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Background: A set of 2,5-diaryl-1,2,4-triazol-3-ones was synthesized in two steps and evaluated as regards their activity in some relevant biological targets related to cancer. Objective: This study is focused on the synthesis and the biological evaluation of 2,5-diaryl-1,2,4-triazol-3-ones. In this sense, the effect of the synthetic triazolones on the proliferation of HT-29 and A549 cancer cells and on HEK non-cancer cells has been measured. In addition, the effects of triazolones on the expression of hTERT, c-Myc and PD-L1 genes and on the production of c-Myc and PD-L1 proteins have also been evaluated. Method: A set of 2,5-diaryl-1,2,4-triazol-3-ones was synthesized in two steps. Firstly, N-(aminocarbonyl)-3-methoxybenzamide was prepared by coupling 3-methoxybenzoic acid and cyanamide followed by aqueous HCl hydrolysis. Then, the 2,5-diaryl-1,2,4-triazol-3-ones were obtained upon reaction of N-(aminocarbonyl)-3-methoxybenzamide with arylhydrazines in decaline at 170 degrees C. The ability of the triazolones to inhibit cell proliferation was measured against two human carcinoma cell lines (colorectal HT-29 and lung A549), and one non-tumor cell line (HEK-293) by MTT assay. The downregulation of the synthetic triazolones on the expression of the hTERT, c-Myc and PD-L1 genes was measured by an RT-qPCR analysis. Their ability to regulate the expression of the c-Myc and PD-L1 proteins, as well as their direct interaction with c-Myc protein, was determined by the ELISA method. Finally, the direct interaction of triazolones with PD-L1 protein was assessed by the thermal shift assay. Results: Ten 2,5-diaryl-1,2,4-triazol-3-ones were synthesized and characterized by spectroscopic methods. A thorough study by H-1, C-13, N-15 and F-19 NMR spectroscopy showed that all the synthetic compounds exist as 4H-triazolones and not as hydroxytriazoles or 1H-triazolones. Some triazolones showed relatively high activities together with very poor toxicity in non-tumor cell line HEK-293. 2-(2-fluorophenyl)-5-(3-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (4) was particularly active in downregulating c-Myc and PD-L1 gene expression although 2-(4-chloro-2-fluorophenyl)5-downregulatory activities in the three genes studied. Considering protein expression, the most active compounds are 2-(4-fluorophenyl)-5-(3-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (5) and 2-(2,4,6-trifluorophenyl)-5-(3-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (10) (c-Myc expression) and 2-(2,3,5,6-tetrafluorophenyl)-5-(3-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (11) and (8) (PD-Ll expression). Conclusion: Some of the triazolones studied have shown relevant activities in the inhibition of the hTERT, c-Myc and PD-L1 genes, and in the inhibition of c-Myc and PD-L1 protein secretion, the 2-(4-chloro-2-fluorophenyl)-5-(3-methoxyphenyl)-2,4-dihydro-3H-1,2,4-triazol-3-one (8) was found to be a particularly promising lead compound.

Pyrimidines, pyrroles, cycloreversion,CO extrusion, Two possible mechanisms for the transformation of a 1,4-dihydropyrrolo[3,2-b]pyrrole derivative into a tetrasubstituted pyrrole have been studied theoretically and one of them has been found in reasonable accord with the experimental data. This mechanismis part of the very rare example of rearrangement of dihydropyrimidines into pyrroles.

DFT calculations have been carried out on 6,6-dimethyl-7-nitroso-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-ö]pyridine concerning energies, absolute shieldings (GIAO) and molecular graphs (AIM) to determine the molecular structure of the compound (tautomerism and conformation of the nitroso group)., This work has been supported by the Spanish Ministerio de Economía y Competitividad (CTQ2015-63997-C2-2-P) and Comunidad Autónoma de Madrid (S2013/MIT-2841, Fotocarbon). Computer, storage and other resources from the CTI (CSIC) are gratefully acknowledged.

When 5H-dibenz[b,f]azepine is dissolved in pure sulfuric acid it undergoes an oxidative dismutation into two acridine derivatives: 9-formylacridine and 9,9'-ethene-1,2-diyl-bis-acridine., DGI/MCyT of Spain (project BQU-2000-0645), European Community Marie Curie individual Fellowship (program: “Improving Human Research Potential and the Socio-economic Knowledge Base”, contract number: HMPF-CT-2001-01120), Spanish "Ministerio de Educación, Ciencia y Deportes" postdoctoral fellowship (SB2001-0174).

Issue in Honor of Prof. Binne Zwanenburg, When 5H-dibenz[b,f]azepine is dissolved in pure sulfuric acid it undergoes an oxidative dismutation into two acridine derivatives: 9-formylacridine and 9,9'-ethene-1,2-diyl-bis-acridine., Thanks are given to the DGI/MCyT of Spain for financial support (project number BQU-2000- 0645), and to the European Community for a Marie Curie individual Fellowship (program: “Improving Human Research Potential and the Socio-economic Knowledge Base”, contract number: HMPF-CT-2001-01120). CD thanks the Spanish MECD for a grant (SB2001-0174).

In a recent study Alkorta et al. found that B3LYP/6-31G* method failed to reproduce experimentally observed 1H NMR shift by 13.2 ppm. In an attempt to understand the origin of this anormus discrepancy we recalculated magnetic properties of tridehydro(12)annulene and three additional bicyclic dehydroannulenes by variety of density functional methods and CASSCF approach.

The 13C NMR spectra of the bromide of the protonated iminophosphorane-substituted sponge 7 were recorded at different fields. Together with the use of 13C satellites of the 31P NMR spectrum, these experiments allow determination of a reasonable set of chemical shifts and coupling constants. The most interesting are a 4hJPP = 1.6 Hz, determined directly from the 31P NMR spectrum, which probably involves the hydrogen bond, and a 2Δ31P(13C) isotope shift of 9 ppb.

The basicity of simple 4,5-dihydropyrazoles (Δ2-pyrazolines) was previously discussed on the basis of protonation at position 1 in the case of 1-unsubstituted, 1-methyl and 1-phenyl derivatives. The pKa of 15 4,5-dihydropyrazoles substituted at position 1 by p-nitrophenyl, 2,4-dinitrophenyl and 2,4,6-trinitrophenyl groups have now been determined. After examining some linear free energy relationships, to discuss these pKa values further, DFT theoretical calculations, including temperature effects, were carried out on the parent compounds (no C-substituents) for the 1-unsubstituted, 1-methyl, 1-phenyl, 1-p-nitrophenyl and 1-(2′,4′,6′)trinitrophenyl series. These calculations predict an inversion of N-1 and N-2 basicity between 1-phenyl and 1-p-nitrophenyl-4,5-dihydropyrazoles. Since there were no experimental data for the protonation of 4,5-dihydropyrazoles in the gas phase, chemical ionization mass spectrometry was used to try to determine the structure of protonated 1-methyl- and 1,3-dimethyl-5-phenyl-4,5-dihydropyrazoles (3 and 7, respectively). In both cases, it appears that these pyrazoles are protonated on N1, but the production of another isomeric species cannot be completely ruled out for 7H+. Copyright © 2000 John Wiley & Sons, Ltd.