Name: one-pot microwave-assisted conversion of anomeric nitrate-esters to trichloroacetimidates
Uploaded: 2018-01-15T13:00:00.000+00:00
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Description: Watch this Scientific Journal Video about One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates at JoVE.com

저자 밴 더 빌 트 대학 재정 지원에 대 한 화학 생물학 연구소를 인정 하 고 싶습니다. 미스터 버클리 엘리스와 교수 존 맥 클린 High-Resolution 질량 스펙트럼 분석에 대 한 인정 됩니다.

1. 대표 전자 레인지-Denitration 지원
<ol><li>Azido 질 산 에스테 르를 배치 (1.0 equiv., 0.2 m m o l) 8 mL 전자 레인지 반응 유리병에서. 반응의 규모는 반응 진행에 어떤 악영향 없이 여러 mmol을 늘릴 수 있습니다.</li>
	<li>Azido-질 산 에스테 르 20 %aq. 아세톤 (0.1 M 2.0 mL)에 녹. 반응 배를 피리 딘 (5.0 equiv., 0.08 mL, 1.0 mmol)을 추가 합니다. 전자 레인지 방사선 유리병 뚜껑과 전자 레인지 원자로 캐비티에 반응 배를 놓습니다.</li>
	<li>교 반 및 고정된 유지 시간 15 분 동안 120 ° C에서 솔루션 비추는 보류 시간 얼마나 방사선 지정 된 온도 및 결과 압력 발생 합니다 나타냅니다. 램프 2 분 동안 모든 반응 보고 온도에 열. 내장 IR 센서가 온도 모니터링 합니다.</li>
	<li>15 분 후 얇은 층 크로마토그래피 (TLC)를 사용 하 여 시작 물자의 소비를 확인 하는 반응 혼합물을 분석 합니다. Eluent는으로 1:1 에틸 아세테이트/hexanes를 사용 합니다.<ol>
<li>TLC 판 ceric 암모늄 molybate 얼룩을 사용 하 여 시각화. 반응 물 및 제품의 Rf 달라 집니다 하지만 줄이는 알코올 반응 보다 일반적으로 0.05에서 0.1 낮은 Rf .</li>
	</ol>
</li>
</ol>2입니다.는 trichloroacetimidate의 형성
<ol><li>시작 물자의 완전 한 소비에 따라 항공사를 사용 하 여 감소 볼륨에 용 매를 증발. 다음, (dichloromethane) 채널2Cl2 (1.0 mL)로 희석 하 고 주사기를 사용 하 여 물 층을 제거. 물 레이어 제거 되 면 얼음 물 목욕을 사용 하 여 0 ° C에 반응 혼합물을 냉각 한다.</li>
	<li>다음, 반응 배를 DBU (10 eq, 0.3 mL, 1.9 mmol)와 2,2,2-trichloroacetonitrile (50 eq, 1.0 mL, 10 mmol)을 추가 합니다. 두 시 약 과잉에 추가 되 고 기지의 1 해당 고 1 상응 하는 2,2,2 trichloroacetonitrile의 최소 필요.</li>
	<li>주위 온도에 온난 하는 동안 저 어 반응 혼합물을 허용 한다. TLC 확인 시작 물자의 소비에 의해 반응을 모니터링 합니다.<ol>
<li>Eluent는으로 1:1 에틸 아세테이트/hexanes를 사용 합니다. TLC 판 ceric 암모늄 molybate 얼룩을 사용 하 여 시각화. 반응 물 및 제품의 Rf 달라질 수 있습니다.</li>
	</ol>
</li>
	<li>시작 물자의 완전 한 소비 후 복구 플라스 크에 반응 혼합물을 전송 하 고 혼합물 vacuo에서 30 ° c.에 집중 솔벤트의 증발 갈색 기름 원유 옅은 노란색을 제공 합니다.</li>
	<li>Eluent로 1.5 cm 크로마토그래피 열과 1:4 에틸 아세테이트/hexanes 실리 카 젤 컬럼 크로마토그래피에 의해 원유 제품을 정화. imidate의 물리적 형태는 분자에서 분자를 달라 집니다.</li>
</ol><img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56610/56610fig1v3.jpg"> 그림 1. 2-azido-1-trichloroimidates 2-azido-1-질 산 에스테 르의 한 냄비 변환의 대표적인 예. <a href="//cloudflare-jove-com.bdigitaluss.remotexs.co/files/ftp_upload/56610/56610fig1v3large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭 하십시오.</a>

