Novos derivados do sistema heterocíclico 1H-pirazolo[3,4-b]piridina: síntese e assinalamentos de hidrogênios e carbonos por RMN 1D e 2D

Abstract

BY 1D AND 2D NMR. The synthesis and NMR analysis of seven new 4-(aryl)amino-5-carboethoxy-1,3-dimethyl-1H-pyrazolo[3,4b]pyridines (7-13) are described. The synthetic approach used involved the preparation of intermediates 5-aminopyrazol (4), the enamine derivative (5) and the 4-chloro-1H-pyrazolo[3,4b]pyridine (6). Compounds (7-13) were obtained by treatment of 6 with the desired aniline. The structures of new heterocyclic compounds and their precursors intermediates were assigned on the basis of spectral analysis including 1D and 2D NMR experiments [ 1 H; 13 C{ 1 H} and DEPT; 1 H x 1 H-COSY; 1 H x 13 C-COSY, n J CH , n = 1, 2 or 3 (HETECOR and COLOC)].

Antileishmanial Pyrazolopyridine Derivatives: Synthesis and Structure−Activity Relationship Analysis

“…Chemistry. The pyrazolopyridine derivatives of series I , 4-(3‘- or 4‘-X-phenylamino)-5-carbethoxy-1,3-dimethyl-1 H -pyrazolo[3,4- b ]pyridine, where X = H ( 4 ), 4‘-NO 2 ( 5 ), 4‘-OH ( 6 ), 4‘-Br ( 7 ), 4‘−F ( 8 ), 4‘-OCH 3 ( 9 ), 4‘-CH 3 ( 10 ), 4‘-OAc ( 11 ), 4‘-Cl ( 12 ), 3‘-NO 2 ( 13 ), 3‘-OCH 3 ( 14 ), 3‘-CH 3 ( 15 ), and 3‘-Cl ( 16 ), were prepared − by nucleophilic substitution reactions between the intermediate 4-chloro-1 H -pyrazolo[3,4- b ]pyridine ( 3 ) and the appropriate 3- or 4-substituted anilines (Scheme ).

1

…”

Synthesis and characterization of new 1H-pyrazolo[3,4-b]pyridine phosphoramidate derivatives

“…High resolution mass spectra (EI-70eV) were performed on a Varian MAT CH7 8500 direct inlet instrument. The Clsubstituted pyrazolo [3,4-b]pyridine (4a-c) [21][22][23][24] and aminoalkylphosphoramidates (7a-d) 25,26 compounds were prepared as previously reported.…”

Synthesis of New Conjugates 1H‑Pyrazolo[3,4-b]pyridine-phosphoramidate and Evaluation against Leishmania amazonensis

“…31 Nucleophilic aromatic substitution by amines has been used as a versatile route to new pyrazolopyridine derivatives. 2,8,32,33 An halogen atom such as chlorine in the C-4 position as the leaving group and an ester or cyano group in the C-5 position as the withdrawing group propitiate the 1H-pyrazolo [3,4- with excess of the aminoalkylphosphoramidates (13a-e) in THF at 90 °C to obtain three series of substituted 1H-pyrazolo[3,4-b]pyridine phosphoramidates (14a-e, 15a-e and 16a-e) as solids in 67-83% yield (Scheme 2).…”