- HYDROLYSIS IN THE ABSENCE OF BULK WATER 2. CHEMOSELECTIVE HYDROLYSIS OF NITRILES USING TETRAHALOPHTHALIC ACIDS
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The reaction of nitriles with tetrafluorophthalic or tetrachlorophthalic acid gives carboxylic acids in good yield.The reaction is chemoselective in that the nitrile functionality can be hydrolyzed in the presence of ester groups.
- Rounds, William D.,Eaton, Jefferson T.,Urbanowicz, John H.,Gribble, Gordon W.
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Read Online
- Discovery of a 3-amino-6-phenyl-pyridazine derivative as a new synthetic antineuroinflammatory compound
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Excessive glial activation, with overproduction of cytokines and oxidative stress products, is detrimental and a hallmark of neurodegenerative disease pathology. Suppression of glial activation is a potential therapeutic approach, and protein kinases are targets of some antiinflammatory drugs. To address an unmet need for selective inhibitors of glial activation, we developed a novel 3-amino-6-phenylpyridazine derivative that selectively blocks increased IL-1β, iNOS, and NO production by activated glia, without inhibition of potentially beneficial glial functions.
- Mirzoeva, Salida,Sawkar, Anu,Zasadzki, Magdalena,Guo, Ling,Velentza, Anastasia V.,Dunlap, Vincent,Bourguignonl, Jean-Jacques,Ramstrom, Helena,Haiech, Jacques,Van Eldik, Linda J.,Watterson
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Read Online
- The value of 2JP–CO as a diagnostic parameter for the structure and thermal reactivity of carbonyl-stabilised phosphonium ylides
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A survey of 20 carbonyl-stabilised phosphonium ylides with recently reported X-ray structures shows a strong correlation between the C[dbnd]P to C[dbnd]O torsion angle and the value of 2JP–CO, with high values being associated with an anti configuration and low with syn. Seven new X-ray structural determinations are reported, several for types of ylide not crystallographically characterised before, and these also conform to this pattern. The value of 2JP–CO is then correlated with whether or not thermal extrusion of Ph3PO occurs to give alkynes for over 200 ylides and an empirical rule developed that the extrusion never occurs for ylides where this value is > 11 Hz. This is used to rationalise the anomalous behaviour of some trioxo ylides and cyclic ylides, two of which afford cycloalkynes, isolated after rearrangement as the isomeric 1,3-dienes. The rule also holds for a family of novel highly fluorinated ylides which afford fluorinated alkynes in good yield upon flash vacuum pyrolysis.
- Aitken, R. Alan,Boubalouta, Youcef,Chang, Da,Cleghorn, Lee P.,Gray, Ian P.,Karodia, Nazira,Reid, Euan J.,Slawin, Alexandra M.Z.
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p. 6275 - 6285
(2017/09/29)
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- Unusual Adsorption at the Air-Water Interface of a Zwitterionic Carboxybetaine with a Large Charge Separation
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The structures of layers of three different dodecylcarboxybetaine surfactants adsorbed at the air-water interface have been determined by neutron reflection. The zwitterionic compounds differed in the length of the spacer separating the quaternary ammonium and carboxylate groups, which was (CH2)1, (CH2)4, or (CH2)8. The limiting area per molecule was found to be 45, 52, or 84 ?2, respectively, and compared reasonably with results from surface tension showing that the Gibbs prefactor is 1 in each case. Isotopic labeling was used to distinguish between the position of the alkyl and spacer groups in the layer. The spacer was found to be well-immersed in water for the (CH2)1 and (CH2)4 spacers but significantly above water for the (CH2)8 spacer. The distribution of the (CH2)8 spacer along the surface normal was found to be similar to that of the dodecyl group; i.e., it projects out of the water, contrary to an earlier hypothesis that it forms a loop. Comparison of the overlap of water with dodecyl and spacer groups also indicates that the (CH2)8 spacer is well out of the water. This in turn suggests that the anionic carboxylic acid group, which is dissociated in solution, is not ionized in the adsorbed layer. A further observation is that the dodecylcarboxybetaine with the (CH2)8 spacer reaches surface saturation at one-tenth of the critical micelle concentration. This is highly unusual and is attributed to the long spacer destabilizing the micelle relative to the surface layer.
- Ma, Kun,Li, Pei Xun,Dong, Chu Chuan,Thomas, Robert K.,Penfold, Jeffrey
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p. 3340 - 3347
(2016/05/10)
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- Catalytic Access to Alkyl Bromides, Chlorides and Iodides via Visible Light-Promoted Decarboxylative Halogenation
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Herein is reported the catalytic, visible light-promoted, decarboxylative halogenation (bromination, chlorination, and iodination) of aliphatic carboxylic acids. This operationally-simple reaction tolerates a range of functional groups, proceeds at room temperature, and is redox neutral. By employing an iridium photocatalyst in concert with a halogen atom source, the use of stoichiometric metals such as silver, mercury, thallium, and lead can be circumvented. This reaction grants access to valuable synthetic building blocks from the large pool of cheap, readily available carboxylic acids.