<ol>
	<li>Nicolaou, K. C., Mitchell, H. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adventures+in+Carbohydrate+Chemistry:+New+Synthetic+Technologies,+Chemical+Synthesis,+Molecular+Design,+and+Chemical+Biology+A+list+of+abbreviations+can+be+found+at+the+end+of+this+article.+Telemachos+Charalambous+was+an+inspiring+teacher+at+the+Pancyprian+Gymnasium,+Nicosia,+Cyprus.">Adventures in Carbohydrate Chemistry: New Synthetic Technologies, Chemical Synthesis, Molecular Design, and Chemical Biology A list of abbreviations can be found at the end of this article. Telemachos Charalambous was an inspiring teacher at the Pancyprian Gymnasium, Nicosia, Cyprus.</a> Angew. Chem. Int. Ed. Engl. 40 (9), 1576-1624 (2001).</li><li>Danishefsky, S. J., Allen, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+the+laboratory+to+the+clinic:+A+retrospective+on+fully+synthetic+carbohydrate-based+anticancer+vaccines.">From the laboratory to the clinic: A retrospective on fully synthetic carbohydrate-based anticancer vaccines.</a> Angew. Chem. Int. Ed. Engl. 39 (5), 836-863 (2000).</li><li>Nicolaou, K. C., Hale, C. R. H., Nilewski, C., Ioannidou, H. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Constructing+molecular+complexity+and+diversity:+total+synthesis+of+natural+products+of+biological+and+medicinal+importance.">Constructing molecular complexity and diversity: total synthesis of natural products of biological and medicinal importance.</a> Chemical Society Reviews. 41 (15), 5185-5238 (2012).</li><li>Zhu, X., Schmidt, R. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+principles+for+glycoside-bond+formation.">New principles for glycoside-bond formation.</a> Angew. Chem. Int. Ed. Engl. 48 (11), 1900-1934 (2009).</li><li>Danishefsky, S. J., Bilodeau, M. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycals+in+organic+synthesis:+The+evolution+of+comprehensive+strategies+for+the+assembly+of+oligosaccharides+and+glycoconjugates+of+biological+consequence.">Glycals in organic synthesis: The evolution of comprehensive strategies for the assembly of oligosaccharides and glycoconjugates of biological consequence.</a> Angew. Chem. Int. Ed. Engl. 35 (13-14), 1380-1419 (1996).</li><li>Bongat, A. F., Demchenko, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+trends+in+the+synthesis+of+O-glycosides+of+2-amino-2-deoxysugars.">Recent trends in the synthesis of O-glycosides of 2-amino-2-deoxysugars.</a> Carbohydr. Res. 342 (3-4), 374-406 (2007).</li><li>Feizi, T., Fazio, F., Chai, W. C., Wong, C. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Carbohydrate+microarrays+-+a+new+set+of+technologies+at+the+frontiers+of+glycomics.">Carbohydrate microarrays - a new set of technologies at the frontiers of glycomics.</a> Curr. Opin. Struct. Biol. 13 (5), 637-645 (2003).</li><li>Palmacci, E. R., Plante, O. J., Seeberger, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oligosaccharide+synthesis+in+solution+and+on+solid+support+with+glycosyl+phosphates.">Oligosaccharide synthesis in solution and on solid support with glycosyl phosphates.</a> Eur. J. Org. Chem. (4), 595-606 (2002).</li><li>Stallforth, P., Lepenies, B., Adibekian, A., Seeberger, P. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2009+Claude+S.+Hudson+Award+in+Carbohydrate+Chemistry.+Carbohydrates:+a+frontier+in+medicinal+chemistry.">2009 Claude S. Hudson Award in Carbohydrate Chemistry. Carbohydrates: a frontier in medicinal chemistry.</a> J. Med. Chem. 52 (18), 5561-5577 (2009).</li><li>Danishefsky, S. J., Mcclure, K. F., Randolph, J. T., Ruggeri, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Strategy+for+the+Solid-Phase+Synthesis+of+Oligosaccharides.">A Strategy for the Solid-Phase Synthesis of Oligosaccharides.