85364-59-6

Upstream product

• 4891-38-7 phenylpropynoic acid methyl ester 
• 97607-60-8 N-amino-3-(hydroxymethyl)pyridinium mesityl sulfonate 
• 127717-32-2 3-(1-hydroxyethyl)-4-methyl-2-phenylpyrazolo<1,5-a>pyridine 
• 1817-57-8 4-phenyl-3-butyne-2-one 
• 31382-86-2 N-<(phenylcarbonyl)imino>-3-methylpyridinium inner salt 
• 42599-24-6 E-styryl iodide 
• 59046-22-9 (3-methylpyridin-1-ium-1-yl)amide 
• 108-99-6 3-Methylpyridine 
• 127717-24-2 3-acetyl-4-methyl-2-phenylpyrazolo<1,5-a>pyridine 
• 7338-94-5 1,3-diphenyl-2-propynone 
• 115748-26-0 3-benzoyl-4-methyl-2-phenylpyrazolo<1,5-a>pyridine 
• 85372-17-4 2,4,6-Trimethyl-benzenesulfonate1-amino-3-(3-phenyl-propynoyloxymethyl)-pyridinium; 
• 115748-35-1 3-(α-hydroxybenzyl)-4-methyl-2-phenylpyrazolo<1,5-a>pyridine 

Relevant academic research and scientific papers

Synthesis of 2- and 2,3-substituted Pyrazolo[1,5- a ]pyridines: Scope and mechanistic considerations of a domino direct alkynylation and cyclization of n -iminopyridinium ylides using alkenyl bromides, alkenyl iodides, and alkynes

Direct functionalization and tandem processes have both received considerable recent interest due to their cost and time efficiency. Herein we report the synthesis of difficult to obtain 2-substituted pyrazolo[1,5-a] pyridines through a tandem palladium-catalyzed/silver-mediated elimination/direct functionalization/cyclization reaction involving N-benzoyliminopyridinium ylides. As such, these biologically important molecules are prepared in an efficient, high-yielding manner, only requiring a two-step sequence from pyridine. Aryl-substituted alkenyl bromides and iodides are effective ylide coupling partners. Mechanistic studies led to the use of terminal alkynes, which extended the scope of the reaction to include alkyl substitution on the unsaturated reactive site. The optimization, scope, and mechanistic considerations of the process are discussed.

Synthesis of 2-Substituted Pyrazolo[1,5-a]pyridines through Cascade Direct Alkenylation/Cyclization Reactions

[Chemical equation presented] The synthesis of 2-substituted pyrazolo[1,5-a]pyridines from N-iminopyridinium ylides is described. These medicinally interesting compounds are formed through a cascade process involving a palladium-catalyzed direct alkenylation reaction followed by silver-mediated cyclization. The reaction can be performed with a wide range of electron-poor and electron-rich alkenyl iodides in good yields. This work represents perhaps the most direct route for the preparation of these compounds.

Acid-Catalyzed Reactions of 3-(Hydroxymethyl)- and 3-(1-Hydroxyethyl)pyrazolopyridines

Treatment of 3-(hydroxymethyl)pyrazolopyridines with trifluoroacetic acid in refluxing dichloromethane led to the formation of bis(pyrazolopyrid-3-yl)methanes or bis pyrid-3-yl)>methyl ethers depending upon the concentration of trifluoroacetic acid.In contrast, similar treatment of 3-(1-hydroxyethyl)pyrazolopyridines gave a mixture of 3-vinylpyrazolopyridines and 1,3-bis(pyrazolopyrid-3-yl)-1-butenes.

Acid-Catalyzed Reactions of 3-(α-Hydroxybenzyl)pyrazolopyridines

Treatment of 3-(α-hydroxybenzyl)pyrazolopyridines with trifluoroacetic acid in dichloromethane resulted in the formation of pyrazolopyridines, bispyrid-3-yl)benzyl> ethers, and phenylbis(pyrazolopyrid-3-yl)methanes,

Synthesis of Peri-fused Indolizines and Azaindolizines by Intramolecular 1,3-Dipolar Cycloaddition of 3-(Phenylpropynoyloxyalkyl)pyridine N-Ylides

Treatment of 3-(phenylpropynoyloxymethyl)-N-aminopyridium salt with potassium carbonate in methanol gave unexpectedly 4-methyl-2-phenylpyrazolopyridine and methyl 6- and 4-hydroxymethyl-2-phenylpyrazolopyridine-3-carboxylates.Similar treatme

INTRAMOLECULAR 1,3-DIPOLAR CYCLOADDITION OF 3-PHENYLPROPIOLOYLOXYALKYLPYRIDINIUM N-IMINES

Treatment of N-aminopyridinium salt (3a) with base in methanol gave unexpected product (4) but the salts (3b,c) in acetonitrile yielded normal adducts with 7- or 8-membered lactone (6b,c).