57402-36-5Relevant academic research and scientific papers
Synthesis and Raman spectra of 3-deoxy-α-l-rhamnosides as model sugars of the Ascaris egg shell
Joly, Jean-Pierre,Roze, Frédéric,Banas, Sandrine,Quilès, Fabienne
, p. 3236 - 3241 (2010)
The synthesis of two 3-deoxy-α-l-rhamnosides (i.e., 3,6-dideoxy-l-arabino-hexopyranosides) as models of ascaroside natural products is reported. The present approach is based on a Ferrier rearrangement from l-rhamnal, epoxidation of the resulting glycal and reductive opening of the isolated β-epoxide. The 3-deoxy-α-rhamnoside linked to a long aglycone chain was used to ascertain by Raman vibrational spectroscopy the presence of this peculiar sugar in the inner shell of Ascaris eggs.
Unexpected AChE inhibitory activity of (2E)α,β-unsaturated fatty acids
Loesche, Anne,Wiemann, Jana,Al Halabi, Zayan,Karasch, Julia,Sippl, Wolfgang,Csuk, René
, p. 3315 - 3319 (2018/09/17)
A small library of (E) α,β-unsaturated fatty acids was prepared, and 20 different saturated and mono-unsaturated fatty acids differing in chain length were subjected to Ellman's assays to determine their ability to act as inhibitors for AChE or BChE. While the compounds were only very weak inhibitors of BChE, seven molecules were inhibitors of AChE holding IC50 = 4.3–12.8 M with three of them as significant inhibitors of this enzyme. The results have shown trans 2-mono-unsaturated fatty acids are better inhibitors for AChE than their saturated analogs. Furthermore, the screening results indicate that the chain length is crucial for obtaining an inhibitory efficacy. The best results were obtained for (2E) eicosenoic acid (14) showing inhibition constants Ki = 1.51 ± 0.09 M and Ki′ = 7.15 ± 0.55 M. All tested compounds were mixed-type inhibitors with a dominating competitive part. Molecular modelling calculations indicate a different binding mode of active/inactive compounds for the enzymes AChE and BChE.
Amplifying (Im)perfection: The Impact of Crystallinity in Discrete and Disperse Block Co-oligomers
Van Genabeek, Bas,Lamers, Brigitte A. G.,De Waal, Bas F. M.,Van Son, Martin H. C.,Palmans, Anja R. A.,Meijer
supporting information, p. 14869 - 14872 (2017/10/31)
Crystallinity is seldomly utilized as part of the microphase segregation process in ultralow-molecular-weight block copolymers. Here, we show the preparation of two types of discrete, semicrystalline block co-oligomers, comprising an amorphous oligodimethylsiloxane block and a crystalline oligo-l-lactic acid or oligomethylene block. The self-assembly of these discrete materials results in lamellar structures with unforeseen uniformity in the domain spacing. A systematic introduction of dispersity reveals the extreme sensitivity of the microphase segregation process toward chain length dispersity in the crystalline block.
Identification of β-hydroxy fatty acid esters and primary, secondary-alkanediol esters in cuticular waxes of the moss Funaria hygrometrica
Busta, Lucas,Budke, Jessica M.,Jetter, Reinhard
, p. 38 - 49 (2015/12/01)
The plant cuticle, a multi-layered membrane that covers plant aerial surfaces to prevent desiccation, consists of the structural polymer cutin and surface-sealing waxes. Cuticular waxes are complex mixtures of ubiquitous, typically monofunctional fatty acid derivatives and taxon-specific, frequently bifunctional specialty compounds. To further our understanding of the chemical diversity of specialty compounds, the waxes on the aerial structures of the leafy gametophyte, sporophyte capsule, and calyptra of the moss Funaria hygrometrica were surveyed. Respective moss surfaces were extracted, and resulting lipid mixtures were analyzed by gas chromatography-mass spectrometry (GC-MS). The extracts contained ubiquitous wax compound classes along with two prominent, unidentified classes of compounds that exhibited some characteristics of bifunctional structures. Microscale transformations led to derivatives with characteristic MS fragmentation patterns suggesting possible structures for these compounds. To confirm the tentative structure assignments, one compound in each of the suspected homologous series was synthesized. Based on GC-MS comparison with the authentic standards, the first series of compounds was identified as containing esters formed by β-hydroxy fatty acids and wax alcohols, with ester chain lengths varying from C42 to C50 and the most prominent homolog being C46. The second series consisted of fatty acid esters of 1,7-alkanediols, linked via the primary hydroxyl group, with ester chain lengths C40-C52 also dominated by the C46 homolog. The β-hydroxy acid esters were restricted to the sporophyte capsule, and the diol esters to the leafy gametophyte and calyptra. Based on their homolog and isomer distributions, and the presence of free 1,7-triacontanediol, possible biosynthetic reactions leading to these compounds are discussed.
