Fmoc和Boc双取代赖氨酸环二肽的合成及其凝胶化性能研究

以Boc-Lys(Cbz)-OH为原料首先合成出赖氨酸环二肽, 进而再分别与Fmoc-OSu和(Boc)₂O反应得到Fmoc和Boc双取代赖氨酸环二肽. 发现这两种赖氨酸环二肽衍生物在常见醇类、甲苯和氯代溶剂中能形成稳定的热可逆凝胶, 最低凝胶化浓度(MGC)范围为1%～5% (w). 凝胶的储存模量均高于损耗模量, 并且复合粘度在频率扫描范围内呈线性降低趋势. 电镜分析表明, 凝胶因子在不同溶剂中可自组装成微纳米纤维网络结构, 纤维直径越细, 凝胶透明度越高. 红外和荧光光谱分析表明在自组装的过程中氢键主要在甲苯和氯代溶剂中发挥驱动力的作用, π-π堆积主要在醇类溶剂中起作用. 核磁氢谱测试表明来自凝胶因子骨架上酰胺和侧链上氨酯基中的氢键共同参与了凝胶化过程.     

赖氨酸环二肽有机凝胶因子的合成及其选择性凝胶化与染料吸附

在利用半胱氨酸修饰赖氨酸环二肽制备对称性四肽的过程中, 通过两种脱除Trt(三苯甲基)的方法分别得到含有Fmoc(芴甲氧羰基)的非环与大环四肽产物, 其结构得到了核磁、质谱、红外、元素分析等证实。 它们能使多种有机溶剂凝胶化, 且具有热可逆性, 由扫描电子显微镜(SEM)可观察到凝胶内部均为三维网络结构。 在体积分数低至0.1%的含氯有机溶剂/水两相体系中, 它们依然可以进行选择性凝胶化。 此外, 该有机凝胶干胶由于内部微纳米网络结构以及Fmoc基团的存在, 可以直接从水溶液中吸收多种染料分子, 且吸附能力随温度的升高而提高。     

Gelation capability of cysteine-modified cyclo(L-Lys-L-Lys)s dominated by Fmoc and Trt protecting groups

A series of symmetrical peptidomimetics(3–8) based on cysteine-modified cyclo(L-Lys-L-Lys)s were synthesized, and their gelation capability in organic solvents was dominated by fluorenylmethyloxycarbonyl(Fmoc) and triphenylmethyl(Trt) protecting groups and the exchange of thiol-to-disulfide as well. The peptidomimetics holding Trt(3 and 4) showed no gel performance, while the Fmoc groups promoted 5 and 6 to give rise to thermo-reversible organogels in a number of organic solvents. The self-assembled fibrillar networks were distinctly evidenced in the organogels by transmission electron microscopy(TEM) and scanning electron microscopy(SEM) observations. Fourier transform infrared spectroscopy(FT-IR) and fluorescence analyses revealed that the hydrogen bonding and ?-? stacking play as major driving forces for the self-assembly of these organogelators. A ?-turn secondary structure was deduced for the organogel of 6 by virtue of X-ray diffraction, FT-IR and circular dichroism(CD) measurements, and an interdigitated bilayer structure was also presented.     

Synthesis and characterization of poly(L‐lactide)s and poly(D‐lactide)s of controlled molecular weight