</a> Science. 260 (5112), 1307-1309 (1993).</li><li>Demchenko, A. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stereoselective+chemical+1,2-cis+O-glycosylation:+From+'sugar+ray'+to+modern+techniques+of+the+21st+century.">Stereoselective chemical 1,2-cis O-glycosylation: From 'sugar ray' to modern techniques of the 21st century.</a> Synlett. (9), 1225-1240 (2003).</li><li>Fraserreid, B., Wu, Z. F., Udodong, U. E., Ottosson, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Armed-Disarmed+Effects+in+Glycosyl+Donors+-+Rationalization+and+Sidetracking.">Armed-Disarmed Effects in Glycosyl Donors - Rationalization and Sidetracking.</a> J. Org. Chem. 55 (25), 6068-6070 (1990).</li><li>Bohe, L., Crich, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+propos+of+glycosyl+cations+and+the+mechanism+of+chemical+glycosylation;+the+current+state+of+the+art.">A propos of glycosyl cations and the mechanism of chemical glycosylation; the current state of the art.</a> Carbohydr. Res. 403, 48-59 (2015).</li><li>Toshima, K., Tatsuta, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+Progress+in+O-Glycosylation+Methods+and+Its+Application+to+Natural-Products+Synthesis.">Recent Progress in O-Glycosylation Methods and Its Application to Natural-Products Synthesis.</a> Chem. Rev. 93 (4), 1503-1531 (1993).</li><li>Koenigs, W., Knorr, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ueber+einige+Derivate+des+Traubenzuckers+und+der+Galactose.">Ueber einige Derivate des Traubenzuckers und der Galactose.</a> Chem. Ber. 34 (1), 957-981 (1901).</li><li>Mukaiyama, T., Murai, Y., Shoda, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+Efficient+Method+for+Glucosylation+of+Hydroxy+Compounds+Using+Glucopyranosyl+Fluoride.">An Efficient Method for Glucosylation of Hydroxy Compounds Using Glucopyranosyl Fluoride.</a> Chem. Lett. (3), 431-432 (1981).</li><li>Meloncelli, P. J., Martin, A. D., Lowary, T. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycosyl+iodides.+History+and+recent+advances.">Glycosyl iodides. History and recent advances.</a> Carbohydrate Research. 344 (9), 1110-1122 (2009).</li><li>Lian, G., Zhang, X., Yu, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thioglycosides+in+carbohydrate+research.">Thioglycosides in carbohydrate research.</a> Carbohydr. Res. 403, 13-22 (2015).</li><li>Schmidt, R. R., Kinzy, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anomeric-Oxygen+Activation+for+Glycoside+Synthesis+-+the+Trichloroacetimidate+Method.">Anomeric-Oxygen Activation for Glycoside Synthesis - the Trichloroacetimidate Method.</a> Advances in Carbohydrate Chemistry and Biochemistry. 50, 21-123 (1994).</li><li>Schmidt, R. R., Toepfer, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Glycosylation+with+highly+reactive+glycosyl+donors:+efficiency+of+the+inverse+procedure.">Glycosylation with highly reactive glycosyl donors: efficiency of the inverse procedure.</a> Tetrahedron Lett. 32 (28), 3353-3356 (1991).</li><li>Keith, D. J., Townsend, S. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct,+microwave-assisted+substitution+of+anomeric+nitrate-esters.">Direct, microwave-assisted substitution of anomeric nitrate-esters.</a> Carbohydr. Res. 442, 20-24 (2017).</li><li>Bukowski, R., 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=Synthesis+and+Conformational+Analysis+of+the+T-Antigen+Disaccharide(B-D-Gal-(1->3)-a-D-GalNAc-OMe).">Synthesis and Conformational Analysis of the T-Antigen Disaccharide(B-D-Gal-(1->3)-a-D-GalNAc-OMe).</a> Eur. J. Org. Chem. 14, 2697-2705 (2001).</li></ol>

