- Porphyrin dimers linked by conjugated butadiynes
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1,3-Butadiynes R---C≡C---C≡C---R, where R = 5′-substituted nickel(II) octaethylporphyrin (NiOEP) (1e), 2′-substituted nickel(II) 5′, 10′, 15′, 20′-tetraphenylporphyrin (NiTPP) (4e), and 2′-substituted nickel(II) heptaethylporphyrin (NiHEP) (5d), have been prepared from the respective bromovinyl species by dehydrobromination and oxidative coupling. The published synthesis of (1e) has been improved to achieve a 40% yield for four steps from NiOEP. The metal-free bis(OEP) diyne was prepared by acid treatment of (1e), while more strenuous conditions led to a novel furan substituted at the 2- and 5-positions with OEP units. The visible absorption spectra of the 5′- and 2′-substituted diynes differ markedly, the former compounds exhibiting split absorption bands and red shifts indicative of extensive chromophore interaction.
- Arnold, Dennis P.,Nitschinsk, Lisa J.
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Read Online
- Biradical intermediate in the [2 + 2] photocycloaddition of dienes and alkenes to [60]fullerene
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The photocycloaddition of vinylcyclopropanes to C60 yields stereospecifically a five-membered [60]fullerene adduct. These results suggest a biradical intermediate of the [2 + 2] photocycloaddition between dienes or arylalkenes and C60. An electron transfer between the triplet excited state of C60 and the unsaturated substrates precedes the formation of the intermediate. Copyright
- Hatzimarinaki, Maria,Roubelakis, Manolis M.,Orfanopoulos, Michael
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Read Online
- Preparation method of benzofuran derivative
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The invention discloses a preparation method for synthesizing a benzofuran derivative. The specific implementation method is as shown in the specification. The method has novel synthetic route, simpleand convenient operation, high yield, and good safety, and is suitable for industrial production. A novel synthetic method of an intermediate VI is also designed, a Wittig reaction is carried out, and then ring-closing is carried out to obtain a benzofuran ring.
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Paragraph 0064; 0066; 0073
(2020/02/06)
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- Highly Enantioselective Synthesis of Propargyl Amide with Vicinal Stereocenters through Ir-Catalyzed Hydroalkynylation
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Chiral propargyl amines are valuable synthetic intermediates for the preparation of biologically active compounds and functionalized amines. Catalytic methods to access propargyl amines containing vicinal stereocenters with high diastereoselectivity are particularly rare. We report an unprecedented strategy for the synthesis of enantioenriched propargyl amines with two stereogenic centres. An iridium complex, ligated by a phosphoramidite ligand, catalyzes the hydroalkynylation of β,β-disubstituted enamides to afford propargyl amides in a highly regio-, diastereo-, and enantioselective fashion. Stereodivergent synthesis of all four possible stereoisomers was achieved using this strategy.
- Li, Bi-Jie,Zhang, Su-Lei,Zhang, Wen-Wen
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supporting information
p. 6874 - 6880
(2020/03/19)
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- Synthesis and evaluation of various heteroaromatic benzamides as analogues of –ylidene-benzamide cannabinoid type 2 receptor agonists
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The CB2 receptor is an attractive target for the treatment of a wide range of diseases and pathological conditions. Compounds that selectively activate the CB2 receptor are desirable as this avoids CB1-mediated psychoactive effects. Heteroarylidene-benzamides have demonstrated efficacy as selective CB2 receptor agonists. We aimed to expand the structure-activity relationship studies of this series of compounds by investigating the heteroaromatic core via the synthesis and in vitro evaluation of a small library of various heteroaromatic benzamide analogues. As heteroaromatic amides are privileged scaffolds in drug design, methods to synthesise them are of interest. Concise and reliable synthetic strategies were developed to access these novel analogues. The –ylidene-benzamide moiety is shown to be essential for CB activity as all amide derivatives exhibit no functional activity at either CB2 or CB1 receptors.
