- Total synthesis of the proposed structure of trichodermatide A
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A short total synthesis of the published structure of racemic trichodermatide A is reported. Our synthesis involves a Knoevenagel condensation/Michael addition sequence, followed by the formation of tricyclic hexahydroxanthene-dione and a diastereoselective bis-hydroxylation. The final product, the structure of which was confirmed by X-ray crystallography, has NMR spectra that are very similar, but not identical, to those of the isolated natural product. Quantum chemically computed 13C shifts agree well with the present NMR measurements. (Chemical Equation Presented).
- Myers, Eddie,Herrero-Gmez, Elena,Albrecht, Irina,Lachs, Jennifer,Mayer, Peter,Hanni, Matti,Ochsenfeld, Christian,Trauner, Dirk
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- A CONVENIENT METHOD FOR THE STEREOSPECIFIC SYNTHESIS OF (E)-3-ALKEN-1-OLS UTILIZING THE RING-OPENING REACTION OF 2,3-DIHYDROFURAN WITH ORGANOCUPRATES
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(E)-3-Alken-1-ols were stereospecifically synthesized in good yields utilizing the regioselective nucleophilic ring-opening reaction of 2,3-dihydrofuran with several kinds of organocuprates under mild conditions.
- Fujisawa, Tamotsu,Kurita, Yoshitsugu,Kawashima, Masatoshi,Sato, Toshio
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- Metal/Ammonia Reduction of Ethers of 3-Decyn-1-ol: Effects of Structure and Conditions on Cleavage and Rearrangement
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Reduction of the THP, ethyl, tert-butyl and tert-butyldimethylsilyl (TBDMS) ethers of 3-decyn-1-ol with sodium in ammonia/THF results in extensive hydrogenolysis of the carbon-oxygen bond and concomitant bond migration, producing a mixture of 2- and 3-decenes and a very low yield of the desired (E)-homoallylic ether.Reduction in the presence of 2-methyl-2-propanol led to excellent yields of the desired (E)-3-decenol ethers.The 4- and 5-decyn-1-ol ethers were reduced normally to the (E)-decen-1-ol ethers except in the case of the TBDMS ethers which were cleaved to the (E)-alcohols under some of the reaction conditions.
- Doolittle, Robert E.,Patrick, Delrea G.,Heath, Robert H.
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- INTRAMOLECULAR HYDROSILATION OF ACETYLENES: REGIOSELECTIVE FUNCTIONALIZATION OF HOMOPROPARGYL ALCOHOLS
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Platinum-catalyzed intramolecular hydrosilation of hydrodimethylsilyl ethers of homopropargyl alcohols proceeds regioselectively in a 5-exo-dig mode.The resulting vinylsilanes can be transformed into 3-alkanon-1-ol and 3-bromo-3-alken-1-ol derivatives by H2O2 oxidation and bromine cleavage, respectively.
- Tamao, Kohei,Maeda, Kimio,Tanaka, Tetsu,Ito, Yoshihiko
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- THE BETAIN-YLID ROUTE TO TRANS-ALKENOLS
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The trans-selective variant of the Wittig reaction can be successfully applied to the synthesis of alkenol-type pheromones.
- Schlosser, Manfred,Tuong, Huynh Ba,Schaub, Bruno
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- CYCLOALKYL-CONTAINING CARBOXYLIC ACIDS AND USES THEREOF
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The present application discloses a compound of formula (I) or a salt thereof: (I) and compositions comprising such compound or salt thereof. The use of such compound, salt thereof or composition comprising same for treating anemia or leukopenia, fibrosis, cancer, hypertension and/or a metabolic condition in a subject is also disclosed.
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Page/Page column 47; 69
(2021/06/26)
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- Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
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A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
- Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
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p. 2278 - 2290
(2019/06/17)
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- Influence of the chemical structure on odor qualities and odor thresholds in homologous series of alka-1,5-dien-3-ones, alk-1-en-3-ones, alka-1,5-dien-3-ols, and alk-1-en-3-ols
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Odor qualities and odor thresholds in air in homologous series of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding ketones were evaluated by gas chromatography-olfactometry. In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality changed successively from pungent for the compounds with five carbon atoms via metallic, vegetable-like for the six- and seven-carbon odorants to mushroom-like for the compounds with eight and nine carbon atoms. With further increase in chain length the mushroom-like impression decreased and changed to citrus-like, soapy, or herb-like. In both series, two odor threshold minima were found for the six-carbon and also for the eight- and nine-carbon odorants, respectively. In contrast to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding ketones did not change significantly with geranium-like, metallic odors and an increasing mushroom-like odor note with increasing chain length. The lowest thresholds were found for the eight- and nine-carbon (Z)-compounds, respectively.
