Imidazo pyri dines

V,(V,6-trimcthyl-2-(4-methylphcnyl)imidazo 1,2-a pyri-dine-3-methanamine... 

The ring systems reviewed include the perhydropyrazolo[l,2-a]-pyridazines (1), perhydropyrazolo[l,5- ]pyridines (2), perhydro-isoxazolo[2,3-a]pyridines (3), perhydropyrrolo[l, 2-/>]pyridazines(4), perhydro-imidazo[ 1,5-u]pyridines (5), perhydro-oxazolo[3,4-o]pyri-dines (6), perhydrothiazolo[3,4-u]pyridines (7), perhydropyrrolo[l,2-c]pyrimidines (8), perhydropyrrolo[l,2-c][l,3]oxazines (9), perhydro-imidazo[l,2-u]pyridines (10), perhydro-oxazolo[3,2-a]pyridines (11),... 

Recent analyses of a Free-Wilsontype have included the in vitro inhibitory activity of a series of heterocyclic compounds against K. pneumonia (197). Other applications of the Free-Wilson approach have included studies on the antimycobacterial activity of 4-alkyl-thiobenzanilides, the antibacterial activity of fluoronapthyridines, and the benzodiazepine receptor-binding ability of some non-benzodi-apzepine compounds such as 3-X-imidazo-[l,2-6]pyridazines, 2-phenylimidazo[l,2-o ]pyri-dines,2-(alkoxycarbony)imidazo[2,l-p]benzo-thiazoles, and 2-arylquinolones(198-200). 

Imidazo[l,5-fl]pyridines are synthesised by the dehydrative cyclisation of iV-acyl-2-aminomethyl-pyri-dines or of thioamides, ° which can be prepared and ring closed under very mild conditions. 3-Amino -oxy and -thio derivatives are available via related cyclisations. 

Mishra and Ghosh (2011) found that Cu(l)-NaHS04 Si02 could be utilized as a novel and efQdent heterogeneous catalyst for the synthesis of imidazo[l,2-fl]pyri-dines using three-component reactions of 2-aminopyridines, aldehydes, and terminal alkynes in one pot (Scheme 4.56). Under this catalytic systan, diverse imidazo[l,2-fl]pyridine derivatives were generated in moderate to excellent yields. 

This intramolecular hydroarylation of alkynes was also applied to the synthesis of imidazo[l,2-fl]pyridines by A -coupling of 2-aminopyridine, alkynes, and aldehydes [183]. Singh et al. reported that this reaction is successfully catalyzed by a heterogeneous catalyst composed by nano-FejO and KHSO SiOj, affording the desired imidazo[l,2-fl]pyri-dines in 55-89% yields. The catalyst could be recovered by applying an external magnetic field and reused six times without significant loss of activity. 

Ducray R, Boutron P, Didelot M, Germain H, Each F, Lamorlette M, Legriffon A, Maudet M, Menard M, Pasquet G, Renaud F, Simpson I, Young GL (2010) A versatile route to 3-(pyrimidin-4-yl)-imidazo[l, 2-a]pyridines and 3-(pyrimidin-4-yl)-pyrazolo[l, 5-a]pyri-dines. Tetrahedron Lett 51 4755 758... 

Rana BK, Bertolasi V, Pal S, Mitra P, Dinda J. Hehcal metal cage of silver(I) and mer-cury(ll)-N-heterocycHc carbene complexes of l,4-phenylene-bis imidazo[l,5-a]pyri-dine-4-iumhexaflurophosphate. J Mol Struct. 2013 1049 458-463. 

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