- Synthesis and nuclear magnetic resonance spectroscopic properties of some acetylenic tellura fatty acid esters
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Five positional isomers of acetylenic tellura stearate (-5) have been synthesized by three different routes.The number of methylene groups located between the acetylenic system and the tellurium metal varies from 0 to 4.The 1H and 3C NMR spectroscopic properties have been studied.The tellurium atom induces strong deshielding effects on the adjacent methylene protons, which in combination with the deshielding effects of the acetylenic system allows most of the methylene groups between the tellurium and the triple bond to be identified by 1H NMR spectroscopic analysis.The tellurium causes a very strong shielding effects (ca. -27.1 ppm) on the carbon shift of the adjacent α-methylene carbon atom, but weak deshielding effect on the β-(ca. +2.6 ppm) and γ-(ca. +2.3 ppm) methylene carbon atoms.Carbon shifts of methylene carbon atoms, especially those which are located between the tellurium atom and the triple bond, are found very much upfield (δc 0.65-4.81) and in one case in the negative region (δc -17.95) of the 13C NMR spectrum.Most of the signals of the carbon nuclei of these analogue have been identified and from the results of these analyses the number of methylene groups between the acetylenic system and the tellurium atom can be determined. - Keywords: acetylenic, NMR spectroscopy; positional isomers; synthesis; unsaturated tellura; stearate analogues
- Jie, Marcel S. F. Lie Ken,Chau, Sherman H.
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- A New Aldol Condensation of α-Allenic Esters with Aldehydes, Including a One-Pot Synthesis of Enyne Compounds
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DABCO-catalyzed condensations of ethyl 2,3-butadienoate (1a) with aldehydes at -6 to 25 deg C gave 3-hydroxy-2-vinylidenealkanoates 3 in 41-54percent yields.Butyllithium-promoted condensations of 1a with aldehydes at -105 to -70 deg C afforded 3 in 56-67p
- Tsuboi, Sadao,Kuroda, Hirofumi,Takatsuka, Satoshi,Fukawa, Takashi,Sakai, Takashi,Utaka, Masanori
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Read Online
- Synthesis method of gypsy moth sex pheromone
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The invention belongs to the technical field of chemical synthesis, and particularly relates to an efficient synthesis method of gypsy moth sex pheromone. According to the synthesis method of gypsy moth sex pheromone, silica gel immobilized ionic liquid is added as a catalyst in the step of asymmetric epoxidation based on an existing synthesis method, so that the Sharpless reaction is effectivelypromoted, the product synthesis rate in the step is increased from 60% to 85%, the synthesis rate of the whole reaction process is further greatly increased, and the synthesis efficiency of the gypsymoth sex pheromone is effectively improved.
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Paragraph 0008; 0033-0035
(2020/07/13)
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- Total Syntheses of (R)-Strongylodiols C and D
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The first total syntheses of two marine natural products, (R)-strongylodiols C and D, with 99% ee were achieved. The key steps of the strategy include the zipper reaction of an alkyne, the asymmetric alkynylation of an unsaturated aliphatic aldehyde catalyzed with Trost's ProPhenol ligand, and the Cadiot-Chodkiewicz cross-coupling reaction of a chiral propargylic alcohol with a bromoalkyne.
- Liu, Feipeng,Zhong, Jiangchun,Li, Shuoning,Li, Minyan,Wu, Lin,Wang, Qian,Mao, Jianyou,Liu, Shikuo,Zheng, Bing,Wang, Min,Bian, Qinghua
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supporting information
p. 244 - 247
(2016/02/05)
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- A marine natural product (R, Z) - 24-methyl-twenty-five carbon -16-butene -2,4-diyne -1,6-diol and its antimer synthesis method
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The invention relates to a synthetic method of a marine natural product namely (R, Z)-24-methyl-25-carbon-16-butylene-2,4-diyne-1,6-diol and an enantiomer thereof, and belongs to the field of chemical synthesis. The synthetic method comprises the following steps: firstly, preparing long chain alkyl iodide by using a series of simple reactions including bromination, oxidation, esterification, reduction and the like; and then, performing multiple steps of reactions including coupling, dislocation, oxidation, selective reduction, asymmetric alkynylation addition, esterification, hydrolysis and the like by taking propargyl alcohol and the long chain alkyl iodide as starting materials to synthesize the marine natural product namely (R, Z)-24-methyl-25-carbon-16-butylene-2,4-diyne-1,6-diol and the enantiomer thereof, wherein the key step is that trimethylsilylacetylene and alkynal are subjected to asymmetric addition reaction to generate alkynol segments with high optical purity by one step. The synthetic method provided by the invention reports the synthesis of the natural product of the type for the first time, and has the characteristics of simple and convenient steps, relatively high total yield, good product stereoselectivity and the like, and the optical purity of each of the two types of synthesized products is more than 99%ee.