- Lorber, Katja,Schieberle, Peter,Buettner, Andrea
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p. 1025 - 1031
(2014/03/21)
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- Influence of the chemical structure on odor qualities and odor thresholds in homologous series of alka-1,5-dien-3-ones, alk-1-en-3-ones, alka-1,5-dien-3-ols, and alk-1-en-3-ols
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Odor qualities and odor thresholds in air in homologous series of synthesized alk-1-en-3-ols and alka-1,5-dien-3-ols and their corresponding ketones were evaluated by gas chromatography-olfactometry. In the series of the alk-1-en-3-ols and alk-1-en-3-ones the odor quality changed successively from pungent for the compounds with five carbon atoms via metallic, vegetable-like for the six- and seven-carbon odorants to mushroom-like for the compounds with eight and nine carbon atoms. With further increase in chain length the mushroom-like impression decreased and changed to citrus-like, soapy, or herb-like. In both series, two odor threshold minima were found for the six-carbon and also for the eight- and nine-carbon odorants, respectively. In contrast to this, the odor qualities in the series of the (Z)- and (E)-alka-1,5-dien-3-ols and their corresponding ketones did not change significantly with geranium-like, metallic odors and an increasing mushroom-like odor note with increasing chain length. The lowest thresholds were found for the eight- and nine-carbon (Z)-compounds, respectively.
- Lorber, Katja,Schieberle, Peter,Buettner, Andrea
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p. 1025 - 1031
(2015/04/22)
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- Stereoselective total synthesis of the nonenolide (+)-microcarpalide
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The enantiomer [(+)-1] of the nonenolide natural product microcarpalide [(-)-1] has been prepared from (S)-malic acid (3) and 3-decyn-1-ol (11) via a sixteen step sequence involving, inter alia, two metathesis processes.
- Banwell, Martin G.,Loong, David T. J.
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p. 713 - 734
(2007/10/03)
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- Total synthesis of gibbilimbols A-D
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Gibbilimbols A-D (1-4) were synthesized in 32-49% yield over four steps from commercially available starting materials. A copper-catalyzed coupling of 4-methoxyphenylmagnesium bromide with various unsaturated alkyl bromides was the key step in assembling the (long-chain alkyl)-phenol skeleton.
- Vyvyan, James R.,Holst, Christian L.,Johnson, Allison J.,Schwenk, Cheryl M.
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p. 2263 - 2265
(2007/10/03)
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- Mesogenic materials with anomalous birefringence dispersion and high second order susceptibility (X(2)).
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This invention provides LC compositions useful as birefringent materials in electrooptic devices which exhibit zero or low negatively sloped birefringence dispersion (e.g., exhibiting positive birefringence dispersion significantly lower than that of currently available LC compositions) or more preferably positively sloped birefringence dispersion in which birefringence of the material increases with wavelength. The invention provides compounds useful as components of LC compositions which exhibit negative birefringence where no is higher than ne. The compounds of this invention are dimers of LC-like compounds in which the monomers are linked to each other through a high birefringence moiety (dimerization linker). The LC monomers consist of an LC core and one or two tail groups. Preferred monomers for this invention have low birefringence in comparison to the birefrigence of the monomer linking moiety. The dimers have normal positive birefringence dispersion to have birefringence that is lower in absolute value at longer wavelengths. But since they have negative birefringence, their birefringence actually increases (i.e., goes less negative) as wavelength increases.
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- A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes
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A detailed study shows that the chiral ketone catalyzed asymmetric epoxidations of hydroxyalkenes are highly pH dependent. The lower enantioselectivity obtained at low pH is attributed to the substantial contribution of the direct epoxidation by Oxone. At high pH the epoxidation mediated by chiral ketone out-competes the racemic epoxidation, leading to higher enantioselectivity. The effective substrates include allylic alcohol, homoallylic alcohol, and bishomoallylic alcohol. In most cases, over 90% ee was obtained.
- Wang, Zhi-Xian,Shi, Yian
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p. 3099 - 3104
(2007/10/03)
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- SYNTHESIS OF DODEC-5E-EN-1-OL - THE PHEROMONE OF TRICIMBA CINCTA - AND TETRADEC-5E-1-YL ACETATE - AN IMITATOR OF THE PHEROMONE OF RHYNCHOPACHA SP.
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On the basis of a modified Knoevenagel reaction starting from octanal and decanal, the stereodirected synthesis has been effected of dodec-5E-en-ol (the pheromone of the grass fly Tricimba cincta - and tetradec-5E-en-yl acetate) an imitator of the pheromone of the moth Rhynchopacha sp.
- Verba, G. G.,Bukulova, L. M.,Abduvakhabov, A. A.,Kamaev, F. G.
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p. 113 - 116
(2007/10/02)
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- The Copper(I)-catalysed Coupling of Grignard Reagents with 5-Lithio-2,3-dihydrofuran and 6-Lithio-3,4-dihydro-2H-pyran
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The organocuprates derived from reaction of Grignard reagents with CuBr*Me2S react with 5-lithio-2,3-dihydrofuran and 6-lithio-3,4-dihydro-2H-pyran via a 1,2-metallate rearrangement to generate an alkenylmagnesium cuprate.
- Barber, Christopher,Bury, Paul,Kocienski, Philip,O'Shea, Michael
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p. 1595 - 1597
(2007/10/02)
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- MODIFIED KNOEVENAGEL CONDENSATIONS. SYNTHESIS OF (E)-3-ALKENOIC ACIDS.
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Condensation of aliphatic aldehydes with a three molar excess of malonic acid and 0.001 mole piperidinium acetate in refluxing xylene, with continuous removal of the water formed, gave almost exclusively (E)-3-alkenoic acids, in good yield (60-85percent) and of high stereochemical purity (95-99percent).
- Ragoussis, Nikitas
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