저자 아무 경쟁 금융 관심사 있다.

이 자습서에 설명 된 프로토콜 질 산 에스테 르 반응, 유용한 기능을 변환 하는 메서드를 제공 합니다. 넓은 의미에서 탄수화물 합성의 과정을 통해 특정 훈련을 완료 하는 데 전자 레인지 원자로 고용 수 있도록 어려운 변환 손쉬운 일상적인 가능성이 있다. 이 자습서에서 우리의 목표는 마이크로파 방사선의 맥락에서 탄수화물을 처리 하는 방법을 보여 줍니다.
부모 반응의 ?...

분자 생물학에 있는 그들의 편 재 때문에 탄수화물 화학 합성에 대 한 오랜 목표 되었습니다. 1 , 2 , 3 어떤 성공적인 합성 캠페인의 핵심 처리한후 체인 만들려고 glycosylation 반응의 정확한 배포가입니다. 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 당연한, 있다 glycosidic 채권을 설치 하는 방법의 많은 수 없습니다. 13 , 14 는 Koenigs Knorr 메서드는 가장 이른 알려진된 절차 중 하나 이며 커플링 glycosyl 염화 또는 평범한 사람 중 금속 (수은 또는 은색) 활성화의 밑에 보통 알코올 구성 요소를 포함. 15 관련된 glycosyl 불 화물 처음 소개 기증자로 1981에서 Mukaiyama 그룹 그리고 그들의 증가 한 열과 화학 안정성 때문에 광범위 하 게 응용 프로그램을 발견 했다. 16 반응 스펙트럼의 반대쪽 끝에 다른 할로겐 보다 훨씬 반응성은 glycosyl iodides 있습니다. 증가 된 반응성 증가 stereocontrol, 특히 때 α 연결 oligosaccharides 형성을 동반 된다. 17 "haloglycosides", 뿐만 아니라 thioglycosides 발견 했다 다양 한 유틸리티, 부분적으로, 형성, 다양 한 반응 조건, 및 electrophilic 시 약으로 활성화 하는 안정성의 그들의 용이성으로 인해. 18
Anomeric 알코올 "산소"를 포함 하는에 잠재적인 그룹을 활성화 하 고 궁극적으로 수락자 분자에서 알코올에 의해 난민을 떠나 변환에 초점 위에서 설명한 방법. Anomeric 산소 활성화 슈미트 학교에 의해 설명 된 대로 자체, C1 산소 떠나는 그룹으로 변환에 집중 한다. 19 이 방법은 가장 강력한 이며 화학 glycosylation 반응에서 널리 이용 된다. Trichloroacetimidate 기증자는 쉽게 감소 설탕과 탄산 칼륨 (K2CO3) 또는 1, 8-diazabicyclo [5.4.0] undec-7-ene (DBU) 등 자료의 trichloroacetonitrile에서 준비 됩니다. 이러한 종 다음 루이스 산을 사용 하 여 활성화 됩니다. 20
최근에, 우리는 2-azido-1-trichloroacetimidate 기증자 직접 glycals에서 준비 될 수 있다 보고 있다. 과정 2 반응을, 2-azido-1-질 산 에스테 르에서 한 냄비 절차를 포함 한다. 21 이 상세한 프로토콜 고수익 변환을 성공적으로 완료에 실무자를 지원 하기 위한 것입니다. 특히 전자 레인지-열 denitration에는 초점을 맞추고 보조 난방 시퀀스의 첫 번째 단계가입니다. 우리는 또한 유기 합성 반응 기 전자 레인지 사용에 영상 자습서를 제공 하도록 하겠습니다.

