Gli autori desiderano ringraziare il Dott. Jumpei Morimoto e il Dr. Todd Doran per la preziosa assistenza. Questo lavoro è stato supportato da un contratto del NHLBI (NO1-HV-00242).

<ol>
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S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+novel+targeting+peptides+for+human+ovarian+cancer+cells+using+&amp;#34;one-bead+one-compound&amp;#34;+combinatorial+libraries.">Identification of novel targeting peptides for human ovarian cancer cells using &amp;#34;one-bead one-compound&amp;#34; combinatorial libraries.</a> Mol Cancer Ther. 4, 806-813 (2005).</li><li>Udugamasooriya, D. G., Dineen, S. P., Brekken, R. A., Kodadek, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Peptoid+&#8220;Antibody+Surrogate&#8221;+That+Antagonizes+VEGF+Receptor+2+Activity.">A Peptoid &#8220;Antibody Surrogate&#8221; That Antagonizes VEGF Receptor 2 Activity.</a> Journal of the American Chemical Society. 130, 5744-5752 (2008).</li><li>Shah, N. 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Gli autori dichiarano di non avere interessi finanziari in competizione.

Peptide ammidi terziarie (PTA) sono una superfamiglia di oligomeri peptidomimetici. Oltre ai peptidi ben studiato, peptoids e peptidi N-metilati, una gran parte di composti all&#39;interno di questa famiglia rimane understudied, majorly a causa della mancanza di metodo sintetico per accedere generali peptidi N-alchilati. Qui si descrive un metodo efficace per sintetizzare PTA con blocchi chirali derivati ​​da amminoacidi. In precedenza, abbiamo riportato di utilizzare un nuovo percorso sub-monomero di librerie di si...

Peptidomimetici sono composti che imitano la struttura di peptidi naturali. Essi sono progettati per mantenere la bioattività mentre superare alcuni dei problemi associati con peptidi naturali, tra cui la permeabilità cellulare e stabilità contro proteolisi 1-3. A causa della natura oligomerica di questi composti, grandi librerie sintetiche possono essere facilmente accessibili attraverso vie sintetiche monomeriche o sub-monomerici 4-7. Una delle classi più studiati di peptidomimetici è peptoids. Peptoids sono oligomeri di glicine N-alchilati, che possono essere sintetizzati facilmente usando una strategia sub-monomero 8, 9. Molti ligandi di proteine ​​utili sono stati identificati con successo da screening di librerie di grandi dimensioni peptoid sintetico contro bersagli proteici 1, 10-14. Tuttavia, &quot;hits&quot; individuati dalle biblioteche peptoid raramente archivio un&#39;elevata affinità verso gli obiettivi della proteina 1,10-14,22. One major differenza tra peptoids e peptidi naturali è che la maggior parte dei peptoids generalmente non hanno la capacità di formare strutture secondarie a causa della mancanza di centri chirali e vincoli conformazionali. Per risolvere questo problema, strategie multiple sono state sviluppate negli ultimi dieci anni, in gran parte incentrata sulla modifica delle catene laterali presenti sulle principali atomi di azoto catena 15-22. Recentemente, abbiamo sviluppato una nuova via sintetica per introdurre catene laterali di aminoacidi naturali su una dorsale peptoid per creare peptidi ammidi terziarie 23. Peptide ammidi terziarie (PTA) sono una famiglia di super-peptidomimetici che includono ma non sono limitate a peptidi (R 2 = H), peptoids (R 1 = H) e peptidi N-metilato (R 1 ≠ H, R 2 = Me) . (Vedi figura 1) La via sintetica impiega aminoacidi naturali come fonte di chiralità e catene laterali sul45;-carbonio, e ammine primarie disponibili in commercio per fornire N-sostituzioni. Pertanto, uno spazio chimico più grande di quello di peptidi semplici, peptoids o peptidi N-metilato può essere esplorato. Spettri di dicroismo circolare hanno dimostrato che le molecole del PTA sono altamente strutturati in soluzione. Caratterizzazione di uno dei complessi PTA-proteina mostra chiaramente che i vincoli conformazionali di PTA sono richiesti per il legame. Recentemente, abbiamo anche scoperto che alcune delle molecole PTA possiedono una migliore permeabilità cellulare rispetto ai loro omologhi peptoid e peptidi. Noi crediamo che queste librerie PTA possono essere una buona fonte di ligandi ad alta affinità per le proteine ​​target. In questo articolo, discuteremo la sintesi di un campione unico tallone di un composto (OBOC) biblioteca PTA in dettaglio insieme ad alcune condizioni migliori per l&#39;accoppiamento e la scissione di questi composti.

