Pyridine Core (pyridine + core)

Distribution by Scientific Domains


Selected Abstracts


ChemInform Abstract: A Convenient Synthesis of Linear Pyridinoimidazo[1,2-a]pyridine and Pyrroloimidazo[1,2-a]pyridine Cores.

CHEMINFORM, Issue 11 2008
Mounir Andaloussi
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]


Second-Generation Inhibitors for the Metalloprotease Neprilysin Based on Bicyclic Heteroaromatic Scaffolds: Synthesis, Biological Activity, and X-Ray Crystal-Structure Analysis

HELVETICA CHIMICA ACTA, Issue 4 2005
Stefan Sahli
A new class of nonpeptidic inhibitors of the ZnII -dependent metalloprotease neprilysin with IC50 values in the nanomolar activity range (0.034,0.30,,M) were developed based on structure-based de novo design (Figs.,1 and 2). The inhibitors feature benzimidazole and imidazo[4,5- c]pyridine moieties as central scaffolds to undergo H-bonding to Asn542 and Arg717 and to engage in favorable , - , stacking interactions with the imidazole ring of His711. The platform is decorated with a thiol vector to coordinate to the ZnII ion and an aryl residue to occupy the hydrophobic S1, pocket, but lack a substituent for binding in the S2, pocket, which remains closed by the side chains of Phe106 and Arg110 when not occupied. The enantioselective syntheses of the active compounds (+)- 1, (+)- 2, (+)- 25, and (+)- 26 were accomplished using Evans auxiliaries (Schemes,2, 4, and 5). The inhibitors (+)- 2 and (+)- 26 with an imidazo[4,5- c]pyridine core are ca. 8 times more active than those with a benzimidazole core ((+)- 1 and (+)- 25) (Table,1). The predicted binding mode was established by X-ray analysis of the complex of neprilysin with (+)- 2 at 2.25-Å resolution (Fig.,4 and Table,2). The ligand coordinates with its sulfanyl residue to the ZnII ion, and the benzyl residue occupies the S1, pocket. The 1H -imidazole moiety of the central scaffold forms the required H-bonds to the side chains of Asn542 and Arg717. The heterobicyclic platform additionally undergoes ,-, stacking with the side chain of His711 as well as edge-to-face-type interactions with the side chain of Trp693. According to the X-ray analysis, the substantial advantage in biological activity of the imidazo-pyridine inhibitors over the benzimidazole ligands arises from favorable interactions of the pyridine N-atom in the former with the side chain of Arg102. Unexpectedly, replacement of the phenyl group pointing into the deep S1, pocket by a biphenyl group does not enhance the binding affinity for this class of inhibitors. [source]


(E)- N -{[6-Chloro-4-(4-chlorophenyl)-3-methyl-1-phenyl-1H -pyrazolo[3,4- b]pyridin-5-yl]methylene}benzene-1,2-diamine: a three-dimensional framework structure built from only two hydrogen bonds

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2010
Yurina Díaz
The molecules of the title compound, C26H19Cl2N5, are conformationally chiral, with none of the aryl groups coplanar with the pyrazolo[3,4- b]pyridine core of the molecule. A single unique N,H...N hydrogen bond links the molecules into two symmetry-related sets of C(11) chains running parallel to the [011] and [01] directions, respectively, and these two sets of chains are linked into a continuous three-dimensional framework structure by a single unique C,H...N hydrogen bond which forms a chain parallel to the [100] direction. [source]


Concise Total Synthesis of the Thiazolyl Peptide Antibiotic GE2270,A

CHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2008
Oscar Delgado Dr.
Abstract The potent antibiotic thiazolylpeptide GE2270,A was synthesized starting from N - tert -butyloxycarbonyl protected valine in a longest linear sequence of 20 steps and with an overall yield of 4.8,%. Key strategy was the assembly of the 2,3,6-trisubstituted pyridine core by consecutive cross-coupling reactions starting from 2,6-dibromo-3-iodopyridine. The complete Southern fragment was installed by Negishi cross-coupling of 3-zincated 2,6-dibromopyridine at the terminal 2-iodothiazole of a trithiazole (87,%). The substituent at C-6 representing the Northern part of the molecule was introduced in form of the truncated tert -butyl 2-bromothiazole-4-carboxylate after metalation to a zinc reagent by another Negishi cross-coupling (48,%). Decisive step of the whole sequence was the macrocyclization to a 29-membered macrolactam, which was conducted as an intramolecular Stille cross-coupling occurring at C-2 of the pyridine core and providing the desired product in 75,% yield. The required stannane was obtained by amide bond formation (87,%) between a complex dithiazole fragment representing the Eastern part of GE2270,A and a 3,6-disubstituted 2-bromopyridine. Final steps included attachment of a serine-proline amide dipeptide to the Northern part of the molecule (65,%), formation of the oxazoline ring and silyl ether deprotection (55,% overall). [source]