- Synthesis of peptide dendrimers with polyhedral oligomeric silsesquioxane cores via click chemistry
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Inorganic polyhedral oligomeric silsesquioxane (POSS) was used as the core for the synthesis of poly(l-lysine) peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1/
- Pu, Yu-Ji,Yuan, Hui,Yang, Ming,He, Bin,Gu, Zhong-Wei
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- Anti-proliferative scar external pharmaceutical preparation
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The invention discloses an anti-proliferative scar external pharmaceutical preparation, which comprises a drug, a drug carrier and an auxiliary material, the drug carrier is a virus rupture-imitating phospholipid, and the hydrophilic head of the phospholipid is connected with different generation numbers of polyarginine dendritic polypeptide molecules through amido bonds or ester bonds. Drug-loaded deformable liposome prepared from the drug carrier has a rich guanidyl structure, is easy to penetrate through skin epidermis to be taken by cells, and has a strong function of destroying cell membranes. Finally, the drug carrier is wrapped in the gel to form an in-situ delivery system, and a multi-effect integrated external preparation which has continuous drug delivery capacity and superstrong scar tissue infiltration capacity and is capable of destroying scar fibroblasts and eliminating hyperplastic tissues is formed.
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Paragraph 0046-0050; 0054-0055
(2021/06/12)
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- Preparation method of amino-acid ester
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The invention relates to a preparation method of amino-acid ester, and belongs to the field of synthesis of organic compounds. The preparation method of the amino-acid ester comprises the following steps: taking sulfur trioxide as a catalyst and a water-binding agent, catalyzing amino acid and alcohol to react so as to prepare sulfate of the amino-acid ester, then concentrating a reaction system to remove a reaction solvent and then adding water for dissolving, and neutralizing ammonia water to prepare the amino-acid ester. According to the technical scheme, the provided preparation method ofthe amino-acid ester has the advantages of mild reaction process, high yield, good purity, simplicity in operation and low cost. Concentrated condensate water of central mother liquor of the preparation method of the amino-acid ester can be directly subjected to biochemical treatment, solid by-products are high-purity ammonium sulfate, and can serve as chemical fertilizers, a reaction process is green and pollution-free, and thus, environmental protection is facilitated.
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Paragraph 0010
(2019/03/15)
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- Preparation and application of guaifenazulene aldole dicondensate (by machine translation)
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The invention belongs to the field, and particularly relates to chemical preparation and application. When the problem group is subjected to chemical synthesis research on the skeleton by guaiguazulene and piperidine acid as raw materials, the derivative trans - 1, 2 - (1, 4 - diazulyl) ethene ene derivative of guaiabazulene is found. H1N1 Influenza virus testing, indicating that the compound is level, 25 mm in vitro antiviral activity superior to that of positive drug ribavirin. In vivo activity tests prove, the compound not only can inhibit the pneumonia symptoms, but also can reduce the titer, and the survival rate. , The survival rate, 5 mg/kg/day the lung virus titer . of virus-infected mice can be remarkably improved when stomach tube-like dosages are used for gastric lavage. In general, the activity of the compound is comparable, and the activity of the compound is comparable to that of oseltamivir. The utility model can be used for preparing antiviral drugs. The invention opens up a new way for deep research and development of new antiviral drugs, which is a new approach. (by machine translation)
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Paragraph 0019; 0020
(2019/08/02)
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- Metalloporphyrin dimers bridged by a peptoid helix: Host-guest interaction and chiral recognition
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Co-facial porphyrins have been designed to construct porphyrin tweezers with versatile molecular recognition capabilities. In this study, we synthesized metalloporphyrin-peptoid conjugates (MPPCs) displaying two metalloporphyrins on a peptoid scaffold with either achiral unfolded (1) or helical (2 and 3) secondary structures. Host-guest complexation of MPPCs was realized with various guests of different lengths and basicities, and the extent of complexation was measured by UV-vis and circular dichroism (CD) spectroscopic titration. Intermolecular and intramolecular chirality induction were observed on achiral and chiral peptoid backbones, respectively. Spectroscopic data indicated that a broad scope of achiral guests can be recognized by chiral 2; in particular, longer and more flexible guests were seen to bind more tightly on 2. In addition, chiral 2 provided a distinct CD couplet with DL-, D-, or L-Lys-OMe, which was a result of the diastereomeric host-guest complex formation. Our results indicated that MPPCs can recognize, contrast, and analyze various achiral, chiral, or racemic molecules. Based on co-facial metalloporphyrins present on peptoid scaffolds, we developed a novel class of porphyrin tweezers, which can be further utilized in asymmetric catalysis, molecular sensing, and drug delivery.
