7-Amino-3-phenyl-2-methyl-pyrazolopyrimidine derivatives inhibit human rhinovirus replication.

Small molecules that exhibit broad-spectrum enteroviral inhibitory activity by targeting viral replication proteins are highly desired in antiviral drug discovery studies. To discover new human rhinovirus (hRV) inhibitors, we performed a high-throughput screening of 100,000 compounds from the Korea Chemical Bank library. This search led to identification of two phosphatidylinositol-4-kinase IIIß (PI4KIIIß) inhibitors having the pyrazolo-pyrimidine core structure, which display moderate anti-rhinoviral activity along with mild cytotoxicity. The results of a study aimed at optimizing the activity of the hit compounds showed that the pyrazolo-pyrimidine derivative 6f exhibits the highest activity (EC50 = 0.044, 0.066, and 0.083 µM for hRV-B14, hRV-A16, and hRV-A21, respectively) and moderate toxicity (CC50 = 31.38 µM). Furthermore, 6f has broad-spectrum activities against various hRVs, coxsackieviruses and other enteroviruses, such as EV-A71, EV-D68. An assessment of kinase inhibition potencies demonstrated that 6f possesses a high and selective kinase inhibition activity against PI4KIIIß (IC50 value of 0.057 µM) and not against PI4KIIIα (>10 µM). Moreover, 6f exhibits modest hepatic stability (46.9 and 55.3 % remaining after 30 min in mouse and human liver microsomes, respectively). Finally, an in vivo study demonstrated that 6f possesses a desirable pharmacokinetic profile reflected in low systemic clearance (0.48 L∙h-1 kg-1) and modest oral bioavailability (52.4 %). Hence, 6f (KR-26549) appears to be an ideal lead for the development of new antiviral drugs.

Crystal structure determination and analyses of Hirshfeld surface, crystal voids, inter-molecular inter-action energies and energy frameworks of 1-benzyl-4-(methyl-sulfan-yl)-3a,7a-di-hydro-1H-pyrazolo-[3,4-d]pyrimidine.

The pyrazolo-pyrimidine moiety in the title mol-ecule, C13H12N4S, is planar with the methyl-sulfanyl substituent lying essentially in the same plane. The benzyl group is rotated well out of this plane by 73.64 (6)°, giving the mol-ecule an approximate L shape. In the crystal, C-H⋯π(ring) inter-actions and C-H⋯S hydrogen bonds form tubes extending along the a axis. Furthermore, there are π-π inter-actions between parallel phenyl rings with centroid-to-centroid distances of 3.8418 (12) Å. A Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯H (47.0%), H⋯N/N⋯H (17.6%) and H⋯C/C⋯H (17.0%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 76.45 Å3 and 6.39%, showing that there is no large cavity in the crystal packing. Evaluation of the electrostatic, dispersion and total energy frameworks indicate that the cohesion of the crystal structure is dominated by the dispersion energy contributions.

Crystal structure determination, Hirshfeld surface, crystal void, inter-molecular inter-action energy analyses, as well as DFT and energy framework calculations of 2-(4-oxo-4,5-di-hydro-1H-pyra-zolo[3,4-d]pyrimidin-1-yl)acetic acid.

In the title mol-ecule, C7H6N4O3, the bicyclic ring system is planar with the carb-oxy-methyl group inclined by 81.05 (5)° to this plane. In the crystal, corrugated layers parallel to (010) are generated by N-H⋯O, O-H⋯N and C-H⋯O hydrogen-bonding inter-actions. The layers are associated through C-H⋯π(ring) inter-actions. A Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H⋯O/O⋯H (34.8%), H⋯N/N⋯H (19.3%) and H⋯H (18.1%) inter-actions. The volume of the crystal voids and the percentage of free space were calculated to be 176.30 Å3 and 10.94%, showing that there is no large cavity in the crystal packing. Computational methods revealed O-H⋯N, N-H⋯O and C-H⋯O hydrogen-bonding energies of 76.3, 55.2, 32.8 and 19.1 kJ mol-1, respectively. Evaluations of the electrostatic, dispersion and total energy frameworks indicate that the stabilization is dominated via dispersion energy contributions. Moreover, the optimized mol-ecular structure, using density functional theory (DFT) at the B3LYP/6-311G(d,p) level, was compared with the experimentally determined one. The HOMO-LUMO energy gap was determined and the mol-ecular electrostatic potential (MEP) surface was calculated at the B3LYP/6-31G level to predict sites for electrophilic and nucleophilic attacks.

Thio-substituted derivatives of 4-amino-pyrazolo[3,4-d]pyrimidine-6-thiol as antiproliferative agents.

The current study was designed to identify new compounds as potential antiproliferative drug candidates. Synthesis of heteroaromatic bicyclic and monocyclic derivatives as purine bioisosters was employed. Their antiproliferative activity was studied against U937 cancer cells. The most effective compounds were evaluated for their selectivity against cancer cells, the possible mechanism of cell death, and their interference with DNA replication. Among the synthesized compounds, only three (4b, 4j and 4l) demonstrated a value of IC50 less than 20 µM. However, two of them (4b and 4l) were specific against cancer cells, with 4l presenting high selectivity. The presence of substituted pyrazolo[3,4-d]pyrimidine core is as essential for this activity as the presence of substituents at the thiol function in 6-position.

