저자는 재정 지원을 위해 도이치 Forschungsgemeinschaft, 바이엘 제약 AG, Chemtura의하여 Organometallics GmbH의 카멘, 바이엘 서비스 GmbH, BASF AG 및 사졸 GmbH에 감사드립니다.

1. 티타늄 (IV) 급의 -butoxide/Triethylchlorosilane 용액의 조제 <ol><li> 티탄 (IV) 급 - 부톡 사이드 (1 mmol)의 건조 디클로로 메탄 10 ㎖에 400 mg의 (400 μL)을 녹이고. RT에서이 용액에 150 밀리그램 (170 μL) triethylchlorosilane (1 밀리몰)를 추가합니다. 이 디클로로 메탄 용액을 1 ㎖ 0.1 밀리몰 티탄을 포함 (IV) 급 - 부톡 사이드 및 0.1 밀리몰 triethylchlorosilane. </li></ol> 2. 테트라 페닐 -1,2 - 에탄 디올의 피나 콜 반응 (1) 2 Ethylbutyraldehyde 함께 <ol><li> 테트라 페닐 -1,2 - 에탄 디올 (1, 1 밀리몰) 및 3 ㎖의 건조 디클로로 메탄에 새로 증류 ethylbutyraldehyde -2 - (3 밀리몰)의 (300) MG (370 μL) 중 366 mg의 해결. </li><li> 별도로 준비 티타늄의 0.5 ML을 추가합니다 (IV) 급 -butoxide/triethylchlorosilane 솔루션 (0.05 mmol)을 첨가 하였다. </li><li> 밀봉 된 반응 관에 RT에서 생성 된 혼합물을 교반 하였다. </li><li> 확인 합니실리카겔 TLC 플레이트 상 (60 F254) - (1분의 9 헥산 / 아세톤을 용리액) RM 반응물을 박층 크로마토 그래피에 의해 완성된다. 반응 종료는 테트라 페닐 -1,2 - 에탄 디올 (1)는 더 이상 (~ 12 시간)을 검출 할 수없는 시점에 도달한다. 상품의 RF-값은 0.3 (14)이다. </li><li> 디클로로 메탄 50 ㎖로 생성 된 반응 혼합물을 희석. </li><li> 분별 깔때기에 염화 암모늄 수용액과 탄산 수​​소 나트륨 포화 용액 20 ㎖로 연속적으로 희석 된 반응 혼합물을 씻는다. </li><li> 분액 깔때기로 유기층을 분리. </li><li> 건조 황산 마그네슘 교반 유기층 건조시켰다. </li><li> 플루트를 불 ㄴ 종이 필터에 의해 현탁액을 여과하고 여과 액을 수집합니다. </li><li> 회전 증발기 (10 ~ 30 mmHg로)를 사용하여 40 ° C에서 진공 여과 액에서 디클로로 메탄을 제거합니다. 용매의 증발은 20 분을 필요로 할 것이다. </li><li> 잔류 물을 정제1,2 - 디올 2F 280 mg의 취득 헥산 / 아세톤의 구배 (19시 1분부터 아래 16시 4분 예정)로 실리카 겔 컬럼 (0.035-0.070 mm, ACROS)를 통한 플래쉬 칼럼 크로마토 그래피에 의하여 (0.99 밀리몰). </li><li> 등을 CDCl3 용매를 사용하여 1 H 핵 자기 공명 분광법 (NMR)에 의해 1,2 - 디올 2F의 신원을 확인한다. 