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Paragraph 0010; 0025-0026
(2020/05/06)
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- A marine natural product (R) - 24-methyl-twenty-five carbon -2, 4, 16- three alkyne -1,6-diol and its antimer synthesis method
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The invention discloses a synthetic method for a marine natural product (R)-24-methyl-pentacosa-2,4,16-trialkynyl-1, 6-diol and enantiomer thereof, which belongs to the field of chemical synthesis. According to the invention, propargyl alcohol is used as a starting material, and a plurality of steps of reactions like coupling, transposition, oxidation, selective reduction, asymmetric alkynylation addition, esterification and hydrolysis are carried out to synthesize the marine natural product and enantiomer thereof; a key step is that trimethyl silicon-based acetylene and alkynal undergo asymmetric addition so as to produce a high-optical purity alkynol fragment in one step; and long-chain iodoalkane added in the process of synthesis is prepared through a series of simple reactions including bromination, oxidation, esterification, reduction and the like, so reaction route is greatly shortened. The synthesis of the natural product provided by the invention is reported for the first time; the synthetic method has the characteristics of simple steps, high total yield, good product stereoselectivity, etc.; and the optical purities of the products with two configurations are both greater than 99% ee.
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Paragraph 0009; 0026-0027
(2019/02/04)
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- Catalytic asymmetric synthesis of (S,4E,15Z)-docosa-4,15-dien-1-yn-3-ol, an antitumor marine natural product
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Abstract An efficient enantioselective total synthesis of an antitumor marine natural product (S,4E,15Z)-docosa-4,15-dien-1-yn-3-ol 1 with 96% ee and 15% overall yield has been achieved; this is the first preparation of 1 via asymmetric catalytic strategy
- Liu, Fei-Peng,Zhong, Jiang-Chun,Zheng, Bing,Li, Shuo-Ning,Gao, Gui,Wang, Zhong-Yu,Li, Min-Yan,Hou, Shi-Cong,Wang, Min,Bian, Qing-Hua
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p. 961 - 965
(2015/09/01)
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- Synthesis of long-chain fatty acid derivatives as a novel anti-Alzheimer's agent
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In order to develop new drugs for Alzheimer's disease, we prepared 17 fatty acid derivatives with different chain lengths and different numbers and positions of double bonds by using Wittig reaction and stereospecific hydrogenation of triple bonds as key reactions. Among them, (4Z,15Z)- octadecadienoic acid (10) and (23Z,34Z)-heptatriacontadienoic acid (16) showed the most potent neurite outgrowth activities on Aβ(25-35)-treated rat cortical neurons, which activities were comparable to that of a positive control, NGF. Both fatty acids 10 and 16 possess two (Z)-double bonds at the n-3 and n-14 positions, which might be important for the neurite outgrowth activity.
- Zhang, Hong-Yan,Yamakawa, Yu-Ichiro,Matsuya, Yuji,Toyooka, Naoki,Tohda, Chihiro,Awale, Suresh,Li, Feng,Kadota, Shigetoshi,Tezuka, Yasuhiro
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p. 604 - 608
(2014/01/23)
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- Scalable synthesis of the pink gypsy moth Lymantria mathura sex pheromone (-)-mathuralure
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Mathuralure (1) is the major sex pheromone component of the pink gypsy moth Lymantria mathura, a potentially devastating invasive species to North America. To support population monitoring of this moth, a gram-scale synthesis of (-)-mathuralure (1) was developed. This process relies on coupling an alkynyl lithium species with a chloroepoxide and provides access to the natural product in a 10% yield over 10 steps.
