Yazarların açıklayacak bir şeyi yok.

Dikkat: Kullanmadan önce lütfen ilgili tüm malzeme güvenlik bilgi formlarına (MSDS) başvurun. Tüm çapraz bağlanma reaksiyonları, kapalı bir argon atmosferi altında (1 atm) şişelerde yapılmalıdır. 1. Allyl Asetat ile Akrilamidlerin Olefinasyonu ile Butadienlerin Hazırlanması <ol><li> Uyumlu bir manyetik karıştırma çubuğuna sahip vidalı kapaklı bir şişeyi (8 mL) 120 ° C&#39;de fırında 2 saatten fazla kurutun. Kullanmadan önce ateşli flakonu üfleyerek oda sıcaklığına soğutun. </li><li> Analitik bir balans kullanın ve 3.7 mg (~ 3 mol%, 0.005 mmol) [Ru ( p- simen) Cl2] 2 (kahverengi toz) ve 13.7 mg (% 20 mol, 0.04 mmol) AgSbF6 Katı) yukarıdaki reaksiyon şişesine ilave edin. NOT: Bu yeni bir metodolojidir, çapraz kuplaj reaksiyonları atık oluşumunu azaltmak için konsept ispatı için küçük bir ölçekte yapılmıştır. AgSbF 6 , bir klorürü oluşturmak üzere klorürü soyabilen bir katkı maddesi olarak kullanılır.Elektrofilik CH bağ aktivasyonu için katyonik rutenyum kompleksi 13 . Ag2C03 gibi diğer gümüş tuzları da test edilmiştir, ancak ürün saptanmamıştır. Katalizörün ağırlığı ([Ru ( p- simen) Cl2] 2 ) çok doğru değildir ve 3.4-3.9 mg aralığındadır. </li><li> Reaksiyon şişesine 1 mL kuru 1,2-dikloroetan ilave edin. NOT: Çözücü miktarı esnektir-1 mL 1,2-dikloroetan, çapraz bağlanma reaksiyonu için minimum hacim hacmini karşılamak için yeterlidir. Bununla birlikte, bu ölçeğin reaksiyonu için biraz daha (~ 0.1 mL) çözücü de izin verilir. 1,2-dikloroetan, kullanımdan önce 3-A&#39;lik bir moleküler elek üzerinde kurutulmuştur. </li><li> Analitik bir balans kullanın ve yukarıdaki reaksiyon şişesine akrilamit (0,2 mmol, 1.0 eşdeğer katı veya yağ) ekleyin. </li><li> 43 μL (0.4 mmol, 2.0 eşdeğer) allil asetat (renksiz bir sıvı) eklemek için bir mikro-şırınga kullanın. <br/&gt; NOT: Burada, akrilamidin homo-eşlenmesini engellemek ve akrilamidin tamamen dönüştürülmesini sağlamak için aşırı miktarda allil asetata ihtiyaç duyulmaktadır. Daha az alil asetat (1.5 eşdeğer) eklendiğinde, ürün verimi düşer. Daha fazla alil asetat (3.0 eşdeğer) ilavesi, verimi daha da iyileştiremez. Uygulamada, allil asetatın homo-birleşimi gözlemlenmemiştir ve kalan alil asetat geri kazanılabilir. </li><li> Reaksiyon şişesini argon gazı ile hafifçe üfleyin ve şişeyi mümkün olan en kısa sürede uyumlu bir vidalı kapakla örtün. NOT: