81211-83-8

Upstream product

• 7295-76-3 3-methoxypyridine 
• 36016-40-7 mesitylenesulfonylhydroxylamine 
• 38202-27-6 ethyl O-(2-mesitylenesulfonyl)acetohydroxamate 
• 36016-39-4 N-(tert-butoxycarbonyl)-O-(mesitylsulfonyl)hydroxylamine 

Downstream Products

• 941319-51-3 N-{3-[3-(2-chloro-4-pyrimidinyl)-6-(methyloxy)pyrazolo[1,5-a]pyridin-2-yl]phenyl}-2,2,2-trifluoroacetamide 
• 941319-52-4 N-{3-[3-(2-chloro-4-pyrimidinyl)-4-(methyloxy)pyrazolo[1,5-a]pyridin-2-yl]phenyl}-2,2,2-trifluoroacetamide 
• 909717-95-9 ethyl 4-methoxypyrazolo[1,5-a]pyridine-3-carboxylate 

Relevant academic research and scientific papers

Regioselective Synthesis of Pyrazolo[1,5- a]pyridine via TEMPO-Mediated [3 + 2] Annulation-Aromatization of N-Aminopyridines and α,β-Unsaturated Compounds

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.

PYRAZOLOPYRIDINE DERIVATIVE OR PHARMACOLOGICALLY ACCEPTABLE SALT THEREOF

A pyrazolopyridine derivative represented by the following formula (I) or a pharmacologically acceptable salt thereof exhibits a strong EP1 receptor antagonistic effect. Thus, the derivative or the pharmacologically acceptable salt is useful as

Phosphodiesterase inhibitors. Part 4: Design, synthesis and structure-activity relationships of dual PDE3/4-inhibitory fused bicyclic heteroaromatic-4,4-dimethylpyrazolones

(-)-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.

Pyrazolopyridine-4-Yl Pyridazinone Derivatives and Addition Salts Thereof, and Pde Inhibitors Comprising the Same Derivatives or Salts as Active Ingredient

Novel pyrazolopyridine-4-yl pyridazinone derivatives serve as phosphodiesterase inhibitors and are useful compounds for use in pharmaceutical products. Specifically, the compounds of the present invention are pyrazolopyridine-4-yl pyridazinone derivatives represented by the following general formula (1): (Example: 6-(2-ethyl-7-methoxy-pyrazolo[1,5-a]pyridine-4-yl)-5-methyl-4, 5-dihydro-3(2H)-pyridazinone).