- Mowat, Jeffrey,Senior, James,Kang, Baldip,Britton, Robert
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supporting information
p. 235 - 239
(2013/05/09)
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- Patterned monolayer self-assembly programmed by side chain shape: Four-component gratings
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A molecular recognition strategy based on alkadiyne side chain shape is used to self-assemble a four-component, 1D-patterned monolayer at the solution-HOPG interface. The designed monolayer unit cell contains six molecules and spans 23 nm × 1 nm. The unit cell's internal structure and packing are driven by complementary shapes and lengths of six different alkadiyne side chains. A solution of the four compounds on HOPG self-assembles monolayers (i) comprised, almost entirely, of the intended unit cell, (ii) exhibiting patterned domains spanning 104 nm2, and (iii) which are sufficiently robust that patterned domains survive solvent rinsing and drying. The patterned monolayer affords 1D-feature spacings ranging from 3.3 to 23 nm. The results demonstrate the remarkable selectivity afforded by molecular recognition based on alkadiyne side chain shape and the ability to program highly complex 1D-patterns in self-assembled monolayers.
- Xue, Yi,Zimmt, Matthew B.
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supporting information; experimental part
p. 4513 - 4516
(2012/04/23)
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- Structure-Activity relationship of aliphatic compounds for nematicidal activity against pine wood nematode (Bursaphelenchus xylophilus)
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Nematicidal activity of aliphatic compounds was tested to determine a structure-activity relationship. There was a significant difference in nematicidal activity among functional groups. In a test with alkanols and 2E-alkenols, compounds with C8-C11 chain length showed 100% nematicidal activity against pine wood nematode, Bursaphelenchus xylophilus, at 0.5 mg/mL concentration. C6-C10 2E-alkenals exhibited >95% nematicidal activity, but the other compounds with C 11-C14 chain length showed weak activity. Nematicidal activity of alkyl acetates with C7-C11 chain length was strong. Compounds belonging to hydrocarbons, alkanals, and alkanoic acetates showed weak activity at 0.5 mg/mL concentration. Nematicidal activity of active compounds was determined at lower concentrations. At 0.25 mg/mL concentration, whole compounds except C8 alkanol, C8 2E-alkenol, and C7 alkanoic acid showed >80% nematicidal activity. C 9-C11 alkanols, C10-C11 2E-alkenols, C8-C9 2E-alkenals, and C9-C10 alkanoic acids showed >80% nematicidal activity at 0.125 mg/mL concentration. Only C11 alkanol exhibited strong nematicidal activity at 0.0625 mg/mL concentration, the lowest concentration that was tested. 2010 American Chemical Society.
- Seo, Seon-M.I.,Junheon, Kim,Eunae, Kim,Park, Hye-M.I.,Kim, Young-Joon,Park, I.L.-Kwon
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experimental part
p. 1823 - 1827
(2010/09/09)
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- Synthesis of polyacetylenic acids isolated from Nanodea muscosa
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The first total synthesis of two linear polyacetylenic compounds is described. The synthesis of (E)-octadec-13-en-11-ynoic acid 1 and (E)-octadec-13-en-9,11-diynoic acid 2 by using the vinylic telluride coupling reaction was accomplished.
- Alves, Diego,Nogueira, Cristina W.,Zeni, Gilson
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p. 8761 - 8764
(2007/10/03)
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- Synthesis and biological evaluation of a "natural" insect repellent
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(11Z)-11,19-Icosadienyl acetate (1) has been shown to be an efficient repellent against the ant Myrmica rubra whereas its corresponding (11E) stereoisomer 2 does not exhibit any repellent activity at all. Several synthetic strategies for these two compounds have been evaluated.