<table border="0" cellpadding="0" cellspacing="0" width="889">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">2,4,6 trimethylpyridine</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">161950010</td>
			<td style="width:311px;">CAS:108-75-8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">2-morpholinoethanamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">06680&#160;</td>
			<td>CAS:2038-03-1&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">48% HBr Water solution</td>
			<td style="width:169px;">ALFA AESAR</td>
			<td style="width:160px;">AA14036AT</td>
			<td>CAS:10035-10-6</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Acetaldehyde</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">402788</td>
			<td>CAS:75-07-0&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Acetonitrile</td>
			<td style="width:169px;">Fisher</td>
			<td style="width:160px;">SR015AA-19PS</td>
			<td>CAS:75-05-8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Anhydrous Tetrahydrofuran (THF)</td>
			<td style="width:169px;">EMD</td>
			<td style="width:160px;">EM-TX0277-6&#160;</td>
			<td>CAS:109-99-9</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Benzylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">185701</td>
			<td>CAS:100-46-9</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">bis(trichloromethyl) carbonate (BTC)</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">258950050</td>
			<td>CAS:32315-10-9</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Bromoacetic acid</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">106570010</td>
			<td>CAS:79-08-3</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Chloranil</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">23290</td>
			<td>CAS:118-75-2</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Cyclohexanemethylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">101842</td>
			<td>CAS:3218-02-8</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;">D2O</td>
			<td style="width:169px;">Cambridge Isotope</td>
			<td style="width:160px;">DLM-4-99.8-1000</td>
			<td>CAS:7789-20-0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">D-alanine</td>
			<td style="width:169px;">Anaspec</td>
			<td style="width:160px;">61387-100</td>
			<td>CAS:338-69-2&#160;&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">Dichloromethane (DCM)</td>
			<td style="width:169px;">Fisher</td>
			<td style="width:160px;">BJ-NS300-20</td>
			<td>CAS:75-09-2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">Dimethylformamide (DMF)</td>
			<td style="width:169px;">Fisher</td>
			<td style="width:160px;">BJ-076-4</td>
			<td>CAS:68-12-2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">Ethylene glycol</td>
			<td style="width:169px;">Oakwood</td>
			<td style="width:160px;">44710</td>
			<td>CAS:107-21-1</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">Isopentylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">W321907</td>
			<td>CAS:107-85-7</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">KBr</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">424070025</td>
			<td>CAS:7758-02-3</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">L-alanine</td>
			<td style="width:169px;">Anaspec</td>
			<td style="width:160px;">61385-100</td>
			<td>CAS:56-41-7&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">3-Methoxypropylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">M25007</td>
			<td>CAS:5332-73-0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">2-Methoxyethylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">143693</td>
			<td>CAS:109-85-3</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N-(3-Aminopropyl)-2-pyrrolidinone</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">136565&#160;</td>
			<td>CAS:7663-77-6&#160;</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N,N&#39;-Diisopropylcarbodiimide (DIC)</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">115211000</td>
			<td>CAS:693-13-0</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">N,N-Diisopropylethylamine (DIPEA)</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">D125806</td>
			<td>CAS:7087-68-5</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;">NaNO2</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">424340010</td>
			<td>CAS:7631-99-4</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:21px;width:249px;">NAOD 40% solution in water</td>
			<td style="width:169px;">ACROS</td>
			<td style="width:160px;">200058-506</td>
			<td>CAS:7732-18-5</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Piperidine</td>
			<td style="width:169px;">ALFA AESAR</td>
			<td style="width:160px;">A12442-AE</td>
			<td>CAS:110-89-4</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Piperonylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">P49503&#160;</td>
			<td>CAS:2620-50-0</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Propylamine</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">240958</td>
			<td>CAS:107-10-8</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Trifluoroacetic acid</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">299537</td>
			<td>CAS:76-05-1</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">&#945;-Cyano-4-hydroxycinnamic acid&#160;</td>
			<td style="width:169px;">Sigma-Aldrich</td>
			<td style="width:160px;">39468</td>
			<td>CAS:28166-41-8&#160;&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">&#945;-ketoglutarate</td>
			<td style="width:169px;">ALFA AESAR</td>
			<td style="width:160px;">AAA10256-22</td>
			<td style="width:311px;">CAS:328-50-7</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Tentagel Resin with RINK linker</td>
			<td style="width:169px;">Rapp-Polymere</td>
			<td style="width:160px;">S30023</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Alanine transaminase</td>
			<td style="width:169px;">Roche</td>
			<td style="width:160px;">10105589001</td>
			<td>AKA: Glutamate-Pyruvate Transaminase (GPT)</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:249px;">Incubator</td>
			<td style="width:169px;">New Brunswick Scientific</td>
			<td style="width:160px;">Innova44</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">NMR</td>
			<td style="width:169px;">Bruker</td>
			<td style="width:160px;">400MHz</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">MALDI mass spectrometer</td>
			<td style="width:169px;">Applied Biosystems&#160;</td>
			<td style="width:160px;">4800 MALDI-TOF/TOF</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Lyophilizer</td>
			<td style="width:169px;">SP Scientific</td>
			<td style="width:160px;">VirTis benchtop K</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Syringe reactor</td>
			<td style="width:169px;">INTAVIS&#160;</td>
			<td style="width:160px;">Reaction Column</td>
			<td>3ml, 5ml, 10ml, 20ml</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:249px;">Vacuum manifold&#160;</td>
			<td style="width:169px;">Promega</td>
			<td style="width:160px;">A7231</td>
			<td>Vac-Man</td>
		</tr>
	</tbody>
</table>