- Candish, Lisa,Standley, Eric A.,Gómez-Suárez, Adrián,Mukherjee, Satobhisha,Glorius, Frank
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supporting information
p. 9971 - 9974
(2016/07/19)
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- Synthesis of 7-triazole-substituted camptothecin via click chemistry and evaluation of in vitro antitumor activity
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Camptothecin (CPT) is a natural topoisomerase I inhibitor with powerful antineoplastic activity against colorectal, breast, lung and ovarian cancers. To discover more potent antitumor agents, a series of new CPT derivatives were synthesized utilizing click chemistry. All compounds were assessed for cytotoxicity against A549, HCT-116, HT-29, LoVo, MDA-MB-231 cell lines, and some compounds exhibited good in vitro potency. Furthermore, all compounds kept or enhanced Topo I inhibition. A series of novel 7-triazole substituted camptothecin via click chemistry was designed, synthesized, and evaluated for their in vitro antitumor activity. Copyright
- Wang, Lei,Yuan, Wei,Zhang, Jie,Tong, Linjiang,Luo, Yu,Chen, Yi,Lu, Wei,Huang, Qingqing
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p. 157 - 162
(2014/03/21)
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- Volatile amphibian pheromones: Macrolides from mantellid frogs from madagascar
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Amphibians like water, but do they also notice volatile compounds in the air? Yes, they do. Macrolides, such as phoracantholide-J (see picture; upper right structure) or the newly discovered natural product gephyromantolide-A (left structure), are used for communication by mantelline frogs from Madagascar. Copyright
- Poth, Dennis,Wollenberg, Katharina C.,Vences, Miguel,Schulz, Stefan
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supporting information; experimental part
p. 2187 - 2190
(2012/04/10)
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- Anti-inflammatory piperazinyl-benzyl-tetrazole derivatives and intermediates thereof
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This invention relates to tetrazoles and their pharmaceutically acceptable salts which are selective agonists for the delta opioid receptor, particularly useful in the treatment of inflammatory diseases such as arthritis, psoriasis, asthma, inflammatory bowel disease, disorders or respiratory function, gastrointestinal disorders such as functional bowel disease and functional GI disorders, of formula (I) wherein R1is H, C2-C6alkanoyl, C1-C6alkyl, C2-C6alkenyl, C2-C6alkynyl, (C3-C7cycloalkyl)-(C1-C4alkyl), (C1-C4alkoxy)-(C1-C4alkyl), carboxy-(C1-C4alkyl), aryl-(C1-C4alkyl) or heteroaryl-(C1-C4alkyl); R2and R3are each independently H or C1-C4alkyl; R4is selected from (i) H, (ii) a group of the formula R6—(CH2)m—Z—(CH2)n—, where m is 0, 1, 2 or 3, n is 1, 2 or 3, Z is a direct link or O, and R6is —CO2H or —CO2(C1-C4alkyl), and (iii) a group of formula (a) where R7is H or C1-C4alkyl; and R5is hydroxy, C1-C4alkoxy or —NHSO2(C1-C4alkyl); with the proviso that when Z is O, m is 1, 2 or 3 and n is 2 or 3.
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- Diesters of carbonic acid endowed with antiviral and anti-inflammatory activity
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Diesters of carbonic acid disubstituted with primary, secondary or tertiary amine groups, pharmaceutically acceptable salts thereof, and their use as antiviral and inti-inflammatory agents.
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- Heterocyclic compouds
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A compound of the general formula wherein: n is 0 or 1; M1 is an amino group; Q is an aromatic heterocyclic group containing a basic nitrogen atom; M2 is an imino group; L is a template group; and A is an acidic group, or an ester or amide derivative thereof, or a sulphonamide group; and pharmaceutically acceptable salts and pro-drugs thereof, for use in the treatment of a disease in which platelet aggregation mediated by the binding of adhesion molecules to GPIIb-IIIa is involved. Novel compounds are also disclosed.
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- Synthesis of 7,8,9,10,11,12,20,21,22,23,24,25-Dodecahydrodibenzotetraoxacyclodocosin, a Crown Ether
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A number of symmetrical diesters and an unsymmetrical type have been synthesised from pyrocatechol.Under conditions in which intramolecular acyloin formation was anticipated the product from one symmetrical compound, ethyl 4-(o-ethoxycarbonylpropoxyphenoxy)butyrate, was a cyclic bis-β-keto-ester resulting in reasonable yield from intermolecular Dieckmann cyclisation.Hydrolysis to the 9,22 diketone, and its reduction to 7,8,9,10,11,12,20,21,22,23,24,25-dodecahydrodibenzotetraoxacyclodocosin 'dibenzo-22-crown-4', proceeded smoothly.An unsymmetrical intermediate, methyl 4-(o-ethoxycarbonylmethoxypropylphenoxy)butyrate, was prepared for similar cyclisation and in preliminary experiments appeared to give acyloin and β-keto-ester products.The method represents a different approach to crown ether systems of certain types.
- Tyman, John H. P.,Grundy, Jesse,Brown, George R.
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p. 336 - 343
(2007/10/02)
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- Unidirectional Dieckmann Cyclizations on a Solid Phase and in Solution
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Dieckmann cyclization of 2percent divinylbenzene-copolystyrene resin alkyl pimelates and analogous benzyl alkyl pimelates is reported.The use of uniquely single-labeled dioate esters has allowed analysis of the direction of closure via decarboxylation of the keto ester products.The influence of steric factors on the competition between enolate condensation and transesterification and upon the direction of closure of the cyclization has been evaluated, and the conditions for achieving >99percent regioselective closure are described.Modifications in the conditions of solid-phase peptide synthesis required for successful high-temperature enolate cyclization have been developed and the results are compared to solution reactions of benzyl alkyl esters under similar conditions.The resin attachment afforded a clear benefit over the benzyl models and greatly simplified isolation and purification of the resulting β-keto esters.
- Crowley, John I.,Rapoport, Henry
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p. 3215 - 3227
(2007/10/02)
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