This work was funded by the Spanish Ministerio de Econom&#236;a y Competitividad (CTQ 2013-41067-P). H.B. acknowledge with thanks a MEC-FPI grant.

1. işlevselleştirilmesi 2,15-Dimethylhexahelicene <ol><li> 2,15-dimethylhexahelicene ve Dibromination <ol><li> % 30 benzoil peroksit (BPO) (% 70 0.356 g (1.0 mmol) 2,15-dimethylhexahelicene bölgesinin 0.374 g (2.1 mmol) yeni yeniden kristalize N-bromosuksinımid bölgesinin (NBS) ve 24 mg (0.07 mmol) ağırlıkça tartılır dengeleyici olarak su). Manyetik bir karıştırma çubuğuna sahip 100 ml&#39;lik bir Schlenk şişesi içinde, tüm katı maddeler yerleştirin. Schlenk hat atıl gaz ile doldurulması, ardından gazı tahliye üç döngü nitrojen atmosferi altında koyun. </li><li> Karbon tetraklorid ve 21 ml (CCl4) ekleyin. kuvvetlice karıştırarak, dikkatlice çözücünün büyük kaybını önlemek için aynı boşaltılmasıyla çözelti / işlem doldurma (aşama 1.1.1) gaz çıkışına. </li><li> geri akışta ısı (77 ° C) 4 saat boyunca bir yağ banyosu ile bir karışımı. 1H-Nükleer manyetik rezonans (NMR) reaksiyonu kontrol edin. 3.7 ppm ve 4.0 ppm sho arasındaki ikiliULD görünür. Gruplar (Şekil 1) - Bunlar diastereotopic -CH2 varlığını gösterir. </li><li> Bir kez işlenmiş oda sıcaklığına Karışım soğumaya bırakılmış ve çözücüyü vakum altında çıkarın. Pompa kirlenmesini önlemek için sıvı nitrojen dolu bir tuzak kurdu. </li><li> , 30 ml diklorometan (DCM), ham yeniden çözünmesine yuvarlak dipli bir şişeye aktarın ve silika jel ile 4 g karışımı (tipik olarak, ham ağırlık olarak 5 misli ekleme). Bir döner buharlaştırıcı içinde karışım konsantre edilir. </li><li> Mobil faz olarak arada, heksan / etil asetat (95: 5) ile, daha önce karıştırılmış SiO2 jel kolonu (uzunluk 20 cm civarında ve 4.5 cm kalınlığında) doldurun. kolonunun üstüne karışımı ekleyin ve kum (2 cm) bir katman ekleyin. </li><li> Dikkatli bir şekilde yeni mobil fazda dökün ve (tipik olarak tüp başına 20 ml ve beklenen ürün elüsyon yakınındaki 4 mi) test tüplerinde fraksiyonlar toplanarak kromatografisi gerçekleştirin. ince tabaka kromatografisi ile kontrol fraksiyonlarınve görüntü UV ışık altında Aynı mobil faz (5 heksan / etil asetat 95) ile (TLC). İstenen ürün (4b) döner buharlaştırıcı içerisinde çözücüden Tüm fraksiyonlar istediği birleştiren ve kapatma çıkarılmasından sonra sarı bir yağ olarak 0.35 bir tutma faktörü (Rf) olarak elüte gerekir. 334 mg (% 65 verim) elde edilmelidir. NOT: Tüm savurma teknikleri, şu andan itibaren bu kadar yaygın protokollerin en kullanılacaktır ısıtma ve kolon kromatografisi ayarları için bir yağ banyosu kullanımı, detaylı olarak ele alınacaktır olmayacak ve sadece bir kaç yorum, gerektiğinde olacak verilebilir. </li></ol></li></ol><img alt="Şekil 1" src="/files/ftp_upload/53954/53954fig1.jpg" /> . Şekil 1, 1 &#39;H-NMR spektrası (500 MHz, CDCI3) 2,15 arasında -dimethylhelicene (üstte) ve 2 saat sonra alınan bir kısım yeni sinyaller, 2 -CH karşılık -.., kırmızı bir daire (alt) olarak tasvir edilmektedir <a href="https://www.jove.com/files/ftp_upload/53954/53954fig1large.jpg" target="_blank">, bu rakamın büyük halini görmek için lütfen buraya tıklayınız.</a> <ol start="2"><li> 2,15-bis sentezi (azidometil) hexahelicene <ol><li> 2,15-bis (bromometil) hexahelicene ve sodyum azid 0.390 g (6 mmol) 0.103 g (0.2 mmol) tartılır. Manyetik çubuğu ile donatılmış ve azot atmosferi altına 50 ml&#39;lik bir Schlenk şişesi içinde iki katı yerleştirin. </li><li> Su, 5.2 ml (H2 O) ile tetrahidrofuran (THF) 8.6 ml karıştırın ve bir Schlenk şişesi içine çözücülerin dökün. çözüm Degas. </li><li> 3 saat geri akış sıcaklığına (65 ° C) ısıtın. 