- Csuk, René,Niesen, Anja
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p. 934 - 942
(2007/10/03)
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- Elucidation of the stereostructure of the annonaceous acetogenin (+)-montecristin through total synthesis
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Total syntheses of ent-5-epi-montecristin (1a) and of (-)-montecristin (1b) were accomplished. The stereocenters of compounds 1a and 1b were established by asymmetric dihydroxylations of the trans-configurated β,γ-unsaturated esters 6 (→4, up to 80% ee; S
- Harcken,Brueckner
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- 2,3-EPOXY DERIVATIVES AS ANTI RETROVITAL CHEMOTHERAPEUTIC AGENTS
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The present invention is related to compounds, compositions and methods of treating viral infections. Compounds of the present invention have the following general formula: STR1 wherein R is selected from--CH 2 OH,--CO 2 R 2,--CONR 3 R 4, or COR 5, wherein R 2 is hydrogen or a lower alkyl group, R 3 and R 4 are each independently hydrogen or a lower alkyl group, R 5 is an amino acid residue bound via a terminal nitrogen or peptide having at least two amino acid residues; and wherein R 1 is C 5-C 13 alkyl, aryl, aralkyl, aralkyl(lower alkyl) ether, or C 5-C. sub.13 alkyl (lower alkyl)ether.
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- Pheromone synthesis; CXXXIII. Synthesis of both the enantiomers of (3Z,9Z)-cis-6,7-epoxy-3,9-nonadecadiene, a pheromone component of Erannis defoliaria
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Both the enantiomers of (3Z,9Z-cis-6,7-epoxy-3,9-nonadecadiene, a pheromone component of Erannis defoliaria, were synthesized using the Sharpless asymmetric epoxidation as the key step.
- Mori,Brevet
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p. 1125 - 1129
(2007/10/02)
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- Identification and enantioselective synthesis of (Z,Z)-6,9-c/s-3S,4R-epoxynonadecadiene, the major sex pheromone component of Boarmia selenaria
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(Z,Z)-6,9-cis-3S,4R-Epoxynonadecadiene has been identified as the major sex pheromone component of the Geometrid Boarmia selenaria. A short and efficient synthesis of the chiral methylene-interrupted diene-epoxide has been developed for both enantiomers.
- Becker
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p. 4923 - 4926
(2007/10/02)
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- A facile synthesis of cotton bollworm (Heliothis armigera) pheromone components: (Z)-11-Hexadecenal and (Z)-9-hexadecenal
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(Z)-Hexadecenal (1) and (Z)-9-hexadecenal (2) have been synthesised starting from easily accessible propargyl alcohol.Alkylation of propargyl alcohol yields 3 and 4, which on acetylene-zipper reaction give terminal acetylenes (5 and 6, R'=H).Alkylation of 5 and 6 followed by depyranylation afford 7 and 8.Partial cis-hydrogenation of these with P2Ni followed by PCC oxidation give compounds 1 and 2.
- Mithran, S.,Mamdapur, V. R.
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p. 755 - 756
(2007/10/02)
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- Synthesis of the optical antipodes of 4-alkyl-γ-lactones
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Optical antipodes of 4-alkyl-γ-lactones 3 have been prepared by photochemical rearrangement of optically active α,β-epoxy diazomethyl ketones 1 in ethanol to give 4-hydroxy-alkenoates 2, followed by reduction of the alkene bond and subsequent lactonization.The required epoxy diazomethyl ketones 1 were obtained via the following sequence of reactions: alkylation of 2-propyn-1-ol, subsequent reduction to the alkenols 6, Sharpless epoxidation to 2,3-epoxy alcohols 7, oxidation to glycidic esters 8 and finally conversion to diazo ketones 1.The enantiomeric purities range from 84 to 100percent.
- Thijs, Lambertus,Waanders, Peter P.,Stokkingreef, Edwin H. M.,Zwanenburg, Binne
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p. 332 - 337
(2007/10/02)
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- CI(NO) Spectra of n-Alkyn-1-ols
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n-Alkyn-1-ols show fragmentation patterns which are influenced by the length of the chain and by the relative positions of the hydroxyl group and triple bond, and which allow a localization of the site of unsaturation.
- Brauner, A.,Budzikiewicz, H.
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p. 324 - 326
(2007/10/02)
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