- Further Improvements of the Synthesis of Alkynes from Aldehydes
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A highly convenient way to perform the synthesis of alkynes from aldehydes is reported. The procedure utilizes a new in situ preparation of dimethyldiazomethylphosphonate. As a consequence a commercially available reagent can now be used, circumventing a disadvantage of earlier protocols. The easy one-pot procedure avoids the use of strong bases, low temperatures and inert gas techniques.
- Roth, Gerald J.,Liepold, Bernd,Müller, Stephan G.,Bestmann, Hans Jürgen
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- Activity-Based Probes for 15-Lipoxygenase-1
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Human 15-lipoxygenase-1 (15-LOX-1) plays an important role in several inflammatory lung diseases, such as asthma, COPD, and chronic bronchitis, as well as various CNS diseases, such as Alzheimer's disease, Parkinson's disease, and stroke. Activity-based probes of 15-LOX-1 are required to explore the role of this enzyme further and to enable drug discovery. In this study, we developed a 15-LOX-1 activity-based probe for the efficient activity-based labeling of recombinant 15-LOX-1. 15-LOX-1-dependent labeling in cell lysates and tissue samples was also possible. To mimic the natural substrate of the enzyme, we designed activity-based probes that covalently bind to the active enzyme and include a terminal alkene as a chemical reporter for the bioorthogonal linkage of a detectable functionality through an oxidative Heck reaction. The activity-based labeling of 15-LOX-1 should enable the investigation and identification of this enzyme in complex biological samples, thus opening up completely new opportunities for drug discovery.
- Eleftheriadis, Nikolaos,Thee, Stephanie A.,Zwinderman, Martijn R. H.,Leus, Niek G. J.,Dekker, Frank J.
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- Synthesis of alkynes from vinyl triflates using tetrabutylammonium fluoride
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A convenient method for the preparation of alkynes and alkynyl esters from ketones and β-keto esters is described which involves the formation of vinyl triflates, followed by elimination with tetrabutylammonium fluoride trihydrate, to give alkynes. Unlike established elimination methods, the method requires neither a strong base nor anhydrous conditions.
- Okutani, Masaru,Mori, Yuji
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p. 393 - 396
(2015/06/17)
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- In situ generation of the Ohira-Bestmann reagent from stable sulfonyl azide: Scalable synthesis of alkynes from aldehydes
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We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench-stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a scalable and convenient approach for the transformation of aldehydes into terminal alkynes. The method features an easier workup compared to the existing in situ protocol due to increased aqueous solubility of waste products.
- Jepsen, Tue Heesgaard,Kristensen, Jesper Langgaard
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p. 9423 - 9426
(2015/02/19)
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- Studies towards the identification of the sex pheromone of Thyrinteina arnobia
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The eucalyptus brown-looper Thyrinteina arnobia (Lepidoptera: Geometridae) is considered an important pest in Brazilian native plants, e.g. Psidium guajava, and exotic plants, such as Eucalyptus species. In this work we describe the isolation of the pheromone components of T. arnobia, using glands extract and solid phase micro extraction (SPME) of virgin females. The samples were analyzed by gas chromatography with an electroantennographic detector (GC-EAD), and mass spectrometry (GC-MS). Two reproducible electroantennographic responses were elicited in the male antenna of T. arnobia and one of them was identified as 3,4-epoxy-6,9-heneicosadiene by CG-MS. The racemic synthesis of this epoxydiene was carried out in 10 steps and 28percent overall yield. The four stereoisomers of the epoxydiene were also synthesized employing the corresponding enantiomeric enriched epoxyalcohols.
- Moreira, Jardel A.,Neppe, Tiago,De Paiva, Marcelo M.,Deobald, Anna M.,Batista-Pereira, Luciane G.,Paixa?o, Marcio W.,Corre?a, Arlene G.
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p. 1933 - 1941
(2014/01/06)
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- Fritsch-Buttenberg-Wiechell rearrangement to alkynes from gem-dihaloalkenes with lanthanum metal
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The first example of the FBW rearrangement using of lanthanum metal and a catalytic amount of iodine was disclosed. When gem-diiodo- and gem-dibromoalkenes were treated with lanthanum metal in the presence of a catalytic amount of iodine, the reductive dehalogenation of these compounds smoothly proceeded to produce the corresponding alkynes in moderate to good yields.
- Umeda, Rui,Yuasa, Takumi,Anahara, Namika,Nishiyama, Yutaka
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supporting information; experimental part
p. 1916 - 1919
(2011/05/14)
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- Thieme Chemistry Journal Awardees - Where are they now? A general one-step synthesis of alkynes from enolisable carbonyl compounds
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Terminal and internal acetylenes were obtained in good to excellent isolated yields from carbonyl compounds by converting the carbonyl functionality into the enol nonaflate intermediate followed by elimination to give the C-C triple bond. The one-pot transformations were uniformly induced by phosphazene bases combined with mildly electrophilic nonafluorobutane-1-sulfonyl fluoride. The method is the most general among those reported to date as it applies to both acyclic ketones and aldehydes. Only moderate kinetic regioselectivity in favour of alk-1-yne achieved from methyl n-alkyl ketone represents a limitation of the method. In all the other instances, individual acetylenic products were obtained. Georg Thieme Verlag Stuttgart.