High molecular weight poly(L ‐lactide)s (PLLAs) and poly(D ‐lactide)s (PDLAs) were synthesized in toluene at 70 °C by ring‐opening polymerization of optically pure L ‐lactide and D ‐lactide, using tin(II) 2‐ethylhexanoate (SnOct₂) and 2‐(2‐methoxyethoxy)ethanol as initiator and coinitiator, respectively. Under these conditions, polarimetry as well as ¹³C NMR spectroscopy indicated that the synthesized poly(lactide)s (PLAs) are more than 99% isotactic. The molecular weight was successfully controlled by adjusting the monomer‐to‐initiator molar ratio. Gel permeation chromatography and MALDI‐TOF mass spectrometry analyses showed that the polydispersity index of the PLAs is below 1.1. Moreover, MALDI‐TOF spectra showed two different chain distributions, one characterized by an even number of lactic acid repeat units and the other by an odd number of lactic acid repeat units. The second distribution, indicative of the presence of intermolecular transesterification reactions, appears at the very beginning of the polymerization and its intensity increases with the polymerization time. Finally, a reversible reaction kinetic model was used to determine the monomer equilibrium concentration ([M]_eq = 1.4 ± 0.5%) and the propagation rate constant (k_p = 14.4 ± 0.5 L mol^?1 h^?1) of the polymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1944–1955, 2007     

Synthesis and properties of poly(hydroxyurethane)s

Bis(cyclic Carbonate)s 1 were prepared by the reaction of bis(epoxide)s and atmospheric pressure of CO₂ in the presence of sodium iodide and triphenylphosphine as catalysts at 100°C in high yield. Polyaddition of 1 and hexamethylenediamine ( 2a ) or dodecamethylenediamine ( 2b ) in dimethylsulfoxide or N,N-dimethylacetamide (DMAc) at 70 or 100°C for 24 h afforded corresponding poly(hydroxyurethane)s with M?_n 20,000–30,000. When ethylenediamine ( 2c ) or 1,3-propanediamine ( 2d ) was used as a diamine, poly(hydroxyurethane)s with lower molecular weight were obtained. The presence of water, methanol, or ethyl acetate in the solvent had little effect on the M?_n of the polymer obtained, because of the high chemoselectivity of the reaction of the five-membered cyclic carbonate and amine. Polyaddition of bis(cyclic carbonate) bearing ester groups and 2a also afforded the corresponding poly(hydroxyurethane) without aminolysis of the ester groups. Poly(hydroxyurethane) 3 obtained from the bis(cyclic carbonate) derived from bisphenol A was less soluble in organic solvents than model polyurethane 8 having no hydroxy groups obtained from 4,4′-isopropylidenebis(2-hydroxyethoxybenzene) and hexamethylene diisocyanate, and was thermally stable as well as 8.3 easily undertook crosslinking at room temperature by the treatment with hexamethylene diisocyanate or aluminium triisopropoxide in DMAc or tetrahydrofuran. The gel crosslinked by aluminium triisopropoxide regenerated the original polymer at room temperature by treatment with 1.5 equiv of 1.2M HCl in N-methylpyrollidinone for 1 h. © 1993 John Wiley & Sons, Inc.     

Synthesis of Poly(Ether Sulfone)s End-Capped with Metal Containing Phthalocyanines

Abstract

A series of low molecular weight poly(aryl ether sulfone)s with metallophthalocyanine (PcM) end groups were synthesized by reacting o-phthalonitrile end-capped poly(aryl ether sulfone)s with excess phthalonitrile and metal salts/metals in high boiling solvents. The metals selected for this study were copper and iron. The polymers were soluble in common organic solvents. They were characterized by ¹H NMR, IR, GPC and UV-VIS spectroscopy. Appearance of an absorption band at around 700 nm confirmed the presence of phthalocyanine moieties in these polymers. The possibility of occurrence of any stacking phenomenon of the PcM rings was studied by annealing the polymers in a Thermo-Gravimetric/Differential Thermal Analysis (TG/DTA) instrument. An increase in T_g was observed for the PcM containing polymers perhaps indicating the aggregation of the terminal PC rings in the solid state.     