split-and-pool synthesis and characterization of peptide tertiary amide library

Peptidomimetici sono grandi fonti di leganti proteici. La natura oligomerica di questi composti in grado di accedere a grandi librerie sintetiche su fase solida utilizzando la chimica combinatoriale. Una delle classi più ben studiati di peptidomimetici è peptoids. Peptoids sono facili da sintetizzare e hanno dimostrato di essere resistente alla proteolisi e cellula-permeabile. Negli ultimi dieci anni, molte leganti proteici utili sono stati identificati attraverso lo screening di librerie peptoid. Tuttavia, la maggior parte dei ligandi identificati dalle biblioteche peptoid non vengono visualizzati alta affinità, con rare eccezioni. Ciò può essere dovuto, in parte, alla mancanza di centri chirali e vincoli conformazionali nelle molecole peptoid. Recentemente, abbiamo descritto una nuova via sintetica per accedere peptidi ammidi terziarie (PTA). PTA sono una superfamiglia di peptidomimetici che includono ma non sono limitate a, peptidi peptoids e peptidi N-metilati. Con catene laterali su entrambi α-carbonio e atomi di azoto catena principale,la conformazione di queste molecole sono notevolmente limitata dalla impedimento sterico e allilico 1,3 ceppo. (Figura 1) Il nostro studio suggerisce che queste molecole PTA sono altamente strutturate in soluzione e possono essere utilizzati per identificare ligandi proteici. Crediamo che queste molecole possono essere una futura fonte di ligandi ad alta affinità della proteina. Qui si descrive il metodo di sintesi che unisce la potenza di entrambi split-e-pool e le strategie sub-monomeri per sintetizzare un campione unico tallone di un composto (OBOC) biblioteca di PTA.

