- Functional group transformations of diols, cyclic ethers, and lactones using aqueous hydrobromic acid and phase transfer catalyst under microwave irradiation
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Synthesis of bromoalkanols has been achieved from diols, ethers, and lactones using aq HBr (48%) and tetrabutylammonium iodide/bromide as phase transfer catalyst under microwave irradiation. This environmentally benign route provides enhanced yields of products and does away with the use of benzene as compared to existing conventional methods.
- Kad, Goverdhan L.,Kaur, Irvinder,Bhandari, Monica,Singh, Jasvinder,Kaur, Jasamrit
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- New synthesis of nematocidal natural products dithiocynates thiocyanatin A and 1,8,16-trihydroxyhexadecane
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A new and short synthesis of nematocidal natural products, thiocyanatin A and 1,8,16-trihydroxyhexadecane, from readily available starting compounds 1,7-heptanediol and 1,9-nonanediol in six steps is described.
- Singh, Ashima,Sharma,Singh, Jasvinder
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- Rhodium-catalyzed reduction of esters to alcohols using diphenylsilane
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Carboxylic esters were reduced to alcohols by diphenylsilane catalyzed by a Rh complex at room temperature. For example, ethyl decanoate and ethyl phenylacetate were converted to decanol and 2-phenylethanol by [RhCl(cod)]2 / 4PPh3 for 72 hours in 98 and 92% yields, respectively. Wilkinson's catalyst is also usable, and the reduction of ethyl decanoate finished in 6 hours at room temperature. The bromo-substituent on ethyl 7-bromoheptanoate remained intact through this reduction.
- Ohta, Tetsuo,Kamiya, Masahiro,Kusui, Keisuke,Michibata, Tsugumi,Nobutomo, Mami,Furukawa, Isao
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- New method for synthesis of methacrylate-type polymerizable ionic liquids
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A new method for the synthesis of polymerizable ionic liquids bearing a methacrylate moiety was developed with the aim to avoid premature polymerization of synthesized compounds. Spacer length between the imidazolium cation and the polymerizable functional group varied from 2 to 10 carbon atoms. Different 1-(n-hydroxyalkyl)-3-methylimidazolium bromides and 1-[n-(methacryloyloxy)- alkyl]-3-methylimidazolium bromides were obtained with very good yields (more than 90%).
- Pohako-Esko, Kaija,Taaber, Triinu,Saal, Kristjan,Lohmus, Ruenno,Kink, Ilmar,Maeeorg, Uno
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- Simple but precise engineering of functional nanocapsules through nanoprecipitation
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A general, rapid, and undemanding method to generate at will functional oil-filled nanocapsules through nanoprecipitation is reported. On the basis of polymer and hexadecane/water/acetone phase diagrams, the composition can be set so that polymer chains p
- Yan, Xibo,Delgado, Marco,Fu, Amy,Alcouffe, Pierre,Gouin, Sebastien G.,Fleury, Etienne,Katz, Joseph L.,Ganachaud, Francois,Bernard, Julien
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- Reduction of carboxylic acid derivatives using diphenylsilane in the presence of a Rh-PPh3 complex
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Reductions of carboxylic acid derivatives by silanes in the presence of rhodium complexes were studied. Carboxylic esters were reduced to alcohols by diphenylsilane catalyzed by [RhCl(cod)]2/4PPh3 or [RhCl(PPh3)3] at room temperature in up to 99% yields. For example, ethyl decanoate and ethyl phenylacetate were converted to decanol and 2-phenylethanol in 98 and 92% yields, respectively. Carboxylic acids were also reduced by this reducing system to the corresponding alcohols in high yields. Furthermore, N-monosubstituted amides were reduced to secondary amines in moderate to good yields. For sterically hindered amides, the yields were moderate, and imines were produced in competitive yields.
