A novel set of 4-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidine and 5-substituted-1-phenyl-pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized and evaluated as potential anti-inflammatory agents. The newly prepared compounds were assessed through the examination of their in vitro inhibition of four targets; cyclooxygenases subtypes (COX-1 and COX-2), inducible nitric oxide synthase (iNOS) and nuclear factor kappa B (NF-κB). Compounds 8a, 10c and 13c were the most potent and selective ligands against COX-2 with inhibition percentages of 79.6%, 78.7% and 78.9% at a concentration of 2 μM respectively, while compound 13c significantly inhibited both COX subtypes. On the other hand, fourteen compounds showed high iNOS inhibitory activities with IC50 values in the range of 0.22-8.5μM where the urea derivative 11 was the most active compound with IC50 value of 0.22 μM. Most of the tested compounds were found to be devoid of inhibitory activity against NF-kB. Moreover, almost all compounds were not cytotoxic, (up to 25 μg/ml), against a panel of normal and cancer cell lines. The in silico docking results were in agreement with the in vitro inhibitory activities against COXs and iNOS enzymes. The results of in vivo anti-inflammatory and antinociceptive studies were consistent with that of in vitro studies which confirmed that compounds 8a, 10c and 13c have significant anti-inflammatory and analgesic activities comparable to that of the control, ketorolac. Taken together, dual inhibition of COXs and iNOS with novel pyrazolopyrimidine derivatives is a valid strategy for the development of anti-inflammatory/analgesic agents with the probability of fewer side effects.Copyright © 2014 Elsevier B.V. All rights reserved.

Two new series of pyrazolo[3,4-d]pyrimidine bearing thiazolidinone moiety were designed and synthesized. The newly synthesized compounds were evaluated for their in vitro (COX-1 and COX-2) inhibitory assay. Compounds that showed promising COX-2 selectivity were further subjected to in vivo anti-inflammatory screening applying formalin induced paw edema (acute model) and cotton-pellet induced granuloma (chronic model) assays using celecoxib and diclofenac sodium as reference drugs. The histopathological and ulcerogenic potential were also determined. In vivo anti-inflammatory data showed that compounds 2, 6, 7d displayed anti-inflammatory activity higher than both references in the formalin induced paw edema model. On the other hand, compounds 2, 3d, 3e, 7b and 7d displayed anti-inflammatory activity greater than or nearly equivalent to diclofenac sodium in the cotton pellet-induced granuloma assay. Moreover, most of the tested compounds revealed good gastrointestinal safety profile. Collectively, compounds 2 and 7d were considered as promising candidates in managing both acute and chronic inflammation with safe gastrointestinal margin.Copyright © 2018 Elsevier Inc. All rights reserved.

To promote the discovery and development of new fungicide with novel scaffolds or modes of action, a series of novel 5-(2-chloroethyl)-1-phenyl-6-(pyridin-4-yl)-1,5-dihydro-4H-pyrazolo[3,4-d]pyrimidin-4-one derivatives were synthesized, and evaluated for their antifungal activities.The bioassay data showed that compound 8IIId (EC = 1.93 mg/L) is superior to boscalid (EC = 6.71 mg/L) against Valsa mali. We introduced chiral groups on the structure of 8IIId, and two chiral configurations were respectively synthesized, which are 8Vc and 8Vd. Surprisingly, 8Vc showed significant antifungal activities against Valsa mali and Physalospora piricola with EC values of 0.22 and 0.55 mg/L. Physiological and biochemical studies showed that the primary action mechanism of compound 8Vc on Valsa mali may involve changing mycelial morphology and increasing cell membrane permeability.These results demonstrated that 8Vc could be further modified as fungicide and provided a valuable reference for antifungal agents with pyrazolo[3,4-d]pyrimidin-4-one skeleton.This article is protected by copyright. All rights reserved.

3,6-Dimethyl-1-phenyl-1H-pyrazolo[3,4-d][1,3]oxazin-4-one (3) was prepared by hydrolysis of ethyl 5-amino-3-methyl-1-phenyl-1H-pyrazole-4-carboxylate (1) to afford the corresponding carboxylic acid 2, which was reacted with acetic anhydride to give 3. The pyrazolo[3,4-d][1,3]oxazin-4-one 3 was reacted with hydroxylamine hydrochloride, urea, thiourea, thiosemicarbazide, phenylhydrazine and aromatic amines to afford the corresponding pyrazolo[3,4-d]pyrimidin-4-ones 4, 5a,b, 6, 7, 8a-e, respectively. Condensation of pyrazoloxazine derivative 3 with 99% hydrazine hydrate afforded the 5-aminopyrazolo[3,4-d] pyrimidine derivative 9. Coupling of 9 with aromatic aldehydes yielded a series of 3,6-dimethyl-5-(4-substitutedbenzylideneamino)-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin- 4-ones 10a-e. The new compounds were tested for their antitumor activity on the MCF-7 human breast adenocarcinoma cell line. Almost all the tested compounds revealed antitumor activity, especially 3,6-dimethyl-5-(4-nitrobenzylideneamino)-1-phenyl-1,5-dihydropyrazolo[3,4-d]pyrimidin-4-one (10e) which displayed the most potent inhibitory activity with a half maximal inhibitory concentration (IC₅₀) of 11 µM.

A modified formalin test in mice was investigated. The pain response curve induced by 0.5% formalin was biphasic, having 2 peaks, from 0 to 5 min (first phase) and from 15 to 20 min (second phase). A low concentration of formalin was used, allowing the effects of weak analgesics to be detected. Centrally acting drugs such as narcotics inhibited both phases equally. Peripherally acting drugs such as aspirin, oxyphenbutazone, hydrocortisone and dexamethasone only inhibited the second phase. Aminopyrine and mefenamic acid which acted on both central and peripheral sites inhibited both phases, but the second phase was inhibited by lower doses. Thus, this method enables one to easily distinguish the site of action of analgesics. Furthermore, pain response in the first phase was inhibited by capsaicin-treated desensitization and Des-Arg9-(Leu8)-bradykinin (bradykinin inhibitor). The second phase was inhibited by compound 48/80 pretreatment, indomethacin and bradykinin inhibitor. Therefore, it is suggested that substance P and bradykinin participate in the manifestation of the first phase response, and histamine, serotonin, prostaglandin and bradykinin are involved in the second phase. These results indicate that the first and second phase responses induced by formalin have distinct characteristic properties, and it is a very useful method for examining pain, nociception and its modulation by pharmacological or other means.