Selenium derivatives of imidazo[1,2-a]pyridines

Hand, Elli S.; Paudler, William W.

doi:10.1021/jo00908a014

Cited by 12 publications

(10 citation statements)

References 6 publications

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“…[60] Several other reports on lithiation of imidazo[1,2-a]pyridines have appeared. [63] [63] CH(OH)Me MeCHO 80 [63] CH(OH)Ph PhCHO 81 [63] Bz BzCl 30 [63] CO 2 H C O 2 77 [63] SMe MeSSMe 64 [63] 12 Studies on selenation of the title system [65] revealed that reaction of 1 with selenium dioxide affords selectively the monoselenide 100, the reactivity of which has also been studied. [63] [63] CH(OH)Me MeCHO 80 [63] CH(OH)Ph PhCHO 81 [63] Bz BzCl 30 [63] CO 2 H C O 2 77 [63] SMe MeSSMe 64 [63] 12 Studies on selenation of the title system [65] revealed that reaction of 1 with selenium dioxide affords selectively the monoselenide 100, the reactivity of which has also been studied.…”

Section: Synthesis By Substituent Modificationmentioning

confidence: 99%

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Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Neier¹,

Bellus²

2002

Category 2, Hetarenes and Related Ring Systems

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In contrast to Section 12.5.1.1.1.1, where in most cases the first reaction step is the quaternization of a pyridin-2-amine derivative followed by nucleophilic attack of the 2-amino group on an appropriate functional group to form the imidazole ring, several ring closures have been elaborated starting from substituted pyridin-2-amines. In these cases, the â-carbon atom of the carbon chain attached to the 2-amino group bears an appropriate functional group, and a nucleophilic attack of the pyridine ring nitrogen atom at this center results in formation of the imidazole ring. Such syntheses are shown in Scheme 8.

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Section: Synthesis By Substituent Modificationmentioning

confidence: 99%

“…[61,62] Directed metalation of 3-methoxy-2-phenylimidazo[1,2-a]pyridine (93) has been studied in detail. [65] 12.5.1.2.4 [65] 12.5.1.2.4…”

Section: Synthesis By Substituent Modificationmentioning

confidence: 99%

Product Class 5: Azaindolizines with Two Nitrogen Atoms in the Five-Membered Ring

Neier¹,

Bellus²

2002

Category 2, Hetarenes and Related Ring Systems

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“…We also developed reactions of imidazopyridines, Se powder, and triarylbismuthanes using a CuI/1,10-phenanthroline catalytic system that did not require a base or an additive [32]. On the other hand, the synthesis of a diselenide and a selenide bearing two imidazo [1,2-a]pyridine rings, such as bis(imidazo[1,2-a]pyridin-3-yl) selenide and the corresponding diselenides, have only been reported by Paulder et al [33]; however, the reported reaction was somewhat disadvantageous since it used SeO 2 (which is an oxidant) as the selenium source under acidic conditions, and the substrate scope and limitations have not been clarified. Moreover, the syntheses of bis(2-arylimidazo[1,5-a]pyridin-3-yl) selenides and diselenides have recently been investigated using Cu-catalyzed reactions involving imidazo [1,5-a]pyridines, which are isomers of imidazo [1,2-a]pyridines, with Se powder [34].…”

Section: Introductionmentioning

confidence: 99%

“…However, in this reaction, selenides and diselenides were generated in ratios of approximately 1:1; hence, an efficient selective synthesis has not yet been achieved. Inspired by the aforementioned reports and our continuing studies in the synthesis of organoselenium compounds containing imidazo [1,2-a]pyridine rings [27][28][29][30][31][32][33][34], the synthesis of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides by the Cu-catalyzed tandem C-H selenation of 2-arylimidazo[1,2-a]pyridines with Se powder is presented herein. This reaction was used to selectively synthesize selenides and diselenides bearing two imidazopyridine rings by simply controlling the amount of selenium added.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and anticancer activity of bis(2-arylimidazo[1,2-a]pyridin-3-yl) selenides and diselenides: the copper-catalyzed tandem C–H selenation of 2-arylimidazo[1,2-a]pyridine with selenium

Matsumura

Takahashi

Yamauchi

et al. 2020

Beilstein J. Org. Chem.

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Most heteroaryl selenides and diselenides are biologically active, with some reported to act as antioxidants and show activities that are medicinally relevant; hence, the development of efficient methods for their synthesis is an important objective. Herein, a simple method for the synthesis of selenides and diselenides bearing imidazo[1,2-a]pyridine rings and their anticancer activity are described. The double C–H selenation of imidazo[1,2-a]pyridine with Se powder was catalyzed by CuI (10 mol %) ligated with 1,10-phenanthroline (10 mol %) at 130 °C under aerobic conditions. The selenides or diselenides were prepared almost selectively using selenium powder in an appropriate quantity under otherwise identical reaction conditions. The prepared selenides and diselenides bearing two imidazo[1,2-a]pyridine rings were all novel compounds. Among the prepared diselenides and selenides that exhibited cytotoxicity against cancer cells, bis[2-(4-methoxyphenyl)imidazo[1,2-a]pyridin-3-yl] diselenide showed an excellent anticancer activity and low cytotoxicity toward noncancer cells, suggesting that this diselenide is a potential lead compound for anticancer therapy.

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“…this transformation,16 (2) hydriodic acid is known to form iodine in the presence of air,17 (3) selenides readily form dihaloselenides when treated with halogen,6,7 and ( 4) the latter can be converted to dihydroxyselenides7-we propose the all-encompassing mechanism A.…”

mentioning

confidence: 94%