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In this study, research and development for the synthetic process of a PDE10A inhibitor are described; in particular, an efficient regioselective construction of the quinoxaline unit, a cost-effective pyrazolo[1,5-a]pyrimidine formation, and a cost-saving approach in a nucleophilic aromatic substitution (SNAr) reaction by introducing oxazolidinone as an electron-withdrawing group to a chloropyrazolo[1,5-a]pyrimidine core are key points. The newly developed process has been successfully scaled up to 40 kg. Furthermore, a one-pot tandem reaction from aminopyrazole to dichloropyrazolo[1,5-a]pyrimidine by activating malonic acid with POCl3 was discovered. The finding contributed to avoiding isolation of the hygroscopic pyrazolo[1,5-a]pyrimidin-5(4H)-one intermediate, which caused complicated filtration and drying processes observed in the first scale-up campaign.

The protein kinase MKK7 is linked to neuronal development and the onset of cancer. The field, however, lacks high-quality functional probes that would allow for the dissection of its detailed functions. Against this background, we describe an effective covalent inhibitor of MKK7 based on the pyrazolopyrimidine scaffold.

A fluorescent sensor L based on a pyrazolopyrimidine core simultaneously detects Cu2+ and Ni2+ ions by photoluminescence quenching, even in the presence of other metal cations. Sensor L possesses high association constants of 5.24 × 103 M−1 and 2.85 × 104 M−1 and low detection limits of 0.043 μM and 0.038 μM for Cu2+ and Ni2+, respectively. The binding stoichiometry ratios of L to Cu2+ or Ni2+ is 1:1 as determined by Benesi-Hildebrand and Job's plots, and by crystal structures. DFT calculations on L-Cu2+ indicated reduced electron donation from the coordinated pyrazolopyridine to the fused pyrimidine and pendant phenyl group which, together with a smaller HOMO-LUMO orbital gap could favour non-radiative decay and explain the observed fluorescence quenching. Sensor L possessed low cytotoxicity and good imaging characteristics for Cu2+ and Ni2+ in living cells, suggesting potential applications for detecting Cu2+ and Ni2+ in vivo.

Irreversible inhibition of disease-associated proteins with small molecules is a powerful approach for achieving increased and sustained pharmacological potency. Here, we introduce α-chlorofluoroacetamide (CFA) as a novel warhead of targeted covalent inhibitor (TCI). Despite weak intrinsic reactivity, CFA-appended quinazoline showed high reactivity toward Cys797 of epidermal growth factor receptor (EGFR). In cells, CFA-quinazoline showed higher target specificity for EGFR than the corresponding Michael acceptors in a wide concentration range (0.1–10 μM). The cysteine adduct of the CFA derivative was susceptible to hydrolysis and reversibly yielded intact thiol but was stable in solvent-sequestered ATP-binding pocket of EGFR. This environment-dependent hydrolysis can potentially reduce off-target protein modification by CFA-based drugs. Oral administration of CFA quinazoline NS-062 significantly suppressed tumor growth in a mouse xenograft model. Further, CFA-appended pyrazolopyrimidine irreversibly inhibited Bruton’s tyrosine kinase with higher target specificity. These results demonstrate the utility of CFA as a new class warheads for TCI. Discovery and exploitation of inherent reaction features of chlorofluoroacetamide (CFA) as a warhead such as low off-target activity and reversible reactivity with cysteine enable specific covalent inhibition of targeted kinases.

A new series of 1-substituted pyrazolopyrimidine derivatives were synthesized as potent BTK inhibitors and they were evaluated by enzyme-based assay and anti-proliferation against multiple B-cell lymphoma cell lines in vitro. Among these compounds, 9h exhibited the highest potency against BTK enzyme, with IC50 value of 4.2 nM. In particular, 8 and 9f performed better inhibition against the proliferation of B lymphoma cell lines DOHH2 and WSU-DLCL2 than the clinical drug ibrutinb. In addition, the test toward the normal PBMC cells showed that 8 possessed low cell cytotoxicity. All these explorations indicated that 8 could serve as a valuable anti-tumor agent for B-cell lymphoblastic leukemia treatment.