- Ohta, Tetsuo,Kamiya, Masahiro,Nobutomo, Mami,Kusui, Keisuke,Furukawa, Isao
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- Stereoselective synthesis of the Paulownia bagworm sex pheromone
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According to our retrosynthesis, the main chain of the target molecule could be constructed using a C5?+?C7?+?C5 strategy. The key induction reaction afforded chiral methyl group moieties using different Evans templates with different configurations. Li2CuCl4 was effectively employed in the Csp3[sbnd]Csp3 coupling protocol. The target molecular was obtained in a 12.6% overall yield with nine steps in the longest linear route.
- Sun, Zhi-Feng,Zhou, Lu-Nan,Zhang, Tao,Du, Zhen-Ting
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- Total Synthesis of the Antitumor Depsipeptide FE399 and Its S-Benzyl Derivative: A Macrolactamization Approach
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An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.
- Tonoi, Takayuki,Ikeda, Miyuki,Sato, Teruyuki,Inohana, Takehiko,Kawahara, Ryo,Murata, Takatsugu,Shiina, Isamu
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- Parthenogenesis, calling behavior, and insect-released volatiles of leafminer moth Phyllonorycter emberizaepenella.
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We proved that the leafminer moth Phyllonorycter emberizaepenella (Lepidoptera: Gracillariidae) reproduces by parthenogenesis of the thelytoky type. Despite a complete absence of males, parthenogenetically reproducing females diurnally demonstrated the calling posture normally used for releasing signaling compounds. Two compounds, which we collected from a calling female, were identified as potential sex pheromone components: (8E, 10E)-8,10-tetradecadienyl acetate and (8E,10E)-8,10-tetradecadienol, the latter occurring only in trace amounts. In field experiments, no males were attracted to traps baited with either the potential sex pheromone or with virgin females. Both the pattern of behavior and the chemical characteristics of the pheromone of Ph. emberizaepenella species were similar to those known for Lepidoptera with the usual amphimictic mode of reproduction. Theoretical speculations that in thelytoky, where there is no need to find a sexual partner, the individuals would obtain certain advantages due to reduction in their sexual behavior, were, thus, not confirmed for Ph. emberizaepenella.
- Mozuraitis, Raimondas,Buda, Vincas,Liblikas, Ilme,Unelius, Carl Rikard,Borg-Karlson, Anna-Karin
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- A mild and versatile method for the tetrahydropyranylation of alcohols and their detetrahydropyranylation
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An efficient and mild method for tetrahydropyranylation of alcohols and their detetrahydropranylation using NH4Cl is described. This protocol provides a useful alternative tetrahydropyranylation of alcohols and their deprotection at different pH.
- Yadav,Srinivas, Dale,Reddy, Gondi Sudershan
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- An Effective Method for the Preparation of ω-Bromoalkanols from α,ω-Diols
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Pure ω-bromoalkanols 2 (n=2-12), not contaminated by any dibromoalkanes or unreacted diols 1, were prepared in good yields by refluxing a mixture of diols 1, aqueous (48percent) hydrogen bromide, and benzene using a Dean-Stark water separator.
- Kang, Suk-Ku,Kim, Won-Sup,Moon, Byoung-Ho
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- Synthesis and field evaluation of methyl-branched ketones, sex pheromone components produced by lithosiinae female moths in the family of arctiidae
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Female moths of Lyclene dharma dharma (Arctiidae, Lithosiinae) produce a novel sex pheromone composed of three methyl-branched ketones (I-III) in a ratio of 2: 1: 1. In order to confirm the structure of III (6, 14- dimethyl-2-octadecanone), a mixture of its four stereoisomers was synthesized via chain elongation by two Wittig reactions, starting from 1, 7-hexanediol. GC-MS data of the synthetic III were satisfactorily coincident with those of the natural component. In addition to the racemic mixtures of I (6-methyl-2-octadecanone) and II (14-methyl-2-octadecanone), previously synthesized, the activity of III was evaluated in the Iriomote Islands, and effective male attraction was observed for the 2: 1: 1 mixture of I-III. This result indicates that the females do not produce only one stereoisomer for each component or that the response of the males is not disturbed by the other stereoisomers of natural isomers produced by the females. The field test also revealed that the twocomponent lure of I and II captured as many males as the mixture of I-III, while lures baited with two components in other combinations and with only one component scarcely exhibited any male attraction ability.
