A Convenient Synthesis of New Pyrazolo[4,3‐d]pyrimidines and Their Fused Heterocycles

Abstract

A series of some fused heterocycles originated from pyrazolopyrimidines were synthesized using 4‐amino1‐methyl‐3‐propyl‐1H‐pyrazole‐5‐carboxamide as a starting material. The nucleophilic substitution reactions with different amino acids followed by cyclization and Suzuki–Miyaura cross‐coupling reactions with different aryl boronic acids of 7‐chloro‐5‐(4‐chlorophenyl)‐1‐methyl‐3‐propyl‐1H‐pyrazolo[4,3‐d]pyrimidine were performed. Also, the oxidative cyclization reactions of 1‐(5‐(4‐chlorophenyl)‐1‐methyl‐3‐propyl‐1H‐pyrazolo[4,3‐d]pyrimidin‐7‐yl)hydrazine with different aldehydes in the presence of diacetoxy iodobenzene are described. All the synthesized compounds were characterized by analytical and spectroscopic methods.

Novel Pyrazolo[4,3-d]pyrimidine as Potent and Orally Active Inducible Nitric Oxide Synthase (iNOS) Dimerization Inhibitor with Efficacy in Rheumatoid Arthritis Mouse Model

“…Synthon 4A was a key intermediate for title compounds, which was achieved by chlorination reaction in the presence of POCl 3 . 38 Nucleophilic substitution reactions of compound 4A with various amines gave title compounds A1−13 (Scheme 1). On the basis of compound A13, compounds A14−17 were prepared through simple derivation.…”

“…Compound 3A was afforded through intramolecular cyclization reaction. Synthon 4A was a key intermediate for title compounds, which was achieved by chlorination reaction in the presence of POCl 3 . Nucleophilic substitution reactions of compound 4A with various amines gave title compounds A1 – 13 (Scheme ).…”

Synthesis of some novel pyrazolopyrimidotriazepine, pyrazolotriazolopyrimidine, and pyrazolopyrimidotetrazine derivatives

“…They have important properties as antimetabolites in purine biochemical reactions. [25] Pyrazolopyrimidine-fused heterocycles have received great attention [26] especially pyrazolotriazolopyrimidine derivatives. [14][15][16][17] On the other hand, 1,2,4-triazoles play very important role in the medicinal chemistry due to different biological activities such as antioxidant, [18] analgesic [19] antimalarial, [20] anti-carbonic anhydrase, [21] antiviral, [22] antibacterial, [23] fungicidal, [24] anti-xanthine oxidase, and anti-urease.…”

Design, Multicomponent Synthesis and Characterization of Diversely Substituted Pyrazolo[1,5‐a] Pyrimidine Derivatives

“…Pyrazolopyrimidines have multiple pharmacological activities including hypnotic , anti‐inflammatory , anti‐tumor, antimycobacterial , antidiabetic, antiphlogistic agents, antidepressants, analgesics , and anti‐viral . Several diverse biological activities have been reported for pyrazolopyrimidine ring systems which are described as below.…”