- A Methyl Scan of the Pyrrolidinium Ring of Nicotine Reveals Significant Differences in Its Interactions with a7 and a4b2 Nicotinic Acetylcholine Receptors
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The two major nicotinic acetylcholine receptors (nAChRs) in the brain are the a4b2 and a7 subtypes. A "methyl scan" of the pyrrolidinium ring was used to detect differences in nicotine's interactions with these two receptors. Each methylnicotine was investigated using voltage-clamp and radioligand binding techniques. Methylation at each ring carbon elicited unique changes in nicotine's receptor interactions. Replacing the 19-N-methyl with an ethyl group or adding a second 19-N-methyl group significantly reduced interaction with a4b2 but not a7 receptors. The 29-methylation uniquely enhanced binding and agonist potency at a7 receptors. Although 39- A nd 59-trans-methylations were much better tolerated by a7 receptors than a4b2 receptors, 49-methylation decreased potency and efficacy at a7 receptors much more than at a4b2 receptors. Whereas cis-59-methylnicotine lacked agonist activity and displayed a low affinity at both receptors, trans-59-methylnicotine retained considerable a7 receptor activity. Differences between the two 59-methylated analogs of the potent pyridyl oxymethylene-bridged nicotine analog A84543 were consistent with what was found for the 59-methylnicotines. Computer docking of the methylnicotines to the Lymnaea acetylcholine binding protein crystal structure containing two persistent waters predicted most of the changes in receptor affinity that were observed with methylation, particularly the lower affinities of the cis-methylnicotines. The much smaller effects of 19-, 39-, and 59-methylations and the greater effects of 29- A nd 49-methylations on nicotine a7 nAChR interaction might be exploited for the design of new drugs based on the nicotine scaffold.
- Xing, Hong,Andrud, Kristin W.,Soti, Ferenc,Rouchaud, Anne,Jahn, Stephan C.,Lu, Ziang,Cho, Yeh-Hyon,Habibi, Sophia,Corsino, Patrick,Slavov, Svetoslav,Rocca, James R.,Lindstrom, Jon M.,Lukas, Ron J.,Kem, William R.
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supporting information
p. 168 - 180
(2020/09/12)
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- Tacrine-xanomeline and tacrine-iperoxo hybrid ligands: Synthesis and biological evaluation at acetylcholinesterase and M1 muscarinic acetylcholine receptors
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We synthesized a set of new hybrid derivatives (7-C8, 7-C10, 7-C12 and 8-C8, 8-C10, 8-C12), in which a polymethylene spacer chain of variable length connected the pharmacophoric moiety of xanomeline, an M1/M4-preferring orthosteric muscarinic agonist, with that of tacrine, a well-known acetylcholinesterase (AChE) inhibitor able to allosterically modulate muscarinic acetylcholine receptors (mAChRs). When tested in vitro in a colorimetric assay for their ability to inhibit AChE, the new compounds showed higher or similar potency compared to that of tacrine. Docking analyses were performed on the most potent inhibitors in the series (8-C8, 8-C10, 8-C12) to rationalize their experimental inhibitory power against AChE. Next, we evaluated the signaling cascade at M1 mAChRs by exploring the interaction of Gαq-PLC-β3 proteins through split luciferase assays and the myo-Inositol 1 phosphate (IP1) accumulation in cells. The results were compared with those obtained on the known derivatives 6-C7 and 6-C10, two quite potent AChE inhibitors in which tacrine is linked to iperoxo, an exceptionally potent muscarinic orthosteric activator. Interestingly, we found that 6-C7 and 6-C10 behaved as partial agonists of the M1 mAChR, at variance with hybrids 7-Cn and 8-Cn containing xanomeline as the orthosteric molecular fragment, which were all unable to activate the receptor subtype response.