Herein, a dual-response fluorescent sensor, L, based on pyrazolopyrimidine was designed and developed for the simultaneous detection of Ni2+ and Cu2+ ions in the presence of other metal ions; the structural characterization of L was carried out by FTIR spectroscopy, NMR spectroscopy, HRMS and X-ray diffraction analysis. The sensor L effectively displayed fluorescence quenching towards the Ni2+ and Cu2+ ions with high sensitivity without interference from other metal ions. The results reveal that L binds to Ni2+ and Cu2+ in a 2 : 1 pattern, which matches well with the result of the Job's plot. The association constants of L with Ni2+ and Cu2+ were 3.2 × 104 M−1 and 7.57 × 104 M−1, respectively. The detection limits (DLs) are down to 8.9 nM for Ni2+ and 8.7 nM for Cu2+. The fluorescence imaging of L in T-24 cells was investigated because of the low cytotoxicity of L, indicating that L could be used to detect Ni2+ and Cu2+ in living cells.

Anti-Wolbachia therapy has been identified as a viable treatment for combating filarial diseases. Phenotypic screening revealed a series of pyrazolopyrimidine hits with potent anti-Wolbachia activity. This paper focuses on the exploration of the SAR for this chemotype, with improvement of metabolic stability and solubility profiles using medicinal chemistry approaches. Organic synthesis has enabled functionalization of the pyrazolopyrimidine core at multiple positions, generating a library of compounds of which many analogues possess nanomolar activity against Wolbachia in vitro with improved DMPK parameters. A lead compound, 15f, was selected for in vivo pharmacokinetics (PK) profiling in mice. The combination of potent anti-Wolbachia activity in two in vitro assessments plus the exceptional oral PK profiles in mice puts this lead compound in a strong position for in vivo proof-of-concept pharmacodynamics studies and demonstrates the strong potential for further optimization and development of this series for treatment of filariasis in the future.

Root rot caused by Pythium aphanidermatum is one of diseases of olive trees. Three synthetic chemical compounds were tested to assess their inhibitory effect on Pythium aphanidermatum Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), Ethyl 5-amino-7-((3-hydroxy-5-methyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(8) and Ethyl 5-amino-7-((5-amino-2,7-dihydroxypyrazolo[1,5-a]pyrimidin-3-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(9) were synthesis to study their effect on mycelium growth, zoospore and oospore production of P. aphanidermatum isolated from young olive trees cultivated in Ain Seleen, Fayoum governorate, Egypt. Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), showed high efficiency as growth inhibition of fungal mycelia, followed by (pyrazolopyrimidine 9, and then pyrazolopyridine 8 at 10 mg/ L. Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7), showed its ability to decline the production of zoo-spores and oospores of the fungus at concentration 300 mg/L, compared to other chemicals of Ethyl 5-amino-7-((5-amino-2,7-dihydroxypyrazolo[1,5-a]pyrimidin-3-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(9), Ethyl 5-amino-7-((3-hydroxy-5-methyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate(8). Rate of inhibition in all treatments reached more than 85% in case of the use of Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7). This study offers data for the use of Ethyl 5-amino-7-((3,5-dimethyl-1H-pyrazol-4-yl)diazenyl)-3,4,8,8a-tetrahydro-2H-pyrano[2,3-b]pyridine-6-carboxylate (7) in controlling fungal disease to olive feeder roots infected by P. aphanidermatum

Bumped kinase inhibitors (BKIs) that target Cryptosporidium parvum calcium-dependent protein kinase 1 have been well established as potential drug candidates against cryptosporidiosis. Recently, BKI-1649, with a 7H-pyrrolo[2,3-d]pyrimidin-4-amine, or "pyrrolopyrimidine", central scaffold, has shown improved efficacy in mouse models of Cryptosporidium at substantially reduced doses compared to previously explored analogs of the pyrazolopyrimidine scaffold. Here, two pyrrolopyrimidines with varied substituent groups, BKI-1812 and BKI-1814, were explored in several in vitro and in vivo models and show improvements in potency over the previously utilized pyrazolopyrimidine bumped kinase inhibitors while maintaining equivalent results in other key properties, such as toxicity and efficacy, with their pyrazolopyrimidine isosteric counterparts.