Flakon mümkün olduğunca çabuk bir vidalı kapakla örtülmelidir çünkü çapraz bağlanma reaksiyonu için atıl bir atmosfer önemlidir. Yukarıdaki protokolü bir eldiven kutusunda yapmak daha iyidir. </li><li> Reaksiyon karışımını ilave bir 5 dakika boyunca oda sıcaklığında karıştırın. </li><li> Reaksiyon şişesini bir yağ banyosu içinde 16-18 saat karıştırarak 110 ° C&#39;ye ısıtın. NOT: Genellikle, koyu kırmızıya renk değişikliği indBu reaksiyonun gerçekleştiği anlamına gelir. </li><li> Şişeyi soğuttuktan sonra, çözeltinin etil asetat: petrol eteri (2: 1 veya 1: 3) karışımlarını kullanarak karışımın bir akrilamit standardıyla karşılaştırılarak reaksiyonun ilerlemesini izlemek için ince tabakalı kromatografi (TLC) plakaları geliştirin . NOT: Başlangıç ​​materyalinin niteliğine bağlı olarak, reaksiyon tamamlanmayabilir. Ürünlerin ve başlangıç ​​malzemelerinin tipik Rf değerleri 0,3-0,7 aralığındadır. Akrilamid başlangıç ​​malzemesi bütadien ürününden daha düşük bir çalışma noktası olarak gözlemlenmiştir. </li><li> Ham ürünü en az DCM&#39;de eritin ve onu petrol eteri ile ıslak bir silika sütunun üzerine koyun. Çapraz bağlayıcı ürün , eluent olarak bir etil asetat: petrol eteri (1: 100 ila 1: 4) karışımı kullanılarak kolon kromatografisiyle ayrılır. <ol><li> Ayrıştırıcıyı ayrı bir şişe içerisinde toplayın, çözücüyü bir döner buharlaştırıcıda buharlaştırın veD 2 saat boyunca yüksek vakum altına yerleştirin. </li><li> NMR spektroskopisi ile karakterizasyon için yaklaşık 20-50 mg ürün elde edin. NOT: Tepkime karışımı doğrudan reaksiyon tamamlandıktan sonra saflaştırma için sütun kromatografisine uygulanmalıdır. </li></ol></li></ol> 2. Dienamidlerin Karakterizasyonu <ol><li> 1 H ve 13 C NMR spektroskopisini kullanarak nihai ürünün saflığını karakterize edin ve değerlendirin 14 . Tipik olarak, karbonil karbonun kimyasal kayması 13 C NMR spektrumunda 170 ppm civarında gözükmektedir. Butadien fonksiyonel grubunun üç sp 2 protonu 6.0 ve 5.6 ppm civarında karakteristik pikler ile temsil edilmektedir. </li><li> Dien ürününün karakteristik karbonil ve CC çift bağ pikini tanımlamak için kızılötesi spektroskopiyi 14 kullanın. </li><li> Ürünün moleküler kütlesini belirleyin ve yüksek tayf kullanılarak kimliğini doğrulayın.Çözünürlüklü Kütle Spektrometresi (HRMS) 14 . </li><li> Katı ürünlerin erime noktalarını belirleyin 14 . </li></ol>

