- Exploring the synthetic potential of a marine transaminase including discrimination at a remote stereocentre
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The marine transaminase, P-ω-TA, can be employed for the transamination from 1-aminotetralins and 1-aminoindanes with differentiation of stereochemistry at both the site of reaction and at a remote stereocentre resulting in formation of ketone products with up to 93% ee. While 4-substituents are tolerated on the tetralin core, the presence of 3- or 8-substituents is not tolerated by the transaminase. In general P-ω-TA shows capacity for remote diastereoselectivity, although both the stereoselectivity and efficiency are dependent on the specific substrate structure. Optimum efficiency and selectivity are seen with 4-haloaryl-1-aminotetralins and 3-haloaryl-1-aminoindanes, which may be associated with the marine origin of this enzyme. This journal is
- Schwarz, Maria,Murphy, Edel J.,Foley, Aoife M.,Woods, David F.,Castilla, Ignacio Abreu,Reen, F. Jerry,Collins, Stuart G.,O'gara, Fergal,Maguire, Anita R.
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p. 188 - 198
(2021/01/18)
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- Weinreb Amide, Ketone and Amine as Potential and Competitive Secondary Molecular Stations for Dibenzo-[24]Crown-8 in [2]Rotaxane Molecular Shuttles
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This paper reports the synthesis and study of new pH-sensitive DB24C8-based [2]rotaxane molecular shuttles that contain within their axle four potential sites of interaction for the DB24C8: ammonium, amine, Weinreb amide, and ketone. In the protonated state, the DB24C8 lay around the best ammonium site. After either deprotonation or deprotonation-then-carbamoylation of the ammonium, different localizations of the DB24C8 were seen, depending on both the number and nature of the secondary stations and steric restriction. Unexpectedly, the results indicated that the Weinreb amide was not a proper secondary molecular station for the DB24C8. Nevertheless, through its methoxy side chain, it slowed down the shuttling of the macrocycle along the threaded axle, thereby partitioning the [2]rotaxane into two translational isomers on the NMR timescale. The ketone was successfully used as a secondary molecular station, and its weak affinity for the DB24C8 was similar to that of a secondary amine.
- Coutrot, Frédéric,Gauthier, Maxime
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p. 17576 - 17580
(2021/12/09)
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- Copper-Catalyzed Regioselective Borocarbonylative Coupling of Unactivated Alkenes with Alkyl Halides: Synthesis of β-Boryl Ketones
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The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu-catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of β-boryl ketones has been developed. A broad range of β-boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity.
- Wu, Fu-Peng,Yuan, Yang,Schünemann, Claas,Kamer, Paul C. J.,Wu, Xiao-Feng
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supporting information
p. 10451 - 10455
(2020/05/08)
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- Weinreb Amide as Secondary Station for the Dibenzo-24-crown-8 in a Molecular Shuttle
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Here is reported the synthesis of a new molecular shuttle: it consists of a dibenzo-24-crown-8 (DB24C8) that surrounds a molecular axle containing an ammonium group and a newly considered Weinreb amide as stations. At the protonated state the DB24C8 is localized around the best ammonium station, while deprotonation-carbamoylation of the ammonium triggers the shuttling of the macrocycle around the Weinreb amide site. Further post-interlocking modification of the [2]rotaxane was attempted through the cleavage of the Weinreb amide bond using a Grignard reagent. While the non-interlocked molecular axle was cleaved after a short time in mild conditions, the Weinreb amide bond remained unaltered in the [2]rotaxane species over time, even in the presence of a larger amount of Grignard and at a higher temperature, highlighting the protection shield of the macrocycle around the encircled axle.
- Gauthier, Maxime,Coutrot, Frédéric
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p. 3391 - 3395
(2019/02/19)
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- Potent heterocyclic ligands for human complement C3a receptor
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The G-protein coupled receptor (C3aR) for human inflammatory protein complement C3a is an important component of immune, inflammatory, and metabolic diseases. A flexible compound (N2-[(2,2-diphenylethoxy)acetyl]-l-arginine, 4), known as a weak C3aR antagonist (IC50 μM), was transformed here into potent agonists (EC50 nM) of human macrophages (Ca2+ release in HMDM) by incorporating aromatic heterocycles. Antagonists were also identified. A linear correlation between binding affinity for C3aR and calculated hydrogen-bond interaction energy of the heteroatom indicated that its hydrogen-bonding capacity influenced ligand affinity and function mediated by C3aR. Hydrogen-bond accepting heterocycles (e.g., imidazole) conferred the highest affinity and agonist potency (e.g., 21, EC50 24 nM, Ca2+, HMDM) with comparable efficacy and immunostimulatory activity as that of C3a in activating human macrophages (Ca2+, IL1β, TNFα, CCL3). These potent and selective modulators of C3aR, inactivated by a C3aR antagonist, are stable C3a surrogates for interrogating roles for C3aR in physiology and disease.