Fused pyrimidines, especially pyrazolo[3,4-d]pyrimidines, are among the most preferred building blocks for pharmacology studies, as they exhibit a broad spectrum of biological activity. In this study, new derivatives of pyrazolo[3,4-d]pyrimidine were synthesized by alkylation of the N1 nitrogen atom. We synthesized 3-iodo-1H-pyrazolo[3,4-d]pyrimidin-4-amine 2 from commercially available aminopyrazolopyrimidine 1 using N-iodosuccinimide as an iodinating agent. The synthesis of compound 2 started with nucleophilic substitution of 3-iodo-1H-pyrazolo[3,4-d]pyrimidin-4-amine with R-X (X: -OMs, -Br, -Cl), affording N-alkylated pyrazolo[3,4-d]pyrimidine. We performed this synthesis using a weak inorganic base and the mild temperature was also used for a two-step procedure to generate N-alkylated pyrazolo[3,4-d]pyrimidine derivatives. Also, all compounds were tested for their ability to inhibit acetylcholinesterase (AChE) and the human carbonic anhydrase (hCA) isoforms I and II, with Ki values in the range of 15.41 ± 1.39-63.03 ± 10.68 nM for AChE, 17.68 ± 1.92-66.27 ± 5.43 nM for hCA I, and 8.41 ± 2.03-28.60 ± 7.32 nM for hCA II. Notably, compound 10 was the most selective and potent CA I inhibitor with a significant selectivity ratio of 26.90.

Photodynamic therapy (PDT) is a clinically approved therapeutic strategy that combines a specific wavelength of light and light-activated photosensitizers (PSs). The usage of PDT for cancer treatment is often hampered by the lack of tumor selectivity of PSs, which may cause photodamage to surrounding normal tissues. Recently, translocator protein (TSPO) has attracted great interest as a tumor biomarker, whose expression correlates with tumor aggressiveness. In this study, we report the development of a series of novel TSPO-PSs based on quinazoline, pyrazolopyrimidine, and tetrahydrocarbazole structures. These TSPO-PSs bind to TSPO with nanomolar affinities and demonstrated efficient and target-specific PDT effect upon light irradiation. Therefore, they may have great potential in the treatment of tumors associated with high-TSPO expression.

Building on the pyrazolopyrimidine CK2 (casein kinase 2) inhibitor scaffold, we designed a small targeted library. Through comprehensive evaluation of inhibitor selectivity, we identified inhibitor 24 (SGC-CK2-1) as a highly potent and cell-active CK2 chemical probe with exclusive selectivity for both human CK2 isoforms. Remarkably, despite years of research pointing to CK2 as a key driver in cancer, our chemical probe did not elicit a broad antiproliferative phenotype in >90% of >140 cell lines when tested in dose-response. While many publications have reported CK2 functions, CK2 biology is complex and an available high-quality chemical tool such as SGC-CK2-1 will be indispensable in deciphering the relationships between CK2 function and phenotypes.

The design, synthesis and structure–activity relationships associated with a series of C2-substituted pyrazolopyrimidines as potent allosteric inhibitors of HIV-1 integrase (ALLINIs) are described. Structural modifications to these molecules were made in order to examine the effect on potency and, for select compounds, pharmacokinetic properties. We examined a variety of C2-substituted pyrazolopyrimidines and found that the C2-amide derivatives demonstrated the most potent antiviral activity of this class against HIV-1 infection in cell culture.

