- Design, synthesis and pharmacological evaluation of hybrid molecules out of quinazolinimines and lipoic acid lead to highly potent and selective butyrylcholinesterase inhibitors with antioxidant properties
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A set of hybrid molecules were synthesized out of lipoic acid, α,ω-diamines of different lengths serving as spacers, and cholinesterase (ChE) inhibiting [2,1-b]quinazolinimines. Depending on the length of the alkylene spacer the amide hybrids are inhibitors of acetylcholinesterase (AChE) with inhibitory activities of 0.5-4.6 μM and inhibitors of butyrylcholinesterase (BChE) with activities down to 5.7 nM, therefore greatly exceeding the inhibitory activities of the parent quinazolinimines by factors of up to 1000. Due to increasing activity at BChE with increasing length of the alkylene spacer ~100-fold selectivity toward BChE is reached with a hepta- and an octamethylene spacer. Kinetic measurements reveal competitive and reversible inhibition of both ChEs by the hybrids. Furthermore, cell viability and antioxidant activity (using the ORAC-fluorescein assay) of several hybrids were evaluated, showing cytotoxicity at concentrations from 3.7 to 10.2 μM and antioxidant properties are in the range of 0.4-0.8 Trolox equivalents (lipoic acid = 0.6).
- Decker, Michael,Kraus, Birgit,Heilmann, Joerg
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- Mechanism of Hydrolysis and Alcoholysis of 2-Ethoxy-N-vinylpyrrolidiniminium Tetrafluoroborate
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N-Vinyl-2-ethoxypyrrolidiniminium tetrafluoroborate, 1, undergoes rapid hydrolysis to give acetaldehyde and ethyl 2-aminobutyrate, 2.Imidate 1 reacts with methanol or ethanol, however, to give the N-(1-alkoxyethyl)-2-alkoxypyrrolidiniminium tetrafluoroborate 7 or 9, respectively.Both hydrolysis and alcoholysis appear to be pseudo first order and the mechanism of each can be explained by initial formation of an "enamine-like" intermediate.The mechanism of both reactions is presented.
- Smith, Michael B.,Shroff, Hitesh N.
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- Direct NHC-catalysed redox amidation using CO2 for traceless masking of amine nucleophiles
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The N-heterocyclic carbene (NHC)-catalysed redox amidation reaction is poorly developed and usually requires catalytic co-additives for electron-rich amine nucleophiles. We report a masking strategy (using CO2) that couples release of the free amine nucleophile to catalytic turnover, and in doing so, enables direct catalytic redox amidation of electron-rich amines.
- Davidson, Robert W. M.,Fuchter, Matthew J.
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supporting information
p. 11638 - 11641
(2016/10/04)
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- SUBSTITUTED PHENOXYPROPYLCYCLOAMINE DERIVATIVES AS HISTAMINE-3 (H3) RECEPTOR LIGANDS
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The present invention provides compounds of formula I: their use as H3 antagonists/inverse agonists, processes for their preparation, and pharmaceutical compositions thereof.
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Page/Page column 26
(2011/02/24)
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- Modular routes towards new N,O-bidentate ligands containing an electronically delocalised β-enaminone chelating backbone
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Polyketones are synthesised by a transition-metal-catalysed copolymerisation of olefins and carbon monoxide. Nickel complexes with N,O-chelating ligands turned out to be promising catalysts in that field. In this work a series of new N,O ligands with an electronically delocalised β-enaminone backbone were synthesised and fully characterised. The ligand design was inspired by the ligand found in the most efficient nickel catalyst for polyketone synthesis and developed to a highly modular LEGO-like arsenal of reactions to versatile substituted β-enaminone ligands. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Beckmann, Udo,Eichberger, Eva,Lindner, Monika,Bongartz, Melanie,Kunz, Peter C.
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supporting information; experimental part
p. 4139 - 4147
(2009/04/11)
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- 95. Asymmetric synthesis of the alkaloids mayfoline and N(1)-Acetyl-N(1)-deoxymayfoline
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The total syntheses of the spermidine alkaloids (-)-mayfoline (11) and (+)-N(1)-acetyl-N(1)-deoxymayfoline (12) are described. These macrocyclic lactams belong to the most interesting conjugates of the polyamine derivatives very commonly found in nature. The enantioselective syntheses were achieved through resolution of the methyl 3-amino-3-phenylpropanoate (2) by recrystallization of its (+)-L-tartrate salt. Construction of the 13-membered ring ensued through condensation, reductive ring expansion (internal bond cleavage), and finally a transamidation reaction involving a second ring expansion.
- Kuehne, Paul,Linden, Anthony,Hesse, Manfred
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p. 1085 - 1094
(2007/10/03)
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- 82. Enantioselective reduction of electrophilic C=C bonds with sodium tetrahydroborate and 'semicorrin' cobalt catalysts
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'Semicorrin' cobalt complexes, prepared in situ from cobalt(II) chloride and the corresponding ligands, are efficient catalysts for the enantioselective reduction of electrophilic C=C bonds with NaBH4. The best selectivities (> 90% ee) are achieved with α,β-unsaturated carboxamides and carboxylates. Analogous α,β-unsaturated nitriles, sulfones, and phosphonates afford enantiomenc excesses of 50-70%. Interestingly, in the reduction of α,β-unsaturated sulfones, the highest enantioselectivities were obtained with unsymmetrical 'semicorrins', whereas in all other cases C2-symmetric 'semicorrins' proved to be superior.
- Misun, Marian,Pfaltz, Andreas
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p. 961 - 972
(2007/10/03)
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- A MILD AND FACILE ROUTE TO ω-AMINO ESTERS
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Lactim ethers are conveniently prepared from the corresponding lactam.The salt prepared by protonation with HCl or HBF4 is hydrolyzed in neutral water at ambient temperatures to give good yields of the ω-amino ester.
- Menezes, Royce,Smith, Michael B.
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p. 1625 - 1636
(2007/10/02)
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