TGK מודה והמדרשה הבינלאומית למדע והנדסה (IGGSE) של מינכן Technische Universität עבור התמיכה הכספית שלהם. HK מודה המרכז חלבון משולב המדע במינכן (CIPSM) על תמיכתם.

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החוקרים אין לחשוף.

מפלסת הדרך guanidinylation הינה נגזרת פפטיד מחזורית orthogonally deprotected, (ג (OrnD (OT Bu) GF (N Me) V)), אשר מסונתז על ידי פרוטוקול Fmoc רמת סינתזה פפטיד מוצק שלב (SPPS). Ornithin שימש הנגזר מוגן orthogonally, (Fmoc-Orn (DDE) -OH), אשר ניתן deprotected עם הידרזין ב DMF לאחר cyclization של הפיגום פפטיד. מבשר פפטיד מטוה...

בין קבוצות pharmacophoric בשכיחותו הליגנדים טבעיים היא קבוצת guanidine, אשר מעורבים באינטראקציות מרובות 1, 2. לדוגמא, היא משמשת תורם מממן פי ארבעה פוטנציאל באינטראקציות אג&quot;ח מימן מעורב אינטראקציות אלקטרוסטטיות, כגון גשרי מלח או אינטראקציות π קטיון. בשנת כימיה רפואית, בקבוצה זו נמצאת לעתים קרובות סמים לתרופות 4, למרות שפעמים רבות מאוד כמו mimetics guanidine 5, 6. הסיבה לפיתוח mimetics guanidine היא הסרה של הקבוצה guanidine בכל מקום, בעלי מטען חשמלי חיובי, כמו גם את ההתאמה של lipophilicity של ליגנד. בשנת הליגנדים peptidic, חומצת אמינו הקבוצה המכילה guanidine היחידה היא ארגינין, אשר על כן מופיעה בדרך כלל באזור ביו של הליגנדים peptidic. יחסי ציבור מאודלדוגמה ominent עבור משפחה ליגנד-המכיל ארגינין היא תת-המשפחה של integrins מחייב RGD. באופן כללי, integrins הם מחלקה של קולטנים הידבקות התא, אשר להשתלט הפונקציות החשובות בכל אורגניזמים גבוה. חלק מהפעולות הללו כרוכים הידבקות התא, הגירה, והישרדות התא. לפיכך, הם מעורבים גם באינדיקציות פתולוגיים, כגון סרטן סיסטיק. Integrins הם חלבונים heterodimeric transmembrane המורכבת α- ו β-למקטע היוצרות 24 תת integrin ידוע כיום; 8 מהם מכירים את רצף tripeptide Arg-גלאי-ASP (= RGD) ב הליגנדים שלהם 7. האזור מחייב ממוקם במפגש בין שני תתי סוגים אלה בחלק התאי, קבוצת ראש integrin שנקראה 8. RGD מוכרת על ידי שתי אינטראקציות נפוצות: באזור מתכת-יון-תלות באתר הדבקה (מידאס), הנמצא למקטע בטא ואשר נקשר החומצה קרבוקסילית של הליגנדים (Cha לוואיב של ASP); וקבוצת guanidine של הליגנדים, הנמצאת למקטע אלפא. רוב תת integrin הם מופקרים ולשתף לפחות חלק מטריקס הטבעי שלהם (ECM) הליגנדים 9. לפיכך, לפיתוח הליגנדים integrin מלאכותיים, המוקד העיקרי הוא, מלבד זיקה מחייבת גבוהה, את הסלקטיביות תת. לאחרונה, הצלחנו לחשוף מרכיב מפתח עבור הדור של הליגנדים-סלקטיבית תת: קבוצת guanidine. באמצעות שינויים ברורים, הליגנדים biselective עבור αv- ו α5 המכילים תת integrin ניתן להפוך תרכובות סלקטיבית על ידי שינויים פשוטים על הקבוצה guanidine, אשר לאחר מכן ניתן להפלות את 10 α-יחידות משנה שונות. בכיס αv, קבוצת guanidine אינטראקצית צד-על באמצעות גשר מלח bidentate עם Asp218 11, 12. ג אינטראקציה זולהיות גם ציין α5β1 (כאן, עם Asp227 ב α5), אך בנוסף, קץ-על האינטראקציה של הקבוצה guanidine עם שאריות GLN (Gln221) הוא ציין שיש 13. לפיכך, שינינו את קבוצת guanidine בשני אופנים מנוגדים: במקרה אחד, על ידי חסימת הצד-על אינטראקציה עם מתילציה של δ N של קבוצת guanidine, ובמקרה השני, עם מתילציה של ω N guanidine, חסימת האינטראקציה סוף-על. באופן מפתיע, שינוי קטן זה הוביל לשינוי סלקטיביות מוחלט של הליגנדים. בנוסף אלקילציה, שיטת functionalization חדשה הוצגה בפרסום זה. שיטת functionalization הקלסית לסוג זה של ליגנד pentapeptidic היא דרך נטיית שרשרת הצד של חומצת אמינו לא מעורבת מחייב (למשל, K ב ג (RGDfK)) 14, 15. כאן,אנו מראים כי functionalization הוא גם אפשרי על ידי שינוי guanidine - שהוא חיוני עבור מחייב - עם acyl או מקשר alkylated. המטען החיובי כי הוא חיוני מחייב נשמר, ומודלים מראים כי נקודות השרשרת הארוכות מכייס המחייב, ובכך מתן אפשרות אידיאלית עבור הקובץ המצורף של linkers נוסף תיוג יחידות (למשל, תווית פלורסנט או chelator עבור מולקולרי הַדמָיָה). בעבודה זו, אנו מתרכזים בצעדי ההכנה עבור השינוי של קבוצת guanidine ב הליגנדים המכיל ארגינין. זה כרוך הסינתזה של מיני -methylated ω N, כמו גם guanidines עם יחידות ומקשרות יותר. השינויים השונים מהווים קבוצות acyl ו אלקיל.