高分子量聚苯硫醚树脂的合成

用H_2S、NaOH、p-C_6H_4Cl_2为原料,以Na_3PO_4作助剂,在六甲基磷酰三胺中进行常压缩聚反应4～5 h,得到线型、结晶性的高分子量聚苯硫醚。熔点>290℃,热分解温度>500℃,熔融低切变粘度为0.30～68.0×10~3Pa(303℃测定)。产品直接作抽丝试验,得到高分子量聚苯硫醚纤维。本法设备简单、操作容易、反应体系活性高、溶剂稳定。     

含5-氟尿嘧啶短肽的合成及其抗肿瘤活性研究

肿瘤细胞与正常细胞在酶系上存在差别,利用这些差别,chakravarty等设计并合成缬-亮-赖三肽与苯二胺氮芥等抗肿瘤原药结合的抗肿瘤短肽药物,它们的抗肿瘤选择性比苯二胺氮芥等抗肿瘤原药提高5～7倍。我们在前文中报道了5-氟尿嘧啶乙酰(丙酰)二肽和三肽的合成及抗动物肿瘤试验,初步结果表     

Synthesis of poly(n‐butyl acrylate) containing multiblocks with a narrow molecular weight distribution using cyclic trithiocarbonates

The polymerization of n‐butyl acrylate in the presence of two cyclic trithiocarbonates (CTTCs) and the synthesis of multiblock poly(n‐butyl acrylate) have been investigated. The CTTCs not only can be stepwise incorporated into the polymer chain via reversible addition–fragmentation chain transfer (RAFT) but also can be polymerized into polytrithiocarbonate, which functions as a macro‐RAFT agent in turn. Through two kinds of mechanisms, multiblock poly(n‐butyl acrylate) containing narrow‐polydispersity blocks can be prepared. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6600–6606, 2006     

Design and Solid-Phase Synthesis of Multiple Muramyl Dipeptide (MMD)

As a non-specific modulator of macrophage, muramyl dipeptide elicits potentially multiple biological activities1, such as adjuvancy, antitumor, antiinfection, etc. Particularly, its adjuvancy has been studied by application for HIV vaccine. However, muramyl dipeptide can not serve as clinical agent due to its short lifetime in vivo, low immunogenicity, toxicity, and side effect such as pyrogenicity. Therefore, multiplied muramyl dipeptide (MMD) might increase its immunogenicity, decrease i…     

Synthesis and properties of poly(thiourethane)s having soft oligoether segments

Polyaddition of bis(five‐membered cyclic dithiocarbonate), 2,2‐bis[4‐(1,3‐thioxolane‐2‐one‐4‐yl‐methoxy)phenyl]propane ( 1 ), with diamines having soft oligoether segments and property of the obtained poly(thiourethane)s were examined. Treatment of 1 with equivalent diamines in tetrahydrofuran at room temperature gave poly(thiourethane)s having a mercapto group in each unit, which were further treated with acetic anhydride and triethylamine to give the corresponding S‐acetylated poly(thiourethane)s in high yield. Exposing the mercapto group containing poly(thiourethane)s to benzoyl chloride and triethylamine provided the corresponding S‐benzoylated poly(thiourethane)s effectively. Thermal properties of the obtained polymers were evaluated by thermogravimetric analysis and differential scanning calorimetry. The obtained polymers showed 10 wt % loss temperature (T_d10) in the range from 230 to 274 °C, which was relatively high when compared with the T_d10 of an analogous polymer prepared from 1 and 1,6‐hexamethylenediamine. The polymers obtained here exhibited glass transition temperature (T_g) in the range from ?16 °C to 40 °C, which was much lower than the analogous polymer described above, probably due to the soft oligoether segments. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1076–1081     

Synthesis of poly(naphthalenecarboxamide)s with low polydispersity by chain‐growth condensation polymerization

