scholarly journals First total syntheses of chrestifoline-B and (±)-chrestifoline-C, and improved synthetic routes to bismurrayafoline-A, bismurrayafolinol and chrestifoline-D

2014 ◽  
Vol 12 (23) ◽  
pp. 3831-3835 ◽  
Author(s):  
Carsten Börger ◽  
Arndt W. Schmidt ◽  
Hans-Joachim Knölker
Keyword(s):  
Efficient Synthesis ◽  
Total Syntheses ◽  
Type Coupling ◽  
Synthetic Routes

We describe an efficient synthesis of the methylene-bridged biscarbazole alkaloids bismurrayafoline-A, bismurrayafolinol and chrestifoline B–D using an Ullmann-type coupling at the benzylic position.

scholarly journals The Efficient Synthesis of Azasugars from Pentoses

2021 ◽  
Author(s):  
◽  
Michael Meijlink
Keyword(s):  
Clinical Trials ◽  
Biological Properties ◽  
Protecting Groups ◽  
Synthetic Route ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Total Syntheses ◽  
Structural Analogues ◽  
Original Procedure ◽  
Synthetic Routes

<p>Azasugars [e.g., 1-deoxy-aza-xylopyranose (1) Figure 1] are structural analogues of sugars [e.g., α-D-xylopyranose (2)] where the ring oxygen is substituted by a nitrogen atom. The resemblance of azasugars to their carbohydrate counterparts gives them various biological properties, such as the inhibition of glycosidase and glycosyltransferase enzymes, and as such, these compounds have been in clinical trials for the treatment of AIDS, diabetes,and cancer. Synthetic routes to azasugars have often involved the use of protecting groups, and therefore have generally reduced efficiency by requiring additional steps to apply or remove protecting groups or requiring adjustment of stereochemistry during the synthesis. This thesis presents the first example of a synthesis of four sterochemically different piperidine triols through a four-step methodology minimising the use of protecting groups starting from pentoses. The synthesis of D-xylose derived (3R,4r,5S)-piperidine triol was previously obtained in 40% yield over five steps, but was afforded in 45% overall yield over four steps using the methodology described within this thesis. Next, D-ribose derived (3R,4s,5S)-piperidine triol was obtained in 40% overall yield over four steps, which afforded a vast improvement on the previous most efficient synthetic route obtaining the azasugar in 24% yield over four steps. This four-step three-pot methodology has thus allowed for the synthesis of these piperidine triols in overall yields ranging from 4-69%, surpassing previous total syntheses in efficiency and improving overall atom economy. To further probe the applicability of the methodology, N-alkyl analogues (such as butyl-, phenylethyl-, and hydroxyethyl-analogues) of all four different piperidine triols were synthesised in comparable or greater overall yields compared to literature reports without any required adaptation to the original procedure. Included in these N-alkyl analogues are seven novel azasugars which were obtained in overall yields ranging from 6-35%.</p>

scholarly journals The Efficient Synthesis of Azasugars from Pentoses

2021 ◽  
Author(s):  
◽  
Michael Meijlink
Keyword(s):  
Clinical Trials ◽  
Biological Properties ◽  
Protecting Groups ◽  
Synthetic Route ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Total Syntheses ◽  
Structural Analogues ◽  
Original Procedure ◽  
Synthetic Routes

<p>Azasugars [e.g., 1-deoxy-aza-xylopyranose (1) Figure 1] are structural analogues of sugars [e.g., α-D-xylopyranose (2)] where the ring oxygen is substituted by a nitrogen atom. The resemblance of azasugars to their carbohydrate counterparts gives them various biological properties, such as the inhibition of glycosidase and glycosyltransferase enzymes, and as such, these compounds have been in clinical trials for the treatment of AIDS, diabetes,and cancer. Synthetic routes to azasugars have often involved the use of protecting groups, and therefore have generally reduced efficiency by requiring additional steps to apply or remove protecting groups or requiring adjustment of stereochemistry during the synthesis. This thesis presents the first example of a synthesis of four sterochemically different piperidine triols through a four-step methodology minimising the use of protecting groups starting from pentoses. The synthesis of D-xylose derived (3R,4r,5S)-piperidine triol was previously obtained in 40% yield over five steps, but was afforded in 45% overall yield over four steps using the methodology described within this thesis. Next, D-ribose derived (3R,4s,5S)-piperidine triol was obtained in 40% overall yield over four steps, which afforded a vast improvement on the previous most efficient synthetic route obtaining the azasugar in 24% yield over four steps. This four-step three-pot methodology has thus allowed for the synthesis of these piperidine triols in overall yields ranging from 4-69%, surpassing previous total syntheses in efficiency and improving overall atom economy. To further probe the applicability of the methodology, N-alkyl analogues (such as butyl-, phenylethyl-, and hydroxyethyl-analogues) of all four different piperidine triols were synthesised in comparable or greater overall yields compared to literature reports without any required adaptation to the original procedure. Included in these N-alkyl analogues are seven novel azasugars which were obtained in overall yields ranging from 6-35%.</p>

scholarly journals Old Molecule, New Chemistry: Exploring Silicon Phthalocyanines as Emerging N-Type Materials in Organic Electronics