<table><tbody><tr><td>&lt;em&gt;N,N&amp;prime;&lt;/em&gt;-Di-Boc-1H-pyrazole-1-carboxamidine, 98%&amp;nbsp;</td><td>Sigma Aldrich</td><td>434167&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Triphenylphosphine, 99%</td><td>Sigma Aldrich</td><td>T84409&amp;nbsp;SIGMA-ALDRICH</td><td></td></tr><tr><td>Tetrahydrofuran, &gt;99.5%</td><td>Carl Roth</td><td>4745</td><td></td></tr><tr><td>Tetrahydrofuran anhydrous, 99.8%</td><td>Carl Roth</td><td>5182</td><td></td></tr><tr><td>Methanol anhydrous, 99.8%</td><td>Sigma Aldrich</td><td>322415&amp;nbsp;SIGMA-ALDRICH</td><td></td></tr><tr><td>Diisopropyl azodicarboxylate, 98%</td><td>Sigma Aldrich</td><td>225541&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Dichlormethan, for synthesis, 99.5%</td><td>Carl Roth</td><td>8424</td><td></td></tr><tr><td>Silica gel for flash chromtaography</td><td>Sigma Aldrich</td><td>60738&amp;nbsp;SIGMA-ALDRICH</td><td></td></tr><tr><td>n-Pentane, 99%</td><td>Carl Roth</td><td>8720</td><td></td></tr><tr><td>n-Hexane, 99%</td><td>Carl Roth</td><td>CP47</td><td></td></tr><tr><td>Ethylacetate, 99.5%</td><td>Carl Roth</td><td>7338</td><td></td></tr><tr><td>Aminohexanol, 95%</td><td>Sigma Aldrich</td><td>A56353&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>&lt;em&gt;S&lt;/em&gt;-Methylisothiourea hemisulfate, 98%</td><td>Sigma Aldrich</td><td>M84445 ALDRICH</td><td></td></tr><tr><td>Di-&lt;em&gt;tert&lt;/em&gt;-butyl dicarbonate, 99%</td><td>Sigma Aldrich</td><td>205249&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-Dimethylformamid, 99.8%</td><td>Carl Roth</td><td>A529</td><td></td></tr><tr><td>&lt;em&gt;N,N&lt;/em&gt;-Diisopropylethylamin, 99.5%</td><td>Carl Roth</td><td>2474</td><td></td></tr><tr><td>Acetic anhydrid, 99%</td><td>Carl Roth</td><td>4483</td><td></td></tr><tr><td>Chlortrityl resin</td><td>Carbolution</td><td>CC11006</td><td></td></tr><tr><td>Fmoc-Gly-OH, 98%</td><td>Carbolution</td><td>CC05014</td><td></td></tr><tr><td>Piperidin, 99%</td><td>Sigma Aldrich</td><td>104094&amp;nbsp;SIGMA-ALDRICH</td><td></td></tr><tr><td>Fmoc-Orn(Dde)-OH</td><td>Iris-Biotech</td><td>FAA1502</td><td></td></tr><tr><td>HATU, 99%</td><td>Carbolution</td><td>CC01011</td><td></td></tr><tr><td>HOAt, 99%</td><td>Carbolution</td><td>CC01004</td><td></td></tr><tr><td>Fmoc-Val-OH</td><td>Carbolution</td><td>CC05028</td><td></td></tr><tr><td>2-Nitrobenzenesulfonyl chloride, 97%</td><td>Sigma Aldrich</td><td>N11507&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>2,4,6-Collidine, 99%</td><td>Sigma Aldrich</td><td>27690&amp;nbsp;SIGMA-ALDRICH</td><td></td></tr><tr><td>Mercaptoethanol, 99%&amp;nbsp;</td><td>Sigma Aldrich</td><td>M6250&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Diazabicycloundecen, 98%</td><td>Sigma Aldrich</td><td>139009&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Fmoc-D-Phe-OH, 98%</td><td>Sigma Aldrich</td><td>47378&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Fmoc-Asp(OtBu)-OH, 98%</td><td>Carbolution</td><td>CC05008</td><td></td></tr><tr><td>Hexafluoroisopropanol</td><td>Carbolution</td><td>CC03056</td><td></td></tr><tr><td>Diphenylphosphoryl azide, 97%</td><td>Sigma Aldrich</td><td>178756&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>TFA, 99.9%</td><td>Carl Roth</td><td>P088</td><td></td></tr><tr><td>Triisopropylsilan, 98%</td><td>Sigma Aldrich</td><td>233781&amp;nbsp;ALDRICH</td><td></td></tr><tr><td>Acetonitrile, HPLC grade</td><td>Carl Roth</td><td>HN44</td><td></td></tr></tbody></table>