<ol>
	<li>Negishi, E., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+Advances+in+Efficient+and+Selective+Synthesis+of+Di-,+Tri-,+and+Tetrasubstituted+Alkenes+via+Pd-Catalyzed+Alkenylation-Carbonyl+Olefination+Synergy.">Recent Advances in Efficient and Selective Synthesis of Di-, Tri-, and Tetrasubstituted Alkenes via Pd-Catalyzed Alkenylation-Carbonyl Olefination Synergy.</a> Acc Chem Res. 41 (11), 1474-1485 (2008).</li><li>Maryanoff, B. E., Reitz, A. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Wittig+olefination+reaction+and+modifications+involving+phosphoryl-stabilized+carbanions.+Stereochemistry,+mechanism,+and+selected+synthetic+aspects.">The Wittig olefination reaction and modifications involving phosphoryl-stabilized carbanions. Stereochemistry, mechanism, and selected synthetic aspects.</a> Chem Rev. 89 (4), 863-927 (1989).</li><li>Stille, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Palladium-Catalyzed+Cross-Coupling+Reactions+of+Organotin+Reagents+with+Organic+Electrophiles.">The Palladium-Catalyzed Cross-Coupling Reactions of Organotin Reagents with Organic Electrophiles.</a> Angew Chem Int Ed. 25 (6), 508-524 (1986).</li><li>Zhang, Y., Cui, Z., Li, Z., Liu, Z. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pd(II)-Catalyzed+Dehydrogenative+Olefination+of+Vinylic+C-H+Bonds+with+Allylic+Esters:+General+and+Selective+Access+to+Linear+1,3-Butadienes.">Pd(II)-Catalyzed Dehydrogenative Olefination of Vinylic C-H Bonds with Allylic Esters: General and Selective Access to Linear 1,3-Butadienes.</a> Org Lett. 14 (7), 1838-1841 (2012).</li><li>Shang, X., Liu, Z. Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transition+metal-catalyzed+Cvinyl-Cvinyl+bond+formation+via+double+Cvinyl-H+bond+activation.">Transition metal-catalyzed Cvinyl-Cvinyl bond formation via double Cvinyl-H bond activation.</a> Chem Soc Rev. 42 (8), 3253-3260 (2013).</li><li>Hu, X. H., Yang, X. F., Loh, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Alkenylation+and+Hydroalkenylation+of+Enol+Phosphates+through+Direct+C-H+Functionalization.">Selective Alkenylation and Hydroalkenylation of Enol Phosphates through Direct C-H Functionalization.</a> Angew Chem Int Ed. 54 (51), 15535-15539 (2015).</li><li>Kong, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cobalt+(III)-Catalyzed+C-C+Coupling+of+Arenes+with+7-Oxabenzonorbornadiene+and+2-Vinyloxirane+via+C-H+Activation.">Cobalt (III)-Catalyzed C-C Coupling of Arenes with 7-Oxabenzonorbornadiene and 2-Vinyloxirane via C-H Activation.</a> Org Lett. 18 (15), 3802-3805 (2016).</li><li>Feng, C., Feng, D., Loh, T. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rhodium+(III)-catalyzed+C-H+allylation+of+electron-deficient+alkenes+with+allyl+acetates.">Rhodium (III)-catalyzed C-H allylation of electron-deficient alkenes with allyl acetates.</a> Chem Commun. 51 (2), 342-345 (2015).</li><li>Suzuki, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dehydrative+Direct+C-H+Allylation+with+Allylic+Alcohols+under+[Cp*CoIII]+Catalysis.">Dehydrative Direct C-H Allylation with Allylic Alcohols under [Cp*CoIII] Catalysis.</a> Angew Chem Int Ed. 54 (34), 9944-9947 (2015).</li><li>Schwarz, K. J., Amos, J. L., Klein, J. C., Do, D. T., Snaddon, T. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Uniting+C1-Ammonium+Enolates+and+Transition+Metal+Electrophiles+via+Cooperative+Catalysis:+The+Direct+Asymmetric+&#945;-Allylation+of+Aryl+Acetic+Acid+Esters.">Uniting C1-Ammonium Enolates and Transition Metal Electrophiles via Cooperative Catalysis: The Direct Asymmetric &#945;-Allylation of Aryl Acetic Acid Esters.</a> J Am Chem Soc. 138 (16), 5214-5217 (2016).</li><li>Zell, D., Bu, Q., Feldt, M., Ackermann, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mild+C-H/C-C+Activation+by+Z-Selective+Cobalt+Catalysis.">Mild C-H/C-C Activation by Z-Selective Cobalt Catalysis.</a> Angew Chem Int Ed. 55 (26), 7408-7412 (2016).</li><li>Li, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=N-Acyl+Amino+Acid+Ligands+for+Ruthenium(II)-Catalyzed+meta-C-H+tert-Alkylation+with+Removable+Auxiliaries.">N-Acyl Amino Acid Ligands for Ruthenium(II)-Catalyzed meta-C-H tert-Alkylation with Removable Auxiliaries.</a> J Am Chem Soc. 137 (43), 13894-13901 (2015).</li><li>Li, F., Yu, C., Zhang, J., Zhong, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Olefination+of+Electron-Deficient+Alkenes+with+Allyl+Acetate:+Stereo-+and+Regioselective+Access+to+(2Z,4E)-Dienamides.">Olefination of Electron-Deficient Alkenes with Allyl Acetate: Stereo- and Regioselective Access to (2Z,4E)-Dienamides.</a> Org Lett. 18 (18), 4582-4585 (2016).</li><li>Lehman, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The student's lab companion: laboratory techniques for organic chemistry: standard scale and microscale. , (2008).</li></ol>