<table><tbody><tr><td>230 400 mesh silica gel</td><td>SiliCycle Inc</td><td>R10030B</td><td></td></tr><tr><td>TLC plates</td><td>SiliCycle Inc</td><td>TLG-R10014B-527</td><td></td></tr><tr><td>Ceric ammonium molybdate</td><td>Sigma-Aldrich</td><td>A1343</td><td></td></tr><tr><td>Solvent Still</td><td>Mbraun</td><td>MB-SPS-800</td><td></td></tr><tr><td>Infared spectrometer</td><td>Thermo</td><td>Thermo Electron IR100</td><td></td></tr><tr><td>Nuclear Magnetic Resonance</td><td>Bruker</td><td></td><td>400, 600 MHz</td></tr><tr><td>LC/MS</td><td>Thermo/Dionex</td><td></td><td>Single quad, ESI</td></tr><tr><td>HRMS</td><td>Agilent</td><td>Synapt G2 S HDMS</td><td></td></tr><tr><td>Microwave reactor</td><td>Anton Parr</td><td>Anton Parr G10 Monowave 200</td><td></td></tr><tr><td>DBU</td><td>Sigma-Aldrich</td><td>139009</td><td></td></tr><tr><td>CCl&lt;sub&gt;3&lt;/sub&gt;CN</td><td>Sigma-Aldrich</td><td>T53805</td><td></td></tr><tr><td>Pyridine</td><td>Sigma-Aldrich</td><td>270970</td><td></td></tr><tr><td>Acetone</td><td>Fisher Scientific</td><td>A18-20</td><td>Tech. grade</td></tr><tr><td>Phase separator</td><td>Biotage</td><td>120-1901-A</td><td></td></tr><tr><td>Rotary evaporator</td><td>Buchi</td><td>R-100</td><td></td></tr></tbody></table>

one-pot microwave-assisted conversion of anomeric nitrate-esters to trichloroacetimidates

다음 절차의 목표 trichloroacetimidate glycosyl 기증자에 게는 2-azido-1-질 산-에스테 르의 한 냄비 변환의 데모를 제공 하는 것입니다. glycal의 azido nitration, 다음 전자 레인지를 이용한 방사선에서 제품 2-azido-1-질 산 에스테 르를 분해 수 있습니다. 이 변환은 일반적으로 강하게 및 시 약 및 확장 된 반응 시간을 사용 하 여 이루어집니다. 마이크로파 방사선 조사는 가수분해, 짧은 반응 시간, 시 약의 부재에서 유도합니다. Denitration, 다음에 해당 2-azido-1-trichloroacetimidate를 같은 냄비에 중간 anomeric 알콜 변환 됩니다.

3 2-azido-1-질 산 에스테 르의 수영장에 여기에 설명 된 기술을 시연 했다. 각각의 경우에는 반응의 첫 번째 단계 20 분 이내에 완료 했다.
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56610/56610fig2v3.jpg"> 그림 2. 가수분해의 대표적인 예 (1 →2), 그리고 1 의 2-azido-1-질 산 에스테 ?...

Watch this Scientific Journal Video about One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates at JoVE.com

One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates

한 냄비 전자 렌지를 이용한 변환 Anomeric 질 산 에스테 르의 Trichloroacetimidates

2-azido-1-질 산-에스테 르는 해당 2-azido-1-trichloroacetimidate 한 냄비 절차에서를 변환할 수 있습니다. 원고의 목표 탄수화물 합성에 전자 레인지 원자로의 유틸리티를 설명 하는 것입니다.

The goal of the following procedure is to provide a demonstration of the one-pot conversion of a 2-azido-1-nitrate-ester to a trichloroacetimidate ...

one-pot-microwave-assisted-conversion-anomeric-nitrate-esters-to

Universidad San Sebastian

Research

JoVE Journal

Chemistry

7.4K 조회수.  Vanderbilt University. 2-azido-1-질 산-에스테 르는 해당 2-azido-1-trichloroacetimidate 한 냄비 절차에서를 변환할 수 있습니다. 원고의 목표 탄수화물 합성에 전자 레인지 원자로의 유틸리티를 설명 하는 것입니다.