modification and functionalization of the guanidine group by tailor-made precursors

קבוצת guanidine היא אחת קבוצות pharmacophoric החשובות ביותר כימיה רפואית. חומצת האמינו רק נושאת קבוצת guanidine הוא ארגינין. במאמר זה, שיטה קלה השינוי של קבוצת guanidine ב הליגנדים peptidic מסופקת, עם דוגמא של הליגנדים integrin מחייב RGD. זה הודגם לאחרונה כי השינוי המובהק של קבוצת guanidine ב הליגנדים אלה מאפשר אפנון סלקטיבית של תת (למשל, בין תתי הסוגים αv ו α5). יתר על כן, אסטרטגיה ידועה בעבר עבור functionalization דרך קבוצת guanidine הודגמה, ואת הגישה הסינטתית נסקרה במסמך זה. השינויים המתוארים כאן לערב סופני (ω N) קבוצות guanidine alkylated ו acetylated. לסינתזה, מולקולות מבשרות תפורים מסונתזות, אשר לאחר מכן חשופים תגובה עם אמין deprotected orthogonally להעביר את הקדםקבוצת guanidine -modified. לסינתזה של guanidines alkylated, מבשרי מבוסס על N, H -pyrazole-1-carboxamidine -DI-בוק-1 &#39;N משמשים לסנתז תרכובות acylated, מבשר הבחירה להיות נגזרת acylated בהתאמה של N -Boc- S - methylisothiourea, אשר ניתן להשיג ב תגובות אחד ושני צעד.