Condensation polymerization of 6‐(N‐substituted‐amino)‐2‐naphthoic acid esters ( 1 ) was investigated as an extension of chain‐growth condensation polymerization (CGCP). Methyl 6‐(3,7‐dimethyloctylamino)‐2‐naphthoate ( 1b ) was polymerized at ?10 °C in the presence of phenyl 4‐methylbenzoate ( 2 ) as an initiator and lithium 1,1,1,3,3,3‐hexamethyldisilazide (LiHMDS) as a base. When the feed ratio [ 1a ]₀/[ 2 ]₀ was 10 or 20, poly(naphthalenecarboxamide) with defined molecular weight and low polydispersity was obtained, together with a small amount of cyclic trimer. However, polymer was precipitated during polymerization under similar conditions in [ 1a ]₀/[ 2 ]₀ = 34. To increase the solubility of the polymer, monomers 1c and 1d with a tri(ethylene glycol) (TEG) monomethyl ether side chain instead of the 3,7‐dimethyloctyl side chain were synthesized. Polymerization of the methyl ester monomer 1c did not proceed well, affording only oligomer and unreacted 1c , whereas polymerization of the phenyl ester monomer 1d afforded well‐defined poly(naphthalenecarboxamide) together with small amounts of cyclic oligomers in [ 1d ]₀/[ 2 ]₀ = 10 and 29. The polymerization at high feed ratio ([ 1d ]₀/[ 2 ]₀ = 32.6) was accompanied with self‐condensation to give polyamide with a lower molecular weight than the calculated value. Such undesirable self‐condensation would result from insufficient deactivation of the electrophilic ester moiety by the electron‐donating resonance effect of the amide anion. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

聚芳亚胺酰胺缩聚工艺条件探索（英文）

聚芳亚胺酰胺(PAIs)是一种新型高性能聚合物.本文作者讨论了卤素单体种类、溶剂、单体浓度、反应温度、催化体系及其添加量等工艺条件对PAIs相对分子质量和相对分子质量分布的影响,得到了钯催化C-N偶联缩聚反应制备高相对分子质量PAIs的最佳条件,为该类聚合物的进一步拓展和应用提供了参考.     

Synthesis and characterization of Bi-functional photorefractive polymers with high molecular weight and low glass transition temperature

Carbazole-based bi-functional photorefractive polyacrylates were prepared via free radical polymerization and post-azo-coupling reaction. The structure of polymers was characterized by Fourier transform infrared spectroscopy(FTIR) and proton nuclear magnetic resonance(1H-NMR) spectroscopy. The differential scanning calorimetry(DSC) and the thermal gravimetric analysis(TGA) were used to characterize the thermal property of polymers. The results indicate that though the glass transition temperature(Tg) of polymers increases with increasing the ratio of NLO groups, the polymers with different ratios of NLO groups still all show low glass transition temperatures around 60 °C, and good thermal stability, which are favorable to the practical application of these polymers. The gel permeation chromatographic(GPC) result indicates that these polymers all have high-molecular-weight which is favorable to the long term stability of the material. Further, these polymers have good solubility in chloroform solvent, and the solutions can easily be fabricated into optically transparent films. Gain coefficients of 75 cm-1, 185 cm-1 and 66 cm-1 can be observed at zero external electric field without any addition agent or pre-poling for polymers P-2, P-3 and P-4 respectively. The different contents of NLO groups result in the different properties of polymers P-2, P-3 and P-4.     

Bio-based Poly(hydroxy urethane)s: Synthesis and Pre/Post-Functionalization

New and emerging demand for polyurethane (PU) continues to rise over the years. The harmful isocyanate binding agents and their integrated PU products are at the height of environmental concerns, in particular PU (macro and micro) pollution and their degradation problems. Non-isocyanate poly(hydroxy urethane)s (NIPUs) are sustainable and green alternatives to conventional PUs. Since the introduction of NIPU in 1957, the market value of NIPU and its hybridized materials has increased exponentially in 2019 and is expected to continue to rise in the coming years. The secondary hydroxyl groups of these NIPU′s urethane moiety have revolutionized them by allowing for adequate pre/post functionalization. This minireview highlights different strategies and advances in pre/post-functionalization used in biobased NIPU. We have performed a comprehensive evaluation of the development of new ideas in this field to achieve more efficient synthetic biobased hybridized NIPU processes through selective and kinetic understanding.     