- Moir, Michael,Boyd, Rochelle,Gunosewoyo, Hendra,Montgomery, Andrew P.,Connor, Mark,Kassiou, Michael
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supporting information
(2019/08/12)
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- Stereoselective Synthesis of Vinyl Iodides through Copper(I)-Catalyzed Finkelstein-Type Halide-Exchange Reaction
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An efficient method for the stereoselective synthesis of vinyl iodides is described. The reactions of vinyl bromides with potassium iodide proceed smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding vinyl iodides stereospecifically and in satisfactory to excellent yields.
- Feng, Xiujuan,Zhang, Haixia,Lu, Wenbo,Yamamoto, Yoshinori,Almansour, Abdulrahman I.,Arumugam, Natarajan,Kumar, Raju Suresh,Bao, Ming
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supporting information
p. 2727 - 2732
(2017/06/13)
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- Protecting group free, stereocontrolled synthesis of β-halo-enamides
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Enamides, dienamides, and enynamides are important building blocks in synthetic, biological, and medicinal chemistry as well as materials science. Despite the extensive breath of their potential utility in synthetic chemistry, there is a lack of simple, high-yielding methods to deliver them efficiently and as single isomers. In this paper, we present a novel, protecting group free, efficient, and stereoselective approach to the generation of β-halo-enamides. The methodology presented provides a robust synthetic platform from which E- or Z-enamides can be generated in good yields and with complete stereocontrol.
- Pasqua, Adele E.,Crawford, James J.,Long, De-Liang,Marquez, Rodolfo
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experimental part
p. 2149 - 2158
(2012/05/20)
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- Construction of 2,3-dihydrofuran cores through the [3+2] cycloaddition of gold α-carbonylcarbenoids with alkenes
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Treatment of 2-epoxy-1-alkynylbenzenes with electron-rich alkenes and a [AuCl(PR3)]/AgX catalyst in CH2Cl2 led to the formation of 2-alkenyl-1-(2,3-dihydrofuran-4-yl)benzenes. This transformation comprises of a gold-catalyzed redox reaction to form a gold α- carbonylcarbenoid initially, which then reacts in situ with an alkene in a [3+2] cycloaddition. A range of alkenes are amenable to this tandem reaction, amongst them α-sub-stituted styrenes, enol ethers, and 2,3dimethylbutadienes. Deuterium-labeling experiments suggest a stepwise mechanism for the α-carbonylcarbenoid/alkene [3+2] cycloaddition. The resulting 2,3-dihydrofuran products allow access to diverse oxacyclic compounds through a stereoselective ene-oxonium reaction initiated by treatment with HOTf (1mol%; Tf= trifluoromethanesulfonyl). A stepwise pathway is proposed for this reaction. The feasibility for direct transformation of 2-alkenyl-1-alkynylbenzenes into the desired 2,3-dihydrofuran products through initial m-chloroperbenzoic acid oxidation, followed by the addition of gold catalyst and alkene, has also been demonstrated.
- Li, Chia-Wen,Lin, Guan-You,Liu, Rai-Shung
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supporting information; experimental part
p. 5803 - 5811
(2010/08/20)
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- Benzothiazole-based fluorophores of donor-π-acceptor-π-donor type displaying high two-photon absorption
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A series of novel heterocycle-based dyes with donor-π-bridge-acceptor- π-bridge-donor (D-π-A-π-D) structural motif, where benzothiazole serves as an electron-withdrawing core, have been designed and synthesized via palladium-catalyzed Sonogashira and Suzuki-type cross-coupling reactions. All the target chromophores show strong one-photon and two-photon excited emission. The maximum two-photon absorption (TPA) cross sections ΔTPA of the prepared derivatives bearing diphenylamino functionalities occur at wavelengths ranging from 760 to 800 nm and are as large as ~900-1100 GM. One- and two-photon absorption characteristics of the title dyes have also been investigated by using density functional theory (DFT) and the structure-property relationships are discussed. The TPA cross sections calculated by means of quadratic response time-dependent DFT using the Coulomb-attenuated CAM-B3LYP functional support the experimentally observed trends within the series, as well as higher ΔTPA values of the title compounds compared to those of analogous fluorene or carbazole-derived dyes. In contrast, the traditional B3LYP functional was not successful in predicting the observed trend of TPA cross sections for systems with different central cores. In general, structural modification of the π-bridge composition by replacement of ethynylene (alkyne) with E-ethenylene (alkene) linkages and/or replacement of dialkylamino electron-donating edge substituents by diarylamino ones results in an increase of ΔTPA values. The combination of large TPA cross sections and high emission quantum yields makes the title benzothiazole-based dyes attractive for applications involving two-photon excited fluorescence (TPEF).
