The reaction of 1-(N-phenacylidene)amino-1,2,3-triazoles with diphenylnitrilimine

Diphenylnitrilimine reacts with 1-(N-phenacylidene)amino-1,2,3-triazoles 1 to give mainly 1,2,4- and 2H-1,2,3-triazoles 2 and 3 . CNDO/2 calculations were made on the compounds 1 and the cycloaddition was also examined on the basis of the interacting frontier molecular orbitals.     

13C NMR spectra of 1-(N-arylidene)amino-1,2,3-triazoles

The ¹³C nmr spectra of several 1-(N-arylidene)amino-1,2,3-triazoles were determined. The long range influence of substituents on ¹³C resonances of triazole and C = N carbon atoms was examined and a correlation of their chemical shifts with net charge densities (q_{π + σ}) calculated by the CNDO/2 method was made. It was also shown that the dependence of the coupling constants ¹J(CH) for C = N carbon on the substituents is better correlated using electrons in bond values instead of charge densities.     

An improved procedure for the preparation of 1-benzyl-1H-1,2,3-triazoles from benzyl azides

A procedure for the preparation of substituted 1-benzyl-1H-1,2,3-triazoles from benzyl azides under very mild conditions is described. The method provides improved yields and extends the scope of the Dimroth Reaction to other types of active methylene compound to those previously used. Benzyl azides react with active methylene compounds in dimethyl sulphoxide catalysed by potassium carbonate at 35–40° to give 1H-1,2,3-triazoles usually in good yield. Acetonitrile derivatives gave 5-amino-1H-1,2,3-triazoles whereas diethyl malonate gave 5-hydroxy-1H-1,2,3-triazoles. 1H-1,2,3-Triazole-4-carboxylate esters and 1H-1,2,3-triazole-4-ketones were obtained from ethyl acetoacetate and β-diketones respectively. Benzyl methyl ketone reacted to give a 5-methyl-4-phenyl-1H-1,2,3-triazole, but acetone and acetophenone failed to react. Other active methylene compounds which did not react under these reaction conditions included ethyl cyanoacetate, ethyl fluoroacetate and ethyl nitroacetate.     

Identification of 4,5-unsymmetrically substituted l-amino- and 1-(N-arylacetylamino)-1,2,3-triazoles by 13C-NMR

¹³C nmr chemical shifts are used for the structural assignment of isomeric 1-amino-1,2,3-triazoles and 1-(N-arylacetylamino)-1,2,3-triazoles unsymmetrically substituted with phenyl, methyl or hydrogen in the 4,5-positions of the triazole ring. A signal at 11 ± 0.6 ppm indicates a 4-methyl triazole derivative, whereas a signal at 7.9 ± 1 ppm indicates a 5-methyl triazole. A signal at 120 ± 0.5 ppm (C-5) indicates a hydrogen in the 5-position (unsubstituted triazole).     

Oxidation of bis-arylacetylhydrazones of α-dicarbonyl compounds

Oxidation of the title compounds (IV) with lead tetraacetate gives, instead of the expected 1-(α-arylacetyloxyarylethyleneamino)-1,2,3-triazoles, the amides (V), 1-(N-arylacetylamino)-1,2,3-triazoles, as the main products in moderate yields. The reaction mechanism is discussed.     

Functionalisation of 1,2,3-triazole via lithiation of 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazole

The preparation of a number of 5-substituted 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazoles via reaction of 1-[2-(trimethylsilyl)ethoxy]methyl-1H-1,2,3-triazole with n-butyllithium followed by addition of various electrophiles is reported. Removal of the protecting group by action of diluted aqueous hydrochloric acid or by tetrabutylammonium fluoride in tetrahydrofuran leads to the appropriate 4-substituted 1H-1,2,3-triazoles.     

Synthesis of nitro,nitroso, azo,and azido derivatives of (4-R<Superscript>1</Superscript>-5-R<Superscript>2</Superscript>-1,2,3-triazol-1-yl)-1,2,5-oxadiazoles by oxidation and diazotization of the corresponding amines

Nitro-, nitroso-, and azo-1,2,5-oxadiazoles with 4-R¹-5-R²-1,2,3-triazol-1-yl substituents were synthesized by oxidation of amino-(1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (aminotriazolylfurazans). Azido-1,2,5-oxadiazole was prepared by diazotization of amino(triazolyl)furazan followed by treatment of the diazonium salt with sodium azide. Depending on the nature of the substituents and the reagent, triazolylfurazans can undergo destruction to give amino-R-furazans (R = NO₂, N₃, aminofurazanylazo), the amino group being formed from the triazole ring. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1859–1865, August, 2005.     