Qui vi mostriamo tre spettri rappresentativi MALDI da un trimero PTA con linker. Come mostrato nella Figura 6A, quando spaccati a temperatura ambiente utilizzando il 50% di soluzione di TFA / DCM, degradazione significativa si osserva. In Figura 6A, picco 593 e 484 corrispondono al linker e il trimero PTA, rispettivamente, mostrano che l&#39;intera molecola è stato sintetizzato con successo sul tallone ma degradato durante scissione. Quando spaccati in condizioni di bassa temperatura c...

Watch this Scientific Journal Video about Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library at JoVE.com

Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

Peptide ammidi terziarie (PTA) sono una superfamiglia di peptidomimetici che includono ma non sono limitate a peptidi, peptoids e peptidi N-metilato. Qui si descrive un metodo sintetico che combina split-e-pool e le strategie sub-monomeri per sintetizzare un one-tallone biblioteca un composto di PTA.

Split-e-pool Sintesi e caratterizzazione di peptidi Terziario Ammide Biblioteca

Peptidomimetics are great sources of protein ligands. The oligomeric nature of these compounds enables us to access large synthetic libraries on solid ...

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18.0K Views.  The Scripps Research Institute.  Peptide ammidi terziarie (PTA) sono una superfamiglia di peptidomimetici che includono ma non sono limitate a peptidi, peptoids e peptidi N-metilato. Qui si descrive un metodo sintetico che combina split-e-pool e le strategie sub-monomeri per sintetizzare un one-tallone biblioteca un composto di PTA. 

Video: Split-and-pool Synthesis and Characterization of Peptide Tertiary Amide Library

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.

Nucleosidi trifosfati - Dalla sintesi di biochimica Caratterizzazione

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

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Chimica

Amide Coupling Reaction for the Synthesis of Bispyridine-based Ligands and Their Complexation to Platinum as Dinuclear Anticancer Agents

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. Isonicotinic acid, or its derivatives, are coupled to variable length diaminoalkane chains under an inert atmosphere in anhydrous DMF or DMSO with the use of a weak base, triethylamine, and a coupling agent, 1-propylphosphonic anhydride. The products precipitate from solution upon formation or can be precipitated by the addition of water. If desired, the ligands can be further purified by recrystallization from hot water. Dinuclear platinum complex synthesis using the bispyridine ligands is done in hot water using transplatin. The most informative of the chemical characterization techniques to determine the structure and gross purity of both the bispyridine ligands and the final platinum complexes is 1H NMR with particular analysis of the aromatic region of the spectra (7-9 ppm). The platinum complexes have potential application as anticancer agents and the synthesis method can be modified to produce trinuclear and other multinuclear complexes with different hydrogen bonding functionality in the bridging ligand.

This protocol describes the use of amide coupling reactions of isonicotinic acid and diaminoalkanes to form bridging ligands suitable for use in the synthesis of multinuclear platinum complexes, which combine aspects of the anticancer drugs BBR3464 and picoplatin.

Ammide Accoppiamento di reazione per la sintesi di leganti a base di Bispyridine e il loro Complessazione di platino come diciclici agenti antitumorali

Amide coupling reactions can be used to synthesize bispyridine-based ligands for use as bridging linkers in multinuclear platinum anticancer drugs. ...