1H-NMR ile reaksiyonun kontrol edin. -CH 2 - sinyaller 3.75 ppm (Şekil 2) değişmeli. </li><li> Daha sonra, cooKarışımı, oda sıcaklığına aşağı l ve vakumda THF çıkarıldı. H2O, 50 ml ile seyreltin </li><li> bir ayırma hunisine aktarın ve karışım, 40 ml DCM ile üç kez ekstrakte edilir. Bütün organik fazlar bir araya getirin ve saf H2O (50 mi) ile yıkayın. </li><li> 2,15-bis (azomethyl) hexahelicene tekabül Rf = 0.38 bir sarı yağ vermek üzere, mobil faz olarak heksan / etil asetat (85:15) kullanılarak silis jel üzerinde kolon kromatografisiyle saflaştırmak suretiyle (5b). 70 mg (% 80 ürün) elde edilmelidir. </li></ol></li></ol><img alt="şekil 2" src="/files/ftp_upload/53954/53954fig2.jpg" /> Şekil 2: 1 &#39;H-NMR spektrası (500 MHz, CDCI3) 4 b (üst) ve bir kısım 3 saat sonra alınan(altta). alifatik bölgede değişiklikleri unutmayın. <a href="https://www.jove.com/files/ftp_upload/53954/53954fig2large.jpg" target="_blank">Bu rakamın büyük halini görmek için lütfen buraya tıklayınız.</a> Corannulene 2. işlevselleştirilmesi <ol><li> Corannulene bölgesinin Monobromination <ol><li> corannulene 0.125 g (0.5 mmol), taze yeniden kristalize NBS 89 mg (0.5 mmol) ve altın (III) klorür hidrat 17 mg tartılır. </li><li> 10 ml bütün bileşikler, özellikle manyetik bir çubuk ile donatılmış Mikrodalga reaksiyonları için tasarlanan ve daha sonra bir 2-boyunlu yuvarlak dipli bir reaksiyon yardımı ile bir azot atmosferi konulmuştur şişe yerleştirin. </li><li> 1,2-dikloroetan (DCE) ve gazını çözeltisi 7 ml ekleyin. </li><li> altın tuzu partikülleri dağıtmak için 2 dakika süreyle karışımın sonikasyon. </li><li> 2 saat boyunca 100 ° C&#39;de mikrodalga reaktör içindeki ısı. </li><li> Tamamlandığında, yuvarlak dipli bir şişeye, ham transferi ve Rötar çözücünün kaldırmay buharlaşma. </li><li> Mobil faz olarak heksan kullanılarak SiO2 jel üzerinde kolon kromatografisiyle saflaştırmak suretiyle. Not: Bromocorannulene (4a) Rf sarı bir katı olarak elde edilir = 0.38. 99 mg (% 60 ürün) elde edilmelidir. Reaksiyona girmeyen corannulene (3a) geri ve ileri kullanımlar için saklanabilir. Bu Rf görünür = 0.29. </li></ol></li><li> Bomocorannulene ve etinil-trimetil-Sonogashira birleştirilmesi <ol><li> Bromocorannulene 49 mg (0.15 mmol), [PdCl2 (dppf)] 49,50 (1,1-&#39;bis (diphenylphsphino) ferrosen, Cul 3 mg (0.015 mmol) olarak dppf 11 mg (0.015 mmol) tartılır. 51 </li><li> manyetik bir çubuk ile birlikte bir 50 ml&#39;lik bir Schlenk şişesi içinde, tüm katı maddeler yerleştirin ve nitrojen atmosferi altında koyun. </li><li> Trietilamin (3 NEt) 5.0 ml ekleyin ve karışımı degas. </li><li> Son olarak, etinil-trimetil-104 ul (0.75 mmol) ekleyin. </li><li> 2 dakika boyunca karışım sonikasyonmetal tuzu partikülleri dağıtılır. </li><li> Periyodik sese tabi tutularak 24 saat boyunca 85 ° C&#39;de ısı metal tuzlarının çökelmesini önlemek için. NOT: Karışım rengi paladyum (0) varlığını gösteren, yakında siyaha döndü. </li><li> Oda sıcaklığına soğutun ve vakum içinde NEt3 buharlaşır. </li><li> 20 ml DCM içinde yeniden çözünmesi ve heksan ile elüt edilerek silika jeli üzerinde sütun kromatografisi ile saflaştırılması 5a tekabül Rf = 0.28 bir sarı katı madde elde edilmiştir. 