- Do, Nguyen Duc,Kinjo, Masakatsu,Taguri, Tomonori,Adachi, Yasushi,Yamakawa, Rei,Ando, Tetsu
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- Concise synthesis of (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, components of the essential oil of marine green alga Ulva pertusa
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The long-chain aldehydes, (8Z,11Z,14Z)-8,11,14-heptadecatrienal, (7Z,10Z,13Z)-7,10,13-hexadecatrienal, and (8Z,11Z)-8,11-heptadecadienal, were concisely synthesized by using Grignard coupling, catalytic hydrogenation with the Lindlar catalyst, and oxidation with Dess-Martin periodinane as the key steps. Particularly, (8Z,11Z,14Z)-8,11,14-heptadecatrienal and (7Z,10Z, 13Z)-7,10,13-hexadecatrienal both possessed a seaweed-like odor.
- Akakabe, Yoshihiko,Washizu, Kensuke,Matsui, Kenji,Kajiwara, Tadahiko
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- Dual-function antiandrogen/HDACi hybrids based on enzalutamide and entinostat
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The combination of androgen receptor antagonists with histone deacetylase inhibitors (HDACi) has been shown to be more effective than antiandrogens alone in halting growth of prostate cancer cell lines. Here we have designed, synthesized and assessed a se
- Barrett, Ryan R.G.,Nash, Claire,Diennet, Marine,Cotnoir-White, David,Doyle, Christopher,Mader, Sylvie,Thomson, Axel A.,Gleason, James L.
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supporting information
(2021/12/01)
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- Ni-Catalyzed Formal Cross-Electrophile Coupling of Alcohols with Aryl Halides
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Direct coupling of unactivated alcohols remains a challenge in current synthetic chemistry. We herein demonstrate a strategy building upon in situ halogenation/reductive coupling of alcohols with aryl halides to forge Csp2-Csp3 bonds. The combination of 2-chloro-3-ethylbenzo[d]oxazol-3-ium salt (CEBO) and TBAB as the mild bromination reagents enables rapid transformation of a wide range of alcohols to their bromide counterparts within one to 5 min in CH3CN and DMF, which is compatible with the Ni-catalyzed cross-electrophile coupling conditions in the presence of a chemical reductant. The present method is suitable for arylation of a myriad of structurally complex alcohols with no need for prepreparation of alkyl halides. More importantly, the mild and kinetically rapid bromination process has shown good selectivity in the bromination/arylation of symmetric diols and less sterically hindered hydroxyl groups in polyols, thus offering promise for selective functionalization of diols and polyols without laborious protecting/deprotecting operations. The practicality of this work is also evident in the arylation of a number of carbohydrates, drug compounds, and naturally occurring alcohols.
- Lin, Quan,Ma, Guobin,Gong, Hegui
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p. 14102 - 14109
(2021/11/20)
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- Synthesis of C37-Alkenones for Past Climate Reconstructions
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The total syntheses of three C37 methyl-alkenones with different degrees of unsaturation and of their 13C-labelled analogues from commercially available starting materials are presented herein for the first time. These molecules are important to improve the reliability of the measurements and reconstructions of the sea surface temperature and salinity.
- Berton, Giacomo,Pizzini, Sarah,Fabris, Fabrizio,Bertolin, Tommaso,Pafumi, Eugenia,Ceccon, Leonardo,Daelemans, Jonas,Borsato, Giuseppe,Scarso, Alessandro,Piazza, Rossano,Ferretti, Patrizia
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p. 3542 - 3551
(2020/03/26)
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- Synthetic method of 7-bromine-1-heptanol
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The invention provides a synthetic method of 7-bromine-1-heptanol. The synthetic method includes synthesizing dimethyl pimelate, 1, 7-heptandiol and 7-bromine-1-heptanol sequentially. The synthetic method has the advantages that the synthetic method is simple to operate and low in cost; through strict control of consumption and reaction time of hydrobromic acid, reaction conversion rate is increased, generation of dibromo-products is reduced greatly, and product purity, yield and productivity are improved; the content reaches more than 99%, and industrial production is facilitated.