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1334 ◽  
Author(s):  
Nathan J. Yutronkie ◽  
Trevor M. Grant ◽  
Owen A. Melville ◽  
Benoît H. Lessard ◽  
Jaclyn L. Brusso
Keyword(s):  
Organic Thin Film Transistors ◽  
Organic Thin Film ◽  
Field Effect Mobility ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
High Performing ◽  
Silicon Phthalocyanines ◽  
Electron Field ◽  
Synthetic Routes ◽  
Average Electron

Efficient synthesis of silicon phthalocyanines (SiPc) eliminating the strenuous reaction conditions and hazardous reagents required by classical methods is described. Implementation into organic thin-film transistors (OTFTs) affords average electron field-effect mobility of 3.1 × 10−3 cm2 V−1 s−1 and threshold voltage of 25.6 V for all synthetic routes. These results demonstrate that our novel chemistry can lead to high performing SiPc-based n-type OTFTs.

An efficient synthesis of 3-(indol-3-yl)quinoxalin-2-ones with TfOH-catalyzed Friedel–Crafts type coupling reaction in air

2010 ◽  
Vol 51 (15) ◽  
pp. 2023-2028 ◽  
Author(s):  
Yan-Yan Han ◽  
Zhi-Jun Wu ◽  
Xiao-Mei Zhang ◽  
Wei-Cheng Yuan
Keyword(s):  
Coupling Reaction ◽  
Efficient Synthesis ◽  
Type Coupling

scholarly journals Facile, Efficient Synthesis of Star‐Shaped π‐Conjugated Systems by Combined Olefin Metathesis with Wittig‐type Coupling

2017 ◽  
Vol 65 (3) ◽  
pp. 317-324 ◽  
Author(s):  
Takashi Fujio ◽  
Tomohiro Miwata ◽  
Masayoshi Takase ◽  
Shunsuke Sueki ◽  
Kotohiro Nomura
Keyword(s):  
Olefin Metathesis ◽  
Efficient Synthesis ◽  
Conjugated Systems ◽  
Type Coupling

Highly Efficient Synthesis of Tricyclic Amines by a Cyclization/Cycloaddition Cascade: Total Syntheses of Aspidospermine, Aspidospermidine, and Quebrachamine

2007 ◽  
Vol 46 (32) ◽  
pp. 6159-6162 ◽  
Author(s):  
Iain Coldham ◽  
Adam J. M. Burrell ◽  
Laura E. White ◽  
Harry Adams ◽  
Niall Oram
Keyword(s):  
Efficient Synthesis ◽  
Total Syntheses ◽  
Highly Efficient

Synthesis of New 5-amino-7-(aryl)-1,2,3,7-tetrahydro-8-nitroimidazo[1,2-a]pyridine- 6-carboxamide and 6-amino-2,3,4,8-tetrahydro-9-nitro-8-(aryl)-1H-pyrido[1,2- a]pyrimidine-7-carboxamide Derivatives

2018 ◽  
Vol 15 (7) ◽  
pp. 982-988 ◽  
Author(s):  
Fahimeh S. Hosseini ◽  
Mohammad Bayat
Keyword(s):  
Aromatic Aldehydes ◽  
Chromatographic Technique ◽  
Efficient Synthesis ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Synthetic Routes ◽  
High Yields ◽  
Work Up ◽  
Optimal Reaction

Aim and Objectives: Development of simple synthetic routes for widely used organic compounds from readily available reagents is one of the major tasks in organic chemistry. Therefore, new approaches for increasing the molecular diversity of simple starting materials, are needed. Herein, an efficient synthesis of imidazo[1,2-a]pyridine, pyrido[1,2-a]pyrimidine and pyrido[1,2-a][1,3]diazepine derivatives is described. Materials and Methods: A one-pot, multi-component reaction of nitro ketene aminal derived from the addition of various 1,n-diamines to 1,1-bis(methylthio)-2-nitroethene with cyanoacetamide and aromatic aldehydes is described. The reactions are completed within 2-5 h, in ethanol at reflux, in good to high yields (70-93%). The structures of products were deduced from their IR, mass, 1H NMR, and 13C NMR spectra. Results: Optimal reaction conditions for the synthesis of products were obtained, when ethanol was used as the solvent at reflux. This protocol involves Michael reaction, imine–enamine tautomerization, and cyclization sequences. Conclusion: This work represents an efficient synthesis of imidazo[1,2-a]pyridine, pyrido[1,2-a]pyrimidine and pyrido[1,2-a][1,3]diazepine derivatives via a one-pot, multi-component reaction. The advantages of this protocol are mild conditions, easy accessibility of reactants, absence of catalyst, high atom economy, simple work-up and purification process with no chromatographic technique.

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