41 mg (% 78 verim) elde edilmelidir. Not: Ham DCM&#39;de bir Celite pedinden süzüldü ise, uygun bir saf bir örnek elde edilebilir, ancak fosfin türevleridir tamamen kaldırılır. </li></ol></li><li> TMS Korumanın Kaldırılması ile Ethynylcorannulene hazırlanması <ol><li> 5a, 35 mg (0.10 mmol) ve susuz potasyum fluorür 7.3 mg (0.125 mmol) tartılır. </li><li> Manyetik bir bar, ile donatılmış 50 ml&#39;lik bir Schlenk şişesi içinde, tüm katı maddeler yerleştirinazot atmosferi altında koymak d. </li><li> 4 ml THF ve metanol (MeOH) 4 ml karıştırın ve Schlenk şişesi içine dökün. İyice Degas. </li><li> , Oda sıcaklığında reaksiyona opak bir film ile kaplayıp ışıktan uzak şişeyi tutun izin verin. 3.48 ppm bakarak 1H-NMR tarafından reaksiyon kontrol. Ortaya zorundadır -CCH karşılık gelen bir sinyal (Şekil 3). NOT: Bu bileşik, reaktif ve kolayca ayrışan bir terminal alkin taşıyan, ancak aşağıda tarif edilen, çalışma sırasında herhangi bir sorun bulundu. Doğal ışık altında yürütülmüştür. </li><li> Bir kez işlenmiş, vakum altında THF çıkarıldı ve ayırıcı bir huniye her transfer 10 ml su ile seyreltilir. </li><li> DCM (3 x 15 mi) ile ekstrakte sonunda sarı bir katı 6a tekabül için oda sıcaklığında bir döner buharlaştırıcı içinde yuvarlak tabanlı bir şişe içinde Bütün organik fazlar bir araya ve konsantre edilir. 27 mg (kantitatif verim) elde edilmelidir. </li></ol></li></ol><img alt="Şekil 3," src="/files/ftp_upload/53954/53954fig3.jpg" /> Şekil 3:.. 1H-NMR spektrumları 5 a (üst) ve 6 a (alt) (500 MHz, CDC 3) -CCH tekli kırmızı bir daire içinde gösterilmektedir <a href="https://www.jove.com/files/ftp_upload/53954/53954fig3large.jpg" target="_blank">bu rakamın daha büyük bir versiyonunu görmek için lütfen buraya tıklayınız.</a> Click Kimya tarafından 3. Nihai Montaj <ol><li> CuSO 4 Askorbik asit sodyum tuzu 15.3 mg (0.035 mmol) 5b, 6a 20.0 mg (0.073 mmol), 1.4 mg (0.007 mmol), 1.7 mg (0.007 mmol), · 5H 2 O tartılır </li><li> am ile donatılmış 50 ml&#39;lik bir Schlenk şişesi içinde, tüm katı maddeler yerleştirinagnetic çubuğu ve azot atmosferi altında koyun. </li><li> 3, H2O ile yıkanır ve 12 mL THF karıştırın ve Schlenk şişesi içine dökün. iyice çözüm Degas. </li><li> Şişenin üst kısmına bağlı bir kondansatör 3 gün boyunca 65 ° C de ısı ve periyodik olarak sıcaklığın kontrol edilmesi için reaksiyonun kontrol karıştırıldıktan ve çözücü hacmi. 1H-NMR ile reaksiyonun kontrol edin. 3.48 ppm&#39;de sinyal kaybolur ve 7.27 ppm etinil corannulene tüketimini ve triazol birimin varlığını gösteren (Şekil 4) kaydırılabilir. </li><li> Tamamlandığında, vakum altında THF çıkarıldı ve ayırıcı bir huniye karışımı karıştırma, 20 ml su ile seyreltilir. </li><li> DCM (3 x 20 mi) ile ekstrakte edilmiş yuvarlak dipli bir reaksiyon kabı içinde Bütün organik fazlar bir araya ve bir döner buharlaştırıcı içinde konsantre edilir. </li><li> SiO ile kolon kromatografisiyle saflaştırmak 2 jeli heksan / etil asetat (1: 1) Rf, uçuk sarı bir katı verecek şekilde = 0.597 tekabül eder. 27 mg (% 75 ürün) elde edilmelidir. </li></ol><img alt="Şekil 4," src="/files/ftp_upload/53954/53954fig4.jpg" /> Şekil 4: 1 &#39;H-NMR spektrası (500 MHz, CDCI3) 5 B (üst), 6 (orta) ve 2 gün (alt) sonra alınan bir alikot HAM -CCH sinyalinin kaybolması dikkat edin.. <a href="https://www.jove.com/files/ftp_upload/53954/53954fig4large.jpg" target="_blank">, Lütfen Bu rakamın büyük halini görmek için buraya tıklayın.</a>

