Search Results (4)

Using ¹H NMR spectroscopy, we studied the relative mobility of the NO₂ group in 1-alkyl-5-nitro-1,2,4-triazoles in the reaction of nucleophilic heterocyclic substitution by aliphatic oligoethers. The main pathways of the S_N^ipso substitution process and the composition of resultant products from competitive reactions were examined, and the key factors influencing the relative mobility of the nitro group, such as the nitrotriazole substrate constitution, the carbon skeleton length of the O-nucleophilic agent and the process conditions, were discussed. Several independent competitive reactions directed towards the substitution of the nitro group at position C(5) in the alkyltriazole substrate by different types of nucleophiles such as alkoxide-, hydroxide- and triazolonate anions were observed to take place under conditions used. The major reaction yielded oligoethers containing terminal alkyltriazole heterocycles. Secondary reactions occurred to form the corresponding triazolone and N–C triazolyl triazolone structures in the reaction system. Additionally, in excess of the alkaline agent, alkaline hydrolysis was observed to proceed at the final stages of the process involving the O-nucleophile having a longer oligoether backbone in the series studied, leading to the formation of new O-nucleophilic sites. The obtained findings can provide a foundation for devising a method for the modification of a wide range of commercially available aliphatic oligo- or polyethers to prepare functional macromolecules whose terminals carry bioactive 1,2,4-triazole heterocycles located at a desired distance from each other. Full article

The regularities and synthetic potentialities of the alkylation of 4(5)-nitro-1,2,3-triazole in basic media were explored, and new energetic ionic and nitrotriazole-based coordination compounds were synthesized in this study. The reaction had a general nature and ended with the formation of N1-, N2-, and N3-alkylation products, regardless of the conditions and reagent nature (alkyl- or aryl halides, alkyl nitrates, dialkyl sulfates). This reaction offers broad opportunities for expanding the variability of substituents on the nitrotriazole ring in the series of primary and secondary aliphatic, alicyclic, and aromatic substituents, which is undoubtedly crucial for solving the problems related to both high-energy materials development and medicinal chemistry when searching for new efficient bioactive compounds. An efficient methodology for the separation of regioisomeric N-alkyl(aryl)nitrotriazoles has been devised and relies on the difference in their basicity and reactivity during quaternization and complexation reactions. Based on the inaccessible N3-substitution products that exhibit a combination of properties of practical importance, a series of energy-rich ionic systems and coordination compounds were synthesized that are gaining ever-increasing interest for the chemistry of energy-efficient materials, coordination chemistry, and chemistry of ionic liquids. Full article

The alkylation of a series of nitroindazole derivatives with 1,2-dibromoethane afforded the corresponding N-(2-bromoethyl)- and N-vinyl-nitro-1H-indazoles. The Cu(I)-catalysed azide- alkyne 1,3-dipolar cycloaddition was selected to substitute the nitroindazole core with 1,4-disubstituted triazole units after converting one of the N-(2-bromoethyl)nitroindazoles into the corresponding azide. The reactivity in 1,3-dipolar cycloaddition reactions with nitrile imines generated in situ from ethyl hydrazono-α-bromoglyoxylates was studied with nitroindazoles bearing a vinyl unit. The corresponding nitroindazole-pyrazoline derivatives were obtained in good to excellent yields. Full article

A series of novel C15 urushiol derivatives were designed by introducing a pechmann structure and F-, Cl-, and Br-nitro substituents with different electronic properties into its alkyl side chain, as well as a triazolyl functional group in its aromatic oxide. Their chemical structures were determined based on the analysis of the NMR (nuclear magnetic resonance) spectroscopic and mass spectrometric data. The results showed that compound 4 exhibited a strong inhibition of the HepG2 cell proliferation (half maximal inhibitory concentration (IC50): 2.833 μM to human hepatocellular carcinoma (HepG2), and 80.905 μM to human normal hepatocytes (LO2)). Furthermore, it had an excellent synergistic effect with levopimaric acid. The nitrogen atom of the triazole ring formed a hydrogen-bonding interaction with Gly103, Gly154, and Tyr308, which made compound 4 bind to histone deacetylase (HDAC)2 more tightly. One triazole ring and His33 formed a π–π stacking effect; the other, whose branches were deep into the pocket, further enhanced the interaction with HDAC2. Meanwhile, compound 4 involved a hydrophobic interaction with the residues Phe210 and Leu276. The hydrophobic interaction and π–π stacking provided powerful van der Waals forces for the compounds. Full article