- Eremophilane derivatives and other constituents from Senecio species
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The investigation and reinvestigation respectively of 23 Senecio species afforded 11 further cacalol derivatives, a furoeremophilone, 17 eremophilanes, 4 bisabolene derivatives, a shikimic acid derivative, a bis-prenylated p-hydroxybenzaldehyde, menth-2-en- 1,7-diol and a cumol derivative. The configuration of some eremophilanes have been revised. Structures were elucidated by spectroscopic methods. The results are summarized in a table. The chemotaxonomic aspects agree with those of previous investigations.
- Bohlmann, Ferdinand,Zdero, Christa,Jakupovic, Jasmin,Misra, Laxmi N.,Banerjee, Shanta,Singh, Pahup,Baruah, Robindra N.,Metwally, Mohamed A.,Schmeda-Hirschmann, Guillermo,Vincent, Leszek P.D.,King, Robert M.,Robinson, Harold
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Read Online
- A Method for preparing alpha-olefins from Biomass-derived fat and oil
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The present invention relates to a method for preparing alpha-olefins from biomass-derived fats and oils. According to the preparation method, all of the various saturated or unsaturated fatty acids in the biomass-derived fats and oils can be prepared into alpha-olefins, and a conventional problem that the saturated fatty acids do not participate in a reaction or a mixture is generated due to polyunsaturated fatty acids can be solved. Thus, the present invention can be advantageously used to prepare alpha-olefins from biomass.
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Paragraph 0143-0146
(2020/09/22)
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- Unexpected AChE inhibitory activity of (2E)α,β-unsaturated fatty acids
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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.
- Loesche, Anne,Wiemann, Jana,Al Halabi, Zayan,Karasch, Julia,Sippl, Wolfgang,Csuk, René
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supporting information
p. 3315 - 3319
(2018/09/17)
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- Allyl-Palladium-Catalyzed α,β-Dehydrogenation of Carboxylic Acids via Enediolates
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A highly practical and step-economic α,β-dehydrogenation of carboxylic acids via enediolates is reported through the use of allyl-palladium catalysis. Dianions underwent smooth dehydrogenation when generated using Zn(TMP)2?2 LiCl as a base in the presence of excess ZnCl2, thus avoiding the typical decarboxylation pathway of these substrates. Direct access to 2-enoic acids allows derivatization by numerous approaches.
- Zhao, Yizhou,Chen, Yifeng,Newhouse, Timothy R.
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supporting information
p. 13122 - 13125
(2017/09/13)
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- The synthesis of pseudomycin C′ via a novel acid promoted side-chain deacylation of pseudomycin A
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The γ hydroxyl present in the aliphatic side chain of the natural products pseudomycin A and C′ provided a unique handle for the pH dependent side-chain deacylation. Low pH reaction conditions were used to cleave the side chain with minimal degradation of the peptide core. The pseudomycin nucleus intermediate obtained from the deacylation of pseudomycin A was pivotal in the synthesis of novel side-chain analogues. A practical synthesis of a minor fermentation factor pseudomycin C′ and related analogues is reported.
- Rodriguez, Michael J.,Belvo, Matthew,Morris, Robert,Zeckner, Douglas J.,Current, William L.,Sachs, Roberta K.,Zweifel, Mark J.
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p. 161 - 164
(2007/10/03)
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- Method for the preparation of an alkynyl compound
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A novel and efficient method is proposed for the synthetic preparation of a long-chain alkynyl compound in a one-pot reaction without isolating the intermediate from the reaction mixture. The inventive method comprises the steps of: (a) a Grignard coupling reaction of an ω-halogeno-1-alkynyl magnesium halide compound of the general formula X1 MgC C(CH2)n X2, in which X1 is a halogen atom, X2 is an atom of Br or I and n is 3 to 10, and a Grignard reagent of the general formula RMgX1, in which R is a group selected from the class consisting of alkyl groups, alkenyl groups, alkynyl groups, alkapolyenyl groups, aryl groups and hydrocarbon groups having protected hydroxy group to give an intermediate compound of the general formula X1 MgC C(CH2)n R; (b) subjecting the intermediate compound to a reaction with a reactant selected from the class consisting of C2 -synthons, C1 -synthons and chlorosilane compounds having reactivity with the intermediate compound at the X1 Mg-terminal; and (c) hydrolyzing the reaction product obtained in step (b).
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- A New Route to Racemic erythro-Sphingosine and Ceramides. The 1,2-versus 1,4-Addition Reaction of Hexadec-2-enal with 2-Nitroethanol
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The reaction of hexadec-2-enal (5) with 2-nitroethanol (3) in triethylamine gave the 1,2-adducts (8) and (9), while the reaction in methanol-potassium carbonate gave the Michael adducts (6) and (7).Epimerization of the threo-acetonide (10) smoothly gave the erythro-acetonide (11), which gave the amino acetonide (12) on reduction.Phthaloylation, deacetalization, and deprotection of compound (12) gave rac-erythro-sphingosine (1).On the other hand, acylation and deacetalization of compound (12) gave the ceramide (16).
- Hino, Tohru,Nakakyama, Kiyoshi,Taniguchi, Mikio,Nakagawa, Masako
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p. 1687 - 1690
(2007/10/02)
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