The authors have nothing to disclose.

Nihai bileşik 7 düzlemsel olmayan poliaromatik ön-6 Adım 3 a ve her reaksiyonda orta çok iyi verimlerle 3 b sonra hazırlanmıştır. Bu rota görülen başlıca sınırlama hem düzlemsel olmayan poliaromatik bileşiklerin bromination oldu. Bununla birlikte, bileşik 4 bir durumda, serbest corannulene önemli miktarda daha kullanımlar için geri kazanılabilir. 4 B</stron...

Kendi özel geometri, corannulene ve helicenes uzak düzlemsellikten bir yapının ve ilginç özelliklere yol açmaktadır. Son yıllarda 1-15 olabilir moleküllerdir nedeniyle, karbon nanotüpler ve fullerenler moleküler reseptörlerin arama çok aktif bir alandır 16-19 nedeniyle, ağırlıklı olarak, organik güneş pilleri, transistörler, sensörler ve diğer cihazlar için malzeme olarak potansiyel uygulamaları. 20-28 corannulene ve fullerenin arasında şekil mükemmel tamamlayıcılık tasarımı amacı ile çeşitli araştırmacıların dikkatini çekmiştir London kuvvetleri tarafından supramoleküler dernek kurma yeteneğine sahip moleküler reseptörler. 29-39 Yukarıda belirtilen düzlemsel olmayan poliaromatik bileşikler kimyası tamamen düzlemsel moleküller için tarif edilene benzer, ancak arzu edilen seçicilikler ve verimleri elde etmek için uygun koşullar bulmak bazen zor olabilir. 40 </sup&gt; Bu çalışmada her araştırma laboratuarında bulunan kolay ve tipik tekniklerin uygulanması ile iyi verimler ile birkaç adımda üç poliaromatik birimlerine sahip bir molekül (7) &#39;in sentezini sunar. Bu çözelti içinde, C 60 37 ile iyi bir etkileşim kurmak için bir kıskaç benzeri yapıyı alabilir molekülü büyük bir öneme sahiptir; ve bunun nedeni, bir stereojenik ekseninin varlığı için bir kiral molekül helicene bağlayıcı, daha yüksek şiral fulleren sayesinde potansiyel bir reseptör olarak bir araştırma çizgisini açabilir. 41-45 Ancak, yalnızca rasemik helicene bu çalışmada kullanılır. Ticari olarak mevcut olmadıklarında, çünkü, bu noktada, bu reseptörleri sentez tek sınırlama, helicenes ve corannulenes hazırlanmasıdır. Ancak, yeni yöntemlere uygun olarak, zaman, makul bir kısa bir süre içinde uygun miktarlarda elde edilebilir 46-48 başka bir yerde yayımlandığı.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>2,15-Dimethylhexahelicene</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Prepared according to reference 5b,c in the main text.</td>
		</tr>
		<tr>
			<td>Corannulene</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Prepared according to reference 5a in the main text.</td>
		</tr>
		<tr>
			<td>N-Bromosuccinimide (NBS)</td>
			<td>Sigma Aldrich</td>
			<td>B8.125-5</td>
			<td>ReagentPlus&#174;, 99%. Recrystallized from hot water.</td>
		</tr>
		<tr>
			<td>Benzoyl peroxide (BPO)</td>
			<td>Sigma Aldrich</td>
			<td>B-2030</td>
			<td>~70% (titration). 30% water as stabilizer.</td>
		</tr>
		<tr>
			<td>Sodium azide</td>
			<td>Sigma Aldrich</td>
			<td>S2002</td>
			<td>ReagentPlus&#174;, &#8805;99.5%.</td>
		</tr>
		<tr>
			<td>Gold (III) chloride Hydrate</td>
			<td>Sigma Aldrich</td>
			<td>50778</td>
			<td>puriss. p.a., ACS reagent, &#8805;49% Au basis.</td>
		</tr>
		<tr>
			<td>Ethynyltrimethylsilane</td>
			<td>Sigma Aldrich</td>
			<td>218170</td>
			<td>98%.</td>
		</tr>
		<tr>
			<td>[PdCl2(dppf)]</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Prepared according to reference 6 in the main text.</td>
		</tr>
		<tr>
			<td>CuI</td>
			<td>N/A</td>
			<td>N/A</td>
			<td>Prepared according to reference 7 in the main text.</td>
		</tr>
		<tr>
			<td>KF</td>
			<td>Sigma Aldrich</td>
			<td>307599</td>
			<td>99%, spray-dried.</td>
		</tr>
		<tr>
			<td>(+)-Sodium L-ascorbate</td>
			<td>Fluka</td>
			<td>11140</td>
			<td>BioXtra, &#8805;99.0% (NT).</td>
		</tr>
		<tr>
			<td>Copper(II) Sulphate 5-hydrate</td>
			<td>Panreac</td>
			<td>131270</td>
			<td>for analysis.</td>
		</tr>
		<tr>
			<td>Carbon tetrachloride (CCl4)</td>
			<td>Fluka</td>
			<td>87030</td>
			<td>for IR spectroscopy, &#8805;99.9%.</td>
		</tr>
		<tr>
			<td>Dichloromethane (DCM)</td>
			<td>Fisher Scientific</td>
			<td>D/1852/25</td>
			<td>Analytical reagent grade. Distilled prior to use.</td>
		</tr>
		<tr>
			<td>Hexane</td>
			<td>Fisher Scientific</td>
			<td>H/0355/25</td>
			<td>Analytical reagent grade. Distilled prior to use.</td>
		</tr>
		<tr>
			<td>Ethyl acetate</td>
			<td>Scharlau</td>
			<td>AC0145025S</td>
			<td>Reagent grade. Distilled prior to use.</td>
		</tr>
		<tr>
			<td>Tetrahydrofuran (THF)</td>
			<td>Fisher Scientific</td>
			<td>T/0701/25</td>
			<td>Analytical reagent grade. Distilled prior to use.</td>
		</tr>
		<tr>
			<td>1,2-Dichloroethane (DCE)</td>
			<td>Sigma Aldrich</td>
			<td>D6,156-3</td>
			<td>ReagentPlus&#174;, 99%.</td>
		</tr>
		<tr>
			<td>Methanol (MeOH)</td>
			<td>VWR</td>
			<td>20847.36</td>
			<td>AnalaR NORMAPUR.</td>
		</tr>
		<tr>
			<td>Triethyl amine (NEt3)</td>
			<td>Sigma Aldrich</td>
			<td>T0886</td>
			<td>&#8805;99%.</td>
		</tr>
		<tr>
			<td>Silica gel</td>
			<td>Acros</td>
			<td>360050010</td>
			<td>Particle size 40-60mm.</td>
		</tr>
		<tr>
			<td>Sand - low iron</td>
			<td>Fisher Scientific</td>
			<td>S/0360/63</td>
			<td>General purpose grade.</td>
		</tr>
		<tr>
			<td>TLC Silica gel 60 F254</td>
			<td>Merck</td>
			<td>1.05554.0001</td>
			<td></td>
		</tr>
		<tr>
			<td>Monowave 300 (Microwave reactor)</td>
			<td>Anton Para</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sonicator</td>
			<td>Grupo Selecta</td>
			<td>3000513</td>
			<td>6 Litres.</td>
		</tr>
	</tbody>
</table>

preparation of a corannulene-functionalized hexahelicene by copper(i)-catalyzed alkyne-azide cycloaddition of nonplanar polyaromatic units

The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar polyaromatic units, which are two corannulene moieties and a racemic hexahelicene linking them. The compound described in this work is a good host for fullerenes. Several common organic reactions, such as free-radical reactions, C-C coupling or click chemistry, are employed demonstrating the versatility of functionalization that this compound can accept. All of these reactions work for planar aromatic molecules. With subtle modifications, it is possible to achieve similar results for nonplanar polyaromatic compounds.