- Lee, Yen Jea,Kang, Boyeong,Seo, Jiwon
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- Method for preparing amino-acid ester
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The invention relates to a method for preparing an amino-acid ester and belongs to the field of organic compound synthesis. The method comprises the following steps: by taking sulfur trioxide as a catalyst and a water bounding agent, catalyzing amino acid to react with an alcohol so as to prepare sulfate of the amino-acid ester, concentrating the reaction system, removing a reaction solvent, dissolving with water, and further neutralizing with ammonia water, thereby obtaining the amino-acid ester. The method for preparing the amino-acid ester, which is provided by the technical scheme of the invention, has the advantages of being gentle in reaction process, high in yield, high in purity, simple to operate and low in cost. By adopting the method for preparing the amino-acid ester, centrifugal mother liquid condensed water can be subjected to biochemical treatment directly, a solid byproduct of high-purity ammonium sulfate can be generated, the byproduct can be used as a chemical fertilizer, the reaction process is green and pollution-free, and the environment can be protected.
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Paragraph 0023
(2018/12/03)
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- Unveiling and tackling guanidinium peptide coupling reagent side reactions towards the development of peptide-drug conjugates
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Peptide coupling reagents and especially uronium/guanidinium salts have been extensively utilized in solid-phase peptide synthesis. However, the impact of these reagents in solution phase synthesis, normally used in the formation of peptide-drug conjugates (PDCs), has not been fully explored. Herein, we identified that when guanidinium salts are used in classical peptide coupling conditions, besides leading to the formation of amide bonds, a uronium derivative can also be installed on specific amino acid scaffolds. The formation of this side product depends on the reaction conditions, as also on the nucleophilicity of the susceptible groups. Conditions to avoid this side product formation and a putative reaction mechanism describing its formation are reported.
- Vrettos, Eirinaios I.,Sayyad, Nisar,Mavrogiannaki, Eftychia M.,Stylos, Evgenios,Kostagianni, Androniki D.,Papas, Serafim,Mavromoustakos, Thomas,Theodorou, Vassiliki,Tzakos, Andreas G.
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p. 50519 - 50526
(2017/11/10)
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- End-Site-Specific Conjugation of Enoxaparin and Tetradeoxycholic Acid Using Nonenzymatic Glycosylation for Oral Delivery
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Heparin and low molecular weight heparins (LMWHs) have been the drug of choice for the treatment or the prevention of thromboembolic disease. Different methods are employed to prepare the LMWHs that are clinically approved for the market currently. In particular, enoxaparin, which has a reducing sugar moiety at the end-site of polysaccharide, is prepared by alkaline depolymerization. Focusing on this end-site-specific activity of LMWHs, we conjugated the tetraoligomer of deoxycholic acid (TetraDOCA; TD) at the end-site of enoxaparin via nonenzymatic glycosylation reaction. The end-site-specific conjugation is important for polysaccharide drug development because of the heterogeneity of polysaccharides. This study also showed that orally active enoxaparin and tetraDOCA conjugate (EnoxaTD) had therapeutic effect on deep vein thrombosis (DVT) without bleeding in animal models. Considering the importance of end-specific conjugation, these results suggest that EnoxaTD could be a drug candidate for oral heparin development.
- Park, Jooho,Jeon, Ok Cheol,Yun, Jisuk,Nam, Hwajung,Hwang, Jinha,Al-Hilal, Taslim A.,Kim, Kwangmeyung,Kim, Kyungjin,Byun, Youngro
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p. 10520 - 10529
(2016/12/16)
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- Synthesis and properties of bis-porphyrin molecular tweezers: Effects of spacer flexibility on binding and supramolecular chirogenesis
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Ditopic binding of various dinitrogen compounds to three bisporphyrin molecular tweezers with spacers of varying conformational rigidity, incorporating the planar enediyne (1), the helical stiff stilbene (2), or the semi-rigid glycoluril motif fused to the porphyrins (3), are compared. Binding constants Ka = 104-106 M-1 reveal subtle differences between these tweezers, that are discussed in terms of porphyrin dislocation modes. Exciton coupled circular dichroism (ECCD) of complexes with chiral dinitrogen guests provides experimental evidence for the conformational properties of the tweezers. The results are further supported and rationalized by conformational analysis.