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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) - 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 0013; 0053-0054
(2019/02/04)
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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 0013; 0057-0058
(2020/05/06)
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- A practical total synthesis of both e - And Z -isomers of optically pure (S)-14-methylhexadec-8-enal (Trogodermal)
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The total synthesis of both E- and Z-isomers of optically pure (S)-14-methylhexadec-8-enal (trogodermal) is described. Key steps involved Corey-Fuchs reaction, zipper isomerization, and different hydrogenation conditions for cis- and trans-isomers. Georg
- Yadav, Jhillu S.,Chandravathi,Thrimurtulu,Prasad,Ghamdi, Ahmad Alkhazim Al
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p. 1513 - 1518
(2013/07/05)
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- A conformationally frozen peptoid boosts CXCR4 affinity and anti-HIV activity
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There can be only one: Using a peptoid motif obtained by shifting the arginine side chain of a pentapeptide previously developed by Fujii et al. to the neighboring nitrogen atom restricts the conformational freedom and yields a conformationally homogeneou
- Demmer, Oliver,Frank, Andreas O.,Hagn, Franz,Schottelius, Margret,Marinelli, Luciana,Cosconati, Sandro,Brack-Werner, Ruth,Kremb, Stephan,Wester, Hans-Jürgen,Kessler, Horst
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supporting information; experimental part
p. 8110 - 8113
(2012/09/25)
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- EPOXYEICOSATRIENOIC ACID ANALOGS AND METHODS OF MAKING AND USING THE SAME
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Compounds and compositions comprising epoxyeicosatrienoic acid (EET) analogs that act as EET agonists and are useful as medications in the treatment of drug-induced nephrotoxicity, hypertension and other related conditions. Methods of making and using the
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Page/Page column 76
(2012/10/18)
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- 17(R),18(S)-Epoxyeicosatetraenoic acid, a potent eicosapentaenoic acid (EPA) derived regulator of cardiomyocyte contraction: Structure-activity relationships and stable analogues
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17(R),18(S)-Epoxyeicosatetraenoic acid [17(R),18(S)-EETeTr], a cytochrome P450 epoxygenase metabolite of eicosapentaenoic acid (EPA), exerts negative chronotropic effects and protects neonatal rat cardiomyocytes against Ca 2+-overload with EC50 ≈ 1-2 nM. Structure-activity studies revealed that a cis-Δ11,12- or Δ14,15- olefin and a 17(R),18(S)-epoxide are minimal structural elements for antiarrhythmic activity whereas antagonist activity was often associated with the combination of a Δ14,15-olefin and a 17(S),18(R)-epoxide. Compared with natural material, the agonist and antagonist analogues are chemically and metabolically more robust and several show promise as templates for future development of clinical candidates.
- Falck, John R.,Wallukat, Gerd,Puli, Narender,Goli, Mohan,Arnold, Cosima,Konkel, Anne,Rothe, Michael,Fischer, Robert,Müller, Dominik N.,Schunck, Wolf-Hagen
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supporting information; experimental part
p. 4109 - 4118
(2011/08/05)
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- Total synthesis of three natural products: Decyl 8-hydroxyheptadecanoate, undecyl hexadecanoate and 2,3-dihydroxypropyl hexadecanoate
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First syntheses of decyl 8-hydroxyheptadecanoate 1 and undecyl hexadecanoate 2 via utilization of microwave energy and a new improved synthesis of 2,3-dihydroxypropyl hexadecanoate 3 have been accomplished from readily available starting compounds.