- Cirillo, Davide,Dallanoce, Clelia,De Amici, Marco,Holzgrabe, Ulrike,Maspero, Marco,Messerer, Regina,Sotriffer, Christoph,Volpato, Daniela,Yuan Chen, Natalia
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- Hydroxynitrile Lyase Isozymes from Prunus communis: Identification, Characterization and Synthetic Applications
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Biocatalysts originating from Badamu (Prunus communis) have been applied to catalyze the asymmetric synthesis of (R)-4-methylsulfanylmandelonitrile, a key building block of thiamphenicol and florfenicol. Here, four hydroxynitrile lyase (HNL) isozymes from Badamu were cloned and heterologously expressed in Pichia pastoris. The biochemical properties and catalytic performances of these isozymes were comprehensively explored to evaluate their efficiency and selectivity in asymmetric synthesis. Among then, PcHNL5 was identified with outstanding activity and enantioselectivity in asymmetric hydrocyanation. Under the optimized mild biphasic reaction conditions, seventeen prochiral aromatic aldehydes were converted to valuable chiral cyanohydrins with good yields (up to 94%) and excellent optical purities (up to >99.9% ee), which provide a facile access to numerous chiral amino alcohols, hypoglycemic agents, angiotension converting enzyme (ACE) inhibitors and β-blockers. This work therefore underlines the importance of discovering the most potent biocatalyst among a group of isozymes for converting unnatural substrates into value-added products. (Figure presented.).
- Zheng, Yu-Cong,Xu, Jian-He,Wang, Hui,Lin, Guo-Qiang,Hong, Ran,Yu, Hui-Lei
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p. 1185 - 1193
(2017/04/13)
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- Novel 2-methoxyacylhydrazones as potent, selective PDE10A inhibitors with activity in animal models of schizophrenia
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A series of 2-methoxyacylhydrazones were optimized to yield compounds with high affinity for PDE10A. Several compounds demonstrated efficacy in animal models of schizophrenia, including conditioned avoidance response and a pro-psychotic phencyclidine hyperactivity model.
- Cutshall, Neil S.,Onrust, Rene,Rohde, Alex,Gragerov, Sasha,Hamilton, Lauren,Harbol, Kevin,Shen, Hui-Rong,McKee, Shawn,Zuta, Charles,Gragerova, Galina,Florio, Vince,Wheeler, Thomas N.,Gage, Jennifer L.
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scheme or table
p. 5595 - 5599
(2012/09/21)
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- Direct crystallographic observation of catalytic reactions inside the pores of a flexible coordination polymer
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A new flexible porous coordination polymer (PCP), {[Gd2(L) 3(dmf)4]·4 DMF·3 H2O}n (1), was synthesized under solvothermal condition by reacting [Gd(NO 3)3]·6 H2O with the ligand 2,6,2',6'-tetranitro-biphenyl-4,4'-dicarboxylic acid (H2L). Compound 1 had a 3D coordination polymeric structure with two types of 1D channels (A and B) that were occupied by DMF and water molecules. When crystals of 1 were separately exposed to vapors of various aromatic aldehydes, either the lattice or both the lattice and metal-bound solvent molecules were replaced by aldehyde molecules. The aldehyde molecules inside the pores spontaneously underwent cyanosilylation and Knoevenagel condensation reactions upon exposure to vapors of trimethylsilyl cyanide and malononitrile, respectively. These reactions took place at ambient temperature and pressure. Moreover, both the reactants and the products translocated from one cavity to another. The products that occupied the cavity were expunged upon exposure to the vapors of an aldehyde. Because crystallinity was maintained during these chemical transformations, direct crystallographic observation was possible. Herein, we showed that confinement of the reactants inside the void spaces of the PCP led to the products; we also assessed catalytic activities of this PCP in bulk quantities. Copyright
- Das, Raj Kumar,Aijaz, Arshad,Sharma, Manish K.,Lama, Prem,Bharadwaj, Parimal K.