다음과 같이 300 MHz의 NMR 분광계를 들어, 디올의 1 H NMR 스펙트럼은 : δ = 0.78 (t, 3H, J = 7.4 Hz에서), 0.87 (t, 3H, J = 7.3 Hz에서), 1.18-1.40 (m , 4H), 1.75-1.81 (m, 1H), 1.91 (S, 1H, OH), 3.12 (S, 1H, OH), 4.68 (d, 1H, J = 1.2 Hz에서), 7.19-7.37 (m, 6H ), 7.44-7.46 (m, 2H), 7.61-7.63 (m, 2H). </li></ol> 3. 테트라 페닐 -1,2 - 에탄 디올의 피나 콜 반응 (1) 디 에틸 케톤 <ol><li> 테트라 페닐 -1,2 - 에탄 디올 (1, 1 mmol) 및 3에 345 mg의 다이 에틸 케톤 (423 μL) (4 밀리몰)의 366 mg의 해결건조 디클로로 메탄 ML. </li><li> 별도로 준비 티타늄 (IV) 급 -butoxide/triethylchloro-silane 솔루션 (0.1 mmol)을 1 ㎖를 추가합니다. </li><li> 밀봉 된 반응 관에 RT에서 생성 된 혼합물을 교반 하였다. </li><li> 실리카겔 TLC 플레이트 (60 F254)에 : (헥산 / 아세톤 9:1 리제) 반응이 얇은 층 크로마토 그래피에 의해 완료 확인합니다. 테트라 페닐 -1,2 - 에탄 디올 (1) (~ 12 시간)을 검출 할 수 없을 때, 반응의 단부는, 시간에 도달한다. 제품의는 Rf 0.3 14입니다. </li><li> 디클로로 메탄 50 ㎖로 생성 된 반응 혼합물을 희석. </li><li> 분별 깔때기에 염화 암모늄 수용액 및 탄산나트륨 포화 용액 20 ㎖로 연속적으로 희석 된 반응 혼합물을 씻는다. </li><li> 분액 깔때기로 유기층을 분리. </li><li> 건조 황산 마그네슘 교반 유기층 건조시켰다. </li><li> 플루트를 불 ㄴ 종이 FIL하여 현탁액을 여과터 및 여과 액을 수집합니다. </li><li> 회전 증발기 (10 ~ 30 mmHg로)를 사용하여 40 ° C에서 진공 디클로로 메탄을 제거합니다. 휘발성 성분의 증발이 30 분을 필요로 할 것이다. </li><li> 일 250 mg의 취득 (19:1에서부터 16:4까지 내려 가고), 헥산 / 아세톤의 구배로 실리카 겔 컬럼 (0.035-0.070 mm, ACROS)를 통해 플래시 칼럼 크로마토 그래피에 의해 잔류 물을 정제하여, 2 - 디올 4F (0.93 밀리몰). </li><li> 등을 CDCl3 용매를 사용하여 1 H 핵 자기 공명 분광법 (NMR)에 의해 상품의 ID를 확인한다. 다음과 같이 300 MHz의 NMR 분광계를 들어, 디올 4F의 1 H NMR 스펙트럼은 : δ = 0.92 (t, 6H, J = 7.6 Hz에서), 1.78 (m, 4H), 2.03 (S, 1H, OH), 2.83 (S, 1H, OH), 7.26-7.35 (m, 6H), 7.69-7.71 (m, 4H). </li></ol>