מבשר פפטיד המחזורי היה מסונתז כמו פפטיד ליניארי, cyclized, ו orthogonally DDE-deprotected. לאחר המשקעים, הטוהר של המתחם נותח עם HPLC-MS (איור 1). כדי לעקוב אחר ההתקדמות של התגובה, ניתוח HPLC בוצע לאחר זמן תגובת 2-h (איור 2). <p class="jove_content" fo:keep-together.within-page="1" style=...

Watch this Scientific Journal Video about Modification and Functionalization of the Guanidine Group by Tailor-made Precursors at JoVE.com

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors

פרוטוקול לסינתזה של guanidines-modified אלקיל מבוסס על השימוש המבשר המתאימים הוצג.

שינויו Functionalization של קבוצת guanidine ידי מבשרי תפורות

The guanidine group is one of the most important pharmacophoric groups in medicinal chemistry. The only amino acid carrying a guanidine group is arginine. ...

modification-functionalization-guanidine-group-tailor-made

Research

JoVE Journal

Biochemistry

10.5K Views.  Technische Universität München.  פרוטוקול לסינתזה של guanidines-modified אלקיל מבוסס על השימוש המבשר המתאימים הוצג. 

Video: Modification and Functionalization of the Guanidine Group by Tailor-made Precursors

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young&#8217;s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g.&#160;primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

Microwave-assisted Functionalization of Polyethylene glycol and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

This video will illustrate a rapid, efficient method to methacrylate poly(ethylene glycol), enabling chain polymerizations and hydrogel synthesis. It will demonstrate how to similarly introduce methacrylamide functionalities into peptides, detail common analytical methods to assess functionalization efficiency, provide suggestions for troubleshooting and advanced modifications, and demonstrate typical hydrogel characterization techniques.

Functionalization בסיוע מיקרוגל של פולי (אתילן גליקול) ופפטידים על השרף לשימוש בPolymerizations שרשרת וגיבוש Hydrogel

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large ...

Chemistry

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization

The traditional strategy for the introduction of chemical functionalities is the use of solid-phase synthesis by appending suitably modified phosphoramidite precursors to the nascent chain. However, the conditions used during the synthesis and the restriction to rather short sequences hamper the applicability of this methodology. On the other hand, modified nucleoside triphosphates are activated building blocks that have been employed for the mild introduction of numerous functional groups into nucleic acids, a strategy that paves the way for the use of modified nucleic acids in a wide-ranging palette of practical applications such as functional tagging and generation of ribozymes and DNAzymes. One of the major challenges resides in the intricacy of the methodology leading to the isolation and characterization of these nucleoside analogues.
	
	In this video article, we present a detailed protocol for the synthesis of these modified analogues using phosphorous(III)-based reagents. In addition, the procedure for their biochemical characterization is divulged, with a special emphasis on primer extension reactions and TdT tailing polymerization. This detailed protocol will be of use for the crafting of modified dNTPs and their further use in chemical biology.

The protocol described herein aims to explain and abridge the numerous obstacles in the way of the intricate route leading to modified nucleoside triphosphates. Consequently, this protocol facilitates both the synthesis of these activated building-blocks and their availability for practical applications.

נוקלאוזידים triphosphates - מ - סינתזה ביוכימיה באפיון

The  traditional strategy for the introduction of chemical functionalities is the  use of solid-phase synthesis by appending suitably modified ...

