ChemInform Abstract: Preparation of 2‐Aryl‐ and 2‐Aryloxymethylimidazo(1,2‐a)pyridines and Related Compounds.

Sundberg, Richard J.; Dahlhausen, D. J.; Manikumar, Govindarajan; Mavunkel, Babu; Biswas, Atanu; Srinivasan, V. R.; King, Frank; Waid, Philip P.

doi:10.1002/chin.198835192

Cited by 3 publications

(6 citation statements)

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“…The starting materials, bromoketone and 2-aminopyridine, are generally available commercially, whereas 2-amino-5-(N,Ndimethylamino)pyridine was prepared by a known method reported previously. 19 The nitro derivatives, 12a and 14a, where R 3 ) NO 2 , were readily reduced by sodium sulfide to amino derivatives, 12b and 14b, 20,21 in excellent yields. Subsequently, the amino group of 12b and 14b was converted to an N-methylamino group by a selective monomethylation reaction using formic acetic anhydride at ambient temperatures for 30 min, followed by a reduction reaction in the presence of LiAlH 4 .…”

Section: Resultsmentioning

confidence: 99%

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Structure−Activity Relationship of Imidazo[1,2-a]pyridines as Ligands for Detecting β-Amyloid Plaques in the Brain

et al. 2002

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A series of novel beta-amyloid (A beta) aggregate-specific ligands, 2-(4'-dimethylaminophenyl)-6-iodoimidazo[1,2-a]pyridine, 16(IMPY), and its related derivatives were prepared. An in vitro binding study with preformed A beta aggregates showed that 16(IMPY) and its bromo derivative competed with binding of 2-(4'-dimethylaminophenyl)-6-iodobenzothiazole, [125I]7(TZDM), a known ligand for A beta aggregates, with high binding affinities (K(i) = 15 and 10 nM, respectively). In vitro autoradiography of brain sections of a transgenic mouse (Tg2576) with [125I]16(IMPY) displayed high selective binding to amyloid-like structures, comparable to that observed by staining with thioflavin-S visualized under fluorescence. In vivo biodistribution after an intravenous injection of [125I]16(IMPY) in normal mice showed a high initial brain uptake and fast washout, indicating a low background activity associated with this iodinated ligand. Taken together, the data suggests that [123I]16(IMPY) may be useful for imaging A beta aggregates in patients with Alzheimer's disease.

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Section: Resultsmentioning

confidence: 99%

“…This compound was prepared by a previously reported method. 20 Yield 74%, mp 269-270 °C (lit. 20 mp 268-270 °C).…”

Section: -(4′-nitrophenyl)imidazo[12-a]pyridine (12a)mentioning

confidence: 99%

Structure−Activity Relationship of Imidazo[1,2-a]pyridines as Ligands for Detecting β-Amyloid Plaques in the Brain

et al. 2002

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“…The most general synthesis of imidazo[ 1,2-a]pyridines involves cyclization condensation of an halomethyl ketone with a 2-aminopyridine (8)(9)(10)(11). Using this method, a variety of substituents can be introduced on the heterocyclic ring.…”

Section: Resultsmentioning

confidence: 99%

Carbamate derivatives of 2-arylimidazo[1,2-a]pyridinium salts as acetylcholinesterase inhibitors and protective agents against organophosphorus compounds

Sundberg¹,

Dalvie²,

Cordero³

et al. 1993

Chem. Res. Toxicol.

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A series of 2-arylimidazo[1,2-a]pyridinium salts with (N,N-dimethylcarbamoyl)oxy or (N-methylcarbamoyl)oxy groups at the 3'- or 4'-position on the phenyl substituent and various substituents on the imidazo[1,2-a]pyridine ring have been synthesized. The compounds show in vitro inhibitory activity against electric eel acetylcholinesterase (AChE), type III, and several of the compounds show protective effects toward the organophosphorus AChE inhibitor soman in mice. The possible structural relationship of these compounds to physostigmine and pyridostigmine is considered.