Zhejiang Eyaleti Doğal Bilimler Vakfı (ZJNSF) (No. LY15B020008), PCSIRT (No. IRT 1231) ve Hangzhou (Çin) Ulusal Doğal Bilim Vakfı (NSFC) (No 21502037, 21373073 ve 21672048) Mali destek Normal Üniversitesi. GZ, Çin&#39;in Zhejiang Eyaletinden bir Qianjiang Edebiyat ödülünü onayladı.

[Ru ( p- simen) Cl2] 2 , CH / CH eşleşme bütadien ürünlerini vermek için hafif reaksiyon koşullarında etkili bir şekilde çalışan mükemmel işlevsel grup toleranslı, ucuz, kolay erişilebilir, hava-kararlı ve yüksek aktif Ru bazlı bir katalizördür. Gümüş tuz AgSbF 6 , aşağıdaki CH bağ aktivasyonu için katyonik bir rutenyum kompleksi üretmek üzere [Ru ( p- simen) Cl2] 2&#39;nin kloridini soyutlayan bir katkı maddesi olarak kullanıldı. Bunun...

Butadienes yaygın olarak görülür ve çoğu doğal ürünler, ilaçlar ve biyoaktif moleküller 1&#39;de bulunur . Kimyagerler, 1,3-butadien 2 , 3 sentezi için etkili, seçici ve pratik bir sentetik metodoloji geliştirmek için yoğun çaba sarfettiler . Son zamanlarda, çift vinilik CH bağ aktivasyonu yoluyla iki alken arasındaki direkt çapraz bağlar geliştirildi, bu da bütadien sentezi için yüksek bir atomik ve basamaklı ekonomi ile etkili bir strateji olduğunu gösteriyor. Bunların arasında, iki alkenin paladyum katalizli çapraz bağlanması dikkat çekti ve alkenil-Pd türü 4 , 5 yoluyla ( E, E ) konfigüre bütadiyenler sağladı. Örneğin, Liu&#39;nun grubu, alkenlerin ve alil asetatın doğrudan çapraz bağlanmasıyla bir Pd-katalizli bütadien sentezi geliştirdi ( Şekil 1 </Strong&gt; ve Denklem 3 ) 4 . Bu arada, alkenler arasındaki fonksiyonel grup yönlendirmeli çapraz bağlama, tamamlayıcı bir yöntem olan 6 olefinik CH siklometalasyon olayından dolayı mükemmel ( Z, E ) -stereoselektifliğe sahip butadienleri sağladı. Bugüne kadar, enolatlar, amidler, esterler ve fosfatlar gibi bazı yönlendirme grupları, bir dizi değerli ve fonksiyonel 1,3-bütadien temin eden alkenler arasındaki çapraz bağlamaya başarıyla dahil edildi. Bununla birlikte, direkt pratik kullanımda sınırlı yönlendirme grupları olduğundan, yönetilen çapraz bağlanma reaksiyonu geliştirilmemiştir. Özellikle, büyük oranda organik ve inorganik atıklar üreten katalitik döngüyü korumak için stoikiometrik bir oksidan miktarı genellikle gereklidir. Elektron zengin alkenleri kuplaj ortak olarak kullanan çok sınırlı örnekler var. Alil asetat ve türevleri derinden iKatalizör çapraz bağlama, elektron zengin arenlerin Friedel-Crafts allilasyonu ve elektron yetersiz arenlerin katalitik CH harekete geçirilmesi ( Şekil 1 ve Denklem 1 ) de dahil olmak üzere güçlü alilasyon ve olefinleştirme reaktifleri olarak organik dönüşümler üzerinde incelenmiştir. Daha yakın bir zamanda, Loh grubu, allyl asetatlar ile elektron yetersiz alkenlerin rodyum (III) katalizli bir CH alilasyonunu geliştirdi ve 1,4-dienler oluşturdu ( Şekil 1 ve Denklem 2 ). Bu arada, Kanai grubu, bir Co (III) katalizörü 9 kullanarak allil alkoller ile dehidratif bir doğrudan CH allilasyonunu bildirdi. İlginçtir ki, Snaddon ve arkadaşları, asiklik esterlerin doğrudan asimetrik α- alalanımı için yeni bir kooperatif kataliz bazlı yöntem açıkladı 10 . Çok yakın bir tarihte, Ackermann grubu birkaç yeni alilasyon örneğini bildirmişti.G ucuz Fe, Co ve Mn katalizörleri 11 içerir . Bu raporlar, alilasyon ve olefinasyon reaksiyonlarında atılımlar yapmış, ancak çift bağ göçü ve zayıf rejim seçiciliği genellikle kaçınılmaz ve kolayca kontrol edilemiyor. Bu nedenle, değerli molekülleri oluşturmak için allil asetatların daha etkin ve seçici reaksiyon modelleri geliştirilmesi halen çok arzu edilmektedir. CH olefinasyon yoluyla yeni 1,3-butadien sentezine olan ilgimiz ile, allil asetatın önce 1,4-dien veren elektron yetersiz alkenlerin yönlendirilmiş allyrasyonuna katılabileceğini varsaydık. Daha sonra, CC çift bağı 7&#39;nin göç izomerleşmesinden sonra, termodinamik açıdan daha kararlı 1,3-butadien oluşabilir; bu, propen gibi elektronca zengin alkenlerin, kuplaj ortağı olarak çapraz bağlanmasıyla elde edilemeyen dien ürününün oluşturulmasıyla oluşabilir 6 . Burada ucuz bir Ru (III) katalizli olefinik CH bağ olefinatiN, ( Z, E ) -butadienlerin ( Şekil 1 ve Denklem 4 ) oluşturulması için yeni bir sentetik yol açan herhangi bir oksidan yokluğunda allil asetatlarla akrilamid&#39;lerin birleşmesidir 13 .