High-throughput Synthesis of Carbohydrates and Functionalization of Polyanhydride Nanoparticles

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design efficacious vaccines carriers. Nanoparticle-based platforms can prolong the persistence of vaccine antigens, which could improve vaccine immunogenicity1. Several biodegradable polymers have been studied as vaccine delivery vehicles1; in particular, polyanhydride particles have demonstrated the ability to provide sustained release of stable protein antigens and to activate antigen presenting cells and modulate immune responses2-12.
The molecular design of these vaccine carriers needs to integrate the rational selection of polymer properties as well as the incorporation of appropriate targeting agents. High throughput automated fabrication of targeting ligands and functionalized particles is a powerful tool that will enhance the ability to study a wide range of properties and will lead to the design of reproducible vaccine delivery devices.
The addition of targeting ligands capable of being recognized by specific receptors on immune cells has been shown to modulate and tailor immune responses10,11,13 C-type lectin receptors (CLRs) are pattern recognition receptors (PRRs) that recognize carbohydrates present on the surface of pathogens. The stimulation of immune cells via CLRs allows for enhanced internalization of antigen and subsequent presentation for further T cell activation14,15. Therefore, carbohydrate molecules play an important role in the study of immune responses; however, the use of these biomolecules often suffers from the lack of availability of structurally well-defined and pure carbohydrates. An automation platform based on iterative solution-phase reactions can enable rapid and controlled synthesis of these synthetically challenging molecules using significantly lower building block quantities than traditional solid-phase methods16,17.
Herein we report a protocol for the automated solution-phase synthesis of oligosaccharides such as mannose-based targeting ligands with fluorous solid-phase extraction for intermediate purification. After development of automated methods to make the carbohydrate-based targeting agent, we describe methods for their attachment on the surface of polyanhydride nanoparticles employing an automated robotic set up operated by LabVIEW as previously described10. Surface functionalization with carbohydrates has shown efficacy in targeting CLRs10,11 and increasing the throughput of the fabrication method to unearth the complexities associated with a multi-parametric system will be of great value (Figure 1a).

In this article, a high throughput method is presented for the synthesis of oligosaccharides and their attachment to the surface of polyanhydride nanoparticles for further use in targeting specific receptors on antigen presenting cells.

תפוקה גבוהה סינתזה של פחמימות functionalization של חלקיקים Polyanhydride

Transdisciplinary approaches involving areas such as material design, nanotechnology, chemistry, and immunology have to be utilized to rationally design ...

Bioengineering

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important structural element found in many complex natural products and pharmaceuticals. Owing to the continual discovery of new guanidine-containing natural products and designed small molecules, rapid and efficient guanidinylation methods are of keen interest to synthetic and medicinal organic chemists. Because the nucleophilicity and basicity of guanidines can affect subsequent chemical transformations, traditional, indirect guanidinylation is typically pursued. Indirect methods commonly employ multiple protection steps involving a latent amine precursor, such as an azide, phthalimide, or carbamate. By circumventing these circuitous methods and employing a direct guanidinylation reaction early in the synthetic sequence, it was possible to forge the linear terminal guanidine containing backbone of clavatadine A to realize a short and streamlined synthesis of this potent factor XIa inhibitor. In practice, guanidine hydrochloride is elaborated with a carefully constructed protecting array that is optimized to survive the synthetic steps to come. In the preparation of clavatadine A, direct guanidinylation of a commercially available diamine eliminated two unnecessary steps from its synthesis. Coupled with the wide variety of known guanidine protecting groups, direct guanidinylation evinces a succinct and efficient practicality inherent to methods that find a home in a synthetic chemist&#39;s toolbox.

Here, we present a protocol for direct, early stage guanidinylation that enables rapid total synthesis of aminoguanidine-containing small organic molecules. An advanced synthetic intermediate used in the synthesis of a blood coagulation factor XIa inhibitor was prepared using this protocol.

