- Development of a chemical probe for identifying protein targets of α-oxoaldehydes
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The development of a chemical probe for identifying the protein targets of reactive electrophilic α-oxoaldehydes such as methylglyoxal is presented. The probe is evaluated against methylglyoxal using human serum albumin as well as using living cells and lysates.
- Sibbersen, Christian,Palmfeldt, Johan,Hansen, Jakob,Gregersen, Niels,Jorgensen, Karl Anker,Johannsen, Mogens
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Read Online
- Iron(III) Nitrate/TEMPO-Catalyzed Aerobic Alcohol Oxidation: Distinguishing between Serial versus Integrated Redox Cooperativity
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Aerobic alcohol oxidations catalyzed by transition metal salts and aminoxyls are prominent examples of cooperative catalysis. Cu/aminoxyl catalysts have been studied previously and feature "integrated cooperativity", in which CuII and the aminoxyl participate together to mediate alcohol oxidation. Here we investigate a complementary Fe/aminoxyl catalyst system and provide evidence for "serial cooperativity", involving a redox cascade wherein the alcohol is oxidized by an in situ-generated oxoammonium species, which is directly detected in the catalytic reaction mixture by cyclic step chronoamperometry. The mechanistic difference between the Cu- and Fe-based catalysts arises from the use iron(III) nitrate, which initiates a NOx-based redox cycle for oxidation of aminoxyl/hydroxylamine to oxoammonium. The different mechanisms for the Cu- and Fe-based catalyst systems are manifested in different alcohol oxidation chemoselectivity and functional group compatibility.
- Mao, Kaining,Nutting, Jordan E.,Stahl, Shannon S.
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supporting information
p. 10565 - 10570
(2021/07/28)
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- DDX3X inhibitors, an effective way to overcome HIV-1 resistance targeting host proteins
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The huge resources that had gone into Human Immunodeficiency virus (HIV) research led to the development of potent antivirals able to suppress viral load in the majority of treated patients, thus dramatically increasing the life expectancy of people living with HIV. However, life-long treatments could result in the emergence of drug-resistant viruses that can progressively reduce the number of therapeutic options, facilitating the progression of the disease. In this scenario, we previously demonstrated that inhibitors of the human DDX3X helicase can represent an innovative approach for the simultaneous treatment of HIV and other viral infections such as Hepatitis c virus (HCV). We reported herein 6b, a novel DDX3X inhibitor that thanks to its distinct target of action is effective against HIV-1 strains resistant to currently approved drugs. Its improved in vitro ADME properties allowed us to perform preliminary in vivo studies in mice, which highlighted optimal biocompatibility and an improved bioavailability. These results represent a significant advancement in the development of DDX3X inhibitors as a novel class of broad spectrum and safe anti-HIV-1 drugs.
- Boccuto, Adele,Botta, Maurizio,Brai, Annalaura,Bugli, Francesca,Dreassi, Elena,Garbelli, Anna,Giannini, Alessia,Maga, Giovanni,Martini, Maurizio,Pennisi, Carla,Riva, Valentina,Saladini, Francesco,Sanguinetti, Maurizio,Trivisani, Claudia Immacolata,Zamperini, Claudio,Zazzi, Maurizio
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supporting information
(2020/05/22)
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- Synthesis of Two Stereoisomers of Potentially Bioactive 13,19,20-Trihydroxy Derivative of Docosahexaenoic Acid
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The C16-C22 fragment with the acetylene terminus was constructed through the asymmetric dihydroxylation of the corresponding olefin, while the 15-iodo-olefin corresponding to the C11-C15 part was prepared via the asymmetric transfer hydrogenation of the corresponding acetylene ketone followed by hydrozirconation/iodination. Both pieces were joined by a Sonogashira coupling, and the product was further converted into the title compound via a Wittig reaction with the remaining C1-C10 segment and Boland reduction using Zn with TMSCl.
- Ogawa, Narihito,Sone, Shinsaku,Hong, Song,Lu, Yan,Kobayashi, Yuichi
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supporting information
p. 1735 - 1739
(2020/09/02)
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- HETEROCYCLIC COMPOUNDS AND USE THEREOF
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Heterocyclic compounds of Formula (I) shown herein. Also disclosed is a pharmaceutical composition containing one of the heterocyclic compounds. Further disclosed are methods of using one of the heterocyclic compounds for mobilizing hematopoietic stem cells and endothelial progenitor cells into the peripheral circulation, and for treating tissue injury, cancer, inflammatory disease, and autoimmune disease.