- Singh, Ashima,Sharma,Singh, Jasvinder
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experimental part
p. 1648 - 1652
(2011/03/17)
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- Novel eicosanoid derivatives
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The present invention provides compounds (n-3 PUFA derivatives) of formula (I): that modulate conditions associated with cardiac damage, especially cardiac arrhythmias.
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Page/Page column 22
(2010/08/07)
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- Fluoroalkene modification of mercaptoacetamide-based histone deacetylase inhibitors
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Inhibitors of histone deacetylases (HDAC) are emerging as a promising class of anti-cancer agents. The mercaptoacetoamide-based inhibitors are reported to be less toxic than hydroxamate and are worthy of further consideration. Therefore, we have designed a series of analogs as potential inhibitors of HDACs, in which the mercaptoacetamide group was replaced by (mercaptomethyl)fluoroalkene, and their HDAC inhibitory activity was evaluated. Subnanomolar inhibition was observed for all synthetic compounds.
- Osada, Satoshi,Sano, Satoshi,Ueyama, Mariko,Chuman, Yoshiro,Kodama, Hiroaki,Sakaguchi, Kazuyasu
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scheme or table
p. 605 - 611
(2010/05/02)
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- The introduction of π-π stacking moieties for fabricating stable micellar structure: Formation and dynamics of disklike micelles
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(Figure Presented) Enhancing the intermolecular interactions between micelles by introducing a strong π-π stacking moiety and flexible spacers of appropriate length results in the formation of disklike micelles that can maintain their monomolecule-layered
- Song, Bo,Wang, Zhiqiang,Chen, Senlin,Zhang, Xi,Fu, Yu,Smet, Mario,Dehaen, Wim
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p. 4731 - 4735
(2007/10/03)
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- PROCESS
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The present invention relates to a novel process for the preparation of phenethanolamine derivatives, which process comprises the step of reacting a compound of formula RO(CH2)nBRaRb with a compound of formula (
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Page/Page column 16
(2010/02/11)
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- Ethynylation of the ether derivatives of ω-haloalkanols with lithium acetylide-ethylenediamide complex
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A new operationally simple and highly efficient procedure for the ethynylation of ether derivatives of ω-haloalkanols with lithium acetylide-ethylenediamine complex in N,N-dimethylacetamide is described.
- Karpinska,Lewandowska,Grodner
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p. 937 - 942
(2007/10/03)
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- Synthesis of (9E,11Z)-hexadeca-9,11-dienal, sex pheromone of the pecan nut casebearer, Acrobasis nuxvorella (Neunzig)
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The pecan nut casebearer, Acrobasis nuxvorella (Neunzig), is a significant pest of the pecan nut industry. Two alternative syntheses of (9E,11Z)-hexadeca-9,11-dienal, the sex pheromone of the pecan nut casebearer, are described. The key transformation in
- Passaro, Linda C.,Webster, Francis X.
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p. 1187 - 1190
(2007/10/03)
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- Progress toward the development of a safe and effective agent for treating reentrant cardiac arrhythmias: Synthesis and evaluation of ibutilide analogues with enhanced metabolic stability and diminished proarrhythmic potential
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A series of ibutilide analogues with fluorine substituents on the heptyl side chain was prepared and evaluated for class III antiarrhythmic activity, metabolic stability, and proarrhythmic potential. It was found that fluorine substituents stabilized the side chain to metabolic oxidation. Many of the compounds also retained the ability to increase the refractoriness of cardiac tissue at both slow and fast pacing rates. The potential for producing polymorphic ventricular tachycardia in the rabbit model was dependent on the chirality of the benzylic carbon. The S-enantiomers generally had less proarrhythmic activity than the corresponding racemates. One compound from this series (45E, trecetilide fumarate) had excellent antiarrhythmic activity and metabolic stability and was devoid of proarrhythmic activity in the rabbit model. It was chosen for further development.