ישיר, בשלבים מוקדמים Guanidinylation פרוטוקול לסינתזה של מוצרים טבעיים Aminoguanidine המכיל קומפלקס

The guanidine functional group, displayed most prominently in the amino acid arginine, one of the fundamental building blocks of life, is an important ...

Facile Preparation of 4-Substituted Quinazoline Derivatives

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted 2-aminobenzophenones and thiourea in the presence of dimethyl sulfoxide (DMSO). This is a unique complementary reaction system in which thiourea undergoes thermal decomposition to form carbodiimide and hydrogen sulfide, where the former reacts with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, whilst hydrogen sulfide reacts with DMSO to give methanethiol or other sulfur-containing molecule which then functions as a complementary reducing agent to reduce 4-phenylquinazolin-2(1H)-imine intermediate into 4-phenyl-1,2-dihydroquinazolin-2-amine. Subsequently, the elimination of ammonia from 4-phenyl-1,2-dihydroquinazolin-2-amine affords substituted quinazoline derivative. This reaction usually gives quinazoline derivative as a single product arising from 2-aminobenzophenone as monitored by GC/MS analysis, along with small amount of sulfur-containing molecules such as dimethyl disulfide, dimethyl trisulfide, etc. The reaction usually completes in 4-6 hr at 160 &#186;C in small scale but may last over 24 hr when carried out in large scale. The reaction product can be easily purified by means of washing off DMSO with water followed by column chromatography or thin layer chromatography.

A protocol for facile preparation of 4-substituted quinazoline derivatives from 2-aminobenzophenones, thiourea and dimethyl sulfoxide is presented.

הכנה קלילה של נגזרי Quinazoline 4-הוחלפו

Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted ...

Chemoselective Modification of Viral Surfaces via Bioorthogonal Click Chemistry

The modification of virus particles has received a significant amount of attention for its tremendous potential for impacting gene therapy, oncolytic applications and vaccine development.1,2,3 Current approaches to modifying viral surfaces, which are mostly genetics-based, often suffer from attenuation of virus production, infectivity and cellular transduction.4,5 Using chemoselective click chemistry, we have developed a straightforward alternative approach which sidesteps these issues while remaining both highly flexible and accessible.1,2
The goal of this protocol is to demonstrate the effectiveness of using bioorthogonal click chemistry to modify the surface of adenovirus type 5 particles. This two-step process can be used both therapeutically1 or analytically,2,6 as it allows for chemoselective ligation of targeting molecules, dyes or other molecules of interest onto proteins pre-labeled with azide tags. The three major advantages of this method are that (1) metabolic labeling demonstrates little to no impact on viral fitness,1,7 (2) a wide array of effector ligands can be utilized, and (3) it is remarkably fast, reliable and easy to access.1,2,7
In the first step of this procedure, adenovirus particles are produced bearing either azidohomoalanine (Aha, a methionine surrogate) or the unnatural sugar O-linked N-azidoacetylglucosamine (O-GlcNAz), both of which contain the azide (-N3) functional group. After purification of the azide-modified virus particles, an alkyne probe containing the fluorescent TAMRA moiety is ligated in a chemoselective manner to the pre-labeled proteins or glycoproteins. Finally, an SDS-PAGE analysis is performed to demonstrate the successful ligation of the probe onto the viral capsid proteins. Aha incorporation is shown to label all viral capsid proteins (Hexon, Penton and Fiber), while O-GlcNAz incorporation results in labeling of Fiber only.
In this evolving field, multiple methods for azide-alkyne ligation have been successfully developed; however only the two we have found to be most convenient are demonstrated herein &#x2013; strain-promoted azide-alkyne cycloaddition (SPAAC) and copper-catalyzed azide-alkyne cycloaddition (CuAAC) under deoxygenated atmosphere.

Adenovirus particles are engineered to contain either the unnatural amino acid analogue azidohomoalanine or the azido sugar O-GlcNAz. The azide group of each is chemoselectively ligated via "click" chemistry reactions as a means of viral surface modification.