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Page/Page column 20
(2018/08/03)
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- An Efficient Aerobic Oxidation Protocol of Aldehydes to Carboxylic Acids in Water Catalyzed by an Inorganic-Ligand-Supported Copper Catalyst
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A method for the aerobic oxidation of aldehydes to carboxylic acids in water by using an inorganic-ligand-supported copper catalyst was developed. This method was performed with the use of atmospheric oxygen as the sole oxidant under extremely mild aqueous conditions, and furthermore, a wide range of aldehydes with various functional groups were tolerated. The copper catalyst could be recycled and used in successive reactions at least six times without any appreciable degradation in performance. This method is operationally simple and avoids the use of high-costing, toxic, air/moisture-sensitive, and commercially unavailable organic ligands. The generality of this method gives it potential to be used on the industrial scale.
- Yu, Han,Ru, Shi,Zhai, Yongyan,Dai, Guoyong,Han, Sheng,Wei, Yongge
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p. 1253 - 1257
(2018/02/16)
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- Method for preparing acid through oxidating alcohols or aldehydes by oxygen
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The invention provides a method for preparing acid through oxidating alcohols or aldehydes by using oxygen or oxygen in air as an oxidant. The method comprises the steps: oxidating the alcohols or aldehydes to produce the acid at room temperature in an organic solvent in a manner of taking ferric nitrate (Fe(NO3)3.9H2O), 2,2,6,6-tetramethylpiperidyl nitrogen oxide (TEMPO) and an inorganic halide as catalysts and taking the oxygen or air as an oxidant, and oxidating diols to produce lactone; or, carrying out a reaction on the aldehydes, which serve as a raw material, under neutral conditions by taking ferric nitrate as a catalyst, and oxidating the aldehydes to produce the acid and peroxy acid. The method has the advantages that the method is environmentally friendly, the cost is low, the yield is high, the atomic economical efficiency is high, the compatibility of substrate functional groups is good, the reaction conditions are mild, a reaction scale can be enlarged, and the like, so that the method is suitable for being applied to industrial production.
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Paragraph 0051; 0052; 0053; 0054; 0085; 0086; 0087
(2017/09/29)
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- USE OF DDX3 INHIBITORS AS ANTIPROLIFERATIVE AGENTS
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The present invention refers to compounds of formula I or II endowed with DDX3 inhibitory activity, relative pharmaceutical compositions and their use as antihyperproliferative agents. (I) or (II)
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Page/Page column 45
(2017/10/30)
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- Traceless and Chemoselective Amine Bioconjugation via Phthalimidine Formation in Native Protein Modification
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ortho-Phthalaldehyde (OPA) and its derivatives are found to react chemoselectively with amino groups on peptides and proteins rapidly and tracelessly under the physiological condition via formation of phthalimidines, which provides a novel and promising approach when performing bioconjugation on native proteins. The notable advantages of this method over the existing native protein lysine-labeling approaches include a traceless process, a self-reacting, specific and fast reaction, ease of operation, and the ability to use nonhydrolyzable reagents. Its applications have been effectively demonstrated including conjugation of peptides and proteins, and generation of an active PEGlyated l-asparaginase.
- Tung, Chun Ling,Wong, Clarence T. T.,Fung, Eva Yi Man,Li, Xuechen
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supporting information
p. 2600 - 2603
(2016/06/15)
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- HUMAN HELICASE DDX3 INHIBITORS AS THERAPEUTIC AGENTS
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The present invention refers to compounds endowed with RNA helicase DDX3 inhibitory activity of formula I and II and their therapeutic use, in particular for the treatment of viral diseases.
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Page/Page column 53
(2016/09/22)
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- Iron Catalysis for Room-Temperature Aerobic Oxidation of Alcohols to Carboxylic Acids
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Oxidation from alcohols to carboxylic acids, a class of essential chemicals in daily life, academic laboratories, and industry, is a fundamental reaction, usually using at least a stoichiometric amount of an expensive and toxic oxidant. Here, an efficient and practical sustainable oxidation technology of alcohols to carboxylic acids using pure O2 or even O2 in air as the oxidant has been developed: utilizing a catalytic amount each of Fe(NO3)3·9H2O/TEMPO/MCl, a series of carboxylic acids were obtained from alcohols (also aldehydes) in high yields at room temperature. A 55 g-scale reaction was demonstrated using air. As a synthetic application, the first total synthesis of a naturally occurring allene, i.e., phlomic acid, was accomplished.