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저자는 더 경쟁 재정적 이익을 선언하지 않습니다.

반응 시간 및 높은 수율의 전반적인 감소는 전자가 풍부한 카르 보닐 화합물의 전개 (13, 표 2와 17, 표 1 항목 (19) 항목 3 비교)에 의해 관찰된다. 또한, 부피가 큰 치환기와 케톤의 반응에서 수율의 감소는 (11, 표 2와 항목 12)와 비교 비교 조건에서 관찰된다. 카르 보닐 화합물의 넓은 범위가이 신규 한 프로세스에 적용 ...

피나 콜 커플 링 반응은 대칭의 인접한 디올 (1,2 - 디올 pinacols)의 제조에 일반적으로 사용되는 일반적인 방법이다. 이 분야에서 포괄적 인 리뷰를 참조 히라 1, 터지과 조시 2, Ladipo 3, Gansäuer 및 Bluhm은 4를 참조하십시오. 그와 대조적으로, 단지 소수의보고가 대응하는 비대칭 1,2 - 디올 (티타늄 (IV) 클로라이드 / 망간 4.0, 사마륨 (II) 요오다 이드 06 마그네슘을 수득 크로스 피나 콜 커플 링 반응의 효율적인 구현을 참조 출판 / 트리메틸 클로로 실란 (II) (8), 지르코늄 / 주석 9 7, 바나듐, 이테르븀 및 10). 따라서, 분자간 상호 피나 커플 링 반응은 여전히​​, 유기 화학에서의 변형이 특히 촉매 실행 큰 과제로 남아. 크로스 커플 링 제품의 형성은 역학적으로 선호되지이며고전 피나 커플 링 조건 하에서. 비대칭 제품의 충분한 양을 얻기 위해 하나의 카르 보닐 화합물의 첨가가 가능 지연. 이 개념을 개발하는 몇 가지 예를 존재하지만, 그들은 몇 가지 특정 실험 조작에 기초하고 있으며, 따라서 일반화 할 수 없습니다. 또한, 이러한 변환 한 카르 보닐 화합물의 필수 과량 복잡한 생성물 혼합물 (11)의 분리 힘든 결과. 이러한 목적을위한 대안이 필요한 추가적인 시약 몰량 렌더링 한 반응물의 precomplexation 의해 표현된다. 리버시블 피나 반응의 다양한 예 12를 설명 하였다. 이들은 이러한 조건은 크로스 커플 링 제품 선택적 합성을위한 최적의 시작점 수도 고려 이어질. 저 가의 금속뿐만 아니라 이후 반응성 라디칼 종 반응계에서 동시에 형성된다, 비대칭 디올 적합한 카르 보닐 반응물의 존재하에 단독으로 형성 될 수있다. (포르타는 등. 생성하는 AIBN의 화학 양 론적 양의 추가 배치 (2,2 &#39;- 아조 - 비스 - 이소 부티로 니트릴)에 의해 비교 ​​피나 분열 이후의 커플 링을 설명하기 전에 우리가 아는 한 그런 방법은보고 된 바 없음 필요한 라디칼) 13. 여기 프로토콜은 비대칭 1,2 - 디올에 신속하고 운영 체제는 간단한 액세스를 제공하는 시각화됩니다. 비대칭 피나 제품 (&gt; 95 %) 우수한 수율 대부분 액세스 할 수 있습니다. 원하지 않는 대칭 피나 제품은 관찰되지 않습니다. 이 새로운 크로스 피나 방법론 retropinacol / 크로스 피나 결합 서열에 기초한다. 그것은 벤조 피나의 대표적인 반응 (1,1,2,2 - 테트라 페닐 -1,2 - 에탄 디올, 1) 2 ethylbutyraldehyde (알데히드 시리즈) 및 w와 의해 이하에 설명 될 것이다(케톤 시리즈) i 번째 디 에틸.

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:363px;">1.2-Dichloromethane</td>
			<td style="width:179px;">Sigma-Aldrich</td>
			<td style="width:137px;">319929</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Titanium(IV)tert-butoxide</td>
			<td>VWR International</td>
			<td>200014-852</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">2-Ethylbutyraldehyde</td>
			<td>Sigma-Aldrich</td>
			<td>110094</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Benzopinacol</td>
			<td>Aldrich</td>
			<td>B9807</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Triethylchlorosilane</td>
			<td>Aldrich</td>
			<td>&#160;235067</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">hexane, certified ACS</td>
			<td>Fisher scientific</td>
			<td>H29220</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">acetone, certified ACS</td>
			<td>ACROS</td>
			<td>42324</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Ammonium chloride</td>
			<td>ACROS</td>
			<td>19997</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium hydrogen carbonate</td>
			<td>ACROS</td>
			<td>12336</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Magnesium sulphate</td>
			<td>ACROS</td>
			<td>41348</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="26">
			<td height="26" style="height:26px;">silica gel 60 F254 TLC plates</td>
			<td>VWR International</td>
			<td>1,057,140,001</td>
			<td style="width:79px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">&#160;silica gel, 0.035-0.070 for flash-chromatography</td>
			<td>ACROS</td>
			<td>240360300</td>
			<td style="width:79px;"></td>
		</tr>
	</tbody>
</table>

retropinacol/cross-pinacol coupling reactions - a catalytic access to 1,2-unsymmetrical diols