שינוי Chemoselective של משטחים ויראלי באמצעות כימיה לחץ Bioorthogonal

The modification of virus particles has received a significant amount of attention for its tremendous potential for impacting gene therapy, oncolytic ...

Immunology and Infection

Preparation of N-(2-alkoxyvinyl)sulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines

Decomposition of N-tosyl-1,2,3-triazoles with rhodium(II) acetate dimer in the presence of alcohols forms synthetically versatile N-(2-alkoxyvinyl)sulfonamides, which react under a variety of conditions to afford useful N- and O-containing compounds. Acid-catalyzed addition of alcohols or thiols to N-(2-alkoxyvinyl)sulfonamide-containing phthalans provides access to ketals and thioketals, respectively. Selective reduction of the vinyl group in N-(2-alkoxyvinyl)sulfonamide-containing phthalans via hydrogenation yields the corresponding phthalan in good yield, whereas reduction with sodium bis(2-methoxyethoxy)aluminumhydride generates a ring-opened phenethylamine analogue. Because the N-(2-alkoxyvinyl)sulfonamide functional group is synthetically versatile, but often hydrolytically unstable, this protocol emphasizes key techniques in preparing, handling, and reacting these pivotal substrates in several useful transformations.

Preparation of N-2-alkoxyvinylsulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines

Representative experimental procedures for the synthesis of N-(2-alkoxyvinyl)sulfonamides and subsequent conversion to phthalan and phenethylamine derivatives are presented in detail.

הכנת N-(2-alkoxyvinyl) sulfonamides N- tosyl-1,2,3-triazoles, הבאים ההמרה ל שהוחלפו Phthalans ו- Phenethylamines

Decomposition of N-tosyl-1,2,3-triazoles with rhodium(II) acetate dimer in the presence of alcohols forms synthetically versatile ...

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having multifarious bioactivities. Although chemical O-glycosylation is a commonly beneficial strategy to synthesize disaccharide nucleosides, the preparation of substrates such as glycosyl donors and acceptors requires&#160;tedious protecting&#160;group manipulations and a purification at each synthetic step. Meanwhile, several research groups have reported that boronic and borinic esters serve as a protecting or activating group of carbohydrate derivatives to achieve the regio- and/or stereoselective acylation, alkylation, silylation, and glycosylation. In this article, we demonstrate the procedure for the regioselective O-glycosylation of unprotected ribonucleosides utilizing boronic acid. The esterification of 2&#39;,3&#39;-diol of ribonucleosides with boronic acid makes the temporary protection of diol, and, following O-glycosylation with a glycosyl donor in the presence of p-toluenesulfenyl chloride and silver triflate, permits the regioselective reaction of the 5&#39;-hydroxyl group to afford the disaccharide nucleosides. This method could be applied to various nucleosides, such as guanosine, adenosine, cytidine, uridine, 5-metyluridine, and 5-fluorouridine. This article and the accompanying video represent&#160;useful (visual) information for the O-glycosylation of unprotected nucleosides and their analogs for the synthesis of not only disaccharide nucleosides, but also a variety of biologically relevant derivatives.

Regioselective O-Glycosylation of Nucleosides via the Temporary 2',3'-Diol Protection by a Boronic Ester for the Synthesis of Disaccharide Nucleosides

Here, we present protocols for the synthesis of disaccharide nucleosides by the regioselective O-glycosylation of ribonucleosides via a temporary protection of their 2&#39;,3&#39;-diol moieties utilizing a cyclic boronic ester. This method applies to several unprotected nucleosides such as adenosine, guanosine, cytidine, uridine, 5-methyluridine, and 5-fluorouridine to give corresponding disaccharide nucleosides.

Regioselective O- גליקוזילציה של נוקלאוזידים via זמני 2', 3'-Diol הגנה על ידי אסתר Boronic לסינתזה של דו-סוכר נוקלאוזידים

Disaccharide nucleosides, which consist of disaccharide and nucleobase moieties, have been known as a valuable group of natural products having ...

