131988-63-1Relevant articles and documents
Facile Access to 1,4-Disubstituted Pyrrolo[1,2- a ]pyrazines from α-Aminoacetonitriles
Basha, Mushkin,Belema, Makonen,Dhar, T. G. Murali,Gupta, Anuradha,Gupta, Arun Kumar,Indasi, Gopi Kumar,Karmakar, Ananta,Mathur, Arvind,Meanwell, Nicholas A.,Ramalingam, Sridharan,Rampulla, Richard
supporting information, p. 441 - 449 (2020/01/23)
An efficient and practical synthetic protocol for the synthesis of 1,4-disubstituted pyrrolo[1,2- a ]pyrazine derivatives is described that originates from α-substituted pyrroloacetonitriles which, in turn, are readily available from aryl and alkyl aldehydes. The α-pyrroloacetonitriles were subjected to a Friedel-Crafts acylation with methyl chlorooxoacetate followed by reduction of the nitrile group under Pd-catalyzed hydrogenation conditions and finally aromatization with DDQ leading to the desired pyrrolo[1,2- a ]pyrazine derivatives. This method was generalized and successfully applied to various aryl, heteroaryl, and alkyl substrates. The developed protocol provides direct and convenient access to 1,4-disubstituted ring systems in moderate to good overall yields (51-68percent) without the need for purification of the intermediates. Further functionalization via the stepwise halogenation (bromination, iodination) and nitration was also demonstrated. In addition, the potential of the ester functionality for elaboration was demonstrated by manipulating into heterocyclic ring systems, exemplified by conversion into benzoxazole derivatives.
A Methyl Scan of the Pyrrolidinium Ring of Nicotine Reveals Significant Differences in Its Interactions with a7 and a4b2 Nicotinic Acetylcholine Receptors
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.
, p. 168 - 180 (2020/09/12)
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.
Hybrid molecules from xanomeline and tacrine: Enhanced tacrine actions on cholinesterases and muscarinic M1 receptors
Fang, Lei,Jumpertz, Sabine,Zhang, Yihua,Appenroth, Dorothea,Fleck, Christian,Mohr, Klaus,Tr?nkle, Christian,Decker, Michael
scheme or table, p. 2094 - 2103 (2010/08/19)
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.