- Jiang, Xingguo,Zhang, Jiasheng,Ma, Shengming
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supporting information
p. 8344 - 8347
(2016/07/26)
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- Iron-Catalysed Selective Aerobic Oxidation of Alcohols to Carbonyl and Carboxylic Compounds
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A method for aerobic alcohol oxidation catalysed by Fe(NO3)3/2,2’-bipyridine/TEMPO has allowed highly selective conversion of primary alcohols into either aldehydes or carboxylic acids in one-step. The oxidation of primary alcohols proceeded selectively to aldehydes, as TEMPO was present in the reaction. Nevertheless, the aldehydes were further oxidized into carboxylic acids as the reaction time was extended. Detailed investigation of the reaction suggested, that the deoxygenation of TEMPO into TMP enabled the auto-oxidation of aldehydes to carboxylic acids, which was initially inhibited in the presence of TEMPO. The procedure was also efficient in oxidation of secondary alcohols when TEMPO was replaced by the less sterically hindered ABNO.
- Lagerblom, Kalle,Wrigstedt, Pauli,Keskiv?li, Juha,Parviainen, Arno,Repo, Timo
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p. 1160 - 1165
(2016/11/23)
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- Synthesis of chemically-tethered amyloid-β segment trimer possessing amyloidogenic properties
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As amyloid-β (Aβ) undergoes dynamic aggregation, it is impossible to isolate ('hook') the transient Aβ oligomer in an assembly state-pure form (e.g., sole Aβ dimer, trimer, tetramer, etc.). Obtaining such a pure Aβ oligomer would allow us to establish an in vitro system to perform a more detailed investigation of the pathogenic properties of the oligomer. A chemically-tethered Aβ oligomer, constructed only by covalent bonds, could satisfy this demand. Here we designed a chemically-tethered trimer of a pathogenic Aβ fragment (Aβ25-35) (1) and successfully generated it in situ from its precursor (4), a water-soluble and non-aggregative O-acyl isopeptide of 1, in neutral aqueous media. Chemically-tethered 1 possessed stronger amyloidogenic properties, that is, potential for β-sheet structure, fibril formation, and cytotoxicity, than the corresponding monomer Aβ25-35 (6). Trimerization of Aβ25-35 sequence might affect both the aggregative properties and cytotoxicity, based on the present results. This work opens the door for chemical synthesis of oligomers bigger than trimers in an assembly state-pure form, allowing for identification of the most toxic Aβ oligomer.
- Shinoda, Kiyomichi,Sohma, Youhei,Kanai, Motomu
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supporting information
p. 2976 - 2979
(2015/06/22)
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- Enzyme kinetics and inhibition of histone acetyltransferase KAT8
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Lysine acetyltransferase 8 (KAT8) is a histone acetyltransferase (HAT) responsible for acetylating lysine 16 on histone H4 (H4K16) and plays a role in cell cycle progression as well as acetylation of the tumor suppressor protein p53. Further studies on its biological function and drug discovery initiatives will benefit from the development of small molecule inhibitors for this enzyme. As a first step towards this aim we investigated the enzyme kinetics of this bi-substrate enzyme. The kinetic experiments indicate a ping-pong mechanism in which the enzyme binds Ac-CoA first, followed by binding of the histone substrate. This mechanism is supported by affinity measurements of both substrates using isothermal titration calorimetry (ITC). Using this information, the KAT8 inhibition of a focused compound collection around the non-selective HAT inhibitor anacardic acid has been investigated. Kinetic studies with anacardic acid were performed, based on which a model for the catalytic activity of KAT8 and the inhibitory action of anacardic acid (AA) was proposed. This enabled the calculation of the inhibition constant Ki of anacardic acid derivatives using an adaptation of the Cheng-Prusoff equation. The results described in this study give insight into the catalytic mechanism of KAT8 and present the first well-characterized small-molecule inhibitors for this HAT.
- Wapenaar, Hannah,Van Der Wouden, Petra E.,Groves, Matthew R.,Rotili, Dante,Mai, Antonello,Dekker, Frank J.