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyl(tropone)iron

aza-Michael adducts of tricarbonyl(tropone)iron are synthesized by two different methods. Primary aliphatic amines and cyclic secondary amines participate in a direct aza-Michael reaction with tricarbonyl(tropone)iron under solvent-free conditions. Less nucleophilic aniline derivatives and more hindered secondary amines add efficiently to the cationic tropone complex formed by protonation of tricarbonyl(tropone)iron. While the protocol utilizing the cationic complex is less efficient overall for accessing the aza-Michael adducts than the direct, solvent-free addition to the neutral complex, it allows the use of a broader range of amine nucleophiles. Following protection of the amine of the aza-Michael adduct as a tert-butyl carbamate, the diene is decomplexed from the iron tricarbonyl fragment upon treatment with cerium(IV) ammonium nitrate to provide derivatives of 6-aminocyclohepta-2,4-dien-1-one. These products can serve as precursors to diverse compounds containing a seven-membered carbocyclic ring. Because the demetallation requires protection of the amine as a carbamate, the aza-Michael adducts of secondary amines cannot be decomplexed using the protocol described here.

Preparation of 6-aminocyclohepta-2,4-dien-1-one Derivatives via Tricarbonyltroponeiron

Representative experimental procedures for the addition of amine nucleophiles to tricarbonyl(tropone)iron and subsequent demetallation of the resulting complexes are presented in detail.

הכנת 6-האמילוציהועד 2, 4-דיין-1-הנגזרים באמצעות טריקרבוניל (טרופון) ברזל

aza-Michael adducts of tricarbonyl(tropone)iron are synthesized by two different methods. Primary aliphatic amines and cyclic secondary amines participate ...

The Synthesis of RGD-functionalized Hydrogels as a Tool for Therapeutic Applications

The use of polymers as biomaterials has provided significant advantages in therapeutic applications. In particular, the possibility to modify and functionalize polymer chains with compounds that are able to improve biocompatibility, mechanical properties, or cell viability allows the design of novel materials to meet new challenges in the biomedical field. With the polymer functionalization strategies, click chemistry is a powerful tool to improve cell-compatibility and drug delivery properties of polymeric devices. Similarly, the fundamental need of biomedicine to use sterile tools to avoid potential adverse-side effects, such as toxicity or contamination of the biological environment, gives rise to increasing interest in the microwave-assisted strategy.
The combination of click chemistry and the microwave-assisted method is suitable to produce biocompatible hydrogels with desired functionalities and improved performances in biomedical applications. This work aims to synthesize RGD-functionalized hydrogels. RGD (arginylglycylaspartic acid) is a tripeptide that can mimic cell adhesion proteins and bind to cell-surface receptors, creating a hospitable microenvironment for cells within the 3D polymeric network of the hydrogels. RGD functionalization occurs through Huisgen 1,3-dipolar cycloaddition. Some PAA carboxyl groups are modified with an alkyne moiety, whereas RGD is functionalized with azido acid as the terminal residue of the peptide sequence. Finally, both products are used in a copper catalyzed click reaction to permanently link the peptide to PAA. This modified polymer is used with carbomer, agarose and polyethylene glycol (PEG) to synthesize a hydrogel matrix. The 3D structure is formed due to an esterification reaction involving carboxyl groups from PAA and carbomer and hydroxyl groups from agarose and PEG through microwave-assisted polycondensation. The efficiency of the gelation mechanism ensures a high degree of RGD functionalization. In addition, the procedure to load therapeutic compounds or biological tools within this functionalized network is very simple and reproducible.

We present a protocol for the synthesis of RGD-functionalized hydrogels as devices for cell and drug delivery. The procedure involves copper catalyzed alkyne-azide cycloaddition (CuAAC) between alkyne-modified polyacrylic acid (PAA) and a RGD-azide derivative. The hydrogels are formed using microwave-assisted polycondensation and their physicochemical properties are investigated.