Charged Behaviour from Neutral Ligands: Synthesis and Properties of N-Heterocyclic Pseudo-amides
作者:Robert J. Thatcher、David G. Johnson、John M. Slattery、Richard E. Douthwaite
DOI:10.1002/chem.201103319
日期:2012.4.2
characterised as a pseudo‐amide and is a strong donor akin to alkyl phosphines and N‐heterocycliccarbenes. Furthermore, rotation about both N substituent CN bonds occurs, which is in contrast to the two alternative pyridinium positional isomers that exhibit neutral resonance structures. For comparison, compounds and complexes derived from norharman were prepared, which contain an additional CC bond supporting
A new N-demethylation reaction of N-methylazinium derivatives by using boiling pyridinium chloride is described. The reaction is quite clean, fast and yields are almost quantitatives. (C) 1997 Elsevier Science Ltd.
Bivalent β-Carbolines as Potential Multitarget Anti-Alzheimer Agents
Alzheimer's disease (AD) is a prevalent neurodegenerative disorder with multifactorial causes that requires multitargeted treatment. Inhibitors of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) improve cholinergic signaling in the central nervous system and thus AChE inhibitors are well established in the therapy of AD to improve memory disturbances and other cognitive symptoms. On the other hand, AD patients benefit from reduction of pathologic glutamate-induced, Ca2+-mediated excitotoxicity by the N-methyl-D-aspartate receptor (NR) antagonist memantine. New drugs that simultaneously affect both cholinergic transmission and glutamate-induced excitotoxicity may further improve AD treatment. While connecting beta-carboline units by alkylene spacers in two different series of compounds and subsequent evaluation of their AChE/BChE-inhibitory potential, we found that several of these bivalent beta-carbolines were potent NR blockers. The most promising compound was a N-9-homobivalent beta-carboline with a nonylene spacer, which displayed IC50 values of 0.5 nM for AChE, 5.7 nM for BChE, and 1.4 mu M for NR, respectively.
Potent Algicides Based on the Cyanobacterial Alkaloid Nostocarboline
作者:Judith F. Blom、Tobias Brütsch、Damien Barbaras、Yann Bethuel、Hans H. Locher、Christian Hubschwerlen、Karl Gademann
DOI:10.1021/ol052968b
日期:2006.2.1
Nostocarboline and seven derivatives were prepared and displayed minimal inhibitory concentration (MIC) values >= 100 nM against the growth of Microcystis aeruginosa PCC 7806, Synechococcus PCC 6911, and Kirchneriella contorta SAG 11.81, probably via the inhibition of photosynthesis. The natural product hybrid nostocarboline/ciprofloxacin displayed additional antibacterial activity against several Gram-negative bacteria (MICs >= 0.7 mu M). Nostocarboline can thus be considered a potent, selective, readily available, natural algicide.
Studies on semirigid tricyclic analogs of the nigrostriatal toxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine
作者:Raymond G. Booth、Anthony Trevor、Thomas P. Singer、Neal Castagnoli
DOI:10.1021/jm00122a031
日期:1989.2
The tetrahydro-beta-carboline derivedfrom the condensation of N-methyltryptamine and formaldehyde, a semirigid tricyclic analogue of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) tha has been detected in the brains of normal laboratory rats, is biotransformed in a monoamineoxidaseB (MAO-B) catalyzed reaction to the corresponding dihydro compound at a rate that is approximately 0.5% of that