The aim. Development of optimal, high-precision and reproducible methods for quantitative determination of the main substance in the substance Epimidin - 1-(4-methoxyphenyl)-5-[2-[4-(4-methoxyphenyl)piperazin-1-yl]-2-oxo-ethyl]pyrazolo[3,4-d]pyrimidin-4-one by high performance liquid chromatography.Materials and methods. High performance liquid chromatography (HPLC) was performed using a ShimadzuNexeraX2 LC-30AD system (Shimadzu, Japan) equipped with a SPD-M20A diode array detector (DAD). ACE C18 column, size 250 x 4.6 mm, YMC with pre-column, particle size 5 μm, filled with octylsilyl silica gel for chromatography P. During the work acetonitrile and trifluoroacetic acid of HPLC class (Sigma-AldrichGmbH, Switzerland) were used, other chemicals and solvents were of analytical grade. In the study an analytical ware class A were used that meet the requirements of SPhU.Results. The following optimal conditions of chromatographic distribution are established: column C18 (250*4.6 mm); the speed of the mobile phase 1 ml / min; column thermostat temperature 35 °С; injection volume 10 μl; mobile phase A - 0.1 % trifluoroacetic acid; mobile phase B - acetonitrile P; the detection wavelength is 270 nm, the retention time of the test compound is 7.22 minutes. The performance of the column was determined for its main indicators, such as the number of theoretical plates (more than 25410) and the coefficient of symmetry (about 1.00). The technique was tested for the influence of various factors, such as flow rate, mobile phase composition and column thermostat temperature. It was established that the influence of these factors is insignificant and does not affect the results obtained by this method. The method was validated in accordance with the recommendations of SPhU on the parameters of specificity, linearity, correctness, precision, robustness (stability).Conclusions. For the first time, a high-precision and reproducible method for quantitative determination of the main substance in the substance Epimidin with anticonvulsant activity by high-performance liquid chromatography was developed. Conditions for chromatographic analysis (HPLC) were standardized. The requirements for the test “System suitability test criteria for chromatographic methods” are set. Statistical processing of the experimental results shows that the relative uncertainty of the average result is within acceptable limits. The correctness of the method was confirmed by validation studies. The developed technique will be used for pharmaceutical development and standardization of dosage form, Цель. Разработка оптимальной, высокоточного и воспроизводительной методики количественного определения основного вещества в субстанции Епимидину - 1-(4-метоксифенил)-5-[2-[4-(4-метоксифенил)пиперазин-1-ил]-2-оксоэтил]пиразоло[3,4-d]пиримидин-4-она методом высокоэффективной жидкостной хроматографии.Материалы и методы. Высокоэффективную жидкостную хроматографию (ВЭЖХ) проведено используя систему ShimadzuNexeraX2 LC-30AD (Shimadzu, Япония), оснащенную диодным матричным детектором SPD-M20A (DAD). Колонка ACE C18, размер 250 х 4,6 мм, фирмы YMC с предколонкой, с размером частиц 5 мкм, заполненную силикагелем октилсилильним для хроматографии Р. В работе использовали ацетонитрил и трифторуксусную кислоту класса ВЭРХ (Sigma-AldrichGmbH, Швейцария), другие химические вещества и растворители были аналитического сорта. В исследовании использовали аналитический посуду класса A, которая соответствует требованиям ГФУ.Результаты. Установлены следующие оптимальные условия хроматографического разделения: колонка C18 (250*4,6 мм); скорость подвижной фазы 1 мл/мин; температура термостата колонки 35 °С; объем инжекции 10 мкл; подвижная фаза А - 0,1 % трифторуксусная кислота, подвижная фаза Б - ацетонитрил Р; длина волны детектирования 270 нм, время удерживания исследуемого соединения составляет 7.22 мин. Производительность колонки была определена для ее основных показателей, таких как количество теоретических тарелок (более 25410) и коэффициент симметрии (около 1,00). Методика была апробирована на воздействие различных факторов, таких как, скорость потока, состав подвижной фазы и температура термостата колонки. Установлено, что влияние этих факторов является незначительным и не оказывает влияния на результаты, полученные по этой методике. Методика была валидирована согласно рекомендациям ГФУ по параметрам специфичность, линейность, правильность, прецизионность, робаснисть (стабильность).Выводы. Впервые разработана высокоточная и воспроизводимая методика количественного определения основного вещества в субстанции Епимидину с противосудорожной активностью методом высокоэффективной жидкостной хроматографии. Стандартизировано условия проведения хроматографического анализа (ВЭЖХ). Установлены требования к тесту «Проверка пригодности хроматографической системы». Статистическая обработка результатов эксперимента показывает, что относительная неопределенность среднего результата находится в допустимых пределах. Корректность методики подтверждена валидационными исследованиями. Разработанная методика будет использована для фармацевтической разработки и стандартизации лекарственной формы, Мета. Розробка оптимальної, високоточної та відтворюваної методики кількісного визначення основної речовини в субстанції Епімідину - 1-(4-methoxyphenyl)-5-[2-[4-(4-methoxyphenyl)piperazin-1-yl]-2-oxo-ethyl]pyrazolo[3,4-d]pyrimidin-4-one методом високоефективної рідинної хроматографії.Матеріали і методи. Високоефективну рідинну хроматографію (ВЕРХ) проведено використовуючи систему ShimadzuNexeraX2 LC-30AD (Shimadzu, Японія), оснащений діодним матричним детектором SPD-M20A (DAD). Колонка ACE C18, розміром 250 х 4,6 мм, фірми YMC з передколонкою, з розміром часток 5 мкм, заповнену силікагелем октилсилільним для хроматографії Р. В роботі використовувалися ацетонітрил та трифтороцтову кислоту класу HPLC (Sigma-AldrichGmbH, Швейцарія), інші хімічні речовини та розчинники були аналітичного сорту. У дослідженні використовували аналітичний посуд класу A, що відповідаює вимогам ДФУ.Результати. Встановлено наступні оптимальні умови хроматографічного розподілу: колонка C18 (250*4,6 мм); швидкість рухомої фази 1 мл /хв; температура термостату колонки 35 °С; об’єм інжекції 10 мкл; рухома фаза А - 0,1 % трифтороцтова кислота; рухома фаза Б - ацетонітрил Р; довжина хвилі детектування 270 нм, час утримування досліджуваної сполуки становить 7.22 хв. Продуктивність колонки була визначена для її основних показників, таких як кількість теоретичних тарілок (більше 25410) і коефіцієнт симетрії (близько 1,00). Методику було апробовано на вплив різних факторів, таких як, швидкість потоку, склад рухомої фази та температура термостату колонки. Встановлено, що вплив цих факторів є незначущим та не впливає на результати, отримані за цією методикою. Методика була валідована згідно з рекомендаціями ДФУ за параметрами специфічністі, лінійністі, правильністі, прецизійністі, робасністі (стабільність).Висновки. Вперше розроблена високоточна та відтворювана методика кількісного визначення основної речовини у субстанції Епімідину з протисудомною активністю методом високоефективної рідинної хроматографії. Стандартизовано умови проведення хроматографічного аналізу (ВЕРХ). Встановлено вимоги до тесту «Перевірка придатності хроматографічної системи». Статистична обробка результатів експерименту свідчить, що відносна невизначеність середнього результату знаходиться у допустимих межах. Коректність методики підтверджено валідаційними дослідженнями. Розроблена методика буде використана для фармацевтичної розробки та стандартизації лікарської форми

