4-Phenyl-1,2,4-triazole-3,5-dione as a novel and reusable reagent for the aromatization of 1,4-dihydropyridines under mild conditions

Five‐Membered Heterocycles with Three Heteroatoms: Triazoles

“…For example, 4-phenyl-1,2,4-triazole-3,5-dione (239) was found to be a novel and reusable reagent for the aromatization of 1,4-dihydropyridines under mild conditions [281] and to be an efficient and chemoselective reagent for the oxidation of thiols to their corresponding symmetrical disulfides [282]. N-4-(p-Chloro)phenyl-1,2,4-triazole-3,5-dione 240 has been used as an effective oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines to their corresponding pyrazoles under mild conditions at room temperature [283].…”

Metal-free catalytic oxidation of urazoles under mild and heterogeneous conditions via combination of ammonium nitrate and catalytic amounts of silica sulfuric acid

“…They have been used both as substrates and reagents in various organic transformations such as reaction of allylsilanes with triazolinedione [6], triazolinedione-alkene reaction [7], reaction of a triazolinedione with alkenes [8], reaction of *Corresponding authors. E-mail: arashghch58@yahoo.com; Zolfi@basu.ac.ir triazolinedione with carbon nanotubes [9], oxidation of 1,4-dihydropyridines [10], oxidation of alcohols to aldehydes and ketones [11], and oxidative coupling of thioles [12]. High sensitivity and unusual reactivity of 1,2,4-triazole-3,5-diones make them of interest to organic chemists, though difficult to prepare and purify.…”

α-Amination and the 5-exo-trig cyclization reaction of sulfur-containing Schiff bases with N-phenyltriazolinedione and their anti-lipid peroxidation activity

“…Encouraged by the above results and having an interest in the chemistry and synthetic applications of N-phenyltriazolinedione (NPhTAD) [12], a cis-locked cyclic diazene [13], we decided to test it as a dipolarophile in a dipolar cycloaddition reaction with the above imines of glycine esters. Triazolinediones [14] are very reactive electrophiles that are used in ene [15],DielseAlder [16], aromatization [17], polymer modification [18], and initiation of radical addition [19] reactions, together with their extensive use in the synthesis of polyureas [20]. In addition, the urazole ring of PhTAD in the addition products can be transformed to an azo or amino group [21].…”