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experimental part
p. 6866 - 6872
(2012/07/31)
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- Silylcyanation of aldehydes, ketones, and imines catalyzed by a 6,6'-bis-sulfonamide derivative of 7,7'-dihydroxy-8,8'-biquinolyl (azaBINOL)
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6,6'-Bis(methylaminosulfonyl)-7,7'-dihydroxy-8,8'-biquinolyl (3) catalyzes (5-10 mol-%) the addition of trimethylsilyl cyanide to aldehydes (aryl, alkyl, and α,β-unsaturated; 42-92 % yields), ketones (aryl alkyl, dialkyl; 22-82 % yields), and N-benzylaldimines (14-78 % yields) in toluene (0 °C or room temp.) to give the expected cyanohydrin and Strecker adducts following desilylation. Among a series of closely related compounds lacking any one of their defining structural features, bis-sulfonamide 3 and its N,N'-dimethyl derivative are exceptional in catalyzing the silylcyanation of benzaldehyde in the absence of all other additives. Hammett analysis of the competitive silylcyanation of para-substituted benzaldehydes catalyzed by 3 showed a linear free-energy relationship (R2 = 0.928) with a modest positive reaction constant (ρ = +1.52). X-ray diffraction analysis of (±)-3 indicated a cisoid biaryl conformation and the existence of an intramolecular hydrogen bond between C7'-OH and C7-O. Resolution of (±)-3 was achieved by HPLC separation of its tetravalerate derivative on a chiral stationary phase. The absolute configurations of the optical isomers of 3 were assigned by correlation of the ECD spectra with those of related biquinolyls of known configuration. The silylcyanation of aldehydes catalyzed by (-)-(aR)-3 leads to cyanohydrins with a preference for the (S)-configured product with an ee of 10 %. The organocatalytic action of 3 is ascribed to hydrogen bonding and Bronsted acid catalysis effects that are dependent on its acidifying sulfonamide groups, general base capability, and interannular proximity effects made possible by the biaryl structure. Copyright
- Sephton, Selena Milicevic,Wang, Chao,Zakharov, Lev N.,Blakemore, Paul R.
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experimental part
p. 3249 - 3260
(2012/08/08)
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- Redox-neutral α-cyanation of amines
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α-Aminonitriles inaccessible by traditional Strecker chemistry are obtained in redox-neutral fashion by direct amine α-cyanation/N-alkylation or alternatively, α-aminonitrile isomerization. These unprecedented transformations are catalyzed by simple carboxylic acids.
- Ma, Longle,Chen, Weijie,Seidel, Daniel
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supporting information
p. 15305 - 15308
(2012/10/29)
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- Hybrid molecules from xanomeline and tacrine: Enhanced tacrine actions on cholinesterases and muscarinic M1 receptors
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A set of amide- and amine-linked hybrid molecules comprising moieties of the orthosteric M1 muscarinic receptor agonist xanomeline and the Cholinesterase inhibitor and allosteric receptor modulator tacrine were prepared with varying spacer length of 10-17 atoms. The hybrids inhibited acetylcholinesterase with similar or higher potency compared to tacrine. M 1 receptor binding affinity was similar or higher relative to xanomeline and far higher relative to tacrine. Affinities hardly changed when the receptors' orthosteric site was occupied by an inverse agonist ligand. When occupied by the orthosteric activator acetylcholine, affinity for the hybrids declined to unmeasureably low levels. Hybrids did not activate M1 receptors. In vivo studies assaying cognition impairment in rats induced by scopolamine revealed pronounced enhancement of scopolamine action. Taken together, instead of dualsteric (simultaneous allosteric/orthosteric) binding, the hybrids seem to prefer purely allosteric binding at the inactive M 1 receptor.
- Fang, Lei,Jumpertz, Sabine,Zhang, Yihua,Appenroth, Dorothea,Fleck, Christian,Mohr, Klaus,Tr?nkle, Christian,Decker, Michael
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scheme or table
p. 2094 - 2103
(2010/08/19)
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- Synthesis and evaluation of xanomeline analogs-Probing the wash-resistant phenomenon at the M1 muscarinic acetylcholine receptor
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A series of xanomeline analogs were synthesized and evaluated for binding at the M1 muscarinic acetylcholine receptor (M1 receptor). Specifically, compounds that substitute the O-hexyl chain of xanomeline with polar, ionizable, or conformationally restricted moieties were assessed for their ability to bind to the M1 receptor in a wash-resistant manner (persistent binding). From our screen, several novel ligands that persistently bind to the M1 receptor with greater affinity than xanomeline were discovered. Results indicate that persistent binding may arise not only from hydrophobic interactions but also from ionic interactions with a secondary M1 receptor binding site. Herein, a qualitative model that accounts for both binding scenarios is proposed and applied to understand the structural basis to wash-resistant binding and long-acting effects of xanomeline-based compounds.
- Kane, Brian E.,Grant, Marianne K.O.,El-Fakahany, Esam E.,Ferguson, David M.