Corannulene (3 a) ve 2,15-dimethylhexahelicene (3 b) çok iyi verimlerle (Şekil 5) ile birlikte basit bir şekilde mevcut yöntemlerin 46-48 Aşağıdaki hazırlanabilir. Hem nihai molekülün yakınsak sentez için farklı yol açan, başlangıç ​​malzemesi olarak, ortak bir molekülü, 2,7-dimetilnaftalen paylaşır. <im...

Watch this Scientific Journal Video about Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units at JoVE.com

Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

Burada, uygun verimlerle kolay monte üç düzlemsel olmayan poliaromatik ünitelerinden oluşan karmaşık bir organik bileşik, sentezi için bir protokol mevcut.

Bakır (I) &#39;in bir Corannulene-işlevselleştirilmiş Hexahelicene hazırlanması düzlemsel olmayan Poliaromatik Birimleri alkin azid siklo, paladyum

The main purpose of this video is to show 6 reaction steps of a convergent synthesis and prepare a complex molecule containing up to three nonplanar ...

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Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

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11.4K Görüntüleme.  Universidad de Valladolid.  Burada, uygun verimlerle kolay monte üç düzlemsel olmayan poliaromatik ünitelerinden oluşan karmaşık bir organik bileşik, sentezi için bir protokol mevcut. 

Video: Preparation of a Corannulene-functionalized Hexahelicene by CopperI-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units

Preparation and Use of Samarium Diiodide (SmI2) in Organic Synthesis: The Mechanistic Role of HMPA and Ni(II) Salts in the Samarium Barbier Reaction

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of molecular iodine to samarium metal in THF.1,2-3 It is a mild and selective single electron reductant and its versatility is a result of its ability to initiate a wide range of reductions including C-C bond-forming and cascade or sequential reactions. SmI2 can reduce a variety of functional groups including sulfoxides and sulfones, phosphine oxides, epoxides, alkyl and aryl halides, carbonyls, and conjugated double bonds.2-12 One of the fascinating features of SmI-2-mediated reactions is the ability to manipulate the outcome of reactions through the selective use of cosolvents or additives. In most instances, additives are essential in controlling the rate of reduction and the chemo- or stereoselectivity of reactions.13-14 Additives commonly utilized to fine tune the reactivity of SmI2 can be classified into three major groups: (1) Lewis bases (HMPA, other electron-donor ligands, chelating ethers, etc.), (2) proton sources (alcohols, water etc.), and (3) inorganic additives (Ni(acac)2, FeCl3, etc).3
Understanding the mechanism of SmI2 reactions and the role of the additives enables utilization of the full potential of the reagent in organic synthesis. The Sm-Barbier reaction is chosen to illustrate the synthetic importance and mechanistic role of two common additives: HMPA and Ni(II) in this reaction. The Sm-Barbier reaction is similar to the traditional Grignard reaction with the only difference being that the alkyl halide, carbonyl, and Sm reductant are mixed simultaneously in one pot.1,15 Examples of Sm-mediated Barbier reactions with a range of coupling partners have been reported,1,3,7,10,12 and have been utilized in key steps of the synthesis of large natural products.16,17 Previous studies on the effect of additives on SmI2 reactions have shown that HMPA enhances the reduction potential of SmI2 by coordinating to the samarium metal center, producing a more powerful,13-14,18 sterically encumbered reductant19-21 and in some cases playing an integral role in post electron-transfer steps facilitating subsequent bond-forming events.22 In the Sm-Barbier reaction, HMPA has been shown to additionally activate the alkyl halide by forming a complex in a pre-equilibrium step.23
Ni(II) salts are a catalytic additive used frequently in Sm-mediated transformations.24-27 Though critical for success, the mechanistic role of Ni(II) was not known in these reactions. Recently it has been shown that SmI2 reduces Ni(II) to Ni(0), and the reaction is then carried out through organometallic Ni(0) chemistry.28
These mechanistic studies highlight that although the same Barbier product is obtained, the use of different additives in the SmI2 reaction drastically alters the mechanistic pathway of the reaction. The protocol for running these SmI2-initiated reactions is described.

Preparation and Use of Samarium Diiodide SmI2 in Organic Synthesis: The Mechanistic Role of HMPA and NiII Salts in the Samarium Barbier Reaction

A straightforward procedure for the preparation of samarium diiodide (SmI2) in THF is described. The role of two main additives namely hexamethylphosphoramide (HMPA) and Ni(acac)2 in Sm mediated reactions is demonstrated in the Sm-Barbier reaction.