含二茂铁齐聚苯乙炔分子导线的合成

通过二碘代二茂铁与不同炔化物进行Sonogashira偶联反应,合成了3种新颖的含有二茂铁单元的苯乙炔齐聚物,用1H NMR、13C NMR和MS测试技术分别对其结构进行了表征。 并借助量子化学计算对3种分子的电子结构进行了预测,结果显示,该类型分子导线具有不同于其它类型苯乙炔齐聚物的LUMO能级持续衰减特征,因此极有可能具备极为优良的电子传输性能。     

Synthesis and structure of 1-(4-chlorophenyl)-3-(5-methyl-1, 3-dioxan-5-yl)-(1,2),(3,4)-diepoxybutane

The synthesis and X-ray structural study of 1-(4-chlorophenyl)-3-(5-methyl-1,3-dioxan-5-yl)-(1,2), (3,4)-diepoxybutane are described.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 715–718, April, 1995.     

Synthesis and Characterization of Thermotropic Liquid Crystalline Poly(ester-imide)s

A series of thermotropic liquid crystalline poly(ester-imide)s was synthesized by melt polymerization of diacetoxynaphthalene acid and n-(ω-carboxyalkylene) trimellitic imides. All polymers with 2,6 substituent positions (n-2,6 PEIM) on the napthalene ring exhibit liquid crystalline phases, whereas polymers with 2,7 substituent positions (n-2,7 PEIM) do not. This result suggests that the kink structure of n-2,7 PEIMS would hinder the formation of liquid crystalline polymer. The copoly(ester-imide)s with an irregular sequence of aliphatic units and aromatic mesogens showed the liquid crystallinity with the lower transition temperatures and a lesser tendency to crystallize than homopoly(ester-imide)s. The semicrystalline polymers with more regular monomeric sequence in the main chain showed the hysteresis of viscoelastic property in the temperature cycle. A nematic glassy copolymer gave the higher molecular orientation to the fiber than a semicrystalline polymer. © 1997 John Wiley & Sons, Ltd.     

Microwave‐Assisted Single‐Step Synthesis of Poly(alkylene hydrogen phosphonate)s by Transesterification of Dimethyl Hydrogen Phosphonate with Poly(ethylene glycol)

Summary: Poly(alkylene hydrogen phosphonate)s with a number‐average molecular weight of about 3 000 Da were obtained by a transesterification of dimethyl hydrogen phosphonate with poly(ethylene glycol) (PEG 400) under microwave irradiation with a very short reaction time (55 min) relative to that of classical thermal heating (9 h). The structure of the resulting polymer was confirmed by ¹H, ³¹P, and ¹³C NMR spectroscopy. The molecular weight was determined by ¹H, ³¹P{H} NMR spectroscopy, MALDI‐TOF, and GPC.

The transesterification of dimethyl hydrogen phosphonate with poly(ethylene glycol).     

Ferroelectric Poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene)s: Effect of Molecular Weight on Dielectric Property

A series of ferroelectric poly(vinylidene fluoride-trifluoroethylene- chlorotrifluoroethylene), P(VDF-TrFE-CTFE), have been synthesized by a two-step approach. The first step is copolymerization of VDF and CTFE via solution or suspension methods to produce P(VDF-CTFE) copolymers with different molecular weights. The second step is partial de-chlorination to convert copolymers into P(VDF-TrFE-CTFE) terpolymers with precisely controlled compositions. The effect of molecular weight, molecular weight distribution and uniaxially stretching on the dielectric properties has been investigated over a broad range of temperature and frequency. The X-ray diffraction patterns and DSC curves demonstrate the coexistence of the multiple phases in the terpolymers. The dielectric spectra depict the local relaxation processes and relaxor ferroelectric behavior on the basis of the dielectric loss tangent as a function of temperature.