<table border="0" cellpadding="0" cellspacing="0" width="887">
	<tbody>
		<tr height="19">
			<td height="19" style="height:19px;width:284px;">Allyl Acetate</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">A0020</td>
			<td style="width:355px;">&#62; 98.0%(GC), 25 mL package</td>
		</tr>
		<tr height="38">
			<td height="38" style="height:38px;width:284px;">Dichloro(p-cymene)ruthenium(II) dimer</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">D2751</td>
			<td>&#62; 95.0%(T), 5 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Silver hexafluoroantimonate</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">S0463</td>
			<td>&#62; 97.0%(T),&#160; 5 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">1,2-Dichloroethane</td>
			<td style="width:100px;">TCI</td>
			<td style="width:148px;">D0364</td>
			<td>&#62; 99.5%(GC), 500 g package</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;">Rotavapor</td>
			<td style="width:100px;">EYELA</td>
			<td style="width:148px;">N-1200A</td>
			<td>Use to dry solvent</td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:284px;">Silica gel</td>
			<td style="width:100px;">Merck</td>
			<td style="width:148px;">107734</td>
			<td>Silica gel 60 (0.063-0.2 mm), for column chromatoraphy</td>
		</tr>
	</tbody>
</table>

facile preparation of (2z,4e)-dienamides by the olefination of electron-deficient alkenes with allyl acetate

Vinil CH bağ aktivasyonu yoluyla iki alken arasındaki doğrudan çapraz bağlanma, yüksek atomik ve adım ekonomisine sahip butadienlerin sentezi için etkili bir strateji oluşturmaktadır. Bununla birlikte, işlevselliğe yönelik bu çapraz bağlanma reaksiyonu geliştirilmemiştir çünkü pratik kullanımda halen sınırlı yönlendirme grupları bulunmaktadır. Özellikle, büyük miktarlarda atık üreten, genellikle stoikiometrik bir oksidan miktarı gereklidir. Yeni 1,3-bütadien sentezine olan ilgimizden ötürü, elektron yetersiz alkenlerin allil asetat ve dış oksidan içermeyen rutenyumla katalize edilmiş olefinasyonunu tarif ederiz. 2-fenil akrilamid ve allil asetat reaksiyonu bir model reaksiyon olarak seçildi ve istenen dien ürünü optimal koşullar altında iyi stereoseçebilirlik ( Z, E / Z, Z = 88:12) ile% 80 izole verimle elde edildi: 110 ºC&#39;de DCE içinde Ru ( p- simen) Cl2] 2 (% 3 mol) ve AgSbF6 (% 20 mol)Veya 16 saat. Elde edilen optimum katalitik koşullarla, temsil eden α - ve / veya β - ikameli akrilamitler araştırıldı ve alifatik veya aromatik gruplara bakılmaksızın sorunsuz bir şekilde reaksiyona girdi. Ayrıca, farklı N -ikameli akrilamidlerin iyi substratlar olduğu kanıtlanmıştır. Üstelik, farklı alil türevlerinin reaktivitesini inceledik ve asetat oksijenin metale kenetlenmesinin katalitik süreç için çok önemli olduğunu düşündürdü. Reaksiyon mekanizmasını araştırmak için döteryum etiketli deneyler de yapıldı. Akrilamid üzerinde sadece Z- seçmeli H / D değişimleri gözlemlenerek, tersinir bir siklometalizasyon olayı belirlenmiştir. Ek olarak, molekül içi izotop çalışmasında 3.2&#39;lik bir kinetik izotop etkisi (KIE) gözlendi ve olefinik CH metalasyon adımının muhtemelen hız belirleme adımında yer aldığını düşündürdü.