Hazırlanması ve Samaryum Diiodide Kullanımı (SMI<sub&gt; 2</sub&gt;) In Organic Synthesis: Samaryum Barbier Reaksiyonu HMPA ve Ni (II) tuzlarının Mekanistik Rolü

Although initially considered an esoteric reagent, SmI2 has become a common tool for synthetic organic chemists. SmI2 is generated through the addition of ...

Kimya

Isolation and Preparation of Bacterial Cell Walls for Compositional Analysis by Ultra Performance Liquid Chromatography

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the face of turgor pressures several atmospheres in magnitude. Across the diverse shapes and sizes of the bacterial kingdom, the cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by short peptides. Peptidoglycan&#8217;s central importance to bacterial physiology underlies its use as an antibiotic target and has motivated genetic, structural, and cell biological studies of how it is robustly assembled during growth and division. Nonetheless, extensive investigations are still required to fully characterize the key enzymatic activities in peptidoglycan synthesis and the chemical composition of bacterial cell walls. High Performance Liquid Chromatography (HPLC) is a powerful analytical method for quantifying differences in the chemical composition of the walls of bacteria grown under a variety of environmental and genetic conditions, but its throughput is often limited. Here, we present a straightforward procedure for the isolation and preparation of bacterial cell walls for biological analyses of peptidoglycan via HPLC and Ultra Performance Liquid Chromatography (UPLC), an extension of HPLC that utilizes pumps to deliver ultra-high pressures of up to 15,000 psi, compared with 6,000 psi for HPLC. In combination with the preparation of bacterial cell walls presented here, the low-volume sample injectors, detectors with high sampling rates, smaller sample volumes, and shorter run times of UPLC will enable high resolution and throughput for novel discoveries of peptidoglycan composition and fundamental bacterial cell biology in most biological laboratories with access to an ultracentrifuge and UPLC.

The bacterial cell wall is composed of peptidoglycan, a macromolecular network of sugar strands crosslinked by peptides. Ultra Performance Liquid Chromatography provides high resolution and throughput for novel discoveries of peptidoglycan composition. We present a procedure for the isolation of cell walls (sacculi) and their subsequent preparation for analysis via UPLC.

Ultra Performanslı Sıvı Kromatografisi ile Bileşimsel Analiz için Bakteriyel Hücre Duvarlarının İzolasyonu ve Hazırlanması

The bacterial cell wall is critical for the determination of cell shape during growth and division, and maintains the mechanical integrity of cells in the ...

Real-time Monitoring of Reactions Performed Using Continuous-flow Processing: The Preparation of 3-Acetylcoumarin as an Example

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible to ensure consistent product quality over time using this technique. We here show how to interface a commercially available flow unit with a Raman spectrometer. The Raman flow cell is placed after the back-pressure regulator, meaning that it can be operated at atmospheric pressure. In addition, the fact that the product stream passes through a length of tubing before entering the flow cell means that the material is at RT. It is important that the spectra are acquired under isothermal conditions since Raman signal intensity is temperature dependent. Having assembled the apparatus, we then show how to monitor a chemical reaction, the piperidine-catalyzed synthesis of 3-acetylcoumarin from salicylaldehyde and ethyl acetoacetate being used as an example. The reaction can be performed over a range of flow rates and temperatures, the in-situ monitoring tool being used to optimize conditions simply and easily.

Real-time monitoring allows for fast optimization of reactions performed using continuous-flow processing. Here the preparation of 3-acetylcoumarin is used as an example. The apparatus for performing in-situ Raman monitoring is described, as are the steps required to optimize the reaction.

Sürekli akış İşleme kullanma Gerçekleştirilen Reaksiyonları Gerçek zamanlı izleme: Bir Örnek olarak 3-Acetylcoumarin Hazırlanması

By using inline monitoring, it is possible to optimize reactions performed using continuous-flow processing in a simple and rapid way. It is also possible ...

Preparation and Characterization of Individual and Multi-drug Loaded Physically Entrapped Polymeric Micelles

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar concentration forming hydrophobic cores surrounded by hydrophilic shells in aqueous environments. The core of these micelles can be utilized to load hydrophobic, poorly water soluble drugs like docetaxel (DTX) and everolimus (EVR). Systematic characterization of the micelle structure and drug loading capabilities are important before in vitro and in vivo studies can be conducted. The goal of the protocol described herein is to provide the necessary characterization steps to achieve standardized micellar products. DTX and EVR have intrinsic solubilities of 1.9 and 9.6 &#181;g/ml respectively Preparation of these micelles can be achieved through solvent casting which increases the aqueous solubility of DTX and EVR to 1.86 and 1.85 mg/ml, respectively. Drug stability in micelles evaluated at room temperature over 48 hr indicates that 97% or more of the drugs are retained in solution. Micelle size was assessed using dynamic light scattering and indicated that the size of these micelles was below 50 nm and depended on the molecular weight of the polymer. Drug release from the micelles was assessed using dialysis under sink conditions at pH 7.4 at 37 oC over 48 hr. Curve fitting results indicate that drug release is driven by a first order process indicating that it is diffusion driven.

The goal of this protocol is to describe the preparation and characterization of physically entrapped, poorly water soluble drugs in micellar drug delivery systems composed of amphiphilic block copolymers.