The 18 kDa translocator protein (TSPO) is a target for the development of imaging agents to detect neuroinflammation. The clinical utility of second-generation TSPO ligands has been hindered by the presence of a polymorphism, rs6971, which causes a non-conservative substitution of alanine for threonine at amino acid residue 147 (TSPO A147T). Given the complex nature of TSPO binding, and the lack of non-discriminating high-affinity ligands at both wild type and A147T forms of TSPO, a series of novel TSPO ligands containing various heterocyclic scaffolds was developed to explore the pharmacophoric drivers of affinity loss at TSPO A147T. In general, N-benzyl-N-methyl-substituted amide ligands showed increased affinity at TSPO A147T, and a pyrazolopyrimidine acetamide containing this motif displayed low nanomolar binding affinities to both TSPO forms.

Building upon a wealth of published knowledge surrounding the pyrazolopyrimidine scaffold, we designed a small library around the most selective small molecule CK2 inhibitors reported. Through extensive evaluation of this library we identified inhibitor 24 (SGC-CK2-1) as a potent, selective, and cell-active CK2 chemical probe. Remarkably, despite years of research pointing to CK2 as a key driver in cancer, our probe did not elicit an antiproliferative phenotype in cell lines tested. While many publications have attempted tocharacterize CK2 function, CK2 biology is complex and a high-quality chemical tool like SGC-CK2-1 will aid in connecting CK2 functions to phenotypes.

In this study, new pyrazolopyrimidine derivatives were designed and evaluated for anticancer activity. PIM-1 inhibitiory activity were measured for the most potent compounds. Molecular docking study and molecular dynamics were also done. Thus, the novel derivatives of pyrazolo[1,5-a]pyrimidine have been synthesized and characterized using different spectroscopic techniques. HMBC and NOESY experiments were used to confirm regiospecific structure of pyrimidine ring. The newly synthesized derivatives were evaluated for their antitumor activities against HCT-116 and MCF-7 cell lines. These derivatives showed clear in vitro antitumor activities. Compound 5h showed the highest bioactivity (IC50 = 1.51 µM) against HCT-116 cell line. While, compound 6c was the most potent derivative, its IC50 was 7.68 µM against MCF-7 cell line. Compounds 5c, 5g, 5h, 6a and 6c showed PIM-1 inhibitory activity with IC50 of 1.26, 0.95, 0.60, 1.82, 0.67, respectively µM that could be correlated with their cytotoxic effect. Molecular docking study was done to predict the mode of binding of the target compounds inside PIM-1 active site. The molecular dynamic simulation was conducted in order to evaluate stability of binding of the tested compounds.

