First synthesis of 7-amido-[1,2,4]triazolo[1,5-a]pyrimidines using halogen–metal exchange

Eucalyptol: A Bio-Based Solvent for the Synthesis of O,S,N-Heterocycles. Application to Hiyama Coupling, Cyanation, and Multicomponent Reactions

We report here the use of eucalyptol as a bio-based solvent for Hiyama coupling, cyanation, and multicomponent reactions on O,S,N-heterocycles. These heterocycles were chosen as targets or as starting materials given their biological potential; they play an important role in therapeutically active compounds. Once again, eucalyptol proved to be a credible and sustainable alternative to common solvents.

1,2,4-Triazolo[1,5-a]pyrimidines in drug design

The 1,2,4-triazolo[1,5-a]pyrimidine (TP) heterocycle, in spite of its relatively simple structure, has proved to be remarkably versatile as evidenced by its use in many different applications reported over the years in different areas of drug design. For example, as the ring system of TPs is isoelectronic with that of purines, this heterocycle has been proposed as a possible surrogate of the purine ring. However, depending on the choice of substituents, the TP ring has also been described as a potentially viable bio-isostere of the carboxylic acid functional group and of the N-acetyl fragment of ε-N-acetylated lysine. In addition, the metal-chelating properties of the TP ring have also been exploited to generate candidate treatments for cancer and parasitic diseases. In the present review article, we discuss recent applications of the TP scaffold in medicinal chemistry, and provide an overview of its properties and methods of synthesis.

One step synthesis of highly functionalized thiazolo[3,2-b][1,2,4]triazole, triazolo[1,5-a]pyrimidine and triazolo[3,4-b][1,3,4]thiadiazine

An efficient and straight forward methodology for the preparation of novel functionalized thiazolo[3,2-b]triazole, triazolo[1,5-a]pyrimidine and triazolo[3,4-b][1,3,4]thiadiazine.

Synthesis of novel chromene derivatives of expected antitumor activity

Inhibition of tubulin polymerization is one of the important tactics in cancer therapy. Since 4-aryl-4H-chromene derivatives are found to be microtubule-binding agents via interfering with tubulin polymerization so we decide to concentrate our exploration efforts on the combination of this nucleus with 5-, 6-, and/or 7-memebered heterocyclic moieties in a novel series of compounds to explore the effect that might result from this combination. Ten novel compounds were selected for anticancer screening assay against MCF-7 breast cancer cell line in comparison to colchicine as positive control and most of them showed excellent activity.

Synthesis and fungicidal activity of tubulin polymerisation promoters. Part 1: pyrido[2,3-b]pyrazines

BACKGROUND

The excellent fungicidal activity of [1,2,4]triazolo[1,5-a]pyrimidines suggested the search for further analogues with improved properties.

RESULTS

A series of novel trisubstituted pyrido[2,3-b]pyrazines has been designed and prepared as 6,6-biheterocyclic analogues of related 5,6-bicyclic [1,2,4]triazolo[1,5-a]pyrimidines. Their fungicidal activity was evaluated against the plant pathogens Puccinia recondita Rob. ex Desm. f. sp. tritici (Eriks.) CO Johnston (wheat brown rust), Mycosphaerella graminicola (Fuckel) Schroter (Septoria tritici Rob., leaf spot of wheat) and Magnaporthe grisea (Hebert) Barr (Pyricularia oryzae Cav., rice blast). Structure-activity relationship studies revealed the advantage of a fluoro substituent in position 6 and of a secondary amine in position 8.

CONCLUSION

8-Amino-7-aryl-6-halogen-substituted pyrido[2,3-b]pyrazines have been prepared as 6,6-biheterocyclic analogues of similarly substituted triazolopyrimidine fungicides. A concise four-step synthesis route has been worked out to prepare these novel compounds from commercially available starting materials. [(R)-(1,2-Dimethylpropyl)]-[6-fluoro-7-(2,4,6-trifluorophenyl)pyrido[2,3-b]pyrazin-8-yl]amine showed excellent activity against three economically important phytopathogens.