Hazırlanması ve Bireysel Karakterizasyonu ve Multi-ilaç Fiziksel, polimerik misellerin Entrapped Loaded

Amphiphilic block copolymers like polyethyleneglycol-block-polylactic acid (PEG-b-PLA) can self-assemble into micelles above their critical micellar ...

Facile Preparation of Internally Self-assembled Lipid Particles Stabilized by Carbon Nanotubes

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled (functionalized) CNTs are used as stabilizers to produce Pickering type oil-in-water (O/W) emulsions. Lipids namely, Dimodan U and Phytantriol are used as emulsifiers, which in excess water self-assemble into the bicontinuous cubic Pn3m phase. This highly viscous phase is fragmented into smaller particles using a probe ultrasonicator in presence of conventional surfactant stabilizers or CNTs as done here. Initially, the CNTs (powder form) are dispersed in water followed by further ultrasonication with the molten lipid to form the final emulsion. During this process the CNTs get coated with lipid molecules, which in turn are presumed to surround the lipid droplets to form a particulate emulsion that is stable for months. The average size of CNT-stabilized nanostructured lipid particles is in the submicron range, which compares well with the particles stabilized using conventional surfactants. Small angle X-ray scattering data confirms the retention of the original Pn3m cubic phase in the CNT-stabilized lipid dispersions as compared to the pure lipid phase (bulk state). Blue shift and lowering of the intensities in characteristic G and G&#39; bands of CNTs observed in Raman spectroscopy characterize the interaction between CNT surface and lipid molecules. These results suggest that the interactions between the CNTs and lipids are responsible for their mutual stabilization in aqueous solutions. As the concentrations of CNTs employed for stabilization are very low and lipid molecules are able to functionalize the CNTs, the toxicity of CNTs is expected to be insignificant while their biocompatibility is greatly enhanced. Hence the present approach finds a great potential in various biomedical applications, for instance, for developing hybrid nanocarrier systems for the delivery of multiple functional molecules as in combination therapy or polytherapy.

We report on a smart application of carbon nanotubes for kinetic stabilization of lipid particles that contain self-assembled nanostructures in their cores. The preparation of lipid particles requires rather low concentrations of carbon nanotubes permitting their use in biomedical applications such as drug delivery.

Karbon Nanotüpler tarafından Stabilize İçeriden Kendinden monte Lipid Parçacıklar uyduruk hazırlanması

We present a facile method to prepare nanostructured lipid particles stabilized by carbon nanotubes (CNTs). Single-walled (pristine) and multi-walled ...

Preparation of Macroporous Epitaxial Quartz Films on Silicon by Chemical Solution Deposition

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step process based on the preparation of a sol in a one-pot synthesis which is followed by the deposition of a gel film on Si(100) substrates by evaporation induced self-assembly using the dip-coating technique and ends with a thermal treatment of the material to induce the gel crystallization and the growth of the quartz film. The formation of a silica gel is based on the reaction of a tetraethyl orthosilicate and water, catalyzed by HCl, in ethanol. However, the solution contains two additional components that are essential for preparing mesoporous epitaxial quartz films from these silica gels dip-coated on Si. Alkaline earth ions, like Sr2+ act as glass melting agents that facilitate the crystallization of silica and in combination with cetyl trimethylammonium bromide (CTAB) amphiphilic template form a phase separation responsible of the macroporosity of the films. The good matching between the quartz and silicon cell parameters is also essential in the stabilization of quartz over other SiO2 polymorphs and is at the origin of the epitaxial growth.

A protocol is presented for the preparation of piezoelectric macroporous epitaxial films of quartz on silicon by solution chemistry using dip-coating and thermal treatments in air.

Kimyasal Çözüm Biriktirme tarafından Silisyum üzerinde Makrogözenekli Epitaksiyel Kuvars Filmlerin Hazırlanması

This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step ...

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by &#960;-&#960; Stacking Interactions

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE). Characterization of the copolymer revealed a narrow molecular distribution (PDI &#60; 1.03) and confirmed the degree of polymerization of mPEG122-b-(PheGE)15. The critical micelle concentration of the copolymer was evaluated using an established fluorescence method with the aggregation behavior evaluated by dynamic light scattering and transmission electronic microscopy. The potential of the copolymer for use in drug delivery applications was evaluated in a preliminary manner including in vitro biocompatibility, loading and release of the hydrophobic anti-cancer drug doxorubicin (DOX). A stable micelle formulation of DOX was prepared with drug loading levels up to 14% (wt%), drug loading efficiencies &#62; 60% (w/w) and sustained release of drug over 4 days under physiologically relevant conditions (acidic and neutral pH, presence of albumin). The high drug loading level and sustained release is attributed to stabilizing &#960;-&#960; interactions between DOX and the core-forming block of the micelles.

The key steps of living anionic polymerization of phenyl glycidyl ether (PheGE) on methoxy-polyethylene glycol (mPEG-b-PPheGE) are described. The resulting block copolymer micelles (BCMs) were loaded with doxorubicin 14% (wt%) and sustained release of drug over 4 days under physiologically relevant conditions was obtained.

π-π İstifleme etkileşimlerle Stabilize blok kopolimer miselleri hazırlanması için bir amfifilik kopolimerin anyonik polimerizasyonu

In this study, an amphiphilic copolymer that includes a core-forming block with phenyl groups was synthesized by living anionic polymerization of phenyl ...

