81211-83-8Relevant articles and documents
Regioselective Synthesis of Pyrazolo[1,5- a]pyridine via TEMPO-Mediated [3 + 2] Annulation-Aromatization of N-Aminopyridines and α,β-Unsaturated Compounds
Liu, Ya-Zhou,Ma, Xiaofeng,Qiao, Zeen,Shen, Zhongke,Wang, Amu
, (2022/03/01)
A TEMPO-mediated [3 + 2] annulation-aromatization protocol for the preparation of pyrazolo[1,5-a]pyridines from N-aminopyridines and α,β-unsaturated compounds was developed. The procedure offered multisubstituted pyrazolo[1,5-a]pyridines in good to excellent yield with high and predictable regioselectivity. The modification of marketed drugs including Loratadine, Abiraterone, and Metochalcone, and a one-pot three-step gram scale synthesis of key intermediate for the preparation of Selpercatinib were demonstrated. Mechanism studies show that TEMPO serves both as a Lewis acid and as an oxidant.
Phosphodiesterase inhibitors. Part 4: Design, synthesis and structure-activity relationships of dual PDE3/4-inhibitory fused bicyclic heteroaromatic-4,4-dimethylpyrazolones
Ochiai, Koji,Takita, Satoshi,Kojima, Akihiko,Eiraku, Tomohiko,Ando, Naoki,Iwase, Kazuhiko,Kishi, Tetsuya,Ohinata, Akira,Yageta, Yuichi,Yasue, Tokutaro,Adams, David R.,Kohno, Yasushi
, p. 5833 - 5838 (2012/11/07)
(-)-6-(7-Methoxy-2-trifluoromethylpyrazolo[1,5-a]pyridin-4-yl)-5-methyl-4, 5-dihydro-3-(2H)-pyridazinone (KCA-1490) is a dual PDE3/4 inhibitor that exhibits potent combined bronchodilatory and anti-inflammatory activity. Here we show that a 4,4-dimethylpyrazolone subunit serves as an effective surrogate for the 5-methyl-4,5-dihydropyridazin-3(2H)-one ring of KCA-1490 whilst lacking a stereogenic centre. The 2- and 7-substituents in the pyrazolo[1,5-a]pyridine subunit markedly influence the PDE-inhibitory profile and can be adjusted to afford either potent PDE4-selective inhibitors or dual PDE3/4 inhibitors. A survey of bicyclic heteroaromatic replacements for the pyrazolo[1,5-a]pyridine allowed further refinement of the inhibitory profile and identified 3-(8-methoxy-2-(trifluoromethyl)imidazo[1,2-a]pyridin-5-yl)-4, 4-dimethyl-1H-pyrazol-5(4H)-one as an orally active, achiral KCA-1490 analog with well-balanced dual PDE3/4-inhibitory activity.
Studies on diazepines. XVII. Synthesis of monocyclic 1,3-diazepines. (2). Substituent effects on the thermal ring-conversion of 1,2-diazepines into 1,3-diazepines
Kurita,Kojima,Enkaku,Tsuchiya
, p. 3696 - 3705 (2007/10/02)
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