Alternative Routes to the Click Method for the Synthesis of 1,2,3-Triazoles, an Important Heterocycle in Medicinal Chemistry.

Heterocyclic rings having nitrogen atoms are the molecular fragments most used in drug design by using the tools of medicinal chemistry. The 1,2,4-triazole rings are part of an extensive family of drugs that are in use in the pharmaceutical market. More recently, 1,2,3-triazole rings have begun to arouse the great interest of scientists and therefore, many researches have been developed seeking the synthesis of new substances and their possible biological activities. A number of articles have been published by us and others highlighting the synthetic and biological aspects of 1,2,3-triazoles. The growth of new substances of this class was largely due to the simple and selective synthetic method of 1,2,3- triazole ring developed by Sharpless et al. However, some 1,2,3-triazole cannot be synthesized by this method. This review focuses on other synthetic methods that give access to other variations around the 1,2,3-triazole core. The systematic arrangement in this review explores the possibility of providing practical guidance to alternatives of this heterocycle. It has been divided into sections according to the types of starting materials and reactions.

Carbene Transfer Reactions Catalysed by Dyes of the Metalloporphyrin Group.

Carbene transfer reactions are very important transformations in organic synthesis, allowing the generation of structurally challenging products by catalysed cyclopropanation, cyclopropenation, carbene C-H, N-H, O-H, S-H, and Si-H insertion, and olefination of carbonyl compounds. In particular, chiral and achiral metalloporphyrins have been successfully explored as biomimetic catalysts for these carbene transfer reactions under both homogeneous and heterogeneous conditions. In this work the use of synthetic metalloporphyrins (MPorph, M = Fe, Ru, Os, Co, Rh, Ir, Sn) as homogeneous or heterogeneous catalysts for carbene transfer reactions in the last years is reviewed, almost exclusively focused on the literature since the year 2010, except when reference to older publications was deemed to be crucial.

Synthesis and Biological Evaluation of Coumarins Derivatives as Potential Inhibitors of the Production of Pseudomonas aeruginosa Virulence Factor Pyocyanin.

Antimicrobial Resistance (AMR) is a serious problem for the humans since it threatens the effective prevention and treatment of an ever-increasing range of infections caused by bacteria, parasites, viruses and fungi. One way around this problem is to act on the virulence factors, produced by bacteria, which increase their infection effectiveness. In view of these facts, new coumarin derivatives were synthesized and evaluated for their anti-virulence biological activity towards Pseudomonas aeruginosa. The results suggest that coumarin derivatives with a secondary carbon at C-3 position reduces P. aeruginosa growth whereas compounds with one additional substituent have a significant effect over pyocyanin production (10k EC50 7 ± 2 µM; 10l EC50 42 ± 13 µM). Moreover, 10k reduces P. aeruginosa motility and biofilm formation, what is compatible with a quorum sensing related mechanism of action.

Synthesis and Antifungal Activity of Coumarins Derivatives Against Sporothrix spp.

Sporotrichosis is a serious public health problem in Brazil that affects human patients and domestic animals, mainly cats. Thus, the search for new antifungal agents is required also due to the emergence and to the lack of effective drugs available in the therapeutic arsenal. The aim of this study was to evaluate the in vitro antifungal profile of two synthetic series of coumarin derivatives against Sporothrix schenckii and Sporothrix brasiliensis. The three-components synthetic routes used for the preparation of coumarin derivatives have proved to be quite efficient and compounds 16 and 17 have been prepared in good yields. The inhibitory activity of nineteen synthetic coumarins derivatives 16a-i and 17a-j were evaluated against Sporothrix spp. yeasts and the most potent compounds were 16b and 17i. However, according to concentrations able to inhibit (minimum inhibitory concentrations) and kill (minimum fungicidal concentrations) the cells, 17i was more effective than 16b against Sporothrix spp. Thus, 17i exhibited good antifungal activity against S. brasiliensis and S. schenckii, suggesting that it is an important scaffold for the development of novel antifungal agents.

Synthesis and evaluation of the cytotoxic activity of 1,2-furanonaphthoquinones tethered to 1,2,3-1H-triazoles in myeloid and lymphoid leukemia cell lines.

Leukemia is the most common blood cancer, and its development starts at diverse points, leading to distinct subtypes that respond differently to therapy. This heterogeneity is rarely taken into account in therapies, so it is still essential to look for new specific drugs for leukemia subtypes or even for therapy-resistant cases. Naphthoquinones (NQ) are considered privileged structures in medicinal chemistry due to their plethora of biological activities, including antimicrobial and anticancer effects. Nitrogen-containing heterocycles such as 1,2,3-1H-triazoles have been identified as general scaffolds for generating glycosidase inhibitors. In the present study, the NQ and 1,2,3-1H-triazole cores have been combined to chemically synthesize 18 new 1,2-furanonaphthoquinones tethered to 1,2,3-1H-triazoles (1,2-FNQT). Their cytotoxicities were evaluated against four different leukemia cell lines, including MOLT-4 and CEM (lymphoid cell lines) and K562 and KG1 (myeloid cell lines), as well as normal human peripheral blood mononucleated cells (PBMCs). The new 1,2-FNQT series showed high cytotoxic potential against all leukemia cell lines tested, and some compounds (12o and 12p) showed even better results than the classical therapeutic compounds such as doxorubicin or cisplatin. Others compounds, such as 12b, are promising because of their high selectivity against lymphoblastic leukemia and their low activity against normal hematopoietic cells. The cells of lymphoid origin (MOLT and CEM) were generally more sensitive than the myeloid cell lines to this series of compounds, and most of the compounds that showed the highest cytotoxicity were similarly active against both cell lines.

Synthesis, biological activity, and molecular modeling studies of 1H-1,2,3-triazole derivatives of carbohydrates as alpha-glucosidases inhibitors.

A class of drugs in use for treating type II diabetes mellitus (T2D), typified by the pseudotetrasaccharide acarbose, act by inhibiting the alpha-glucosidase activity present in pancreatic secretions and in the brush border of the small intestine. Herein, we report the synthesis of a series of 4-substituted 1,2,3-triazoles conjugated with sugars, including D-xylose, D-galactose, D-allose, and D-ribose. Compounds were screened for alpha-glucosidase inhibitory activity using yeast maltase (MAL12) as a model enzyme. Methyl-2,3-O-isopropylidene-beta-D-ribofuranosides, such as the 4-(1-cyclohexenyl)-1,2,3-triazole derivative, were among the most active compounds, showing up to 25-fold higher inhibitory potency than the complex oligosaccharide acarbose. Docking studies on a MAL12 homology model disclosed a binding mode consistent with a transition-state-mimicking mechanism. Finally, the actual pharmacological potential of this triazole series was demonstrated by the reduction of postprandial blood glucose levels in normal rats. These compounds could represent new chemical scaffolds for developing novel drugs against T2D.