Synthesis and mass spectra of some 1-aroylamino-5-arylaminomethyl-1,2,3-triazoles

The title compounds 2 are prepared from the reaction of 1-(N, N-diaroyl)amino-5-bromomethyl-1,2,3-triazoles with aromatic amines. The fragmentation pattern upon electron impact at 70 eV of compounds 2 is studied. The molecular ion peak is present in all the spectra examined. Besides the [M-28]⁺⁺, there is also a more abundant [M-29]⁺ peak, corresponding to a N₂H loss of the molecular ion. The ion Ar²NH = CH₂ is the base or the most prominent peak.     

Studies on 1,2,3-triazoles. Part XI. A new entry to the benzopyrano[2,3-D]-1,2,3-triazole system. Cyclization of 1-benzyl-5-chloro-4-(2-hydroxybenzoyl)-1H-1,2,3-triazoles

The acylation of simple arenes such as benzene and alkylated benzenes with N-protected 5-chloro-1H-1,2,3-triazole-4-carboxylic acid chlorides under Friedel-Crafts conditions results in excellent yields of the corresponding ketones. Resorcinol dimethyl ethers undergo similar acylation reactions in somewhat lower yield with concomitant monodemethylation, and these derivatives undergo a facile base mediated cyclization to 9-oxo-3H,9H-benzopyrano[2,3-d]-1,2,3-triazoles.     

A tandem of the Cornforth rearrangements of 4-(1,2,3-triazol-1-yl)iminomethyl-1,2,3-thiadiazole

The method for the synthesis of 5-(2,6-dimethylmorpholino)-1,2,3-thiadiazole-4-carbaldehyde was proposed. Its reaction with sodium 1-amino-4-(N-methyl)carbamoyl-1,2,3-triazol-5-olate proceeds through a tandem of the Cornforth rearrangements. The initially formed azomethine isomerizes into sodium 4"-(2,6-dimethylmorpholino)thiocarbonyl-4-(N-methyl)carbamoyl-1,1"-bis[1,2,3]triazolyl-5-olate, which then rearranges to give sodium 4-{N-[4-(2,6-dimethylmorpholinothiocarbonyl)-1,2,3-triazol-1-yl]carbamoyl}-1-methyl-1,2,3-triazol-5-olate.     

First Synthesis of Some New 1-Aryl-4-ethoxycarbonyl- 5-dimethylaminomethyleneamino-1,2,- 3-triazole Under Vilsmeier Conditions

Abstract

Some new 1 - aryl - 4 - ethoxycarbonyl - 5 - dimethylaminomethyleneamino-1,2,3-triazoles were first prepared from 1-aryl-4-ethoxycarbonyl-5-amino-1,2,3-triazoles and N,N-dimethylformamide in the presence of phosphorus oxychloride under mild condition in excellent yields. Their structures were characterized by IR, ¹H NMR, MS, and elemental analysis, and their inhibiting effects on various bacteria were also screened.     

Identification of 4,5-asymmetrically substituted 1-(N-isoimido)-1,2,3-triazoles by benzene induced shifts in NMR spectra—VII

Proton chemical shifts, as well as solvent shifts induced by benzene, can be used for the structure determination of 4,5-asymmetrically substituted 1-(N-isoimido)-1,2,3-triazoles, derived from the oxidation of α-diketone bisaroylhydrazones. The geometry of the postulated ‘collision complex’ is discussed and an attempt is made to estimate theoretically the induced shifts of some of the protons.     

Synthesis of 2(5H)-Furanone Derivatives with Symmetrical and Unsymmetrical Bis-1,2,3-triazole Structure

The interesting bioactivities of 2(5H)-furanone, 1,2,3-triazole, and amino acid derivatives have promoted their combination into one multifunctional molecule. The symmetrical bis-1,2,3-triazoles and mono-1,2,3-triazoles with one free azide group are synthesized respectively by controlling the molar ratio of reactants, N-[5-alkoxy-2(5H)-furanonyl] amino acid propargyl ester and 1,4-diazidobutane. The unsymmetrical bis-1,2,3-triazoles are afforded by the subsequent reaction of mono-1,2,3-triazoles with other terminal alkynes with good to excellent yields in a short time under the same mild “click” reaction conditions. The 32 new compounds obtained in the reactions are characterized by Fourier transform infrared, ¹H NMR, ¹³C NMR, mass spectrometry, and elemental analysis. Because of the diversity of four or five basic units in molecule, this methodology provides easy access to different chiral 2(5H)-furanone compounds with polyheterocyclic structure, especially with unsymmetrical bis-1,2,3-triazole moiety. Importantly, a simple approach is provided for the synthesis of unsymmetrical bis-1,2,3-triazoles using common diazides.     

A new method of synthesis of substituted 1-(1H-imidazole-4-yl)-1H-1,2,3-triazoles and their fungicidal activity

Based on the deoxygenation reaction of 1-(1-tert-butyl-3-nitroazetidine-3-yl)-1H-1,2,3-triazoles a new method for the synthesis of substituted 1-(1H-imidazole-4-yl)-1H-1,2,3-triazoles has been developed. Fungicidal activity of these compounds has been investigated at a range of phytopathogenic fungi.     

