酯谷氨酸乙酯按碳二亚胺法合成.III经肼解或皂化分别得四肽酰肼■和四肽酸■.苄氧羰基谷氨酰胺酰-S-苄基半胱氨酰-S-苄基半胱氨酰-丙氨酰-O-乙酰丝氨酸甲酯(V)分别由已知的苄氧羰基-S-苄基半胱氨酰-S-苄基半胱氨酰-丙氨酰-丝氨酸甲酯XII_a或苄氧羰基-S-苄基半胱氨酰-S-苄基半胱氨酰-丙氨酰-O-乙酰基丝氨酸甲酯XII以溴化氢-乙酸脱去N-保护基后与苄氧羰基谷氨酰胺对硝基苯酯(XIII)按活化酯法缩合而得.如以溴化氢-三氟乙酸脱去XIIa的N-保护基后与XIII按活化酯法缩合则得Va,合成Va的另一方法是将已知的苄氧羰基谷氨酰胺酰-S-苄基半胱氨酰-S-苄基半胱氨酰肼XIV通过迭氮化物法与丙氨酰-丝氨酸甲酯(X)缩合而得.五肽V经溴化氢-乙酸脱去N-保护基后与四肽酰肼IV或四肽酸IV_a分别通过迭氮化物法和碳二亚胺法缩合得到同一的九肽甲酯(I).化合物I用三氟乙酸脱去叔丁酯后肼解得九肽肼(II).化合物I经皂化得相应的九肽酸IIa.     

浊度法表征温敏性微凝胶体积的相转变行为

以N-异丙基丙烯酰胺(NIPAM)、甲基丙烯酸(MAA)为单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,制备了温敏性聚(N-异丙基丙烯酰胺)(PNIPAM)和具有温度、pH敏感性的聚(N-异丙基丙烯酰胺-co-甲基丙烯酸)(PNIPAM-MAA)微凝胶。通过测定不同温度和pH条件下微凝胶浊度变化,表征微凝胶的温度及pH敏感性,描述了NaCl浓度和pH对微凝胶体积相转变温度的影响。同时,测定了微凝胶的临界聚沉浓度及临界絮凝温度,表征了微凝胶的稳定性,讨论了影响微凝胶的稳定性因素。     

Furyl- and thienyl-silatranes and germatranes

We review our research on the synthesis and study of the physical and biological properties of furyl- and thienylgermatranes and -silatranes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 725–732, June, 1992.     

Review and patents and literature

The use of the insect cell/baculovirus expression system for producing recombinant proteins of bacterial, plant, insect, and mammalian origin has become widespread. The popularity of this eukaryotic expression system is due to many factors, including (1) potentially high protein expression levels, (2) ease and speed of genetic engineering, (3) ability to accommodate large DNA inserts, (4) protein processing similar to higher eukaryotic cells (e.g., mammalian cells), and (5) ease of insect cell growth (e.g., suspension growth). The following review of the literature discusses two engineering aspects of recombinant protein synthesis by insect cell cultures: bioreactor scale-up and insect cell line selection. Following this review patent abstracts and additional literature pertaining to expression of recombinant proteins in insect cell culture are listed.     

Ground- and excited-state aromaticity and antiaromaticity in benzene and cyclobutadiene

The aromaticity and antiaromaticity of the ground state (S 0), lowest triplet state (T 1), and first singlet excited state (S 1) of benzene, and the ground states (S 0), lowest triplet states (T 1), and the first and second singlet excited states (S 1 and S 2) of square and rectangular cyclobutadiene are assessed using various magnetic criteria including nucleus-independent chemical shifts (NICS), proton shieldings, and magnetic susceptibilities calculated using complete-active-space self-consistent field (CASSCF) wave functions constructed from gauge-including atomic orbitals (GIAOs). These magnetic criteria strongly suggest that, in contrast to the well-known aromaticity of the S 0 state of benzene, the T 1 and S 1 states of this molecule are antiaromatic. In square cyclobutadiene, which is shown to be considerably more antiaromatic than rectangular cyclobutadiene, the magnetic properties of the T 1 and S 1 states allow these to be classified as aromatic. According to the computed magnetic criteria, the T 1 state of rectangular cyclobutadiene is still aromatic, but the S 1 state is antiaromatic, just as the S 2 state of square cyclobutadiene; the S 2 state of rectangular cyclobutadiene is nonaromatic. The results demonstrate that the well-known "triplet aromaticity" of cyclic conjugated hydrocarbons represents a particular case of a broader concept of excited-state aromaticity and antiaromaticity. It is shown that while electronic excitation may lead to increased nuclear shieldings in certain low-lying electronic states, in general its main effect can be expected to be nuclear deshielding, which can be substantial for heavier nuclei.     

Determination and study on residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil

A QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for the determination of benazolin-ethyl and quizalofop-p-ethyl in rape and soil by high-performance liquid chromatography-tandem mass spectrometry has been developed in this study. The residue and dissipation of benazolin-ethyl and quizalofop-p-ethyl in rape and soil were determined with the developed method. The half-lives of benazolin-ethyl in rape straw and soil were 3.7–5.1 days and 14.3–26.3 days, respectively. The half-lives of quizalofop-p-ethyl in rape straw and soil were 5.0-6.1 days and 0.3–9.7 days, respectively. The residue of benazolin-ethyl and quizalofop-p-ethyl in rapeseed and soil were below the detection limit (i.e., 0.5?mg?kg^?1, the maximum residue level of European Union for quizalofop-p-ethyl).     

Syntheses and structures of P-anilino-P-chalcogeno- and P-anilino-P-iminodiazasilaphosphetidines and their group 12 and 13 metal compounds

The P-anilino-P-chalcogeno(imino)diazasilaphosphetidines [Me(2)Si(mu-N(t)Bu)(2)P=E(NHPh)] (E = O (3), S (4), Se (5), N-p-tolyl (6)) were synthesized by oxidizing the P-anilinodiazasilaphosphetidine [Me(2)Si(N(t)Bu)(2)P(NHPh)] (2) with cumene hydroperoxide, sulfur, selenium, and p-tolyl azide, respectively. The lithium salt of 4 reacted with thallium monochloride to produce ([Me(2)Si(mu-N(t)Bu)(2)P=S(NPh)-kappaN-kappaS]Tl)(7), which features a two-coordinate thallium atom. Treatment of 4-6 with AlMe(3) gave the monoligand dimethylaluminum complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE]AlMe(2)) (E = S (8), Se (9), N-p-tolyl (10)), respectively. In these complexes the aluminum atom is tetrahedrally coordinated by one chelating ligand and two methyl groups, as a single-crystal X-ray analysis of 8 showed. A 2 equiv amount of 4-6 reacted with diethylzinc to produce the homoleptic diligand complexes ([Me(2)Si(mu-N(t)Bu)(2)P=E(NPh)-kappaN-kappaE](2)Zn)(E = S (11), Se (12), N-p-tolyl (13)). A crystal-structure analysis of 11 revealed a linear tetraspirocycle with a tetrahedrally coordinated, central zinc atom.     

多环芳二酐型聚酯亚胺膜的透气性能

多环芳二酐型聚酯亚胺膜的透气性能李悦生，丁孟贤，徐纪平（浙江大学高分子科学与工程研究所，杭州，３１００２７）（中国科学院长春应用化学研究所）关键词聚醚酰亚胺，聚酯酰亚胺，膜，透气性通常的聚酰亚胺加工性能较差，在芳环二酐的苯环间引入醚键等柔性基团后，其...