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p. 289 - 296
(2015/11/09)
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- Synthesis and helical structures of poly(ω-alkynamide)s having chiral side chains: Effect of solvent on their screw-sense inversion
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New ω-alkynamides, (S)-HC≡CCH2CONHCH2CH-(CH3)CH2CH3 (1) and (S)-HC≡CCH2CH2CONHCH-(CH3)CH2CH2CH2CH2CH3 (2) were synthesized and polymerized with a rhodium catalyst in CHCl3 to obtain cis-stereoregular poly(ω-alkynamide)s (poly(1) and poly(2)). Polarimetric, CD, and IR spectroscopic studies revealed that in solution the polymers adopted predominantly one-handed helical structures stabilized by intramolecular hydrogen bonds between the pendent amide groups. This behavior was similar to that of the corresponding poly(N-alkynylamide) counterparts (poly(3) and poly(4)) reported previously, whereas the helical senses were opposite to each other. The helical structures of the poly(ω-alkynamide)s were stable upon heating similar to those of the poly(N-alkynylamide)s, but the solvent response was completely different. An increase in MeOH content in CHCl3/MeOH resulted in inversion of the predominant screw-sense for poly(1) and poly(2). Conversely, poly(3) was transformed into a random coil, and poly(4) maintained the predominant screw-sense irrespective of MeOH content. The solvent dependence of predominant screw-sense for poly(1) and poly(2) was reasonably explained by molecular orbital studies using the conductor-like screening model (COSMO).
- Suzuki, Yuji,Miyagi, Yu,Shiotsuki, Masashi,Inai, Yoshihito,Masuda, Toshio,Sanda, Fumio
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p. 15131 - 15143
(2015/02/19)
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- Stereocontrolled total synthesis of Neuroprotectin D1/Protectin D1 and its aspirin-triggered stereoisomer
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Neuroprotectin D1/Protectin D1, a potent anti-inflammatory, proresolving, and neuroprotective lipid mediator derived biosynthetically from docosahexaenoic acid, was prepared in an enantiomerically pure form via total organic synthesis. The synthetic strategy is highly stereocontrolled and convergent, featuring epoxide opening of glycidol starting materials for the introduction of the 10(R) and 17(S) hydroxyl groups. The desired alkene Z geometry was secured via the cis-reduction of alkyne precursors, while the conjugated E,E,Z triene was introduced at the end, in order to minimize Z/E isomerization. The same strategy, was also employed for the total synthesis of aspirin-triggered neuroprotectin D1/protectin D1 having the 17(R)-stereochemistry. Synthetic compounds obtained with the reported method were matched with endogenously derived materials, and helped establish their complete stereochemistry.
- Petasis, Nicos A.,Yang, Rong,Winkler, Jeremy W.,Zhu, Min,Uddin, Jasim,Bazan, Nicolas G.,Serhan, Charles N.
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body text
p. 1695 - 1698
(2012/05/05)
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- Cycloaddition reactions of 1,3-diazabuta-1,3-dienes with alkynyl ketenes
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The cycloaddition reactions of 'all-carbon' 1,3-diazabuta-1,3-dienes with a few conjugated and unconjugated alkynyl ketenes are described. The reactions provide some interesting azetidinones and dihydropyrimidinones bearing an alkynyl moiety. The regiochemistry of cycloadduct is related with the degree of conjugation of the alkynyl ketene. Moreover, two alternative approaches to 'all-carbon' 1,3-diazabuta-1,3-dienes are reported.
- Abbiati, Giorgio,Contini, Alessandro,Nava, Donatella,Rossi, Elisabetta
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experimental part
p. 4664 - 4670
(2009/10/09)
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- METHOD FOR PREPARING 4-PENTYNOIC ACID
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PROBLEM TO BE SOLVED: To provide a new industrially advantageous method for preparing 4-pentynoic acid. SOLUTION: The method for preparing 4-pentynoic acid of formula (1) comprises reacting a 4-trimethylsilyl-3-butynyl halide represented by formula (2) (wherein X is a halogen; and TMS is a trimethylsilyl group) with a metallic magnesium in a suitable solvent to obtain a 4-trimethylsilyl-3-butyn-1-yl magnesium halide represented by formula (3) (wherein X and TMS are the same as defined above), reacting the 4-trimethylsilyl-3-butyn-1-yl magnesium halide with carbon dioxide to obtain 5-trimethylsilyl-4-pentynoic acid represented by formula (4), and then performing detrimethylsilylation reaction.
