A new short synthetic approach to chlorocyclopentenones related to cryptosporiopsin via a ring expansion strategy: first synthesis of a fungitoxic metabolite from Sporormia affinis

2000 ◽  
Vol 78 (2) ◽  
pp. 270-274 ◽  
Author(s):  
Sidima Kabanyane ◽  
Andreas Decken ◽  
Chao-Mei Yu ◽  
George M Strunz
Keyword(s):  
Methyl Ester ◽  
Acid Methyl Ester ◽  
Ring Expansion ◽  
Selenium Dioxide ◽  
Synthetic Approach ◽  
Expansion Strategy ◽  
Racemic Form ◽  
Coprophilous Fungus ◽  
Acid Methyl ◽  
New Synthesis

A metabolite of the coprophilous fungus, Sporormia affinis, 2-trans-allyl-5-chloro-1-hydroxy-4-oxo-2-cyclopentene-1-carboxylic acid methyl ester, 2, was synthesized in racemic form, by an eight-step sequence, in 11% overall yield. Departing from previous ring-contraction strategies for synthesis of chlorocyclopentenones in the cryptosporiopsin series, the key step in the new synthesis was ring expansion of a substituted cyclobutanone, the product of [2+2] cycloaddition of dichloroketene with methyl 2-trimethylsilyloxyhex-2-enoate.Key words: Sporormia affinis, cryptosporiopsin, chlorocyclopentenone, dichloroketene, [2+2] cycloaddition, ring expansion, selenium dioxide.

Mechanismen der elektronenstoßinduzierten Methanoleliminierung aus ortho- und para-substituierten Benzoesäuremethylestern / Mechanisms of Electron Impact Induced Elimination of Methanol from ortho- and para-Substituted Benzoic Acid Methyl Ester

1976 ◽  
Vol 31 (6) ◽  
pp. 870-875 ◽  
Author(s):  
Rupert Herrmann ◽  
Helmut Schwarz
Keyword(s):  
Mass Spectrometry ◽  
Methyl Ester ◽  
Benzoic Acid ◽  
Electron Impact ◽  
Acid Methyl Ester ◽  
Ring Expansion ◽  
Acid Methyl ◽  
Π Complex ◽  
Fragmentation Reactions ◽  
Ring Expansion Reaction

Using deuterium labelled compounds the mechanisms of methyl as well as methanol elimination from the title compounds have been established. It can be shown that in the case of 4-methoxy-methyl benzoic acid methyl ester the unusual methanol elimination from the [M-methyl]+ ion probably proceeds via the formation of a π-complex and a ring expansion reaction. In addition to this novel fragmentation some ortho-effects and other fragmentation reactions useful for an analytical identification of the ortho/para-isomers by means of mass spectrometry are discussed.

scholarly journals Tulasnein and Podospirone from the Coprophilous Xylariaceous Fungus Podosordaria tulasnei

2004 ◽  
Vol 59 (5-6) ◽  
pp. 379-383 ◽  
Author(s):  
Daniela C. Ridderbusch ◽  
Roland W. S. Weber ◽  
Timm Anke ◽  
Olov Sterner
Keyword(s):  
Sequence Analysis ◽  
Methyl Ester ◽  
Acid Methyl Ester ◽  
Rdna Sequence ◽  
Its Rdna ◽  
Coprophilous Fungus ◽  
Acid Methyl ◽  
Culture Filtrates

Tulasnein (1), a new metabolite with strong antimicrobial and weaker cytotoxic and phyto­toxic activity, was isolated from culture filtrates of three strains of the xylariaceous coprophilous fungus Podosordaria tulasnei. The producing strains were identified by their rhizomorphs and by ITS rDNA sequence analysis. A second new metabolite, podospirone (2), was also produced by all three strains whereas the weakly cytotoxic (+)-3,4-anhydroshikimic acid methyl ester (3) was detected in only one strain.

Evaluation of the Impact of Fatty Acid Methyl Ester (FAME) Contamination on the Thermal Stability of Jet A

2013 ◽  
Author(s):  
Jr Morris ◽  
Shardo Robert W. ◽  
Higgins James ◽  
Cook Kim ◽  
Tanner Rhonda ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Fatty Acid ◽  
Methyl Ester ◽  
Fatty Acid Methyl Ester ◽  
Acid Methyl Ester ◽  
Acid Methyl ◽  
The Impact ◽  
Thermal Stability Of

Optical Absorption Enhancement in Polymer BHJ thin Film Using Ag Nanostructures: A Simulation Study

2020 ◽  
Vol 16 (4) ◽  
pp. 556-567
Author(s):  
Asma Khalil ◽  
Zubair Ahmad ◽  
Farid Touati ◽  
Mohamed Masmoudi
Keyword(s):  
Absorption Spectrum ◽  
Solar Cell ◽  
Methyl Ester ◽  
Butyric Acid ◽  
Organic Solar Cell ◽  
Short Circuit ◽  
Acid Methyl Ester ◽  
Short Circuit Current ◽  
Acid Methyl ◽  
Butyric Acid Methyl Ester

Background: The photo-absorption and light trapping through the different layers of the organic solar cell structures are a growing concern now-a-days as it affects dramatically the overall efficiency of the cells. In fact, selecting the right material combination is a key factor in increasing the efficiency in the layers. In addition to good absorption properties, insertion of nanostructures has been proved in recent researches to affect significantly the light trapping inside the organic solar cell. All these factors are determined to expand the absorption spectrum and tailor it to a wider spectrum. Objective: The purpose of this investigation is to explore the consequence of the incorporation of the Ag nanostructures, with different sizes and structures, on the photo absorption of the organic BHJ thin films. Methods: Through a three-dimensional Maxwell solver software, Lumerical FDTD, a simulation and comparison of the optical absorption of the three famous organic materials blends poly(3- hexylthiophene): phenyl C71 butyric acid methyl ester (P3HT:PCBM), poly[N-9″-heptadecanyl-2,7- carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDTBT:PCBM) and poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt- 4,7-(2,1,3-benzothiadiazole)]: phenyl C71 butyric acid methyl ester (PCDPDTBT:PCBM) has been conducted. Furthermore, FDTD simulation study of the incorporation of nanoparticles structures with different sizes, in different locations and concentrations through a bulk heterojunction organic solar cell structure has also been performed. Results: It has been demonstrated that embedding nanostructures in different locations of the cell, specifically in the active layer and the hole transporting layer had a considerable effect of widening the absorption spectrum and increasing the short circuit current. The effect of incorporation the nanostructures in the active layer has been proved to be greater than in the HTL. Furthermore, the comparison results showed that, PCDTBT:PCBM is no more advantageous over P3HT:PCBM and PCPDTBT:PCBM, and P3HT:PCBM took the lead and showed better performance in terms of absorption spectrum and short circuit current value. Conclusion: This work revealed the significant effect of size, location and concentration of the Ag nanostructures while incorporated in the organic solar cell. In fact, embedding nanostructures in the solar cell widen the absorption spectrum and increases the short circuit current, this result has been proven to be significant only when the nanostructures are inserted in the active layer following specific dimensions and structures.

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