Autophagy is postulated to be required by cancer cells to survive periods of metabolic and/or hypoxic stress. ATG7 is the E1 enzyme that is required for activation of Ubl conjugation pathways involved in autophagosome formation. This article describes the design and optimization of pyrazolopyrimidine sulfamate compounds as potent and selective inhibitors of ATG7. Cellular levels of the autophagy markers, LC3B and NBR1, are regulated following treatment with these compounds.

[Image: see text] This report discloses the discovery and characterization of imidazo[1,2-a]pyrazines and pyrazolo[1,5-c]pyrimidines as selective negative modulators of α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptors (AMPARs) associated with transmembrane AMPAR regulatory protein γ-8. Imidazopyrazine 5 was initially identified as a promising γ-8 selective high-throughput screening hit, and subsequent structure–activity relationship optimization yielded subnanomolar, brain penetrant leads. Replacement of the imidazopyrazine core with an isosteric pyrazolopyrimidine scaffold improved microsomal stability and efflux liabilities to provide 26, JNJ-61432059. Following oral administration, 26 exhibited time- and dose-dependent AMPAR/γ-8 receptor occupancy in mouse hippocampus, which resulted in robust seizure protection in corneal kindling and pentylenetetrazole (PTZ) anticonvulsant models.

Bumped kinase inhibitors (BKIs) have been shown to be potent inhibitors of Toxoplasma gondii calcium-dependent protein kinase 1. Pyrazolopyrimidine and 5-aminopyrazole-4-carboxamide scaffold-based BKIs are effective in acute and chronic experimental models of toxoplasmosis. Through further exploration of these 2 scaffolds and a new pyrrolopyrimidine scaffold, additional compounds have been identified that are extremely effective against acute experimental toxoplasmosis. The in vivo efficacy of these BKIs demonstrates that the cyclopropyloxynaphthyl, cyclopropyloxyquinoline, and 2-ethoxyquinolin-6-yl substituents are associated with efficacy across scaffolds. In addition, a broad range of plasma concentrations after oral dosing resulted from small structural changes to the BKIs. These select BKIs include anti-Toxoplasma compounds that are effective against acute experimental toxoplasmosis and are not toxic in human cell assays, nor to mice when administered for therapy. The BKIs described here are promising late leads for improving anti-Toxoplasma therapy.

Translocator protein (TSPO) is an interesting biological target because TSPO overexpression is associated with microglial activation caused by neuronal damage or neuroinflammation, and these activated microglia are involved in several central nervous system diseases. Herein, novel fluorinated ligands (14a–c and 16a–c) based on a 2-phenylpyrazolo[1,5-a]pyrimidin-3-yl acetamide scaffold were synthesized, and in vitro characterization of each of the novel ligands was performed to elucidate structure activity relationships. All of the newly synthesized ligands displayed nano-molar affinity for TSPO. Particularly, an in vitro affinity study suggests that 2-(5,7-diethyl-2-(4-(3-fluoro-2-methylpropoxy)phenyl)pyrazolo[1,5-a]pyrimidin-3-yl)-N,N-diethylacetamide (14a), which exhibited high nano-molar affinity for TSPO and proper lipophilicity, was suitable for in vivo brain studies. Thus, radiosynthesis from tosylate precursor 13a using fluorine-18 was performed, and [18F]14a was obtained in a 31% radiochemical yield (decay-corrected). Dynamic positron emission tomography (PET) imaging studies were performed in a lipopolysaccharide (LPS)-induced neuroinflammation rat model using [18F]14a to identify the location of inflammation in the brain with a high target-to-background signal ratio. In addition, we validated that the locations of inflammatory lesions found by PET imaging were consistent with the locations observed by histological examination of dissected brains using antibodies. These results suggest that [18F]14a is a novel promising PET imaging agent for diagnosing neuroinflammation, and it may also prove to be applicable for diagnosing other diseases, including cancers associated with altered TSPO expression, using PET techniques.