비대칭 1,2 - 디올을 환원 피나 커플 링 공정에 의해 단단하게 접근 가능하다. 이러한 변화의 성공적인 실행은 명확한 인식과 두 개의 유사한 카르 보닐 화합물 (차 1,2 - 디올 → 보조 1,2 - 디올 또는 케톤 → 알데히드)의 엄격한 차별에 바인딩됩니다. 이 미세 조정은 여전히​​ 유기 화학자를위한 도전과 해결되지 않은 문제입니다. 가 이러한 변화의 성공적인 실행에 대한 몇 가지 보고서를 존재하지만 그들은 일반화 할 수 없습니다. 여기서 우리는 retropinacol / 크로스 피나 커플 시퀀스를 통해 진행하여 촉매 직접 피나 커플 프로세스를 설명한다. 따라서, 비대칭 치환 된 1,2 - 디올은 매우 온화한 조건 하에서 운영 체제는 간단한 성능에 의해 거의 양적 수율에 액세스 할 수 있습니다. 같은 주사기 펌프 기술 또는 반응물의 지연 추가 등의 인공 기술은 필요하지 않습니다. 우리가 설명하는 절차에 매우 빠른 액세스를 제공합니다크로스 피나 제품 (1,2 - 디올, 비시 디올). 거울상 이성질체의 성능 예를 들어,이 새로운 프로세스의 추가 확장, 비대칭 키랄 1,2 - 디올의 합성에 매우 유용한 도구를 제공 할 수 있습니다.

티탄 촉매량 우리 -1,2 - 디올 (4A) 1,1 - 디 페닐 - (1)의 형성을 관찰 (IV) 알콕사이드와 동시에 형성의 존재하에 테트라 페닐 -1,2 - 에탄 디올 (1)과 아세톤의 반응에서 벤조 페논 3 (반응식 1). 아세톤의 경쟁력 피나 결합에 의해 형성된 대응하는 대칭 1,2 - 디올은 검출되지 않았다. 그러나, 양적 전환을 구하는 것이 매우 길고 용인 반응 시간은 이러한 조건 하에서 ?...

Watch this Scientific Journal Video about Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols at JoVE.com

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

retropinacol / 크로스 피나 결합 메커니즘을 기반으로 비대칭 1,2 - 디올의 합성을위한 신규 계좌 설명한다. 때문에 기존의 크로스 피나 커플 링에 비해 반응 상당한 개선의 촉매 실행에 달성된다.

Retropinacol / 크로스 피나 커플 링 반응 - 1,2 - 비대칭 디올에 촉매 액세스

Unsymmetrical 1,2-diols are hardly accessible by reductive pinacol coupling processes. A successful execution of such a transformation is bound to a clear ...

retropinacolcross-pinacol-coupling-reactions-catalytic-access-to-12

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12.9K 조회수.  Humboldt University of Berlin.  retropinacol / 크로스 피나 결합 메커니즘을 기반으로 비대칭 1,2 - 디올의 합성을위한 신규 계좌 설명한다. 때문에 기존의 크로스 피나 커플 링에 비해 반응 상당한 개선의 촉매 실행에 달성된다. 

비디오: Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium Under Mild Reaction Conditions

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family of easy accessible, very cheap, and air stable, but highly active and universally applicable C-C cross-coupling catalysts with an excellent functional group tolerance. Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1), the least stable complex within this series towards protons; e.g. in the form of water, allows an eased nanoparticle formation and hence, proved to be the most active Heck catalyst within this series at 100 &#176;C and is a very rare example of an effective and versatile catalyst system that efficiently operates under mild reaction conditions. Rapid and complete catalyst degradation under work-up conditions into phosphonates, piperidinium salts and other, palladium-containing decomposition products assure an easy separation of the coupling products from catalyst and ligands. The facile, cheap, and rapid synthesis of 1,1',1"-(phosphinetriyl)tripiperidine and 1 respectively, the simple and convenient use as well as its excellent catalytic performance in the Heck reaction at 100 &#176;C make 1 to one of the most attractive and greenest Heck catalysts available.
We provide here the visualized protocols for the ligand and catalyst syntheses as well as the reaction protocol for Heck reactions performed at 10 mmol scale at 100 &#176;C and show that this catalyst is suitable for its use in organic syntheses.

Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1&#039;,1&#039;&#039;-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions

Dichloro{bis[1,1',1''-(phosphinetriyl)tripiperidine]}palladium [(P(NC5H10)3)2Pd(Cl)2] (1) is an easy accessible, cheap, and air stable, but highly active Heck catalyst with an excellent functional group tolerance that efficiently operates under mild reaction conditions to give the coupling products in very high yields.

온화한 반응 조건 하에서 팔라듐 - 디클로로 {비스 [(phosphinetriyl) tripiperidine 1,1 &#39;, 1 &#39;&#39;]} 의해 촉매 Mizoroki-헥 크로스 커플 링 반응

Dichloro-bis(aminophosphine) complexes of palladium with the general formula of [(P{(NC5H10)3-n(C6H11)n})2Pd(Cl)2] (where n = 0-2), belong to a new family ...

