1H-1,2,4-Triazol 3-

Table 7 15N Chemical shifts in ppm for 4,5-dihydro-1H-1,2,3-triazoles 51-61 taken in CDCI3 with nitromethane as external...

Although by no means a preparative route to either 1- or 2-azirines, the elimination of nitrogen (by flash vacuum pyrolysis at 400 °C) from the regioisomeric 4,5-disubstituted 1H-1,2,3-triazoles (376) leads to similarly regioisomeric 1-azirines (377) (73JCS(Pl)550). 

Prepn A soln of 4.20g of 1H-1,2,3-triazole, 13.40g of picryl fluoride, and 100ml of dry DMF, protected from atm moisture, is stirred at room temp for 3 days. This soln Is then poured with stirring into 29 of w. The pptd product is collected by filtration, washed with w, and dried. The product is then dissolved in a minimal amt of acet (ca 400ml), and to this stirred soln is added 1.512 of w, dropwise at first, until crystn is induced, at which time the flow is increased to a slow, steady stream. The pptd product is again collected by filtration, washed with w, and dried to give a I4.6g (90%) yield... 

Three classes of 1,2,3-triazolines can be recognized (Scheme 1). These are identified in Chemical Abstracts since 1972 as dihydro derivatives of 1H-1,2,3-triazoles. Early names are shown in parentheses and are still used in many chemical journals and textbooks, the delta or simple numerals indicating the... 

The resonance structures of the 3-substituted 1,2,3-triazole 1-oxides 456 are discussed in Section 1.1.1. 3-Substituted 1,2,3-triazole 1-oxides 456 are strictly according to IUPAC nomenclature 1-substituted 1H-1,2,3-triazole 3-oxides since when R=H the hydrogen position takes numbering precedence. The alternative, correct name 1-subshtuted 3-oxo-lH-l,2,3-tri-azoles has not been adopted in the literature. In the present review the most commonly used naming is adopted calling structure 456 a 3-sub-stituted 1,2,3-triazole 1-oxide. This naming is accepted by IUPAC, Chem. Abstr. Autonom. 

Heating 4-oxo-477-pyrido[l, 2-u]pyrimidine-3-diazonium tetrafluorobo-rate and its 8-methyl derivative in alcohol at 60-90 °C for 15 min to 5h gave alkyl l-(2-pyridyl)- and 1 -(4-methyl-2-pyridyl)-1H-1,2,3-triazole-4-carboxylates (00H(53)1793). 

Trimethylsilylmethylazide condenses easily with acetylenic dipolarophiles as dimethyl acetylendicarboxylate (DMAD) to give corresponding trimethylsilylmethyl-1H-1,2,3-triazoles.262... 

Second, intramolecular cyclization involving the azido group and the double bond could yield 1,2,3-triazoline derivatives these may be thermally unstable and may undergo nitrogen elimination to afford azirine derivatives. The reaction of perfluoro-2-methylpent-2-ene with NaN3 in a 1 2 acetonitrile-ethanol mixture at — 10°C (2 h) yielded stable 5-ethoxy-5-pentafhioroethyl-4,4-bis(trifluoromethyl)-4,5-dihydro-1H-1,2,3-triazole 9, whose structure was confirmed by X-ray analysis, Fig. 1 (01 JFC(110)21, 97ZOR772). 

Fig-i Simulated conformations of A tris[4-(l-methyl-lfi-l,2,3-triazol-4-yl)phenyl]amine and B tris[4-( 1-methyl-1H-1,2,3-triazol-5-yl)phenyl]amine... 

Most of the important general methods for forming 1H-1,2,3-triazole derivatives involve the thermal 1,3-dipolar cycloaddition of hydrazoic acid or organic azides to suitable dipolarophiles (69CRV345,74AHC(16)33). For example, the cycloaddition of aryl azides to l-alkyl-2,5-dihydropyrroles gives pyrrolo[3,4-rf][l,2,3]triazoIes (equation 34) (80JHC267). 

Keywords 4-aryl- 1H-1,2,3-triazole, [3+2]cycloaddition, 2-aryl-1-nitroethane... 

H-1,2,3-Triazoles, l-alkyl-4,5-dihydro-, 153 1/f-1,2,4-Triazoles, l-farylsulfonyl)- nucleotide condensation with, 218 2H-1,2,3-Triazoles, 2-alkyl- synth., 151-152 2 2-Tribromoethoxycarbonyl (Tbeoc) protected alcohols and amines, 157-158, 163 2,2,2-Trichloroethoxycarbonyl (Tceoc) protected alcohols and amines, 157-158,162-163 2,2 -Trichloroethyl (Tee) protected phosphates, 166-167, 216, 218... 

Synthesis of new antimycobacterial agents based on the 1H-1,2,3-triazoles 13CTM2850. 

CYP121A1 Mycobacterium tuberculosis E.g., 1N40,2IJ7, 3G5H, 4G2G, 4ICT E.g., Fluconazole, cYY, 4,4 -( 1H-1,2,3-triazole-1,5-diyl) diphenol, cYF C-C bond formation of cyclodityrosine (cYY) to form mycocyclosin E.g., [65, 187,414,415, 420]... 

Ichino T, Andrews DH, Rathbone GJ, Misaizu F, Caivi RM, Wren SW, Kato S, Bierbaum VM, Lineberger WC. Ion chemistry of 1H-1,2,3-triazole. J Phys Chem B. 2008 112 545-57. ShumanNS, Friedman JF, Miller TM, Viggiano AA. Electron attachment to 14 halogenated alkenes and alkanes, 300-600 K. J Chem Phys. 2012 137 164306. 

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