Synthesis and Characterization of Functionalized Metal-organic Frameworks

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and technological applications. Their signature property is their ultrahigh porosity, which however imparts a series of challenges when it comes to both constructing them and working with them. Securing desired MOF chemical and physical functionality by linker/node assembly into a highly porous framework of choice can pose difficulties, as less porous and more thermodynamically stable congeners (e.g., other crystalline polymorphs, catenated analogues) are often preferentially obtained by conventional synthesis methods. Once the desired product is obtained, its characterization often requires specialized techniques that address complications potentially arising from, for example, guest-molecule loss or preferential orientation of microcrystallites. Finally, accessing the large voids inside the MOFs for use in applications that involve gases can be problematic, as frameworks may be subject to collapse during removal of solvent molecules (remnants of solvothermal synthesis). In this paper, we describe synthesis and characterization methods routinely utilized in our lab either to solve or circumvent these issues. The methods include solvent-assisted linker exchange, powder X-ray diffraction in capillaries, and materials activation (cavity evacuation) by supercritical CO2 drying. Finally, we provide a protocol for determining a suitable pressure region for applying the Brunauer-Emmett-Teller analysis to nitrogen isotherms, so as to estimate surface area of MOFs with good accuracy.

Synthesis, activation, and characterization of intentionally designed metal-organic framework materials is challenging, especially when building blocks are incompatible or unwanted polymorphs are thermodynamically favored over desired forms. We describe how applications of solvent-assisted linker exchange, powder X-ray diffraction in capillaries and activation via supercritical CO2 drying, can address some of these challenges.

Sintesi e caratterizzazione di funzionalizzato metallo-organici quadri

Metal-organic frameworks have attracted extraordinary amounts of research attention, as they are attractive candidates for numerous industrial and ...

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the hydroxylmethylene phosphine precursor with ammonia in methanol under a nitrogen atmosphere. The N-triphosPh ligand precipitates from the solution after approximately 1 hr of reflux and can be isolated analytically pure via simple cannula filtration procedure under nitrogen. Reaction of the N-triphosPh ligand with [Ru3(CO)12] under reflux affords a deep red solution that show evolution of CO gas on ligand complexation. Orange crystals of the complex [Ru(CO)2{N(CH2PPh2)3}-&#954;3P] (2) were isolated on cooling to RT. The 31P{1H} NMR spectrum showed a characteristic single peak at lower frequency compared to the free ligand. Reaction of a toluene solution of complex 2 with oxygen resulted in the instantaneous precipitation of the carbonate complex [Ru(CO3)(CO){N(CH2PPh2)3}-&#954;3P] (3) as an air stable orange solid. Subsequent hydrogenation of 3 under 15 bar of hydrogen in a high-pressure reactor gave the dihydride complex [RuH2(CO){N(CH2PPh2)3}-&#954;3P] (4), which was fully characterized by X-ray crystallography and NMR spectroscopy. Complexes 3 and 4 are potentially useful catalyst precursors for a range of hydrogenation reactions, including biomass-derived products such as levulinic acid (LA). Complex 4 was found to cleanly react with LA in the presence of the proton source additive NH4PF6 to give [Ru(CO){N(CH2PPh2)3}-&#954;3P{CH3CO(CH2)2CO2H}-&#954;2O](PF6) (6).

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes

Ruthenium phosphine complexes are widely used for homogeneous catalytic reactions such as hydrogenations. The synthesis of a series of novel tridentate ruthenium complexes bearing the N-triphos ligand N(CH2PPh2)3 is reported. Additionally, the stoichiometric reaction of a dihydride Ru&#8211;N-triphos complex with levulinic acid is described.

La sintesi, caratterizzazione e reattività di una serie di rutenio<em&gt; N</em&gt; -triphos<sup&gt; Ph</sup&gt; Complessi

Herein we report the synthesis of a tridentate phosphine ligand N(CH2PPh2)3 (N-triphosPh) (1) via a phosphorus based Mannich reaction of the ...