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“…(16): prepared as described for compound 15 using compound 13 instead of 12: yield 60%; mp 195-198 °C; *H NMR (300 MHz, CDCI3) 6 2.63 (3H, s), 4.12 (2H, s), 7.15 (1H, br s), 7.17 (1H, d, J = 4 Hz), 7.40 (1H, s), 7.57 (2H, d, J = 6 Hz), 7.72 (1H, s), 8.43 (1H, d, J = 4 Hz), 8.55 (2H, d, J = 6 Hz), 9.10 (1H, s). (17). A mixture of compound 15 (2.98 g, 7.24 mmol) and red mercuric oxide (1.57 g, 7.24 mmol) in ra-butanol (40 mL) was saturated with ammonia gas at room temperature and then stirred at 120 °C for 3 h. After being cooled, the mixture was diluted with methanol (150 mL) and filtered through Arbocel filter aid.…”

Section: Methodsmentioning

confidence: 99%

“…The role of the amide group of the benzodiazepines was investigated by preparing the IV-methyl derivative 14, using sodium hydride and methyl iodide in tetrahydrofuran, and the thioamides 15 and 16, using phos- phorus pentasulfide,14 starting from compounds 12 and 13, as indicated. Compound 15 was relatively unreactive toward nucleophiles, and the preparation of 17 required heating 15 in n-butanol saturated with ammonia in the presence of red mercuric oxide as a sulfur scavenger.…”

Section: Scheme 1°3mentioning

confidence: 99%

Novel Antagonists of Platelet-Activating Factor. 1. Synthesis and Structure-Activity Relationships of Benzodiazepine and Benzazepine Derivatives of 2-Methyl-1-phenylimidazo[4,5-c]pyridine

Mj¹,

Cooper²,

Mj³

et al. 1995

J. Med. Chem.

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Following the discovery of moderately potent antagonist activity platelet-activating factor (PAF) in 2-methyl-1-phenylimidazo[4,5-c]pyridine (2) (IC50 = 840 nM), 19 derivatives (3-21) were prepared which incorporated various lipophilic groups attached to the phenyl 4-position. Structure-activity relationships were evaluated where PAF antagonist activity was measured in vitro by determining the concentration of compound (IC50) required to inhibit the PAF-induced aggregation of rabbit washed platelets and in vivo by determining the oral dose (ED50) which protected mice from a lethal injection of PAF. [1,5]Benzodiazepines, e.g., 14 (2,3-dihydro-1-methyl-4-[4-(2-methylimidazo[4,5-c] pyrid-1-yl)phenyl]-1H-[1,5]benzodiazepin-2-one) (IC50 = 4.9 nM, Ed50 = 0.03 mg/kg po), were found to possess equivalent or superior potency to the 1,4-dihydropyridine PAF antagonist UK-74,505 (1,4-(2-chlorophenyl)-1,4-dihydro-3-(ethoxycarbonyl)-6-methyl-2- [4-(2-methylimidazo[4,5-c]pyrid-1-yl)phenyl]-5-[N-(2-pyridyl) carbamoyl]pyridine) in vitro and in vivo. Furthermore, a potent benzazepine, 21 (7,8-dichloro-1-methyl-4-[4-(methylimidazo[4,5-c]pyrid-1-yl) phenyl]-2,3,4,5-tetrahydro-1H-1-benzazepin-2-one) (IC50 = 0.5 nM, ED50 = 0.03 mg/kg po), was discovered. These investigations prompted the synthesis and evaluation of additional diazepine derivatives, which are described in the following paper. The relationship between the key PAF antagonist pharmacophores of 2-methyl-1-phenylimidazo[4,5-c]pyridine, a triazolothienodiazepine (WEB2170), and a pyrrolothiazolidine (RP-52,770) is discussed.

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ChemInform Abstract: Preparation of 2‐Aryl‐ and 2‐Aryloxymethylimidazo(1,2‐a)pyridines and Related Compounds.

Abstract: The 2‐arylimidazopyridines (III) are obtained by cyclocondensation of the 2‐aminopyridines (I) with the substituted α‐bromoacetophenones (II).

Cited by 3 publications

References 1 publication

Structure−Activity Relationship of Imidazo[1,2-a]pyridines as Ligands for Detecting β-Amyloid Plaques in the Brain

Structure−Activity Relationship of Imidazo[1,2-a]pyridines as Ligands for Detecting β-Amyloid Plaques in the Brain

Carbamate derivatives of 2-arylimidazo[1,2-a]pyridinium salts as acetylcholinesterase inhibitors and protective agents against organophosphorus compounds

Novel Antagonists of Platelet-Activating Factor. 1. Synthesis and Structure-Activity Relationships of Benzodiazepine and Benzazepine Derivatives of 2-Methyl-1-phenylimidazo[4,5-c]pyridine

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