- Hrobarikova, Veronika,Hrobarik, Peter,Gajdos, Peter,Fitilis, Ioannis,Fakis, Mihalis,Persephonis, Peter,Zahradnik, Pavol
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experimental part
p. 3053 - 3068
(2010/07/15)
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- SMALL-MOLECULE INHIBITORS OF THE ANDROGEN RECEPTOR
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The present invention provides a method of inhibiting an androgen receptor by administering a compound of Formula I: or a compound of Formula II: wherein R1, R2, R3 and R8 are each independently hydrogen or C1-6 alkyl. R4 is absent or is hydrogen, C1-6 alkyl or C1-6 alkyl-OH. R5 is hydrogen, C1-6 alkyl or —NR6R7. R6 and R7 are each independently hydrogen or C1-6 alkyl, or are combined with the nitrogen to which they are attached to form a heterocycloalkyl having from 5 to 7 ring members. L is a linker of C1-6 alkylene, C2-6 alkenylene, C2-6 alkynylene or C3-6 cycloalkylene. The compounds of Formula I include the salts, hydrates and prodrugs thereof. Each R9 is H, C1-6 alkyl, —OH or —O—C1-6 alkyl. The compounds of Formulas I and II include the salts, hydrates and prodrugs thereof. By administering the compound of Formula I or II, the method inhibits the androgen receptor.
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Page/Page column 10
(2009/01/20)
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- π-extended conjugate phenylacetylenes. Synthesis of 4-[(E) and (Z)-2-(4-ethenylphenyl)ethenyl]pyridine. Dimerization, quaternation and formation of charge-transfer complexes
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The conjugate (E)- and (Z)-(4′-pyridylethenyl)-4-phenylethyne (E-4 and Z-4) has been satisfactorily prepared by two different routes: (a) by dehydrohalogenation of 4′-pyridylethenyl-4-phenyl-β-chloroethene; (b) by the Wittig reaction between p-(iodobenzyl)(triphenyl)phosphine ylide and 4-pyridinecarboxaldehyde, E/Z isomer separation, and cross-coupling with 2-methyl-but-3-yn-2-ol followed the propanone elimination. The Glaser oxidative dimerization of (Z)-4 yields (Z,Z)-1,4-di[(4′-pyridylethenyl)-4-phenyl]-buta-1,3-diyne in good yield, (Z,Z)-5. (E,E)-5 was obtained by phase transfer oxidative dimerisation of (E)-4 in presence of their N-methyl salt (E)-10. Mono- and di-N-methylated salts of conjugate (E,E)-5 and (Z,Z)-5, were obtained by quaternation with iodomethane. The (Z,Z)-5 di-N-methylated salt forms charge-transfer complexes with TCNE, TCNQ and TMPD.
- Rodríguez, J. Gonzalo,Martín-Villamil, Rosa,Lafuente, Antonio
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p. 1021 - 1032
(2007/10/03)
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- The synthesis of benzylphosphine oxidesvia vicarious nucleophilic substitution and alkenes via VNS-Horner-Wittig reactions
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A range of substituted nitrobenzenes react with the anion of (chloromethyl)diphenylphosphinoyl oxide to give the substituted nitrobenzyldiphenylphosphine oxide by vicarious nucleophilic substitution. The novel stereoselective synthesis of E-stilbenes via a one-pot vicarious nucleophilic substitution-Horner-Wittig reaction is described.
