An Efficient Mixed-Ligand Pd Catalytic System to Promote CN Coupling for the Synthesis of N-Arylaminotriazole Nucleosides

Selective Buchwald–Hartwig arylation of C-amino-1,2,4-triazoles and other coordinating aminoheterocycles enabled by bulky NHC ligands and TPEDO activator

A facile method for selective N-(hetero)arylation of coordinating 3(5)-amino-1,2,4-triazoles under Pd/NHC catalysis using TPEDO as a new efficient Pd(ii) to Pd(0) reductant has been developed.

5-Substituted 1,2,4-Triazole-3-Carboxylates and 5-Substituted Ribavirin Analogs Synthesis

Ribavirin analogs substituted at position 5 of the heterocyclic base are interesting for their biological activity. This protocol describes a synthetic route to several such ribavirin analogs with a wide range of substituents.© 2021 Wiley Periodicals LLC. Basic Protocol 1: Synthesis and purification of 5-substituted ethyl 1,2,4-triazole-3-carboxylates - synthetic precursors of nucleobases Basic Protocol 2: Synthesis and purification of protected 1,2,4-triazole nucleoside analogs Basic Protocol 3: Synthesis and purification of 5-substituted ribavirin analogs.

Evidence for “cocktail”-type catalysis in Buchwald–Hartwig reaction. A mechanistic study

The mechanism of the C–N cross-coupling reaction, catalyzed by Pd/NHC, was evaluated at the molecular and nanoscale levels. The first evidence for the involvement of a “cocktail”-type system in the Buchwald–Hartwig reaction is provided.

Nucleoside Analogs with Fleximer Nucleobase

This review article is devoted to the so-called fleximer nucleoside analogs, containing two or more planar moieties in the heterocyclic base, connected by a bond that permits rotation. Such analogs have been proposed as molecular probes for detecting enzyme–substrate interactions and studying the transcription and translation of nucleic acids, but subsequently have attracted the interest of researchers by their antiviral and antitumor activity. The methods used in the synthesis of such compounds, along with their structural features and also biological activity are considered in this review.

Chemical ribosylation of 5-substituted 1,2,4-triazole-3-carboxylates

The chemical ribosylation pathways of 5-substituted-1,2,4-triazole-3-carboxylates are discussed. For the products of the chemical synthesis of the 3(5)-alkyl- or 3(5)-aryl-substituted ribavirin analogues the anomer configuration and isomer composition were determined.

E2F signature is predictive for the pancreatic adenocarcinoma clinical outcome and sensitivity to E2F inhibitors, but not for the response to cytotoxic-based treatments

The main goal of this study was to find out strategies of clinical relevance to classify patients with a pancreatic ductal adenocarcinoma (PDAC) for individualized treatments. In the present study a set of 55 patient-derived xenografts (PDX) were obtained and their transcriptome were analyzed by using an Affymetrix approach. A supervised bioinformatics-based analysis let us to classify these PDX in two main groups named E2F-highly dependent and E2F-lowly dependent. Afterwards their characterization by using a Kaplan-Meier analysis demonstrated that E2F high patients survived significantly less than E2F low patients (9.5 months vs. 16.8 months; p = 0.0066). Then we tried to establish if E2F transcriptional target levels were associated to the response to cytotoxic treatments by comparing the IC50 values of E2F high and E2F low cells after gemcitabine, 5-fluorouracil, oxaliplatin, docetaxel or irinotecan treatment, and no association was found. Then we identified an E2F inhibitor compound, named ly101-4B, and we observed that E2F-higly dependent cells were more sensitive to its treatment (IC50 of 19.4 ± 1.8 µM vs. 44.1 ± 4.4 µM; p = 0.0061). In conclusion, in this work we describe an E2F target expression-based classification that could be predictive for patient outcome, but more important, for the sensitivity of tumors to the E2F inhibitors as a treatment. Finally, we can assume that phenotypic characterization, essentially by an RNA expression analysis of the PDAC, can help to predict their clinical outcome and their response to some treatments when are rationally selected.

Copper-Catalyzed Inter- and Intramolecular C-N Bond Formation: Synthesis of Benzimidazole-Fused Heterocycles

A Cu (II)-catalyzed, inter/intramolecular C-N bond formation for the synthesis of various benzimidazole-fused heterocycles in a concise manner has been reported. The robustness of this reaction is demonstrated by the synthesis of a series of benzimidazole-fused heteroaromatics (e.g., pyrido[1,2-a] benzimidazole, benzimidazo[1,2-a]quinolines, benzimidazo [1,2-a]pyrazine, benzo[4,5] imidazo[2,1-b]thiazoles) directly from 2-aminoheteroarenens and 2-iodoarylboronic acids in one-pot. The novel cascade protocol for C-N bond formation operates via unique combination of Chan-Lam type coupling followed by Ullmann-type reaction.

Efficient and selective azidation of per-O-acetylated sugars using ultrasound activation: application to the one-pot synthesis of 1,2,3-triazole glycosides

A new protocol was developed for the selective transformation of acetyl-sugars to triazolyl nucleosides using in situ generated SO₂(N₃)₂, iron/copper cocatalysis and ultrasound activation.

Microwave promoted C–O coupling for synthesizing O-aryloxytriazole nucleoside analogues

A convenient and effective microwave-promoted synthesis of O-aryloxytriazole nucleosides was established, leading to an interesting candidate with anticancer activity.

C-N bond forming cross-coupling reactions: an overview

Nitrogen containing compounds are of great importance because of their interesting and diverse biological activities. The construction of the C-N bond is of significant importance as it opens avenues for the introduction of nitrogen in organic molecules. Despite significant advancements in this field, the construction of the C-N bond is still a major challenge for organic chemists, due to the involvement of harsh reaction conditions or the use of expensive catalysts in many cases. Thus, it is a challenge to develop alternative, milder and cheaper methodologies for the construction of C-N bonds. Herein, we have selected some prime literature reports that may serve this purpose.