Çalışmalarımız akrilamid ve allil asetattan 1,3-bütadien&#39;in hazırlanması üzerine yoğunlaştı. Tablo 1 , katalizör olarak [Ru ( p- simen) Cl2] 2 kullanılarak çeşitli katkı maddelerinin ve çözücülerin taranması da dahil olmak üzere, koşulların optimizasyonunu göstermektedir. Bir dizi temsilci çözücüyü taradıktan sonra, ürün veriminin% 80&#39;e iyi bir seç...

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Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Elektron yetersiz alkenlerin allil asetat ile rutenyum katalizli olefinasyonu burada tarif edilmiştir. Bir yönlendirici grup olarak aminokarbonil kullanılarak, bu dış oksidan içermeyen protokol, ( Z , E ) -butadien iskeletlerine yeni bir sentetik yol açan yüksek verimlilik ve iyi stereo- ve bölgesel seçiciliğe sahiptir.

Kolay Hazırlık (2<em&gt; Z</em&gt; 4<em&gt; E</em&gt;) - Alil Asetat ile Elektronuz Alkenlerin Olefinasyonu ile Dienamidler

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high ...

facile-preparation-2z4e-dienamides-olefination-electron-deficient

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Unit 1

Facile Preparation of (2Z,4E)-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Dienes, Conjugated Pi Systems, and Pericyclic Reactions

Alkene Structure and Reactivity

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7.3K Görüntüleme.  Hangzhou Normal University.  Elektron yetersiz alkenlerin allil asetat ile rutenyum katalizli olefinasyonu burada tarif edilmiştir. Bir yönlendirici grup olarak aminokarbonil kullanılarak, bu dış oksidan içermeyen protokol, ( Z , E ) -butadien iskeletlerine yeni bir sentetik yol açan yüksek verimlilik ve iyi stereo- ve bölgesel seçiciliğe sahiptir. 

Video: Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate

Formation of Ordered Biomolecular Structures by the Self-assembly of Short Peptides

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control self-assembly and mimicking this process in vitro will bring about major advances in the areas of materials science and nanotechnology. Among the available biological building blocks, peptides have several advantages as they present substantial diversity, their synthesis in large scale is straightforward, and they can easily be modified with biological and chemical entities1,2. Several classes of designed peptides such as cyclic peptides, amphiphile peptides and peptide-conjugates self-assemble into ordered structures in solution. Homoaromatic dipeptides, are a class of short self-assembled peptides that contain all the molecular information needed to form ordered structures such as nanotubes, spheres and fibrils3-8. A large variety of these peptides is commercially available.
This paper presents a procedure that leads to the formation of ordered structures by the self-assembly of homoaromatic peptides. The protocol requires only commercial reagents and basic laboratory equipment. In addition, the paper describes some of the methods available for the characterization of peptide-based assemblies. These methods include electron and atomic force microscopy and Fourier-Transform Infrared Spectroscopy (FT-IR). Moreover, the manuscript demonstrates the blending of peptides (coassembly) and the formation of a &#34;beads on a string&#34;-like structure by this process.9 The protocols presented here can be adapted to other classes of peptides or biological building blocks and can potentially lead to the discovery of new peptide-based structures and to better control of their assembly.

This paper describes the formation of highly ordered peptide-based structures by the spontaneous process of self-assembly. The method utilizes commercially available peptides and common lab equipment. This technique can be applied to a large variety of peptides and may lead to the discovery of new peptide-based assemblies.

Kısa Peptidlerinin Self-meclisi tarafından Sıralı Biyomoleküler Yapıların Oluşumu

In nature, complex functional structures are formed by the self-assembly of biomolecules under mild conditions. Understanding the forces that control ...

Kimya

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of &#946;-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal &#946;-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (&#8804;1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.

An efficient, three-step synthesis of RAFT-based fluorescent glycopolymers, consisting of glycomonomer preparation, copolymerization, and post-modification, is demonstrated. This protocol can be used to prepare RAFT-based statistical glycopolymers with desired structures.

RAFT kontrollü Polimerizasyon yoluyla Tri-bileşenli Floresan Glycopolymers uyduruk ve Etkin Hazırlık

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and ...