Synthesis of phenylazides and 1-phenyl-1,2,3-triazoles bearing (<Emphasis Type="Italic">E</Emphasis>)-2-halovinyl group

Treatment of (E)-3-(4-azidophenyl)- and (E)-3-(2-azidophenyl)acrylic acid with N-halosuccinimides in the presence of LiOAc afforded high yields of phenylazides containing (E)-2-halovinyl group. The latter were transformed to different phenyl-1,2,3-triazoles bearing (E)-halovinyl group by the CuI-catalyzed reaction of 1,3-dipolar cycloaddition.     

Acidic N-dealkylation in nitrotriazolium salts

New selective synthesis of 1-alkyl-5-nitro-1,2,3-triazoles and 1-alkyl-4-nitro-1,2,3-triazoles has been developed, involving acid N-dealkylation of the relative 4-nitro-1,2,3- and 3-nitro- 5-R-1,2,4-triazolium salts. The assortment of novel 1-alkyl- 4(5)-nitro-1,2,3-triazoles has been thus essentially expanded. Treatment of relative 3-nitro-1,2,4-triazolium salts with HCl or HBr proceeds mostly as S_N^ipso-substitution of the nitro group.     

Heterylation of 3-R1-5-R2-1,2,4-Triazoles with Derivatives of 3,5-Dinitro-1,2,4-Triazole

Heterylation of 3-R¹-5-R²-1'2'4-triazoles (pK _a 3-12) with N-alkyl-, N-alkenyl-, N-alkoxy-carbonyl-, N-oxoalkyl-, N-nitroxyalkyl, N-nitroaminoalkyl-3'5-dinitro-1'2'4-triazoles results insubstitution of a nitro group in 5 position of the dinitro compound yielding 1-R-methyl-3-nitro-5-(3-R¹-5-R²-1,2,4-triazolyl)-1,2,4-triazoles. The side processes: Hydroxide-ion attack on C⁵ and (or) N¹ of the ring both in the substrate and in the target compound afford 1-R-methyl3-nitro-1,2,4-triazol-5-ones, 3,5-dinitro-1,2,4-triazole and NH-acids of N-C-bitriazole series. Optimal reaction media are aprotic dipolar substances, and for compounds prone to heterolysis ethyl acetate-water systems. The azole pK _a is the decisive factor controlling the composition and the ratio of reaction products. The process is promising for azoles with pK _a > 5, and the optimal range of pK _a is 8-10.     

Polyfunctional imidazoles: XIII.<Superscript>1</Superscript> Addition and cyclization reactions of 1-aryl-4-chloro-5-(2-nitroethenyl)-1<Emphasis Type="Italic">H</Emphasis>-imidazoles with sulfur and nitrogen nucleophiles

1-Aryl-4-chloro-5-(2-nitroethenyl)-1H-imidazoles reacted with thiols and aromatic amines via Michael addition to give 5-[(1-arylsulfanyl)-2-nitroethyl)]-4-chloro-1H-imidazoles and N-[1-(1-aryl-4-chloro-1H-imidazol-5-yl)-2-nitroethyl]anilines, respectively. [2 + 3]-Cycloaddition of the title compounds to sodium azide afforded 4-(4-chloro-1H-imidazol-5-yl)-1H-1,2,3-triazoles.     

Reactions of benzotriazoles with diethyl ethoxymethylenemalonate; ethylation and michael addition. Comparison with other esters and N-heterocycles

Benzotriazole and its 5-methyl-and 5-nitro derivatives react with diethyl ethoxymethylenemalonate by ethylation at each of the ring N-atoms and through Michael addition, to give the isomeric esters ethyl (E/Z) 3-[5(6)-R-benzotriazol-1-yl]propenoates. Benzotriazole and its 5-nitro derivative react similarly with ethyl acetoacetate but N-ethyl derivatives are obtained in lower yields. Other 1,2,3-triazoles derivatives and indole were ineffective in this reaction while benzimidazole produced similar results but accompanied with a small amount of a benzimidazoline addition product, whose structure has been determined by crystallo-graphic analysis.     

Glycoside Synthesis with Anomeric 1-N-Glycobiosyl-1,2,3-triazoles1

Abstract

1,3-Dipolar cycloaddition of the acetylated 1,2-trans- and 1,2-cis-cellobiosyl, -lactosyl, -maltosyl, and -melibiosyl azides with various acetylenedicarboxylic acid esters gave the corresponding 1-N-glycobiosyl-1,2,3-triazoles (1a,b,c-8a,b,c) which have been used as glycosyl donors for the synthesis of oligosaccharides (15-17) and an anthracycline type antibiotic (18).