Cycloaddition of Synthetic Equivalent of Non-stabilized Aminonitrile Ylides: A New Route to Amino-substituted D2-Imidazolines and D3-1,2,4-Triazolines

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

“…1,2,4-Triazolidines are formed via a retro-1,3-dipolar cycloaddition of imidazolidines in the presence of DEAD [6]. Finally, the nonstabilized azomethine ylides generated from the desilylation of N-[(trimethylsilylmethyl]iminium triflates undergo, in the presence of CsF, a 1,3-dipolar cycloaddition reaction and afford 1,2,4-triazolidines and 1,2,4-triazolines [7]. N-substituted amino acids react in a decarboxylative 1,3-dipolar cycloaddition with DEAD to afford 4N-substituted-1,2,4-triazolidines [8].…”

A Novel and Convenient Synthesis of 3-Amino-2H-1,2,4-Triazoles from Isoselenocyanates and Hydrazine Hydrate

“…High-resolution mass spectra (ESI-HRMS) were determined on an Agilent 6210 TOF instrument. 1 H NMR and 13 C NMR spectra were recorded on Varian Mercury Plus-400 spectrometer (400 and 100 MHz), δ in parts per million, J in Hertz, using TMS as internal standard.…”

“…a Confirmed by IR, 1 H and13 C NMR, MS-ESI, HRMS-ESI. b Isolated yield based on isoselenocyanates 1. c Using isoselenocyanates produced from recycled byproducts.…”

“…Although numerous procedures for the synthesis of 1,2,4-triazoles with various substituents have been reported, few studies have described the direct synthesis of 3-N-substituted-1,2,4-triazoles and 5-unsubstituted-1,2,4triazoles. Over the past 50 years, the most widely used methods for the synthesis of 3-amino-2H-1,2,4-triazoles have involved the reaction of hydrazine hydrate with various cyanamides, such as N-cyanoethanimidothioates 12,13 and N-cyanoimidates, [14][15][16] and the reaction of amines with hydrazonitrile derivates, such as N′-cyanobenzohydrazides. 17,18 However, the substrates used in the above methods require cyanides, which are obtained from hypertoxic cyanogen chloride/bromide reacting with amines, imide or hydrazine salts.…”

Enantioselective synthesis of 1,2,4-triazolines catalyzed by a cinchona alkaloid-derived organocatalyst

“…There are adequate reports on the racemic synthesis of 1,2,4-triazolines with a quaternary C-3 carbon bearing a carboxylic functional group, most of which involved a Mitsunobu reaction of a-amino acids, 4 cycloaddition to oxazoles, 5 addition of imidazopyridine to azodicarboxylates, 6 and reactions of azodicarboxylates with N-[(trimethylsilyl) methyl] iminiumtriflates. 7 In 2010, Tepe et al reported a convenient method for the racemic synthesis of such heterocycles through direct addition of azlactones to azodicarboxylates. 8 Jørgensen 9 and Wang 10 recently reported the synthesis of 1,2,4-triazolines via reactions of azodicarboxylate with a-isocyano esters/amides or 2-azidoacrylates, respectively.…”