Nine 1-phenyl-1H-pyrazolo[3,4-d]pyrimidine derivatives with different substituents in the 4-position of the phenyl group and benzenesulfonamide moiety were synthesized and evaluated against Plasmodium falciparum. Six compounds exhibited activity in vitro against the chloroquine-resistant clone W2 with IC50 values ranging from 5.13 to 12.22 µM. The most active derivative with substituents R1 = F / R2 = CH3 exhibited an IC50 value of 5.13 µM and an IS value of 62.90, which was higher than that of the control drug sulfadoxine. For this reason, it is possible to conclude that the 1H-pyrazolo[3,4-d]pyrimidine system is promising as a prototype for further studies of antimalarial candidates.

Amira EM Abdallah, Galal H Elgemeie Department of Chemistry, Faculty of Science, Helwan University, Helwan, Cairo, Egypt Background: Over the years, pyrazolopyrimidine derivatives have been recognized as having antimicrobial activities. Recently, we reported different synthetic methods to prepare pyrazolopyrimidine derivatives as anticancer and antimicrobial agents. The studies showed that our previously reported 5-aminopyrazoles 2 act as a building block for the preparation of a variety of interesting pyrazolopyrimidines as purine analogs. Purpose: The objective of this study was to describe the direct new method for preparation of novel pyrazolo[1,5-a]pyrimidine derivatives and their corresponding cycloalkane ring-fused derivatives. Also, the new compounds were tested in vitro for their antibacterial and antifungal activity properties. Methods: Pyrazolo[1,5-a]pyrimidine derivatives were prepared by the reaction of our previously reported 5-aminopyrazoles 2 with suitable sodium salts of (hydroxymethylene) cycloalkanones and sodium salts of unsaturated ketones. Results: The structures of the new compounds were characterized according to their mass spectroscopy, 1H NMR, IR and elemental analyses. Compounds 8b, 10e, 10i, and 10n were the most active compounds against Gram-positive and Gram-negative bacterial species. Compound 10i with two moieties of 4-Br-C6H4 revealed increased reactivity compared with ampicillin as standard reference. Conclusion: About twenty two novel pyrazolo[1,5-a]pyrimidine derivatives and their corresponding cycloalkane ring-fused derivatives were prepared through the reaction of 5-aminopyrazoles 2 with different sodium salts of (hydroxymethylene) cycloalkanones and sodium salts of unsaturated ketones. The antibacterial and antifungal activities of the newly synthesized compounds were evaluated and revealed that compounds 8b, 10e, 10i, and 10n were the most active compounds against Gram-positive and Gram-negative bacterial strains. Keywords: pyrazolo[1,5-a]pyrimidines, 5-aminopyrazoles, 2-(hydroxymethylene)-1-cycloalkanones, 2-formylcycloalkanones, antibacterial, antifungal, docking studies

Ca2+/calmodulin-dependent protein kinase II (CAMKIIδ) belongs to the serine/threonine kinase family, which is involved in a broad range of cellular events in cell survival and proliferation as well as a number of other signal transduction pathways. Thus, it is regarded a promising target for treatment of cancers. In the present paper, a three-dimensional quantitative structure–activity relationship and molecular docking were applied to investigate a series of new CAMKIIδ inhibitors of pyrazolopyrimidine derivatives. The determination coefficient (R2) and leave-one-out cross-validation coefficient (Q2) of CoMSIA model are 0.676 and 0.956, respectively. The predictive ability of this model was evaluated by the external validation using a test set of eight compounds with a predicted determination coefficient $$R^{ 2}_{\text{test}}$$ of 0.80, besides the mean absolute error of the test set was 0.328 log units. Docking results are in concordance with CoMSIA contour maps, gave the information for interactive mode exploration. Based on those satisfactory results, newly designed molecules were predicted with highly potent CAMKIIδ inhibitory activity, additionally, they have showed promising results in the preliminary in silico ADMET evaluations. This study could expand our understanding of pyrazolopyrimidine derivatives as inhibitors of CAMKIIδ and would be of great help in lead optimization for early drug discovery of highly potent CAMKIIδ inhibitors.