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

Phosphopeptides Gelişmiş Zenginleştirme için Makrogözenekli Polimer Monoliths üzerinde yüksek Gözenekli Koordinasyon Polymer Coatings Hazırlanması

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

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 ...

A Study of the Complexation of Mercury(II) with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, by electrospray ionization orbitrap mass spectrometry. This strategy is based on previous successful characterization of mercury-dicysteinyl complexes involving tripeptides by utilizing mass spectrometry among other techniques. Mercury(II) chloride and a dicysteinyl tetrapeptide were incubated in a degassed buffered medium at varying stoichiometric ratios. The complexes formed were subsequently analyzed on an electrospray mass spectrometer consisting of a hybrid linear ion- and orbi- trap mass analyzer. The electrospray ionization mass spectrometry (ESI-MS) spectra were acquired in the positive mode and the observed peaks were then analyzed for distinct mercury isotopic distribution patterns and associated monoisotopic peak. This work demonstrates that an accurate stoichiometry of mercury and peptide in the complexes formed under specified electrospray ionization conditions can be determined by using high resolution ESI MS based on distinct mercury isotopic distribution patterns.

A Study of the Complexation of MercuryII with Dicysteinyl Tetrapeptides by Electrospray Ionization Mass Spectrometry

The characterization of complexes formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptides by electrospray ionization orbitrap mass spectrometry is presented.

Elektrosprey İyonizasyon kütle spektrometresi ile Dicysteinyl tetrapeptidlerle ile Merkür (II) kompleksinin Bir Çalışma

In this study we evaluated a method for the characterization of complexes, formed in different relative ratios of mercury(II) to dicysteinyl tetrapeptide, ...

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 ...

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.

4-Değiştirildi Kinazolin Türev kolay hazırlanması

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

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Photoredox Katalizörü kullanarak görünür ışık aracılığı ile dispersiyon polimerleştirilmesi ile solucan gibi miseller Facile sentezi

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

bir bis-iminoguanidinium ligand ile seçici kristalleştirme ile Sülfat Ayırma

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Facile Preparation of Ultrafine Aluminum Hydroxide Particles with or without Mesoporous MCM-41 in Ambient Environments

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis of aqueous aluminum salts is known to produce a wide array of products with a wide range of size distributions, a variety of state-of-the-art instruments (i.e., 27Al/1H NMR, FTIR, ICP-OES, TEM-EDX, XPS, XRD, and BET) were used to characterize the synthesis products and identification of byproducts. The product, which was comprised of nanoparticles (10-30 nm), was isolated using gel permeation chromatography (GPC) column technique. Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) identified the purified material as the gibbsite polymorph of aluminum hydroxide. The addition of inorganic salts (e.g., NaCl) induced electrostatic destabilization of the suspension, thereby agglomerating the nanoparticles to yield Al(OH)3 precipitate with large particle sizes. By utilizing the novel synthetic method described here, Al(OH)3 was partially loaded inside the highly ordered mesoporous framework of MCM-41, with average pore dimensions of 2.7 nm, producing an aluminosilicate material with both octahedral and tetrahedral Al (Oh/Td = 1.4). The total Al content, measured using energy-dispersive X-ray spectrometry (EDX), was 11% w/w with a Si/Al molar ratio of 2.9. A comparison of bulk EDX with surface X-ray photoelectron spectroscopy (XPS) elemental analysis provided insight into the distribution of Al within the aluminosilicate material. Furthermore, a higher ratio of Si/Al was observed on the external surface (3.6) as compared to the bulk (2.9). Approximations of O/Al ratios suggest a higher concentration of Al(O)3 and Al(O)4 groups near the core and external surface, respectively. The newly developed synthesis of Al-MCM-41 yields a relatively high Al content while maintaining the integrity of the ordered silica framework and can be used for applications where hydrated or anhydrous Al2O3 nanoparticles are advantageous.

An ultrafine aluminum hydroxide nanoparticle suspension was prepared via the controlled titration of [Al(H2O)]3+ with L-arginine to pH 4.6 with and without cage-effect confinement within mesoporous channels of MCM-41.

Ortofim Ortamlarda Mesafor MCM-41&#39;li olsun olmasın Ultrafine Alüminyum Hidroksit Parçacıklarının Kolay Hazırlanması

An aqueous suspension of nanogibbsite was synthesized via the titration of aluminum aqua acid [Al(H2O)6]3+ with L-arginine to pH 4.6. Since the hydrolysis ...

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