비디오: One-pot Microwave-assisted Conversion of Anomeric Nitrate-esters to Trichloroacetimidates

Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides (CHIPS)

The direct functionalization of C-H bonds is an important and long standing goal in organic chemistry. Such transformations can be very powerful in order to streamline synthesis by saving steps, time and material compared to conventional methods that require the introduction and removal of activating or directing groups. Therefore, the functionalization of C-H bonds is also attractive for green chemistry. Under oxidative conditions, two C-H bonds or one C-H and one heteroatom-H bond can be transformed to C-C and C-heteroatom bonds, respectively. Often these oxidative coupling reactions require synthetic oxidants, expensive catalysts or high temperatures. Here, we describe a two-step procedure to functionalize indole derivatives, more specifically tetrahydrocarbazoles, by C-H amination using only elemental oxygen as oxidant. The reaction uses the principle of C-H functionalization via Intermediate PeroxideS (CHIPS). In the first step, a hydroperoxide is generated oxidatively using visible light, a photosensitizer and elemental oxygen. In the second step, the N-nucleophile, an aniline, is introduced by Br&#248;nsted-acid catalyzed activation of the hydroperoxide leaving group. The products of the first and second step often precipitate and can be conveniently filtered off. The synthesis of a biologically active compound is shown.

Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS

A two-step procedure for the synthesis of pharmaceutically active indole-derivatives by C-H functionalization with anilines is described, using photo- and Br&#248;nsted acid catalysis.

중간 과산화물을 통해 광화학 및 산 - 촉매 CH 기능화에 의한 항 바이러스 Tetrahydrocarbazole 유도체의 합성 (CHIPS)

The direct functionalization of C-H bonds is an important and long standing goal in organic chemistry. Such transformations can be very powerful in order ...

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Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form catalytically active N-Heterocyclic Carbenes (NHCs). Here we have used ILs as precatalysts in the addition of &#945;,&#946;-unsaturated aldehydes to chalcones to form 1,6-ketoesters, incorporating an anti-diphenyl moiety in a highly stereoselective fashion. The reaction has a broad substrate scope and several functional groups and heteroaromatics can be integrated into the ketoester backbone in generally good yields with maintained stereoselectivity. The reaction protocol is robust and scalable. The starting materials are inexpensive and the products can be obtained after simple filtration, avoiding solvent-demanding chromatography. Furthermore, the IL can be recycled up to 5 times without any loss of reactivity. Moreover, the 1,6-ketoester end product is a potent gelator in several hydrocarbon based solvents. The method enables rapid access to and evaluation of a new class of low molecular weight gelators (LMWGs) from recyclable and inexpensive starting materials.

Ionic liquids (ILs) mediate fast, simple and cheap access to 1,6-ketoesters in high diastereoselectivities and good yields. The reaction protocol is robust and the 1,6-ketoesters can be obtained in gram scale after a simple filtration protocol. Moreover, the 1,6-ketoesters are potent gelators in hydrocarbon solvents.

이온 성 액체에 의해 매개 1,6- Ketoesters의 높은 입체 선택적 합성 : 저 분자량 젤 레이터의 새로운 클래스에 빠른 액세스를 가능하게하는 3 요소 반응

In organic chemistry ionic liquids (ILs) have emerged as safe and recyclable reaction solvents. In the presence of a base ILs can be deprotonated to form ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

의 합성을위한 프로토콜<em&gt; 직교</em&gt; -trifluoromethoxylated 아닐린 파생 상품

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

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

Direct cross-coupling between two alkenes via vinylic C-H bond activation represents an efficient strategy for the synthesis of butadienes with high atomic and step economy. However, this functionality-directed cross-coupling reaction has not been developed, as there are still limited directing groups in practical use. In particular, a stoichiometric amount of oxidant is usually required, producing a large amount of waste. Due to our interest in novel 1,3-butadiene synthesis, we describe the ruthenium-catalyzed olefination of electron-deficient alkenes using allyl acetate and without external oxidant. The reaction of 2-phenyl acrylamide and allyl acetate was chosen as a model reaction, and the desired diene product was obtained in 80% isolated yield with good stereoselectivity (Z,E/Z,Z = 88:12) under optimal conditions: [Ru(p-cymene) Cl2]2 (3 mol %) and AgSbF6 (20 mol %) in DCE at 110 &#186;C for 16 h. With the optimized catalytic conditions in hand, representative &#945;- and/or &#946;-substituted acrylamides were investigated, and all reacted smoothly, regardless of aliphatic or aromatic groups. Also, differently N-substituted acrylamides have proven to be good substrates. Moreover, we examined the reactivity of different allyl derivatives, suggesting that the chelation of acetate oxygen to the metal is crucial for the catalytic process. Deuterium-labeled experiments were also conducted to investigate the reaction mechanism. Only Z-selective H/D exchanges on acrylamide were observed, indicating a reversible cyclometalation event. In addition, a kinetic isotope effect (KIE) of 3.2 was observed in the intermolecular isotopic study, suggesting that the olefinic C-H metalation step is probably involved in the rate-determining step.