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Page/Page column 7
(2008/06/13)
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- Synthesis of (E,Z)-5-bromo-1,1-dimethoxy-5-trimethylsilyl-4-pentene, an upper chain allenic prostaglandin building block
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This work explores the synthetic route to allenic prostaglandins. In a search for more efficient and reliable methods for the introduction of the allene moiety into the side chains of prostaglandins, the synthons, the (E) and (Z) isomers of 1-bromo-5,5-dimethoxy-1-trimethylsilyl-1-pentene (13a) and (13b), have been prepared and converted to R,S-1,1-dimethoxy-6-phenyl-4,5-hexadiene (16), a prostaglandin analog.
- Guzman-Duran, Antonio,Guzman, Esther,Pannell, Keith H.,Lloyd, Winston D.
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p. 3271 - 3283
(2007/10/03)
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- Synthesis of ω-and (ω - 1)-acetylenic acids from five-, six-, or seven-membered cycloalkanones
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A convenient method for the synthesis of ω-and (ω - 1)-acetylenic acids involves free-radical oxidative scission of cycloalkanones containing five-, six, or seven-membered cycles to give the corresponding ω-olefinic acids followed by bromination of the latter and subsequent dehydrobromination under the action of alkalis.
- Starostin,Ignatenko,Lapitskaya,Pivnitsky,Nikishin
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p. 833 - 837
(2007/10/03)
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- Diaziridinyl-aryl and bis-[di(chloroethyl)amino]-aryl oligonucleotide conjugates and reagents for making the same
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Diaziridinyl-aryl and bis-[di(chloroethyl)amino]-aryl oligonucleotide conjugates have a sequence that is complementary in the triplex forming sense to a target sequence in duplex nucleic acid. The diaziridinyl-aryl and bis-[di(chloroethyl)amino]-aryl oligonucleotide conjugates effectively cross-link with both strands of the targeted duplex nucleic acid.
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- Ruthenium-catalyzed alder ene type reactions. A formal synthesis of alternaric acid
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Alternaric acid, a nanomolar fungal germination inhibitor, is typified by a 1,4-diene, consisting of a terminal methylene and an (E)-l,2- disubstituted alkene. A new strategy for the synthesis of natural products containing such functionality stems from the development of a ruthenium- catalyzed addition of terminal alkenes with terminal alkynes. The alkyne substrate, 4-pentynoic acid, is commercially available or can be prepared in two steps by alkylation of tert-butyl acetate. The alkene substrate is prepared from commercially available (S)-2-methyl-l-butanol. This synthesis involves formation of a geometically defined trisubstituted alkene by involving Pd-catalyzed cross-coupling and asymmetric dihydroxylation. The ruthenium-catalyzed coupling proceeds best in the absence of alcohol protecting groups to maximize regioselectivity. The examples of this addition illustrated herein help elucidate some of the important factors controlling regioselectivity. They also illustrate the excellent chemoselectivity. The acyclic unit of alternaric acid, which is simply coupled to a dihydropyrone fragment to complete the synthesis, is available in only 11 steps and 27% overall yield compared to the one extant synthesis also starting from (S)-2- methyl-1-butanol which proceeds in 26 steps and 0.003% overall yield. This new reaction provides a powerful tool in streamlining this synthesis and should prove more generally useful.
- Trost, Barry M.,Probst, Gary D.,Schoop, Andreas
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p. 9228 - 9236
(2007/10/03)
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- EXO- AND ENDOHORMONES, XVI SYNTHESIS OF (4E, 7Z)-4,7-TRIDECADIEN 1-YL ACETATE, THE SEX PHEROMONE FOR THE LEAFMINER LITHOCOLLETIS CORYLIFOLIELLA
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The synthesis of the sex pheromone of the leafminer moth, Lithocolletis corylifoliella, (4E, 7Z)-4,7-tridecadien-1-yl acetate, was based on a C5+C8 scheme.The coupling reaction took place between the Grignard reagent of 4-pentin-1-1-oic acid and 1-bromo-2Z-octene.Propargylic alcohol was used as a starting material in order to obtain the two synthons.