연구

화학

Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions

Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as an intrinsic probe to characterize virtually every chemical process. Nowadays, this technique is extensively applied to determine thermodynamic parameters of biomolecular binding equilibria. In addition, ITC has been demonstrated to be able of directly measuring kinetics and thermodynamic parameters (kcat, KM, &#916;H) of enzymatic reactions, even though this application is still underexploited. As heat changes spontaneously occur during enzymatic catalysis, ITC does not require any modification or labeling of the system under analysis and can be performed in solution. Moreover, the method needs little amount of material. These properties make ITC an invaluable, powerful and unique tool to study enzyme kinetics in several applications, such as, for example, drug discovery.
In this work an experimental ITC-based method to quantify kinetics and thermodynamics of enzymatic reactions is thoroughly described. This method is applied to determine kcat and KM of the enzymatic hydrolysis of urea by Canavalia ensiformis (jack bean) urease. Calculation of intrinsic molar enthalpy (&#916;Hint) of the reaction is performed. The values thus obtained are consistent with previous data reported in literature, demonstrating the reliability of the methodology.

Isothermal titration calorimetry measures heat flow released or absorbed in chemical reactions. This method can be used to quantify enzyme-catalysis. In this paper, the protocol for instrumental setup, experiment running, and data analysis is generally described, and applied to the characterization of enzymatic urea hydrolysis by jack bean urease.

핫 생물 촉매 : 등온 적정 열량 효소 반응의 특성을

Isothermal titration calorimetry (ITC) is a well-described technique that measures the heat released or absorbed during a chemical reaction, using it as ...

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

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

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

이핵 항암제로 플래티넘 비스 피리딘 계 리간드와 이들 착물의 합성 아미드 커플 링 반응

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

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.

연속 흐름 처리를 사용하여 수행 반응의 실시간 모니터링 : 예를 들어 3 Acetylcoumarin의 제조

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 ...

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 ...

A Simple, Low-cost, and Robust System to Measure the Volume of Hydrogen Evolved by Chemical Reactions with Aqueous Solutions

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) hydrogen fuel cells. Researchers seeking to develop such systems require a method of measuring the generated hydrogen. Herein, we describe a simple, low-cost, and robust method to measure the hydrogen generated from the reaction of solids with aqueous solutions. The reactions are conducted in a conventional one-necked round-bottomed flask placed in a temperature controlled water bath. The hydrogen generated from the reaction in the flask is channeled through tubing into a water-filled inverted measuring cylinder. The water displaced from the measuring cylinder by the incoming gas is diverted into a beaker on a balance. The balance is connected to a computer, and the change in the mass reading of the balance over time is recorded using data collection and spreadsheet software programs. The data can then be approximately corrected for water vapor using the method described herein, and parameters such as the total hydrogen yield, the hydrogen generation rate, and the induction period can also be deduced. The size of the measuring cylinder and the resolution of the balance can be changed to adapt the setup to different hydrogen volumes and flow rates.

The study of methods to generate on-demand hydrogen for fuel cells continues to grow in importance. However, systems to measure hydrogen evolution from the reaction of chemicals with water can be complicated and expensive. This article details a simple, low-cost, and robust method to measure the evolution of hydrogen gas.

간단한, 낮은 비용, 강력한 시스템 수성 솔루션과 화학 반응에 의해 진화 수소의 양을 측정하는

There is a growing research interest in the development of portable systems which can deliver hydrogen on-demand to proton exchange membrane (PEM) ...

Laboratory Production of Biofuels and Biochemicals from a Rapeseed Oil through Catalytic Cracking Conversion