Synthesis, Characterization, and Functionalization of Hybrid Au/CdS and Au/ZnS Core/Shell Nanoparticles

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large extinction coefficients which can be tuned across the visible spectrum. Research into the plasmonic enhancement of optical transitions has become popular, due to the possibility of altering and in some cases improving photo-absorption or emission properties of nearby chromophores such as molecular dyes or quantum dots. The electric field of the plasmon can couple with the excitation dipole of a chromophore, perturbing the electronic states involved in the transition and leading to increased absorption and emission rates. These enhancements can also be negated at close distances by energy transfer mechanism, making the spatial arrangement of the two species critical. Ultimately, enhancement of light harvesting efficiency in plasmonic solar cells could lead to thinner and, therefore, lower cost devices. The development of hybrid core/shell particles could offer a solution to this issue. The addition of a dielectric spacer between a gold nanoparticles and a chromophore is the proposed method to control the exciton plasmon coupling strength and thereby balance losses with the plasmonic gains. A detailed procedure for the coating of gold nanoparticles with CdS and ZnS semiconductor shells is presented. The nanoparticles show high uniformity with size control in both the core gold particles and shell species allowing for a more accurate investigation into the plasmonic enhancement of external chromophores.

The synthesis of uniform gold nanoparticles coated with semiconductor shells of CdS or ZnS is performed. The semiconductor coating is conducted by first depositing a silver sulfide shell and exchanging the silver cations for zinc or cadmium cations.

Sintesi, Caratterizzazione, e funzionalizzazione di ibrida UA / CdS e Au / ZnS core / shell nanoparticelle

Plasmonic nanoparticles are an attractive material for light harvesting applications due to their easily modified surface, high surface area and large ...

Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency.
Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position.
We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites&#39; viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a systematic screen for the most biological active conformation. This method provides a general, fast, and facile way to synthesize cyclic peptides.

A simple and general method for the synthesis of cyclic peptides using microwave irradiation is outlined. This procedure enables the synthesis of backbone cyclic peptides with a collection of different conformations while retaining the side chains and the pharmacophoric moieties., and therefore, allows to screen for the bioactive conformation.

Sviluppo di un Backbone ciclico Peptide Biblioteca come potenziale Antiparassitaria Therapeutics Uso Microonde irradiazione

Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Sintesi e caratterizzazione di supramolecolari colloidi

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Synthesis and Characterization of Fe-doped Aluminosilicate Nanotubes with Enhanced Electron Conductive Properties

The goal of the protocol is to synthesize Fe-doped aluminosilicate nanotubes of the imogolite type with the formula (OH)3Al2-xFexO3SiOH. Doping with Fe aims at lowering the band gap of imogolite, an insulator with the chemical formula (OH)3Al2O3SiOH, and at modifying its adsorption properties towards azo-dyes, an important class of organic pollutants of both wastewater and groundwater.
Fe-doped nanotubes are obtained in two ways: by direct synthesis, where FeCl3 is added to an aqueous mixture of the Si and Al precursors, and by post-synthesis loading, where preformed nanotubes are put in contact with a FeCl3&#8226;6H2O aqueous solution. In both synthesis methods, isomorphic substitution of Al3+ by Fe3+ occurs, preserving the nanotube structure. Isomorphic substitution is indeed limited to a mass fraction of ~1.0% Fe, since at a higher Fe content (i.e., a mass fraction of 1.4% Fe), Fe2O3 clusters form, especially when the loading procedure is adopted. The physicochemical properties of the materials are studied by means of X-ray powder diffraction (XRD), N2 sorption isotherms at -196 &#176;C, high resolution transmission electron microscopy (HRTEM), diffuse reflectance (DR) UV-Vis spectroscopy, and &#950;-potential measurements. The most relevant result is the possibility to replace Al3+ ions (located on the outer surface of the nanotubes) by post-synthesis loading on preformed imogolite without perturbing the delicate hydrolysis equilibria occurring during nanotube formation. During the loading procedure, an anionic exchange occurs, where Al3+ ions on the outer surface of the nanotubes are replaced by Fe3+ ions. In Fe-doped aluminosilicate nanotubes, isomorphic substitution of Al3+ by Fe3+ is found to affect the band gap of doped imogolite. Nonetheless, Fe3+ sites on the outer surface of nanotubes are able to coordinate organic moieties, like the azo-dye Acid Orange 7, through a ligand-displacement mechanism occurring in an aqueous solution.