- Gocan, Alexandra,Gansca, Lucia,Oprean, Ioan
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p. 253 - 258
(2007/10/03)
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- Synthesis and Nuclear Magnetic Resonance Studies on a Series of Synthesis Long-chain Tellurophene Fatty Esters
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The synthesis and the results of the 1H and 13C NMR spectroscopic analyses of thirteen 2,5-disubstituted tellurophene fatty esters, containing substituents of different chain lengths, and of a monosubstituted tellurophene ester are repported.The tellurophene esters are obtained by cyclization of the corresponding conjugated intermediates with Na2Te in the presence of AgOAc in methanol.The tellurophene moiety in the alkyl chain induces a deshielding effect on the protons of the adjacent methylene prtons.The shift parameters of the tellurophene moiety on the shifts of the adjacent methylene carbon atoms are also determined.
- Jie, Marcel S. F. Lie Ken,Chau, Sherman H.
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p. 2642 - 2657
(2007/10/03)
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- Tetrapyrroles. III. Homochiral dihydropyrromethenones from N-aminopyrroles and acetylenic acids
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Dihydropyrromethenone 29, a potential precursor for the synthesis of Phytochrome (8), Phycocyanin (9) and Phycoerythrin (10), has been prepared in homochiral form from pyrrolohydrazide 27 by a sequence involving F-induced 5-exo-dig cyclization to afford enamide 28, followed by photochemical 3,5-sigmatropic rearrangement.
- Jacobi,Rajeswari
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p. 6231 - 6234
(2007/10/02)
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- Electron Impact Induced Fragmentation of β-Allenic and γ-Acetylenic Alcohols
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The main fragmentation pathway of ionized hydroxyallenes (1) consists of a methyl loss.Extensive deuterium-labelling experiments indicate that the terminal allenic carbon is implied in this fragmentation.Collisional activation spectra indicate a propenyl-acylium structure (a) for these (+) ions which can originate from a 1,4-hydroxyl migration followed by hydrogen rearrangements.Isomeric hydroxyacetylenes (2) behave similarly, also giving rise, by methyl loss, to acylium ions a.It is proposed that 2(+) radical is irreversibly isomerized into 1(+) radical by a 1,3-hydrogen transfer 'catalysed' by the hydroxy group.The proposed internal proton-bound complex justifies also the easier loss of water from 2(+) radical.Ethyl loss is also a prominent fragmentation for the hydroxyallene and hydroxyacetylene homologues.
- Arseniyadis, Simeon,Maquestiau, Andre,Flammang, Robert,Guenot, Pierre,Carrie, Robert
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p. 909 - 916
(2007/10/02)
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- Two Regiocomplementary Approaches to Angular Furanocoumarins with Chromium Carbene Complexes: Synthesis of Sphondin, Thiosphondin, Heratomin, and Angelicin
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Two regiocomplementary syntheses of the angular furanocoumarin sphondin are described utilizing the benzannulation reaction of furylcarbene complexes of chromium.The high regioselectivity of an intermolecular synthesis employing the reaction of pentacarbonylchromium (8) and methyl 4-pentynoate is thought to be controlled by the preferred conformation of an alkyne-carbene complex intermediate.By utilizing the same acetylene, heratomin and an unnatural derivative of sphondin, 6-methoxy-2-oxo(2H)-thiofuro(2,3-h)benzopyran were prepared from pentacarbonylchromium (37) and pentacarbonylchromium (31), respectively.An intramolecular synthesis of sphondin from oxy>carbene>pentacarbonylchromium (10e) incorporates the acetylene with reversed regiochemistry due to the geometrical constraints of the intramolecular annulation.Control over the formation of the regiochemistry correct for the carbon skeleton of sphondin is possible due to the regioselectivity in the annulation of unsymmetrical aromatic substituents (3-furyl) on the carbene carbon.The intramolecular synthesis is thus related to the intermolecular synthesis by a double reversal in the regiochemistry.A convergent synthesis of sphondin and angelicin is described which has the phenol 72 produced from the intramolecular benzannulation of complex 10e as a branch point and is differentiated by whether the phenol functionality is retained or reduced.