- Lawrence, Nicholas J.,Liddle, John,Jackson, David
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p. 2260 - 2267
(2007/10/03)
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- Mechanism of the [2 + 2] photocycloaddition of fullerene C60 with styrenes
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Stereochemical studies on [2 + 2] photoaddition of cis-/trans-4-propenylanisole (cis-1 and trans-1) and cis-1-(p-methoxyphenyl)ethylene-2-d1 (cis-3-d1) to C60 exhibit stereospecificity in favor of the trans-2 cycloadduct in the former case and nonstereoselectivity in the latter. The observed stereoselectivity in favor of the cis-6-d3 [2 + 2] diastereomer by 12% in the case of the photochemical addition of (E)-1-(p-methoxyphenyl)-2-methyl-prop-1-ene-3,3,3-d3 (trans-5-d3) to C60 is attributed to a steric kinetic isotope effect (k(H)/k(D) = 0.78). The loss of stereochemistry in the cyclobutane ring excludes a concerted addition and is consistent with a stepwise mechanism. Intermolecular secondary kinetic isotope effects of the [2 + 2] photocycloaddition of 3-d0 vs 3-d1, and 3-d6 as well as 5-d0 vs 5-d1, and 5-d6 to C60 were also measured. The intermolecular competition due to deuterium substitution of both vinylic hydrogens at the β-carbon of 3 exhibits a substantial inverse α-secondary isotope effect k(H)/k(D) = 0.83 (per deuterium). Substitution with deuterium at both vinylic methyl groups of 5 yields a small inverse k(H)/k(D) = 0.94. These results are consistent with the formation of an open intermediate in the rate-determining step.
- Vassilikogiannakis,Hatzimarinaki,Orfanopoulos
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p. 8180 - 8187
(2007/10/03)
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- Amino acid analogs for tumor imaging
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The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ?18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an α-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of α-aminoisobutyric acid.
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- Amino acid analogs for tumor imaging
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The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ?18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an α-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of α-aminoisobutyric acid.
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- The synthesis of alkenes via epi-phosphonium species: 2. A phosphorus Ramberg-Backlund reaction
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Stilbene may be synthesised with Z-selectivity from (α- bromobenzyl)benzyldiphenylphosphonium bromide by the action of amine bases. A series of stilbenes was synthesised by the action of N-bromosuccinimide and 2,2,6,6-tetramethylpiperidine directly upon dibenzyldiphenylphosphonium salts. The reaction, essentially a phosphonium analogue of the Ramberg- Backlund displays cis selectivity. The dibenzyldiphenylphosphonium salts were prepared by the one pot polymethylhydrosiloxane/titanium(IV) isopropoxide mediated reduction/alkylation of benzyldiphenylphosphine oxides.
- Lawrence, Nicholas J.,Muhammad, Faiz
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p. 15361 - 15370
(2007/10/03)
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- 5[W(substituted aryl)alkenylene and alkynylene]-2,4-diaminopyrimidines as pesticides
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5-Substituted-2,4-diaminopyrimidines, and agriculturally acceptable salts thereof, when present in insecticidally or acaricidally effective amounts, and with a suitable agricultural carrier, are useful as active ingredients in novel insecticidal and acaricidal compositions. These pyrimidines may be represented by the following formula: STR1 wherein Ar is STR2 and wherein U is an alkenylene or alkynylene moiety, and R, R1, R2, R3, R4, V, W, X, Y, Z and n are as defined herein; also disclosed and claimed are novel intermediates thereof.
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- 6-substituted-3,5-diamino-1,2,4-triazines as insecticides
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An insecticidal composition comprising, in admixture with an agriculturally acceptable carrier, an insecticidally effective amount of a 1,2,4-triazine compound of the formula STR1 wherein m is 0 to 12; n is 0 or 1; T is CH2, CH=CH, or C C; X is Si(CH3)2, C(CH3)2, CH(CH3), or O; or R is methyl, vinyl, cyclopentyl, phenyl, naphthyl, or a substituted phenyl of the formula: STR2 wherein Q, U, W, Y, Z, and R1, R2, R3, R4 are as defined herein; and methods of using the same.