- Hester,Gibson,Buchanan,Cimini,Clark,Emmert,Glavanovich,Imbordino,LeMay,McMillan,Perricone,Squires,Walters
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p. 1099 - 1115
(2007/10/03)
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- Restricting the flexibility of crosslinked, interfacial peptide inhibitors of HIV-1 protease
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Interfacial peptides of HIV-1 protease were crosslinked with varying length alkyl-chains containing either a single cis or trans double bond, or a triple bond to remove degrees of freedom within the tethers. The synthesis of these compounds and their effects on the activity of HIV-1 protease are described.
- Ulysse, Luckner G.,Chmielewski, Jean
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p. 3281 - 3286
(2007/10/03)
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- Antiarrhythmic methanesulfonamides
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Methanesulfonamides are structurally depicted by Formula I' STR1 or its pharmacologically acceptable salts where R3 is a C1-7 alkyl substituted with C3-7 cycloalkyl, or a C1-10 alkyl substituted with one to eigh
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- Design and synthesis of analogues of ionomycin
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Based on the analysis of the crystal structure of the Ca2+ salt of ionomycin and the chemical and physical data on ionomycin, a number of ionomycin analogues have been synthesized to study the structural features affecting the Ca2+ binding and transport. Compounds 2, 3, and 4 were synthesized to study the effect of additional intramolecular oxygen coordination sites on Ca2+ transport. Compounds 5a-5d were prepared to study the effect of lipid solubility on Ca2+ binding and transport. Compounds 6a-6c were prepared to study the effect of the distance between the β-diketone and the carboxyl group on Ca2+ transport. A general synthetic route to these compounds has been developed. The key reactions in this route are the consecutive regioselective alkylations of the dianion of 2,4-pentanedione with the appropriate bromides.
- Hu,Weiler
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p. 1500 - 1511
(2007/10/02)
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- A New Synthetic Method of Macrocyclic Lactones from ω-Iodoalkylacrylates
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When the photostimulated cyclization reaction of ω-iodoalkylacrylates was performed in the presence of metal hydride complexes such as sodium cyanoborohydride (NaBH3CN), sodium borohydride (NaBH4) and potassium borohydride (KBH4), the corresponding macrocyclic lactones were produced.The use of NaBH3CN led to the highest yield of lactones.
- Abe, Motoji,Hayashikoshi, Takaoki,Kurata, Takeo
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p. 1789 - 1792
(2007/10/02)
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- Synthesis of (R)-(+)-patulolide A
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A new total synthesis of (R)-(+)-patulolide A [(11R,2E)-4-oxo-2-dodecen-11-olide] using the cyclization of hydroxy aldehydes with ketenylidenetriphenylphosphorane is described.
- Bestmann,Kellermann,Pecher
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p. 149 - 152
(2007/10/02)
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- Free Radical Macrocyclisation via Propiolate Esters.
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Intramolecular free-radical addition to propiolate esters has provided a new and stereoselective route to 14-16 membered trans-α,β-unsaturated macrocyclic lactones from their corresponding ω-iodoalkyl-propiolate esters under triphenyltin hydride/AIBN mediated conditions.Attempts to synthesise analogous 10-13 membered lactones proved unsuccessful, resulting in acyclic products derived from direct reduction at the radical centre. Key words: Radical; macrocyclisation; propiolate ester; macrocyclic unsaturated lactone; high dilutionm
- Baldwin, Jack E.,Adlington, Robert M.,Ramcharitar, Steve H.
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p. 3413 - 3428
(2007/10/02)
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- The synthesis of β-keto lactones via cyclization of β-keto ester dianions or the cyclization of Meldrum's acid derivatives
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Two new methods to synthesize macrocyclic β-keto lactones have been developed.The first involves the synthesis of ω-halo-β-keto esters and an intramolecular alkylation of the dianions to these compounds.The reaction is complicated by elimination in the small and medium ring systems and by difficulties in purifying the final products.However, it is possible to obtain modest yields of the desired β-keto lactones.This procedure was used to synthesize the 25- and 27-membered ring β-hydroxy lactones that are the constituents of termite defense compounds.The second method involves the thermolysis of acylated Meldrum's acid derivatives, which leads directly to β-keto lactones.This process gives modest yields of macrocyclic systems and good yield of the unsubstituted 3-oxopentan-5-olide (25) .The 14-membered macrocyclic β-keto lactone 9j has a complex 1H NMR spectrum, which has been interpreted in terms of multiple conformations.The temperature dependence of the NMR spectrum of 9j is consistent with entropic, rather than enthalpic, control of the equilibrium.Quasiharmonic entropy calculations are consistent with this model.