- Reid, Robert C.,Yau, Mei-Kwan,Singh, Ranee,Hamidon, Johan K.,Lim, Junxian,Stoermer, Martin J.,Fairlie, David P.
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supporting information
p. 8459 - 8470
(2014/12/11)
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- Tricyclic compounds, their production and use
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A compound of the formula: wherein R1 is H or a substituent; m is 1-3; Ar is an aromatic group which may be substituted; X is a bond or a divalent straight-chain group having 1-6 atoms which may be substituted; Y is —S—, —O—, or —N(R2— (R2 is H or a substituent group), Z is —N= or —C(R3)= (R3 is H or a hydrocarbon group), ring A is a benzene ring; ring B is a 5- to 7-membered ring which may be substituted, or a salt thereof is useful for eliciting a prostaglandin I2 receptor agonistic effect.
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- 2-substituted-(2SR)-2-amino-2-((1SR,2SR)-2-carboxycycloprop-1- yl)glycines as potent and selective antagonists of group II metabotropic glutamate receptors. 1. Effects of alkyl, arylalkyl, and diarylalkyl substitution
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In this paper, we describe the synthesis of a series of α-substituted analogues of the potent and selective group II metabotropic glutamate receptor (mGluR) agonist (1S,1'S,2'S)-carboxy-cyclopropylglycine (2, L-CCG 1). Incorporation of a substituent on the amino acid carbon converted the agonist 2 into an antagonist. All of the compounds were prepared and tested as a aeries of four isomers, i.e., two racemic diastereomers. We explored alkyl substitution, both normal and terminally branched; phenylalkyl and diphenylalkyl substitution; and a variety of aromatic and carbocyclic surrogates for phenyl. Affinity for group II mGluRs was measured using [3H]glutamic acid (Glu) binding in rat forebrain membranes. Antagonist activity was confirmed for these compounds by measuring their ability to antagonize (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid-induced inhibition of forskolin-stimulated cyclic-AMP in RGT cells transfected with human mGluR2 and mGluR3. We found that while alkyl substitution provided no increase in affinity relative to 2, phenylethyl and diphenylethyl substitution, as in 105 and 109, respectively, were quite beneficial. The affinity of 109 was further enhanced when the two aromatic rings were joined by an oxygen or sulfur atom to form the tricyclic xanthylmethyl and thioxanthylmethyl amino acids 113 and 114, respectively. Amino acid 113, with an IC50 of 0.010 μM in the [3H]Glu binding assay, was 52-fold more potent than 2, whose IC50 was 0.47 μM.
- Ornstein, Paul L.,Bleisch, Thomas J.,Arnold, M. Brian,Wright, Rebecca A.,Johnson, Bryan G.,Schoepp, Darryle D.
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p. 346 - 357
(2007/10/03)
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- Synthesis and quantitative structure-activity relationship of a novel series of small conductance Ca2+-activated K+ channel blockers related to dequalinium
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The synthesis, pharmacological testing, and quantitative structure- activity relationship studies of a novel series of bisquinolinium small conductance Ca2+-activated K+ channel blockers (23) related to dequalinium are described. In this series, two quinolinium rings are linked via the 4- position to an α,ω-diamino alkylene chain and the ring N atom is quaternized with a methyl or benzyl group. The exocyclic N atom can be replaced by 0, S, or CH2 but with some loss of potency. The quinoline groups do not have to be quaternized for blocking activity, as long as they are basic enough to be protonated at the site of action. For the quaternary compounds, there is considerable steric tolerance for the group R attached to the ring N atom of the quinoline; a benzyl group gave the optimum potency in this series. Moreover, and in contrast to previously reported results for dequalinium analogues, there is no correlation of activity with N1 charge or E(HOMO). On the other hand, a good correlation was obtained between the blocking potency of the compounds and E(LUMO) [pEMR = 1.16(±0.26)E(LUMO) + 5.33(±1.29) (n = 11, r = 0.83, s = 0.243)]. It has been possible to combine this equation with the previously reported E(LUMO) correlation for a series of dequalinium analogues to include all the compounds of both series [pEMR = 1.17(±0.15)E(LUMO) + 5.33(±0.76) (n = 24, r = 0.85, s = 0.249)]. A possible physical meaning for the E(LUMO) correlation based upon the principle of maximum hardness is discussed.
- Galanakis,Davis,Ganellin,Dunn
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p. 359 - 370
(2007/10/03)
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