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

The ruthenium-catalyzed olefination of electron-deficient alkenes with allyl acetate is described here. By using aminocarbonyl as a directing group, this external oxidant-free protocol has high efficiency and good stereo- and regioselectivity, opening a novel synthetic route to (Z,E)-butadiene skeletons.

손쉬운 준비 (2<em&gt; Z</em&gt;, 4<em&gt; E</em&gt;) - 알렌 아세테이트를 이용한 전자 불충분 알켄의 합성에 의한 디에나 미이드

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

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

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

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

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

N의 준비-(2-alkoxyvinyl) sulfonamides N-토실기-1,2,3-triazoles 및 후속 변환 대체 Phthalans 및 Phenethylamines에서

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

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

The conjugate addition of organometallic reagents to &#945;,&#946;-unsaturated carbonyls represents an important method to generate C&#8211;C bonds in the preparation of all-carbon quaternary centers. Though conjugate additions of organometallic reagents are typically performed utilizing highly reactive organolithium or Grignard reagents, organozinc reagents have garnered attention for their enhanced chemoselectivity and mild reactivity. Despite numerous recent advances with more reactive diorganozinc and mixed diorganozinc reagents, the generation of all-carbon quaternary centers via the conjugate addition of functionalized monoorganozinc reagents remains a challenge. This protocol details a convenient and mild &#8220;one-pot&#8221; preparation and copper mediated conjugate addition of functionalized monoorganozinc bromides to cyclic &#945;,&#946;-unsaturated carbonyls to afford a broad scope of all-carbon quaternary centers in generally excellent yield and diastereoselectivity. Key to the development of this technology is the utilization of DMA as a reaction solvent with TMSCl as a Lewis acid. Notable advantages to this methodology include the operational simplicity of the organozinc reagent preparation afforded by the utilization of DMA as a solvent, as well as an efficient conjugate addition mediated by various Cu(I) and Cu(II) salts. Moreover, an intermediate silyl enol ether can be isolated utilizing a modified workup procedure. The substrate scope is limited to cyclic unsaturated ketones, and the conjugate addition is impeded by stabilized (e.g., allyl, enolate, homoenolate) and sterically encumbered (e.g., neopentyl, o-aryl) monoorganozinc reagents. Conjugate additions to five- and seven-membered rings were effective, albeit in lower yields compared with six-membered ring substrates.

A simple and practical protocol for the efficient conjugate addition of functionalized monoorganozinc bromides to cyclic &#945;,&#946;-unsaturated carbonyls to furnish all-carbon quaternary centers was developed.

관 능 적 모노 아연 브로 미 데스의 결합체 첨가를 통한 전 탄소 4 급 센터의 효율적인 합성

The conjugate addition of organometallic reagents to &#945;,&#946;-unsaturated carbonyls represents an important method to generate C&#8211;C bonds in the ...

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines

A synthetic process for the preparation of a variety of 1-aryl-1H-pyrazole-5-amines was developed. The microwave-mediated nature of this method makes it efficient in both time and resources and utilizes water as the solvent. 3-Aminocrotononitrile or an appropriate &#945;-cyanoketone is combined with an aryl hydrazine and dissolved in 1 M HCl. The mixture is then heated in a microwave reactor at 150 &#176;C, typically for 10-15 min. The product can be readily obtained by basifying the solution with 10% NaOH and isolating the desired compound with a simple vacuum filtration. The use of water as a solvent in this reaction lends to its ease and utility in production, and this method is easily reproducible with a variety of functional groups. Typical isolated yields range from 70-90%, and reactions can be performed on the milligram to gram scale with little to no change in observed yields. Some of the applications of these molecules and their derivatives include pesticides, anti-malarials, and chemotherapeutics, among many others.