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p. 1376 - 1392
(2008/09/18)
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- An asymmetric, chemo-enzymatic synthesis of O-acetylcyanohydrins
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A one-pot chemo-enzymatic synthesis of highly enantiomerically enriched O-acetylcyanohydrins has been developed. The bimetallic (salen)titanium complex 1 is used to convert aldehydes into nonracemic (R)-O-acetylcyanohydrins with 61 to 93 % enantiomeric ex
- Belokon, Yuri N.,Blacker, A. John,Clutterbuck, Lisa A.,Hogg, David,North, Michael,Reeve, Christopher
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p. 4609 - 4617
(2007/10/03)
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- PESTICIDAL SUBSTITUTED 1,2,5,-THIADIAZOLE DERIVATIVES
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Insecticidal and acaricidal compositions comprising an insecticidally or acaricidally effective amount of a 1,2,5-thiadiazole of the formula (I); wherein R, Q and m are as defined in admixture with at least one agriculturally acceptable extender or adjuvant are disclosed. In addition, methods of controlling insects and acarids comprising applying said compositions to a locus of crops where control is desired are disclosed.
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Page/Page column 31-32
(2008/06/13)
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- A new (R)-hydroxynitrile lyase from Prunus mume: Asymmetric synthesis of cyanohydrins
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A new hydroxynitrile lyase (HNL) was isolated from the seed of Japanese apricot (Prunus mume). The enzyme has similar properties with HNL isolated from other Prunus species and is FAD containing enzyme. It accepts a large number of unnatural substrates (benzaldehyde and its variant) for the addition of HCN to produce the corresponding cyanohydrins in excellent optical and chemical yields. A new HPLC based enantioselective assay technique was developed for the enzyme, which promotes the addition of KCN to benzaldehyde in a buffered solution (pH=4.5).
- Nanda, Samik,Kato, Yasuo,Asano, Yasuhisa
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p. 10908 - 10916
(2007/10/03)
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- An enzyme library approach to biocatalysis: Development of nitrilases for enantioselective production of carboxylic acid derivatives
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The discovery, from Nature, of a large and diverse set of nitrilases is reported. The utility of this nitrilase library for identifying enzymes that catalyze efficient production of valuable hydroxy carboxylic acid derivatives is demonstrated. Unprecedented enantioselectivity and substrate scope are highlighted for three newly discovered and distinct nitrilases. For example, a wide array of (R)-mandelic acid derivatives and analogues were produced with high rates, yields, and enantiomeric excesses (95-99% ee). We also have found nitrilases that provide direct access to (S)-phenyllactic acid and other aryllactic acid derivatives, again with high yields and enantioselectivities. Finally, different nitrilases have been discovered that catalyze enantiotopic hydrolysis of 3-hydroxyglutaronitrile to afford either enantiomer of 4-cyano-3-hydroxybutyric acid with high enantiomeric excesses (>95% ee). The first enzymes are reported that effect this transformation to furnish the (R)-4-cyano-3-hydroxybutyric acid which is a precursor to the blockbuster drug Lipitor. Copyright
- DeSantis, Grace,Zhu, Zuolin,Greenberg, William A.,Wong, Kelvin,Chaplin, Jenny,Hanson, Sarah R.,Farwell, Bob,Nicholson, Lawrence W.,Rand, Cynthia L.,Weiner, David P.,Robertson, Dan E.,Burk, Mark J.
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p. 9024 - 9025
(2007/10/03)
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- A study of asymmetric hydrocyanation of heteroaryl carboxaldehydes catalyzed by (R)-oxynitrilase under micro-aqueous conditions
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A number of new optically active heteroaryl cyanohydrins have been prepared by hydrocyanation under micro-aqueous conditions catalyzed by almond meal (containing (R)-oxynitrilase). Substituent effects on the reaction are discussed. This micro-aqueous meth
- Chen, Peiran,Han, Shiqing,Lin, Guoqiang,Huang, Hao,Li, Zuyi
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p. 3273 - 3279
(2007/10/03)
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- Indium trifluoride - A Lewis acid catalyst for the addition of TMSCN to aldehydes in water
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Indium trifluoride promoted chemoselective additions of TMSCN to various aldehydes in water gave the respective cyanohydrins in good yields.