- Lermer, Leonard,Neeland, Edward G.,Ounsworth, James P.,Sims, Russell J.,Tischler, Samuel A.,Weiler, Larry
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p. 1427 - 1445
(2007/10/02)
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- Enantioselective Total Synthesis of Harmonine, a Defence Alkaloid of Ladybugs (Coleoptera: Coccinellidae)
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An efficient and highly enantioselective (ee > 97percent) total synthesis of the ladybug defence alkaloid (17R,9Z)-1,17-diaminooctadec-9-ene in good overall yield is described.As the key step for the generation of the stereogenic center, asymmetric C-C bond formation by nucleophilic addition of methyllithium to an aldehyde SAMP hydrazone is used. Key Words: (17R,9Z)-1,17-Diaminooctadec-9-ene / Harmonine / Ladybug / SAMP hydrazone
- Enders, Dieter,Bartzen, Dominika
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p. 569 - 574
(2007/10/02)
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- Synthesis of Large Macrocyclic Tetraaza Compounds with A Methylene Backbone: Cyclo4, (n = 6,7,8,9 and 10). The Formation of 28-, 32-, 36-, 40- and 44-Membered Rings.
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A series of macrocyclic tetraamines with 28-, 32-, 36-, 40- and 44-membered rings have been efficiently prepared from the corresponding ditosylamide and monobromoalcohol derivatives in 6 steps via a double condensation reaction.Overall yields were: 41, 41, 46, 29, and 33 percent, respectively, for 1,8,15,22-tetraazacyclooctacontane (11a), 1,9,17,25-tetraazacyclodotriacontane (11b), 1,10,19,28, tetraazacyclohexatriacontane (11c), 1,11,21,31-tetraazacyclotetracontane (11d) and 1,12,23,34-tetraazacyclotetratetracontane (11e).
- Tomohiro, Takenori,Uoto, Kouichi,Okuno, Hiroaki (Yohmei)
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p. 1233 - 1239
(2007/10/02)
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- Design, synthesis, and activity of membrane-disrupting bolaphiles
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Four new classes of bolaphiles ("double-headed" single-chain surfactants) have been prepared, via condensation of an homologous series of linear saturated, olefinic, and acetylenic α,ω-dicarboxylic acids with hexaethylene glycol, and evaluated for their ability to induce the release of 5(6)-carboxyfluorescein (CF) entrapped within large unilamellar vesicles derived from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Operationally, the membrane-disrupting activity of the bolaphiles has been found to vary by a factor of ca. 100, when the total number of carbon atoms which separate the carboxylate moieties range from 12 to 24; the most active bolaphile is approximately three times more active than Triton X-100. When the affinity of the bolaphiles toward POPC membranes is considered, the intrinsic membrane-disrupting activity varies by a factor of ca. 230. A "loop" model is proposed to account for the general trends in bolaphile activity that are observed, where the depth of loop penetration and loop width are presumed to be the key factors involved in determining membrane-disrupting activity. The potential utility of these surfactants as antimicrobial agents, and as anti-HIV agents in particular, is briefly discussed.
- Jayasuriya, Nimal,Bosak, Stanislav,Regen, Steven L.