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)

We present herein the optimized synthesis of a triphosphenium bromide salt. Apart from being a versatile metathesis reagent, this unusually stable low-valent-phosphorus-containing compound acts as a useful P+ transfer agent. Unlike traditional methods employed to access low-coordinate phosphorus species which usually require pyrophoric phosphorus-containing precursors (white phosphorus, Tris(trimethylsilyl)phosphine, etc.), or harsh reducing agents (alkali metals, potassium graphite, etc.), the current approach does not involve pyrophoric or explosive reagents and can be done on large scales (&#62;20 g) in excellent yields by undergraduates with basic air-free synthetic training. The bromide counter ion is readily exchanged with other anions such as tetraphenyl borate (described herein) using typical salt metathesis reagents to obtain materials with desired properties and reactivities. The versatility of this P+ transfer approach is exemplified by the reactions of these triphosphenium precursors with an N-heterocyclic carbene and an anionic bisphosphine, each of which readily displace the neutral bisphosphine to give an NHC-stabilized phosphorus(I) cation and a phosphorus(I) containing zwitterion, respectively.

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI

The synthesis of a triphosphenium bromide salt is described and its use as a P+ transfer agent is outlined by reactions with an N-heterocyclic carbene and an anionic bisphosphine, yielding an NHC-stabilized P(I) cation and a P(I) containing zwitterion, respectively.

Bir Triphosphenium Bromür Tuz Hazırlanması ve Tepkime: Fosfor A Rahat ve kararlı Kaynak (I)

We present herein the optimized synthesis of a triphosphenium bromide salt. Apart from being a versatile metathesis reagent, this unusually stable ...

Preparation and Evaluation of 99mTc-labeled Tridentate Chelates for Pre-targeting Using Bioorthogonal Chemistry

Pre-targeting combined with bioorthogonal chemistry is emerging as an effective way to create new radiopharmaceuticals. Of the methods available, the inverse electron demand Diels-Alder (IEDDA) cycloaddition between a radiolabeled tetrazines and trans-cyclooctene (TCO) linked to a biomolecule has proven to be a highly effective bioorthogonal approach to imaging specific biological targets. Despite the fact that technetium-99m remains the most widely used isotope in diagnostic nuclear medicine, there is a scarcity of methods for preparing 99mTc-labeled tetrazines. Herein we report the preparation of a family of tridentate-chelate-tetrazine derivatives and their Tc(I) complexes. These hitherto unknown compounds were radiolabeled with 99mTc using a microwave-assisted method in 31% to 83% radiochemical yield. The products are stable in saline and PBS and react rapidly with TCO derivatives in vitro. Their in vivo pre-targeting abilities were demonstrated using a TCO-bisphosphonate (TCO-BP) derivative that localizes to regions of active bone metabolism or injury. In murine studies, the 99mTc-tetrazines showed high activity concentrations in knees and shoulder joints, which was not observed when experiments were performed in the absence of TCO-BP. The overall uptake in non-target organs and pharmacokinetics varied greatly depending on the nature of the linker and polarity of the chelate.

Preparation and Evaluation of 99mTc-labeled Tridentate Chelates for Pre-targeting Using Bioorthogonal Chemistry

Here, we describe a protocol for radiolabeling and in vivo testing of tridentate 99mTc(I) chelate-tetrazine derivatives for pre-targeting and bioorthogonal chemistry.

Hazırlama ve Değerlendirilmesi<sup&gt; 99m</sup&gt; Bioorthogonal Kimya Kullanarak Öncesi hedeflemek için üç dişli Şelatlar Tc-etiketli

Pre-targeting combined with bioorthogonal chemistry is emerging as an effective way to create new radiopharmaceuticals. Of the methods available, the ...

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that derive from initial 2-bromo-2-butene lithiation followed by acid mediated dienol cyclization. The revised synthesis and purification of the ligand avoids the use of mechanical stirring while still permitting access to significant quantities (39 g) of Cp*H in good yield (58%). The procedure offers other additional benefits, including a more controlled quench of excess lithium during the production of the intermediate heptadienols and a simplified isolation of Cp*H of sufficient purity for metallation with transition metals. The ligand was subsequently used to synthesize [Cp*MCl2]2 complexes of both iridium and ruthenium to demonstrate the utility of the Cp*H prepared and purified by our method. The procedure outlined herein affords substantial quantities of a ubiquitous ancillary ligand support used in organometallic chemistry while minimizing the need for specialized laboratory equipment, thus providing a simpler and more accessible entry point into the chemistry of 1,2,3,4,5-pentamethylcyclopentadiene.

Reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented. The revised protocol for the synthesis and purification of the ligand minimizes the need for specialized laboratory equipment while simplifying reaction workups and product purification. Use of Cp*H in the synthesis of [Cp*MCl2]2 complexes (M = Ru, Ir) is also described.

Değerli Ligand Erişme Geçiş Metaller için altlıklar: 1,2,3,4,5-Pentamethylcyclopentadiene bir Modifiye, Ara Ölçeği Hazırlık

A reliable, intermediate scale preparation of 1,2,3,4,5-pentamethylcyclopentadiene (Cp*H) is presented, based on modifications of existing protocols that ...

Bakır (I) 'in bir Corannulene-işlevselleştirilmiş Hexahelicene hazırlanması düzlemsel olmayan Poliaromatik Birimleri alkin azid siklo, paladyum

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Hazırlanması ve Samaryum Diiodide Kullanımı (SMI