- Blom, Magnus,Norrehed, Sara,Andersson, Claes-Henrik,Huang, Hao,Light, Mark E.,Bergquist, Jonas,Grennberg, Helena,Gogoll, Adolf
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supporting information
(2016/02/05)
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- In situ deprotection and incorporation of unnatural amino acids during cell-free protein synthesis
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The S30 extract from E. coli BL21 Star (DE3) used for cell-free protein synthesis removes a wide range of α-amino acid protecting groups by cleaving α-carboxyl hydrazides; methyl, benzyl, tert-butyl, and adamantyl esters; tert-butyl and adamantyl carboxamides; α-amino form-, acet-, trifluoroacet-, and benzamides and sidechain hydrazides and esters. The free amino acids are produced and incorporated into a protein under standard conditions. This approach allows the deprotection of amino acids to be carried out in situ to avoid separate processing steps. The advantages of this approach are demonstrated by the efficient incorporation of the chemically intractable (S)-4-fluoroleucine, (S)-4,5- dehydroleucine, and (2S,3R)-4-chlorovaline into a protein through the direct use of their respective precursors, namely, (S)-4-fluoroleucine hydrazide, (S)-4,5-dehydroleucine hydrazide, and (2S,3R)-4-chlorovaline methyl ester. These results also show that the fluoroand dehydroleucine and the chlorovaline are incorporated into a protein by the normal biosynthetic machinery as substitutes for leucine and isoleucine, respectively. Copyright
- Arthur, Isaac N.,Hennessy, James E.,Padmakshan, Dharshana,Stigers, Dannon J.,Lesturgez, Stéphanie,Fraser, Samuel A.,Liutkus, Mantas,Otting, Gottfried,Oakeshott, John G.,Easton, Christopher J.
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p. 6824 - 6830
(2013/06/26)
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- Synthesis and antibacterial activities of amphiphilic neomycin B-based bilipid conjugates and fluorinated neomycin B-based lipids
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Investigating the effect of lipid hydrophobicity on the activity of amphiphilic neomycin B conjugates, six polycationic amphiphiles (PAs) were created. Four of the new compounds incorporated either palmitic or arachidic di-lipid lysine tails, while two had single fluorinated undecanoic acid tails. The basicity of half of the compounds was increased through the incorporation of six guanidine moieties, in order to assess the effect of base strength on antimicrobial activity. A panel of ten bacteria was used for the testing, with seven strains obtained from the American Type Culture Collection series and three clinical isolates from Canadian Intensive Care Units. When compared to previous results with hydrocarbon monolipids the PAs all compounds were found to have reduced activity, though the hemolytic activity of the compounds with fluorinated tails was sharply reduced, with only a moderate reduction in antimicrobial activity.
- Bera, Smritilekha,Dhondikubeer, Ramesh,Findlay, Brandon,Zhanel, George G.,Schweizer, Frank
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p. 9129 - 9141
(2012/11/07)
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- Comparison of liquid chromatography-isotope ratio mass spectrometry (LC/IRMS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) for the determination of collagen amino acid δ13C values for palaeodietary and palaeoecological reconstruction
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Results are presented of a comparison of the amino acid (AA) δ13C values obtained by gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC/IRMS). Although the primary focus was the compound-specific stable carbon isotope analysis of bone collagen AAs, because of its growing application for palaeodietary and palaeoecological reconstruction, the results are relevant to any field where AA δ13C values are required. We compare LC/IRMS with the most up-to-date GC/C/IRMS method using N-acetyl methyl ester (NACME) AA derivatives. This comparison involves the analysis of standard AAs and hydrolysates of archaeological human bone collagen, which have been previously investigated as N-trifluoroacetyl isopropyl esters (TFA/IP). It was observed that, although GC/C/IRMS analyses required less sample, LC/IRMS permitted the analysis of a wider range of AAs, particularly those not amenable to GC analysis (e.g. arginine). Accordingly, reconstructed bulk δ13C values based on LC/IRMS-derived δ13C values were closer to the EA/IRMS-derived δ13C values than those based on GC/C/IRMS values. The analytical errors for LC/IRMS AA δ13C values were lower than GC/C/IRMS determinations. Inconsistencies in the δ13C values of the TFA/IP derivatives compared with the NACME- and LC/IRMS-derived δ13C values suggest inherent problems with the use of TFA/IP derivatives, resulting from: (i) inefficient sample combustion, and/or (ii) differences in the intra-molecular distribution of δ13C values between AAs, which are manifested by incomplete combustion. Close similarities between the NACME AA δ13C values and the LC/IRMS-derived δ13C values suggest that the TFA/IP derivatives should be abandoned for the natural abundance determinations of AA δ13C values.
