Antituberculous compounds. XXVIII. Synthesis of pyrazolopyridines

Abstract

In a previous paper it was reported that N′‐alkyl derivative of isonicotinic acid hydrazide (INH) was more active against tuberele bacilli than the acyl derivative containing the same number of carbon atoms. The authors subsequently reported that the pyrido[2, 3‐d]pyridazine was closely related to the acyl derivative of INH except that the terminal carbonyl group was cyclized to the pyridine nucleus, therefore these derivatives were not effective against tubercle bacilli; however, pyridopyridazine, which is similar to the alkyl derivatives of INH, will be more effective against tubercle bacilli. According to the similar expectation, some pyrazolopyridines were prepared.

Design and synthesis of new and significative bifunctional compounds containing two pyrazolo[3,4‐b]pyridine nucleis through multicomponent reaction under microwave irradiation

“…The mixture was irradiated at 250 W and at 100 °C for a given time. The reaction mixture was cooled to room temperature and filtered to give the crude product, which was further washed with ether and ether, and then purified by recrystallization from DMF and ethanol to give pure products (4)(5)(6)(7)(8)(9)(10). 3-Bis(4,4a,7,8,8a,9-hexahydro-3,7,7-trimethyl-1-phenyl-1H H,6.44;N,12.20;Found C,76.83;H,6.36;N,12.33 .…”

“…Dihydropyrazolo [3,4-b]pyridine has also shown vasodilating and antihypertension activities and produced prophylactic effect as calcium antagonist in strok-prone spontaneously hypertensive symptoms [4][5].…”

Docking Studies, Synthesis, and Evaluation of Antioxidant Activities of N-Alkylated, 1,2,4-Triazole, 1,3,4-Oxa-, and Thiadiazole Containing the Aminopyrazolopyridine Derivatives

“…Pyrazole fused pyridines and pyrimidines are known to possess a wide range of biological activity. Specifically pyrazolopyridines exhibit antitubercular, anxiolytic [14].…”

Synthesis of tetrahetrocyclic systems including pyrido[2′,3′:3,4]pyrazolo[1,5‐a]pyrimidine fused with pyrazole derivatives and isolated with 1,3,4‐oxa‐, thiadiazole, and 1,2,4‐tetrazole derivatives

“…In general, the pyrazolopyridines are found to be active antitubercular agents [14,15] active against gram positive and negative bacteria [16]. As well as pyrazolopyrimidines [17,18] are selective inhibitors of cyclic 3 0 ,5 0 -adenosine mono-phosphat (cAMP) phosphodiesterases in vitro, and some of them possess anxiolytic properties comparable to those of benzodiazepines.…”