1227809-84-8

Upstream product

• 911408-88-3 4-(4-methoxyphenyl)-3-methyl-1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-b]pyridin-6(7H)-one 
• 68-12-2 N,N-dimethyl-formamide 

Downstream Products

• 1227810-02-7 C₂₁H₁₇N₅O 

Relevant academic research and scientific papers

Hydrogen-bonded assembly in six closely related pyrazolo-[3,4-b]pyridine derivatives; A simple chain, three types of chains of rings and a complex sheet structure

Six closely related pyrazolo-[3,4-b]pyridine derivatives, namely 6-chloro-3-methyl-1,4-diphenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C20H14ClN3O, (I), 6-chloro-3-methyl-4-(4-methyl-phenyl)-1-phenylpyrazolo-[3,4-b] pyridine-5-carbaldehyde, C21H16ClN3O, (II), 6-chloro-4-(4-chloro-phenyl)-3- methyl-1-phenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C20H13Cl2N3O, (III), 4-(4-bromo-phenyl)-6-chloro-3-methyl-1-phenyl-pyrazolo-[3,4-b] pyridine-5-carbaldehyde, C20H13BrClN3O, (IV), 6-chloro-4-(4-meth-oxy-phenyl)-3- methyl-1-phenyl-pyrazolo-[3,4-b]pyridine-5-carbaldehyde, C21H16ClN3O2, (V), and 6-chloro-3-methyl-4-(4-nitro-phenyl)-1-phenyl-pyrazolo[3,4-b] pyridine-5-carbaldehyde, C20H13ClN4O3, (VI), which differ only in the identity of a single small substituent on one of the aryl rings, crystallize in four different space groups spanning three crystal systems. The mol-ecules of (I) are linked into a chain of rings by a combination of C - H...N and C - H...π(arene) hydrogen bonds; those of (II), (IV) and (V), which all crystallize in the space group P , are each linked by two independent C - H...O hydrogen bonds to form chains of edge-fused rings running in different directions through the three unit cells; the mol-ecules of (III) are linked into complex sheets by a combination of two C - H...O hydrogen bonds and one C - H...π(arene) hydrogen bond; finally, the mol-ecules of (VI) are linked by a single C - H...O hydrogen bond to form a simple chain.

Preparation of 6-chloropyrazolo[3,4-b]pyridine-5-carbaldehydes by Vilsmeier-Haack reaction and its use in the synthesis of heterocyclic chalcones and dipyrazolopyridines

Novel 6-chloropyrazolo[3,4-b]pyridine-5-carbaldehydes 5 have been synthesized from the 4,5-dihydropyrazolo[3,4-b]pyridine-6-ones 4 via Vilsmeier-Haack reaction. Further treatment of carbaldehydes 5 with acetophenones 6 and hydrazine hydrate afforded chalc