Microwave-Assisted Preparation of 1-Aryl-1H-pyrazole-5-amines

1-Aryl-1H-pyrazole-5-amines are prepared from aryl hydrazines combined with either 3-aminocrotononitrile or an &#945;-cyanoketone in a 1 M HCl solution using a microwave reactor. Most reactions are done in 10-15 minutes and pure product can be obtained via vacuum filtration with typical isolated yields of 70-90%.

1-아릴-1 H-피라졸-5-아민의 전자레인지 보조 제제

A synthetic process for the preparation of a variety of 1-aryl-1H-pyrazole-5-amines was developed. The microwave-mediated nature of this method makes it ...

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

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

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

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

트리카보닐(트로폰)철을 통한 6-아미노사이클로헵타-2,4-디엔-1-1-1 유도체 의 제조

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

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

CO2 transformations using a one-pot two-step method are presented herein. The purpose of the method is to give access to a variety of value-added products and notably to generate chiral carbon centers. The crucial first step consists in the selective double hydroboration of CO2 catalyzed by an iron hydride complex. The product obtained with this 4 e- reduction is a rare bis(boryl)acetal, compound 1, which is subjected in situ to three different reactions in a second step. The first reaction concerns a condensation reaction with (diisopropyl)phenylamine affording the corresponding imine 2. In the second and third reaction, intermediate 1 reacts with triazol-5-ylidene (Enders&#39; carbene) to afford compounds 3 or 4, depending on the reaction conditions. In both compounds, C-C bonds are formed, and chiral centers are generated from CO2 as the only source of carbon. Compound 4 exhibits two chiral centers obtained in a diastereoselective manner in a formose-type mechanism. We proved that the remaining boryl fragment plays a key role in this unprecedented stereocontrol. The interest of the method stands on the reactive and versatile nature of 1, giving rise to various complex molecules from a single intermediate. The complexity of a two-step method is compensated by the overall short reaction time (2 h for the larger reaction time), and mild reaction conditions (25 &#176;C to 80 &#176;C and 1 to 3 atm of CO2).

Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy

CO2 transformations are conducted in a one-pot two-step procedure for the synthesis of complex molecules. The selective 4 e- reduction of CO2 with a hydroborane reductant affords a reactive and versatile bis(boryl)acetal intermediate which is subsequently involved in condensation reaction or carbene-mediated C-C coupling generation.

다재다능한CO2를 복합 제품으로 전환: 원포트 2단계 전략

CO2 transformations using a one-pot two-step method are presented herein. The purpose of the method is to give access to a variety of value-added products ...

A Microwave-Assisted Direct Heteroarylation of Ketones Using Transition Metal Catalysis

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal catalysis, the literature on direct heteroarylation is scarce. The presence of heteroatoms such as nitrogen, sulfur and oxygen often make heteroarylation a challenging research field due to catalyst poisoning, product decomposition and the rest. This protocol details a highly efficient direct &#945;-C(sp3) heteroarylation of ketones under microwave irradiation. Key factors for successful heteroarylation include the use of XPhos Palladacycle Gen. 4 Catalyst, excess base to suppress side reactions and the high temperature and pressure achieved in a sealed reaction vial under microwave irradiation. The heteroarylation compounds prepared by this method were fully characterized by proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR) and high-resolution mass spectrometry (HRMS). This methodology has several advantages over literature precedents including broad substrate scope, rapid reaction time, greener procedure and operational simplicity by eliminating the preparation of intermediates such as silyl enol ether. Possible applications for this protocol include, but are not limited to, diversity-oriented synthesis for the discovery of biologically active small molecules, domino synthesis for the preparation of natural products and ligand development for new transition metal catalytic systems.

Heteroaryl compounds are important molecules utilized in organic synthesis, medicinal and biological chemistry. A microwave-assisted heteroarylation using palladium catalysis provides a rapid and efficient method to attach heteroaryl moieties directly to ketone substrates.

전이 금속 촉매를 이용한 케톤 전자레인지 보조 직접 이질화

Heteroarylation introduces heteroaryl fragments to organic molecules. Despite the numerous available reactions reported for arylation via transition metal ...

한 냄비 전자 렌지를 이용한 변환 Anomeric 질 산 에스테 르의 Trichloroacetimidates

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