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p. 5844 - 5850
(2007/10/02)
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- Systematic Syntheses and Charactarization of Dodecadien-1-ols with Conjugated Double Bond, Lepidopterous Sex Pheromones
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Four geometrical isomers of 5,7-, 6,8-, 7,9- and 8,10-dodecadein-1-ols were systematically synthesized by two routes.One involved the Wittig reaction between (E)-2-alkenal and a phosphorane with an appropriate carbon chain, and yielded a mixture of (E,Z)- and (E,E)-isomers in a ratio of ca. 3:2.The other route comprised of the Wittig reaction of a 2-alkynal and the stereoselective reduction of the triple bond to a (Z)-double bond via hydroboration with dicyclohexylborane to give a mixture of (Z,Z)- and (Z,E)-isomers in a ratio of 6:1 10:1.Both the mixtures were separately chromatographed on a silica gel column impregnated with silver nitrate to give four geometrically pure isomers.With 9,11-diene they were analysed by GC on a capillary column, HPLC, silver nitrate impregnated TLC, and 13C NMR.
- Ando, Tetsu,Kurotsu, Yuichi,Kaiva, Mieko,Uchiyama, Masaaki
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p. 141 - 148
(2007/10/02)
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- Z/E-Isomerization of Unsaturated Carboxylic Acids during the Kolbe Electrolysis
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Z-4-Enoic acids partially isomerize to E-configurated products in the Kolbe electrolysis.The results from methyl and deuterium labelled carboxylic acids 2 and 16 support an isomerization via a reversible ring closure to cyclopropylcarbinyl radicals.The double bonds of Z-N-enoic acids with N>/= 5 fully retain their configuration in the Kolbe electrolysis; for N=6,7 cyclic products are formed to some extent, which is in accord with the reactivity of 5- and 6-alkenyl radicals.
- Huhtasaari, Matti,Schaefer, Hans J.,Luftmann, Heinrich
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p. 537 - 548
(2007/10/02)
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- PHEROMONES OF INSECTS AND THEIR ANALOGS. V. A NEW APPROACH TO THE SYNTHESIS OF THE SEX PHEROMONES OF INSECTS OF THE ORDER Lepidoptera WHICH IS BASED ON THE SELECTIVE OZONOLYSIS OF 1-METHYLCYCLOOCTA-1Z,5Z-DIENE
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A new synthesis of 1-acetoxyalk-Z-enes (sex pheromones of insects of the order Lepidoptera) has been developed which is based on the selective ozonolysis of 1-methylcycloocta-1Z-5Z-diene - a cooligomer of isoprene and butadiene.
- Tolstikov, G. A.,Odinokov, V. N.,Galeeva, R. I.,Bakeeva, R. S.,Akhunova, V. R.
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p. 219 - 224
(2007/10/02)
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- A simple approach to 12-azaprostaglandin congeners
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The base-catalysed alkylation of N-acylated 3-pyrrolines has been studied.The reaction has been utilized in an approach to the synthesis of 12-azaprostaglandins according to the following sequence. 3-Pyrroline was acylated with 1-chloro-1-octen-3-one and the resulting amide alkylated at the 2-position with I-(CH2)6C(OCH3)3.Subsequently, the α- and β-(13,14-dihydro)-prostanoid chains were formed by sodium borohyride reduction, followed by hydrolysis.The resulting product, 1-(3-hydroxyoctyl)-2-(6-methoxycarbonylhexyl)-3-pyrroline (13), constitutes a central intermediate for 12-azaprostaglandins.
- Armande, J. C. Lapierre,Pandit, U. K.
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- Structural and Mechanistic Effects on the Rates of Ring-Opening Reactions in the 5-16-Membered-Ring Region
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Partial rate coefficients have been determined for the reaction of cyclic dimethylammonium ions with sodium methoxide in the 7-16-membered-ring region.Three second-order parallel reactions take place and lead to exocyclic demethylation (A), ring-opening substitution (B), and ring-opening olefin-forming elimination (C).The results were compared with the behavior of the five- and six-membered rings.Reaction A shows negligible dependence on ring size.In contrast, reactions B and C are affected by ring size through ring strain and geometry of the transition state: the latter factor is held responsible for major differences in the reactivity profiles between such reactions.
- Cerichelli, Giorgio,Illuminati, Gabriello,Lillocci, Claudio
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p. 3952 - 3957
(2007/10/02)
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