Here, we present a protocol to synthesize and characterize Fe-doped aluminosilicate nanotubes. The materials are obtained by either sol-gel synthesis upon addition of FeCl3&#8226;6H2O to the mixture containing the Si and Al precursors or by post-synthesis ionic exchange of preformed aluminosilicate nanotubes.

Sintesi e caratterizzazione di Fe-drogato Alluminosilicato nanotubi con una maggiore Electron proprietà conduttive

The goal of the protocol is to synthesize Fe-doped aluminosilicate nanotubes of the imogolite type with the formula (OH)3Al2-xFexO3SiOH. Doping with Fe ...

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles (PPAs) and Related Biomaterials

Polyamine-based Peptide Amphiphiles (PPAs) are a new class of self-assembling amphiphilic biomaterials-related to the peptide amphiphiles (PAs). Traditional PAs possess charged amino acids as solubilizing groups (lysine, arginine), which are directly connected to a lipid segment or can contain a linker region made of neutral amino acids. Tuning the peptide sequence of PAs can yield diverse morphologies. Similarly, PPAs possess a hydrophobic segment and neutral amino acids, but also contain polyamine molecules as water solubilizing (hydrophilic) groups. As is the case with PAs, PPAs can also self-assemble into diverse morphologies, including small rods, twisted nano-ribbons, and fused nano-sheets, when dissolved in water. However, the presence of both primary and secondary amines on a single polyamine molecule poses a significant challenge when synthesizing PPAs. In this paper, we show a simple protocol, based on literature precedents, to achieve a facile synthesis of PPAs using solid phase peptide synthesis (SPPS). This protocol can be extended to the synthesis of PAs and other similar systems. We also illustrate the steps that are needed for cleavage from the resin, identification, and purification.

Facile Protocol for the Synthesis of Self-assembling Polyamine-based Peptide Amphiphiles PPAs and Related Biomaterials

The synthesis of polyamine-based peptide amphiphiles (PPAs) is a significant challenge due to the presence of multiple amine nitrogens, which requires judicious use of protecting groups to mask these reactive functionalities. In this paper, we describe a facile method for the preparation of these new class of self-assembling molecules.

Facile protocollo per la sintesi di auto-assemblaggio basato su poliammina Peptide anfifili (PPA) e biomateriali correlate

Polyamine-based Peptide Amphiphiles (PPAs) are a new class of self-assembling amphiphilic biomaterials-related to the peptide amphiphiles (PAs). ...

Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides

This report focuses on the synthesis of an N-terminus 1,2-dithiolane modified self-assembling peptide and the characterization of the resulting self-assembled supramolecular structures. The synthetic route takes advantage of solid-phase peptide synthesis with the on-resin coupling of the dithiolane precursor molecule, 3-(acetylthio)-2-(acetylthiomethyl)propanoic acid, and the microwave-assisted thioacetate deprotection of the peptide N-terminus before final cleavage from the resin to yield the 1,2-dithiolane modified peptide. After the high-performance liquid chromatography (HPLC) purification of the 1,2-dithiolane peptide, derived from the nucleating core of the A&#946; peptide associated with Alzheimer&#39;s disease, the peptide is shown to self-assemble into cross-&#946; amyloid fibers. Protocols to characterize the amyloid fibers by Fourier-transform infrared spectroscopy (FT-IR), circular dichroism spectroscopy (CD) and transmission electron microscopy (TEM) are presented. The methods of N-terminal modification with a 1,2-dithiolane moiety to well-characterized self-assembling peptides can now be explored as model systems to develop post-assembly modification strategies and explore dynamic covalent chemistry on supramolecular peptide nanofiber surfaces.

A protocol for the synthesis of a 1,2-dithiolane modified peptide and the characterization of the supramolecular structures resulting from the peptide self-assembly.