- Lyapkalo, Ilya M.,Vogel, Michael A. K.,Boltukhina, Ekaterina V.,Vav?ík, Ji?í
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scheme or table
p. 558 - 561
(2009/07/09)
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- Tetrabutylammonium fluoride-induced dehydrobromination of vinyl bromides to terminal acetylenes
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Tetrabutylammonium fluoride (TBAF) was found to be a mild and efficient base for the dehydrobromination of vinyl bromides. Treatment of various 2-bromo-1-alkenes with TBAF·3H2O in DMF yielded terminal acetylenes in high yields without undue regard to the presence of water.
- Okutani, Masaru,Mori, Yuji
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p. 6856 - 6859
(2008/02/12)
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- Modular approach to the synthesis of unsaturated 1-monoacyl glycerols
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A modular synthesis of unsaturated 1-monoacylglycerols (1) from cis-1-iodo-1-alkenes [cis-RCH=CHI] and unsaturated carboxylic acids [CH 2=CH(CH2)nCO2H] is described. The method revolves around a Suzuki coupling to establish olefin geometry.
- Coleman, Bridgett E.,Cwynar, Valerie,Hart, David J.,Havas, Fabien,Jakkam, Madan Mohan,Patterson, Suzanne,Ridenour, Sam,Schmidt, Michael,Smith, Eboney,Wells, Angela J.
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p. 1339 - 1342
(2007/10/03)
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- Synthesis of gem-dideuterated tetradecanoic acids and their use in investigating the enzymatic transformation of (Z)-11-tetradecenoic acid into (E,E)-10,12-tetradecadienoic acid
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We report the preparation of the deuterated tetradecanoic acids [2,2,3,3-2H4]-, [2,2,3,3,10,10-2H6]-, and [2,2,3,3,13,13-2H6]-tetradecanoic acids (1, 2, and 3, respectively) and their use to investigate the mechanism of the enzymatic transformation of (Z)-11-tetradecenoic acid into (E,E)-10,12-tetradecadienoic acid. Probes 2 and 3 were prepared from intermediate ketones 7 and 10, which were transformed into the labeled bromides 17 and 18 by reduction with NaBD4, tosylation of the resulting alcohol, replacement of the tosyloxy group by deuteride with LiAlD4, hydrolysis, and reaction with N-bromosuccinimide. The resulting bromides were converted into the α-acetylenic esters 21 and 22, respectively, and the additional deuterium labels were introduced by reduction of the conjugated triple bond with Mg in deuterated methanol. The same sequence of reactions starting with 11-bromoundecane afforded 27. Saponification of the labeled esters 23, 24, and 27 gave the deuterated acids 2, 3, and 1, respectively. The results of the biochemical experiments showed that C10-H removal, but not elimination of C13-H, was sensitive to deuterium substitution in the transformation of (Z)-11-tetradecenoic acid into (E,E)-10,12-tetradecadienoic acid, which is consistent with the hypothesis that this desaturase reaction involves a first slow, C10-H bond cleavage, with probable formation of an unstable allylic intermediate, followed by a second fast C13-H bond removal and concomitant rearrangement.
- Rodriguez, Sergio,Camps, Francisco,Fabrias, Gemma
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p. 8052 - 8058
(2007/10/03)
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- Biologically Active Glycosides from Asteroidea, XXIV. Stereochemistry of the Four Diastereomers of Phytosphingosine
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Diastereomeric D-ribo-(2S,3S,4R)-, D-lyxo-(2S,3S,4S)-, D-arabino-(2S,3R,4S)-, and D-xylo-(2S,3R,4R)-C16-phytosphingosine tetraacetates 2-5 were synthesized from the oxazoline 11 derived from (S)-serine.Detailed physical data were obtained and the stereochemistry can be readily identified, regardless of any new phytosphingosine moiety of the glucosphingolipids which may be detected in nature.
- Sugiyama, Shigeo,Honda, Masanori,Komori, Tetsuya
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p. 1069 - 1078
(2007/10/02)
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- PROTOTROPIC ISOMERIZATION OF ACETYLENIC HYDROCARBONS AND ALCOHOLS UNDER THE INFLUENCE OF LITHIUM 2-AMINOETHYLAMIDE IN ETHYLENEDIAMINE
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The system containing lithium 2-aminoethylamide in ethylenediamine is an effective system for the production of acetylenic hydrocarbons and alcohols with a terminal triple bond.As a result of prototropic isomerization in this system 5-dodecyne, 4-tridecyne, 7-tetradecyne, 2-heptyn-1-ol, 2-nonyn-1-ol, and 2-undecyn-1-ol gave high yields of the corresponding isomers with a terminal triple bond, i.e., 1-dodecyne, 1-tridecyne, 1-tetradecyne, 6-heptyn-1-ol, 8-nonyn-1-ol, and 10-undecyn-1-ol.The synthesis of the long-chain alcohol 8,10-heneicosadiyn-1-ol was realized from the compounds containing a triple bond.
- Remizova, L. A.,Kryukov, A. V.,Balova, I. A.,Favorskaya, I. A.
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p. 909 - 912
(2007/10/02)
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