The Pyrazolo[3,4-d]pyrimidine Derivative, SCO-201, Reverses Multidrug Resistance Mediated by ABCG2/BCRP.

ATP-binding cassette (ABC) transporters, such as breast cancer resistance protein (BCRP), are key players in resistance to multiple anti-cancer drugs, leading to cancer treatment failure and cancer-related death. Currently, there are no clinically approved drugs for reversal of cancer drug resistance caused by ABC transporters. This study investigated if a novel drug candidate, SCO-201, could inhibit BCRP and reverse BCRP-mediated drug resistance. We applied in vitro cell viability assays in SN-38 (7-Ethyl-10-hydroxycamptothecin)-resistant colon cancer cells and in non-cancer cells with ectopic expression of BCRP. SCO-201 reversed resistance to SN-38 (active metabolite of irinotecan) in both model systems. Dye efflux assays, bidirectional transport assays, and ATPase assays demonstrated that SCO-201 inhibits BCRP. In silico interaction analyses supported the ATPase assay data and suggest that SCO-201 competes with SN-38 for the BCRP drug-binding site. To analyze for inhibition of other transporters or cytochrome P450 (CYP) enzymes, we performed enzyme and transporter assays by in vitro drug metabolism and pharmacokinetics studies, which demonstrated that SCO-201 selectively inhibited BCRP and neither inhibited nor induced CYPs. We conclude that SCO-201 is a specific, potent, and potentially non-toxic drug candidate for the reversal of BCRP-mediated resistance in cancer cells.

Crystal structure and Hirshfeld surface analysis of 3-(4-meth-oxy-phen-yl)-1-methyl-4-phenyl-1H-pyrazolo-[3,4-d]pyrimidine.

In the title mol-ecule, C19H16N4O, the planar pyrazolo-pyrimidine moiety is inclined to the attached phenyl rings by 35.42 (4) and 54.51 (6)°. In the crystal, adjacent mol-ecules are linked into chains parallel to [110] and [10] by C-H⋯O and C-H⋯N hydrogen bonds. Additional C-H⋯π(ring) inter-actions lead to the formation of the final three-dimensional network structure. The Hirshfeld surface analysis of the title compound suggests that the most significant contributions to the crystal packing are from H⋯H (48.2%), C⋯H/H⋯C (23.9%) and N⋯H/H⋯N (17.4%) contacts.

Synthesis, evaluation and docking of novel pyrazolo pyrimidines as potent p38α MAP kinase inhibitors with improved anti-inflammatory, ulcerogenic and TNF-α inhibitory properties.

A series of nine new N-substituted-4-((1-phenyl-1H-pyrazolo[3,4-d]pyrimidin-4-yl)amino)benzamides (6a-i) derivatives was synthesized. All the compounds were screened in-vitro for BSA anti-denaturation property, antioxidant assay and p38α MAP kinase inhibition. The in vitro anti-inflammatory assay results revealed that the compounds (6f-i) showed better activity than the compounds 6a-e. Compound 6f bearing the 4-chlorophenyl group showed in vitro anti-inflammatory activity (82.35 ±â€¯4.04) comparable to standard drug diclofenac sodium (84.13 ±â€¯1.63) and better p38α MAP kinase inhibitory activity (IC50 = 0.032 ±â€¯1.63 µM) than the prototypic inhibitor SB203580 (IC50 = 0.041 ±â€¯1.75 µM). The selected active compounds (6f-i) were further studied in animal models for anti-inflammatory activity, ulcerogenic liability, lipid peroxidation and TNF-α inhibition potential. Compound 6f showed promising anti-inflammatory potential with a percentage inhibition of 83.73% when compared to the standard, diclofenac sodium (78.05%). Compound 6f was also found to show reduced ulcerogenic liability and lipid peroxidation in comparison to the standard. This compound also potently inhibited the lipopolysaccharide (LPS)-induced TNF-α production in mice model (ID50 = 8.23 mg/kg) in comparison to SB 203580 (ID50 = 26.38 mg/kg). The molecular docking of compounds 6a-i against p38α MAP kinase receptor was also performed to understand ligand receptor interaction. Amongst all synthesized molecules compound 6f displayed highest docking score of -9.824. It showed hydrogen bonding interactions with Asn115 and pi-cation interaction with Lys53.

Crystal structure of 4-allyl-sulfanyl-1H-pyrazolo-[3,4-d]pyrimidine.

In the title compound, C8H8N4S, the pyrazolo-[3,4-d]pyrimidine ring system is essentially planar, with a maximum deviation from the mean plane of 0.025 (3) Å. The allyl group is disordered over two sites in a 0.512 (6):0.488 (6) ratio. In the crystal, mol-ecules are linked by pairs of N-H⋯N hydrogen bonds, forming inversion dimers with an R 2 (2)(8) graph-set motif.