- Wulff, William D.,McCallum, J. Stuart,Kunng, Fen-Ann
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p. 7419 - 7434
(2007/10/02)
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- SELECTIVITY OF NUCLEOPHILIC ADDITION TO AND SUBSTITUTION AT ISOTHIOCYANATOCARBONYL GROUP. REACTIONS OF 4-PENTINOYL- AND 2-(2-PROPINYL)-4-PENTINOYL ISOTHIOCYANATE WITH AMINES AND METHANOL
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4-Pentinoyl isothiocyanate reacts with primary and secondary amines by either nucleophilic addition to N=C=S group to yield the corresponding thioureas, or a nucleophilic substitution at the carbonyl group to give 4-pentinoic acid amides.The less nucleophilic diphenylamine reacts selectively to afford the product of nucleophilic addition only. 2-(2-Propinyl)-4-pentinoyl isothiocyanate, having a sterically hindered carbonyl group, furnished with primary amines a mixture of amides and thioureas, whereas the bulkier secondary amines react selectively to form thioureasonly.Both isothiocyanates afford with methanol as a nucleophile axclusively the corresponding O-methyl monothiocarbamates.
- Kutschy, Peter,Kristian, Pavol,Dzurilla, Milan,Koscik, Dusan,Nadaskay, Robert
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p. 995 - 1005
(2007/10/02)
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- Intramolecular Reactions of N-Nitrenes with Alkynes: Conformational Anchoring in Spiro-fused 2H-Azirines
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Oxidations of N-aminoquinazolin-4(3H)-ones (7)-(11) with lead tetra-acetate in dichloromethane results in the intramolecular addition of the N-nitrene to the triple bond in each case and azirines (20), (22), (17), (23), and (30), respectively, are isolated with (31) identified as a by-product in the oxidation of compound (11).An X-ray crystal structure determination on compound (17) reveals a remarkable deformation of bond angles at the spiro centre and this feature appears to be common to all azirines.The five membered ring in the azirines (17), (20), (22), and (23) has the envelope conformation (26) and the six-membered ring in the azirine (30) has the twist-boat conformation (32): a possible explanation for this conformational anchoring is offered.
- Atkinson, Robert S.,Grimshire, Michael J.
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p. 1215 - 1224
(2007/10/02)
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- DEPLACEMENTS HOMOLYTIQUES INTRAMOLECULAIRES 10 - ADDITIONS RADICALAIRES A DES PERESTERS γ-INSATURES INFLUENCE DE DIVERS FACTEURS SUR LA FORMATION D'ESTERS CYCLIQUES
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Free radical additions of ZH compounds to γ-unsaturated peresters have been performed in order to determine the limitations upon the induced decomposition (steric affects, type of unsaturation, nature of the neighbouring atom of the perester function).Using γ-ethylenic peresters and percarbonates led generally to lactones and cyclic carbonates.
- Kharrat, A.,Gardrat, C.,Maillard, B.
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p. 535 - 546
(2007/10/02)
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- ORGANOMETALLIC COMPOUNDS OF ZINC AS SELECTIVE NUCLEOPHILIC REAGENTS IN ORGANIC SYNTHESIS
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The ability of the Reformatsky reagent BrZnCH2CO2tBu 1 to undergo substitution reactions has been verified with several substituted bromides.
- Orsini, F.,Pelizzoni, F.
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p. 805 - 816
(2007/10/02)
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- Biocidal esters of alkynoic acids
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This invention relates to novel ester compounds derived from alkynoic acids and to their preparation. This invention is also directed to insecticidal and miticidal compositions comprising an acceptable carrier and an insecticidally or miticidally effective amount of a novel ester compound of this invention as well as a method of controlling pests by subjecting them to an insecticidally or miticidally effective amount of a novel ester compound of this invention.
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- Cyclisation of Acetylenecarboxylic Acid. Synthesis of γ-Methylenebutyrolactones
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Various γ-exo-methylenebutyrolactones have been synthesized in excellent yield by the cyclisation of acetylenecarboxylic acids in the presence of a catalytic amount of mercury(II) oxide.Cyclisation of terminal acetylene compounds proceeded regioselectively to give γ-exo-methylenebutyrolactones as the sole product.Disubstituted acetylenes also gave the (Z)-configurational enol lactone, but small amounts of an (E)-isomer of a γ-exo-enol lactone and a δ-lactone (α-pyrone) were also formed.Spectral properties and stereochemistry of the exo-enol lactones are also discussed.
- Yamamato, Makoto
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p. 582 - 587
(2007/10/02)
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