Six series of pyrrolo[2,3-d]pyrimidine and pyrazolo[3,4-d]pyrimidine derivatives bearing 1,2,3-triazole moiety were designed and synthesized, and some bio-evaluation was also carried out. As a result, four points can be summarized: Firstly, some of compounds exhibited excellent cytotoxicity activity and selectivity with the IC50 values in single-digit μm level. In particular, the most promising compound 16d showed equal activity to lead compound foretinib against A549, HepG2, and MCF-7 cell lines, with the IC50 values of 4.79 ± 0.82, 2.03 ± 0.39, and 2.90 ± 0.43 μm, respectively. Secondly, the SARs and docking studies indicated that the in vitro antitumor activity of pyrrolo[2,3-d]pyrimidine derivatives bearing 1,2,3-triazole moiety was superior to the pyrazolo[3,4-d]pyrimidine derivatives bearing 1,2,3-triazole moiety. Thirdly, three selected compounds (16d, 18d, and 20d) were further evaluated for inhibitory activity against the c-Met kinase, and the 16d could inhibit the c-Met kinase selectively by experiments of enzyme-based selectivity. What is more, 16d could induce apoptosis of HepG2 cells and inhibitor the cell cycle of HepG2 on G2/M phase by acridine orange staining and cell cycle experiments, respectively.

Selective inhibitors of Cryptosporidium calcium-dependent protein kinase 1 ( CpCDPK1) based on the 1 H-pyrazolo[3,4- d]pyrimidin-4-amine (pyrazolopyrimidine, PP) scaffold are effective in both in vitro and in vivo models of cryptosporidiosis. However, the search for distinct safety and pharmacokinetic (PK) properties has motivated our exploration of alternative scaffolds. Here, we describe a series of 7 H-pyrrolo[2,3- d]pyrimidin-4-amine (pyrrolopyrimidine, PrP)-based analogs of PP CpCDPK1 inhibitors. Most of the PrP-based inhibitors described potently inhibit the CpCDPK1 enzyme, demonstrate no toxicity against mammalian cells, and block proliferation of the C. parvum parasite in the low micromolar range. Interestingly, certain substituents that show reduced CpCDPK1 potency when displayed from a PP scaffold provided notably enhanced efficacy in the context of a PrP scaffold. PK studies on these paired compounds show that some PrP analogs have distinct physiochemical properties compared with their PP counterparts. These results demonstrate that inhibitors based on a PrP scaffold are distinct therapeutic alternatives to previously developed PP inhibitors.

Three-component heterocyclizations of pyruvic acids and their esters with 5-aminopyrazoles and aromatic aldehydes, in addition to the sequential versions of these reactions, under different activating conditions were studied. Under conventional heating, pyrazolopyrimidine derivatives containing a hydroxyl group in the 6-position were formed in both two- and three-component treatments. Whereas the application of an inert atmosphere did not influence the outcome of these reactions, the use of ultrasonic irradiation led to the formation of 7-hydroxy-tetrahydropyrazolopyrimidines in multi-component reactions and 6-hydroxy-dihydropyrazolopyrimidines in the case of a step-by-step approach. The products of the latter treatment were further transformed into heteroaromatized 6-hydroxy-pyrazolopyrimidines by conventional heating.

The mTOR and HDAC dual suppression is meaningful for counteracting drug resistance resulted from kinase mutation and bypass mechanisms. Herein, we communicate our recent discovery of a novel structural series of mTOR/HDAC bi-functional inhibitors featuring the pyrazolopyrimidine core via pharmacophore-merging strategy. More than half of them exerted potent dual-target inhibitory activities. In particular, compound 50 exhibited IC50 values of 0.49 and 0.91 nM against mTOR and HDAC1, respectively, along with remarkably enhanced anti-proliferative activity (IC50 = 1.74 μM) against MV4-11 cell line than mTOR inhibitor MLN-0128 (IC50 = 5.84 μM) and HDAC inhibitor SAHA (IC50 = 8.44 μM). Its intracellular intervention of both mTOR signaling and HDAC was validated by the Western blot analysis. Moreover, as the first disclosed mTOR/HDAC dual inhibitor with selectivity for some specific HDAC subtypes, it has the potential to alleviate the adverse effects resulted from pan-HDAC inhibition. Attributed to its favorable in vitro performance, compound 50 is valuable for further functional investigation as a polypharmacological anti-cancer agent.