- Dunn, Philip J. H.,Honch, Noah V.,Evershed, Richard P.
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experimental part
p. 2995 - 3011
(2012/05/20)
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- Two-component dendritic gel: Effect of stereochemistry on the supramolecular chiral assembly
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The self-assembly of diaminododecane solubilised by four different stereoisomeric dendritic peptides to form gel-phase materials in toluene was investigated. The second generation dendritic peptides were based on D- and L-lysine building blocks, and each contained three chiral centres. By designing dendritic peptides in which the configurations of the chiral centres were modified, and applying them as gelator units, the assembly of stereoisomers could be investigated. In all cases, the self-assembly of gelator units resulted in macroscopic gelation. However, the degree of structuring was modulated by the stereoisomers employed, an effect which changed the morphology and macroscopic behavior of the self-assembled state. Enantiomeric (L,L,L or D,D,D) gelator units formed fibrous molecular assemblies, whilst the racemic gel (50% L,L,L: 50% D,D,D) formed a flat structure with a "woven" appearance. Gelator units based on L,D,D or D,L,L dendritic peptides also formed fibrous assemblies, but small-angle X-ray scattering indicated significant morphological differences were caused by the switch in chirality. Furthermore, the macroscopic stability of the gel was diminished when these peptides were compared with their L,L,L or D,D,D analogues. In this paper it is clearly shown that individual stereocentres, on the molecular level, are directly related to the helicity within the fibre. It is argued that the chirality controls the pattern of hydrogen bonding within the assembly, and hence determines the extent of fibre formation and the macroscopic gel strength.
- Hirst, Andrew R.,Smith, David K.,Feiters, Martin C.,Geurts, Huub P. M.
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p. 5901 - 5910
(2007/10/03)
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- Syntheses of dendritic branches based on L-lysine: is the stereochemistry preserved throughout the synthesis?
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This paper reports the syntheses of individual dendritic branches based on L-lysine and functionalised with either Boc or Bz surface groups. Convergent and divergent synthetic approaches were employed and the preservation of stereochemistry during the syntheses was monitored using polarmetry, NMR and HPLC. In addition, racemic dendritic branches based on D,L-lysine were synthesised for comparative purposes. It was observed that the preservation of stereochemistry in the dendritic peptide was dependent on the method of synthesis, with divergent methodology being preferred. The results are discussed in terms of the known stereochemical outcomes of traditional peptide coupling processes, and are generalised to the synthesis of other dendritic peptides. Such observations about the chirality of dendritic peptides are of relevance to chemists developing dendritic systems for applications where single enantiomer dendrimers would clearly be preferred, such as enantioselective catalysis or pharmaceutical chemistry.
- Driffield, Malcolm,Goodall, David M,Smith, David K
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p. 2612 - 2620
(2007/10/03)
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- Diels-Alder reactions of 6-substituted 1-(p-nitrobenzoyl)-5,6-dihydro-2-pyridinones
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The first examples of Diels-Alder cycloaddition reactions of 6-substituted 1-(p-nitrobenzoyl)-5,6-dihydro-2-pyridinones are described. This reaction benefits from the fact that the diene adopts an endo orientation trans to the axial substituent at C-6 due to A1,3 allylic type strain with the N-PNB protecting group.
- Dias,Fernandes,Zukerman-Schpector
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p. 100 - 104
(2007/10/03)
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- A SHORT APPROACH TO FUNCTIONALISED HOMOCHIRAL PIPERIDINONES
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The preparation of homochiral lactam 4 in 5 steps from (S)-lysine is described.Conversion to bicyclic O,N-acetal 5 provides a useful template for further elaboration to highly substituted piperidinones with excellent diastereoselectivity.
- Hermitage, Stephen A.,Moloney, Mark G.
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p. 1463 - 1464
(2007/10/02)
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- Long-wavelength water soluble chlorin photosensitizers useful for photodynamic therapy and diagnosis of tumors
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Novel photosensitizers useful for photodynamic therapy and diagnosis of tumors. Photosensitizers are derived from chlorophyll-a of photosynthetic plants and algae, possess long wavelength absorption between 600 and 800 nm, are stable, and water soluble. A process of preparation of these compounds and method of use for diagnostic and therapeutic purposes.
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