Palladium-catalyzed reduction of carboxylic acids to aldehydes with hydrosilanes in the presence of pivalic anhydride
Fujihara, Tetsuaki,Cong, Cong,Terao, Jun,Tsuji, Yasushi
supporting information, p. 3420 - 3424 (2013/12/04)
A palladium catalyst system that allows the reduction of carboxylic acids to the corresponding aldehydes with hydrosilanes as reducing agent and pivalic anhydride as an indispensable reagent has been developed. A simple mixture of commercially available bis(dibenzylideneacetone)palladium(0) [Pd(dba) 2], tri(para-tolyl)phosphane and methylphenylsilane realized the reduction of various aliphatic carboxylic acids as well as benzoic acids to aldehydes in good to high yields. Copyright
The synthesis of long-chain α-alkyl-β-hydroxy esters using allylic halides in a Frater-Seebach alkylation
Khan, Ashna A.,Chee, Stephanie H.,Stocker, Bridget L.,Timmer, Mattie S. M.
supporting information; experimental part, p. 995 - 1002 (2012/03/27)
The Frater-Seebach alkylation is a highly efficient means to diastereoselectively introduce α-substituents to chiral β-hydroxy esters, however, the yields of reactions in which longer chain alkyl halides are used can be disappointing. To provide a more robust protocol for the alkylation of β-hydroxy esters, we prepared a variety of long-chain allylic iodides with the view that the greater reactivity of the allylic system would lead to enhanced efficiency. Indeed, for all substrates studied, the yield of the α-alkylation was greatly improved for the unsaturated allylic halides compared to their analogous saturated counterparts. Our methodology thus provides an improved means by which to access a variety of important lipophilic compounds such as mycolic acids, which are found on the cell wall of M. tuberculosis. An improved methodology for the introduction of α-substituents to chiral β-hydroxy esters using Frater-Seebach methodology is presented. Long-chain allylic iodides resulted in better yields for the α-alkylation compared to their saturated counterparts. This methodology provides an improved means by which to access a variety of important lipophilic compounds such as mycolic acids. Copyright
Palladium-catalyzed reduction of acid chlorides to aldehydes with hydrosilanes
Fujihara, Tetsuaki,Cong, Cong,Iwai, Tomohiro,Terao, Jun,Tsuji, Yasushi
, p. 2389 - 2392 (2013/07/19)
An efficient synthesis of aldehydes from acid chlorides with hydrosilanes as a reducing agent in the presence of a palladium catalyst has been achieved. A simple mixture of commercially available Pd(dba)2 and Mes 3P as a catalyst realized the reduction of various acid chlorides including aliphatic acid chlorides and a, P-unsaturated acid chlorides to the corresponding aldehydes in good to high yields under mild reaction conditions. Georg Thieme Verlag Stuttgart ? New York.
Semivolatile and volatile compounds in combustion of polyethylene
Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
, p. 615 - 627 (2007/10/03)
The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
Syntheses of the Macrocyclic Spermine Alkaloids (+/-)-Budmunchiamine A-C
Popaj, Kasim,Hesse, Manfred
, p. 180 - 186 (2007/10/03)
The syntheses of four macrocyclic spermine alkaloids, (+/-)-budmunchiamine A-C (1a-c) and (+/-)-budmunchiamine L4 (1), were accomplished by Michael addition of spermine to the α,β-unsaturated esters 3a-d, followed by cyclization of the resulting α,ω-tetraamino esters 4a-d with triethoxyantimony; N-methylation of the amino lactams 6a-c yielded the budmunchiamines A-C (1a-c).
Identification of 1-octacosanal and 6-methoxy-2-benzoxazolinone from wheat as ovipositional stimulants for Hessian fly, Mayetiola destructor
Morris, Bruce D.,Foster, Stephen P.,Harris, Marion O.
, p. 859 - 873 (2007/10/03)
Bioassay-guided fractionations of a dichloromethane extract of wheat epicuticular wax allowed the identification of 1-octacosanal and 6-methoxy-2- benzoxazolinone (MBOA) as the major components that stimulate oviposition by the Hessian fly, Mayetiola destructor. These compounds were identified by their mass spectral fragmentation patterns and by comparison of their gas chromatographic retention times with synthetic samples. Synthetic samples of 1-octacosanal or MBOA stimulated significant oviposition when compared with solvent controls. In combination, these compounds elicited a synergistic effect on the number of eggs laid by females compared to when they were presented alone. In a choice bioassay, a mixture of synthetic 1-octacosanal and MBOA in the approximate concentrations determined to be present in one plant equivalent of crude extract stimulated the same amount of oviposition as one plant equivalent of extract. This showed that together these two compounds appear to be responsible for the major proportion of the ovipositional stimulatory activity of the wheat epicuticular wax extract. Comparison of the activity of five straight-chain primary aldehydes with chain lengths from C22 to C30 revealed a relationship between chain length and the number of eggs laid by female Hessian flies, with 1- hexacosanal and 1-heptacosanal the most active of the aldehydes tested.