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- Syntheses of the Ethyl Esters of the Plant Host-Selective (H-S) Toxins (AF-IIa, AF-IIc and AK-II) Produced by Pathotypes of Alternaria alternata
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Total syntheses of the ethyl esters of the host-selective (H-S) toxins produced by Alternaria alternata (strawberry-type pathogen), AF-IIa and AF-IIc, and by the Japanese pear-type AK-II are reported.The initial synthetic objectives, the 2E,4E,6E, 2E,4Z,6E and 2E,4E,6Z stereoisomers of ethyl 8-hydroxy-9-methyldeca-2,4,6,9-tetraenoate, were attained by the use of acetylene hydrometallation and Pd0-mediated vinyl halide coupling: for this purpose tin chemistry was superior to the use of zirconium compounds.The tetraene-hydroxy esters were epoxidised selectively at the 9,10-double bond by the Sharpless procedure under conditions of kinetic control (50percent reaction), which it was predicted would lead to products of predominantly (8R,9S)-stereochemistry.Esterification of the epoxides produced from the 2E,4E,6E and 2E,4E,6Z hydroxy esters with synthetic (2R,3S)-2-(t-butyldimethylsiloxy)-3-methylpentanoic acid, followed by HPLC separation, gave as the major products, stereoisomers which, after deprotection, were characterised as the ethyl esters AF-toxin IIc and AF-toxin IIa.The stereochemical nature of the minor products in the epoxidations is considered.For the sythesis of the AK-II toxin as its ethyl ester, similar esterification with N-acetyl-L-phenylalanine was carried out, except that the racemisation of the amino acid centre ensued.This led to two major products which were separated and identified as (8R,9S,2'S)- and (8R,9S,2'R)-stereoisomers, the former being identical with the ester of AK-II toxin.
- Crombie, Leslie,Horsham, Mark A.,Jarrett, Sandra R. M.
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p. 1511 - 1524
(2007/10/02)
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- Kinetics of the reaction between triphenylphosphine and some haloalkanes
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Kinetics of reactions RX + (C6H5)2P -> (C6H5)3PR+X- (R = CCl3, CBr3, CH2Br, C4H9 and X = Br, Cl, I) have been studied at different temperatures and in different dielectric media.The values of second order rate constants of the reactions with tetrahalomethanes are much higher than those with partially halogenated alkanes.This suggests that the reaction may be of charge transfer type with tetrahalomethanes while with other haloalkanes it is simple nucleophilic substitution reaction of SN2 type.
- Jain, D V S.,Chadha, R
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p. 929 - 935
(2007/10/02)
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- Synthesis of Three Phenolic Pent-1-en-4-ynes
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Three novel pent-1-en-4-ynes 3, 4 and 5, analogues of the naturally-occurring rooperol 2, have been synthesized.The procedure involves initial protection of the phenolic groups as allyl ethers followed by deprotection with Wilkinson's catalyst.
- Drewes, Siegfried E.,Emslie, Neville D.,Hemingway, Maxine
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p. 1671 - 1679
(2007/10/02)
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- NOVEL REACTIONS OF PHOSPHONIUM YLIDES WITH PERHALOALKANES: FIRST EXAMPLES OF HALOPHILIC ATTACKS BY PHOSPHONIUM YLIDES AND A FACILE ROUTE TO α-HALOALKYLPHOSPHONIUM SALTS
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Phosphonium ylides Ph3=CHR (R = H, CH3, C2H5, n-C3H7, n-C5H11) react readily with perhalofluoroalkanes to afford regiospecifically α-haloalkylphosphonium salts Ph3P+-CHXR Y- (X = I, Br, Cl) in good yields.These reactions reveal a new type of reactivity phosphonium ylides, i.e., the halophilic attack on C-X bonds, and may be useful for the regiospecific synthesis of substituted haloolefins via Wittig reaction.
- Li, Xing-Ya,Hu, Jin-Shan
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p. 6317 - 6320
(2007/10/02)
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