- Loh, Teck-Peng,Xu, Kai-Chen,Ho, Diana Sook-Chiang,Sim, Keng-Yeow
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p. 369 - 370
(2007/10/03)
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- Process for preparing aminoacetonitriles in one vessel
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This invention relates to a process for preparing aminoacetonitriles in one vessel. The process involves the steps of: (A) reacting an alkali metal cyanide with an aldehyde in water to form a cyanohydrin; (B) extracting the cyanohydrin formed in Step (A) into a water immiscible solvent to form a two phase system comprising a water immiscible phase containing the cyanohydrin and an aqueous phase; (C) removing at least 50 weight percent, based on the weight of the water immiscible phase, of the water immiscible solvent from the water immiscible phase thereby concentrating the cyanohydrin; (D) adding a water miscible amide solvent to the concentrated cyanohydrin to form a cyanohydrin solution; and (E) passing ammonia through the cyanohydrin solution to obtain an aminoacetonitrile. Aminoacetonitriles are important intermediates in the preparation of amino acids, thiadiazoles, acylaminoacetonitriles, and imidazole derivatives.
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- Novel functional M1 selective muscarinic agonists. Synthesis and structure-activity relationships of 3-(1,2,5-thiadiazolyl)-1,2,5,6- tetrahydro-1-methylpyridines
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A series of novel 3-(3-substituted-1,2,5-thiadiazol-4-yl)-1,2,5,6- tetrahydro-1-methylpyridines (substituted-TZTP; 5a-1, 7a-h, 8, 9c-n, 11, 13j) were synthesized and tested for central muscarinic cholinergic receptor affinity by using [3H]-oxotremorine-M (Oxo-M) and [3H]-pirenzepine (Pz) as ligands. The potency and efficacy of the compounds for the pharmacological defined M1 and M2 muscarinic receptors were determined on isolated electrically stimulated rabbit vas deferens and on spontaneously beating isolated guinea pig atria, respectively. Selected compounds were also tested for M3 activity in the isolated guinea pig ileum. The C1-8 alkoxy-TZTP 5a-1 analogues all displaced [3H]-Oxo-M and [3H]-Pz with low nanomolar affinity. Depicting chain length against Oxo-M binding and against Pz binding the unbranched C1-8 alkoxy-TZTP (5a-h) derivatives produced U-shaped curves with butoxy- (5d) and (pentyloxy)-TZTP (5e) as the optimum chain length, respectively. This U-shaped curve was also seen in the ability of the compounds 5a-h to inhibit the twitch height in the vas deferens preparation. The (pentyloxy)- (5e) and the (hexyloxy)-TZTP (5f) analogues produced an over 90% inhibition of the twitch height with IC50 values in the low picomolar range. In both the atria and in the ileum preparations 5f had low efficacy and potency. With the (alkylthio)-TZTP (7a-h) analogues the structure- activity relationship was similar to the one observed with the alkoxy (5a-h) analogues, but generally 7a-h had higher receptor affinity and was more potent than the corresponding 5a-h. However, the C3-8 alkyl-TZTP (9c,e,g,h) analogues had 10-100 times lower affinity for the central muscarinic receptors than the corresponding alkoxy and alkylthio derivatives, and their efficacy in the vas deferens preparation was too low to obtain IC50 values. The unsubstituted TZTP (11) compound was a potent but nonselective muscarinic agonist. The two 3-(3-butoxy/(hexyloxy)-1,2,5- oxadiazol-4-yl)-1,2,5,6-tetrahydro-1-methylpyridines (butoxy/(hexyloxy)-OZTP; 19a/b) were also synthesized and tested. Both 19a and 19b had much lower affinity for the central muscarinic receptors than 5d and 5f, and the efficacy of 19a,b was too low to give IC50 values in the vas deferens preparation. Therefore, the C5-6 (alkyloxy)/(alkylthio)-TZTP's represent a unique series of potent functional M1 selective muscarinic agonists.
- Sauerberg,Olesen,Nielsen,Treppendahl,Sheardown,Honore,Mitch,Ward,Pike,Bymaster,Sawyer,Shannon
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p. 2274 - 2283
(2007/10/02)
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- Fungicidal Pyridine Derivatives, II. Derivatives of α-trichloromethyl-3-pyridinemethanol
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The antifungal lead structure α-trichloromethyl-3-pyridinemethanol (1a) was modified and esters, (thio-)carbamates, and sulfonates as well as other derivatives incorporating the pyridiylcarbinol structure were prepared.The optical resolution as well as the N-oxidation of 1a are described.Keywords.Fungicides; Pyridinemethanoles.
- Sauter, Fritz,Stanetty, Peter,Schulner, Josef,Sittenthaler, Wilhelm,Jordis, Ulrich
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p. 863 - 870
(2007/10/02)
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