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil (HGO) for production of transportation fuels through a fluid catalytic cracking (FCC) route. Cracking experiments are performed with a fully automated reaction unit at a fixed weight hourly space velocity (WHSV) of 8 hr-1, 490-530 &#176;C, and catalyst/oil ratios of 4-12 g/g. When a feed is in contact with catalyst in the fluid-bed reactor, cracking takes place generating gaseous, liquid, and solid products. The vapor produced is condensed and collected in a liquid receiver at -15 &#176;C. The non-condensable effluent is first directed to a vessel and is sent, after homogenization, to an on-line gas chromatograph (GC) for refinery gas analysis. The coke deposited on the catalyst is determined in situ by burning the spent catalyst in air at high temperatures. Levels of CO2 are measured quantitatively via an infrared (IR) cell, and are converted to coke yield. Liquid samples in the receivers are analyzed by GC for simulated distillation to determine the amounts in different boiling ranges, i.e., IBP-221 &#176;C (gasoline), 221-343 &#176;C (light cycle oil), and 343 &#176;C+ (heavy cycle oil). Cracking of a feed containing canola oil generates water, which appears at the bottom of a liquid receiver and on its inner wall. Recovery of water on the wall is achieved through washing with methanol followed by Karl Fischer titration for water content. Basic results reported include conversion (the portion of the feed converted to gas and liquid product with a boiling point below 221 &#176;C, coke, and water, if present) and yields of dry gas (H2-C2's, CO, and CO2), liquefied petroleum gas (C3-C4), gasoline, light cycle oil, heavy cycle oil, coke, and water, if present.

This paper presents an experimental method to produce biofuels and biochemicals from canola oil mixed with a fossil-based feed in the presence of a catalyst at mild temperatures. Gaseous, liquid, and solid products from a reaction unit are quantified and characterized. Conversion and individual product yields are calculated and reported.

접촉 분해 변환을 통해 유채 기름에서 바이오 연료와 바이오 케미컬의 실험실 생산

The work is based on a reported study which investigates the processability of canola oil (bio-feed) in the presence of bitumen-derived heavy gas oil ...

A Simple and Efficient Protocol for the Catalytic Insertion Polymerization of Functional Norbornenes

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic nature of the monomer is conserved. The resulting polymer, polynorbornene, has a very high glass transition temperature, Tg, and interesting optical and electrical properties. However, the polymerization of functional norbornenes by this mechanism is complicated by the fact that the endo substituted norbornene monomer has, in general, a very low reactivity. Furthermore, the separation of the endo substituted monomer from the exo monomer is a tedious task. Here, we present a simple protocol for the polymerization of substituted norbornenes (endo:exo ca. 80:20) bearing either a carboxylic acid or a pendant double bond. The process does not require that both isomers be separated, and proceeds with low catalyst loadings (0.01 to 0.02 mol%). The polymer bearing pendant double bonds can be further transformed in high yield, to afford a polymer bearing pendant epoxy groups. These simple procedures can be applied to prepare polynorbornenes with a variety of functional groups, such as esters, alcohols, imides, double bonds, carboxylic acids, bromo-alkyls, aldehydes and anhydrides.

We describe the catalytic insertion polymerization of 5-norbornene-2-carboxylic acid and 5-vinyl-2-norbornene to form functional polymers with a very high glass transition temperature.

기능 노보 넨의 촉매 삽입 중합을위한 간단하고 효율적인 프로토콜

Norbornene can be polymerized by a variety of mechanisms, including insertion polymerization whereby the double bond is polymerized and the bicyclic ...

A Protocol for Safe Lithiation Reactions Using Organolithium Reagents

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented.

The safe and proper use of organolithium reagents is described.

유기 리튬 시약을 사용하여 안전 리튬 화의 반응을위한 프로토콜

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents ...

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. Detailed and generalized protocols are also presented for testing the catalytic activity of such complexes in arylation and Suzuki-Miyaura cross-coupling reactions. Representative results are shown for the catalytic activity of the four complexes in arylation and Suzuki-Miyaura type reactions. For each of the reactions investigated, at least one of the four complexes successfully catalyzed the reaction, qualifying them as promising candidates for catalysis of many carbon-carbon bond-forming reactions. The protocols presented are general enough to be adapted for the synthesis, purification and catalytic activity testing of new palladium N-heterocyclic carbene complexes.

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from benzimidazolium salts. The complexes were tested for catalytic activity in arylation and Suzuki-Miyaura reactions. For each reaction investigated, at least one of the four complexes successfully catalyzed the reaction.

보장<em&gt; N</em&gt; - 헤테로 사이 클릭 카벤 착물 : 벤즈 이미 다 졸리움 염으로부터의 합성 및 탄소 - 탄소 결합 형성 반응에서의 촉매 활성

Detailed and generalized protocols are presented for the synthesis and subsequent purification of four palladium N-heterocyclic carbene complexes from ...