Synthesis of 1,2,3-Triazole Derivatives by Cyclocondensation of Alkyl Azides with Active Methylene Ketones in the System K2CO3/DMSO

Russian Journal of Organic Chemistry - The reaction of β-keto esters or acetylacetone with alkyl azides in the system K2CO3/DMSO proved to be a convenient method of synthesis of tri- and...     

One-potCuAAC synthesis of (1H-1,2,3-triazol-1-yl)methyl-1,3,4/1,2,4-oxadiazoles starting from available chloromethyl-1,3,4/1,2,4-oxadiazoles

The one-pot CuAAC synthesis of (1H-1,2,3-triazol-1-yl)methyl-1,3,4-oxadiazole and (1H-1,2,3-triazol-1-yl)methyl-1,2,4-oxadiazole derivatives via three-component reaction of consequent nucleophilic substitution of chlorine, with azide, and its further “click” reaction, with alkynes, in the presence of CuI was studied. The utility of newly synthesized 2-(azidomethyl)-1,3,4/1,2,4-oxadiazoles and chloromethyl-1,3,4/1,2,4-oxadiazole derivatives was explored, and their limitations were determined. Novel 5-([4-aryl-1H-1,2,3-triazol-1-yl]methyl)-3-(aryl)-1,2,4-oxadiazoles, 2-([4-aryl-1H-1,2,3-triazol-1-yl]methyl)-5-(aryl)-1,3,4-oxadiazoles were obtained in good yields.     

New cascade reaction of azides with malononitrile dimer to polyfunctional [1,2,3]triazolo[4,5-b]pyridine

A new cascade reaction of azides with malononitrile dimer yielding polyfunctional [1,2,3]triazolo[4,5-b]pyridine was found. It was established that during the reaction of aryl azides with malononitrile dimer, under base catalysis, the formed intermediate triazole underwent spontaneous cyclization leading to the pyridine ring annulation. The obtained products have provided a new entry to [1,2,3]triazolo[4,5-b]pyridine.     

Synthesis of isothiocoumarin derivatives

A method was developed for the synthesis of 1-oxo-1H-isothiochromenes from 2-benzofuran-1(3H)-one (phthalide). 3-Bromo-6-chloro- and 3,6-dibromo-2-benzofuran-1(3H)-ones were prepared by the bromination of 6-chloro- and 6-bromo-2-benzofuran-1(3H)-ones and were converted by hydrolysis into 5-chloro- or 5-bromo-2-formylbenzoic acids. The condensation of these acids with rhodanine followed by recyclization gave 7-chloro- and 7-bromo-1-oxo-1H-isothiochromene-3-carboxylic acids.     

Synthesis and transformations of 1-(azidophenyl)-1H-tetrazoles

Diazotization of 1-(aminophenyl)-1H-tetrazoles and subsequent treatment of the diazonium salts with sodium azide gave 1-(azidophenyl)-1H-tetrazoles which were brought into cyclization with ethyl acetoacetate and cyanoacetanilide to obtain 1,2,3-triazole derivatives. Under these conditions, the tetrazole ring may undergo cleavage with formation of cyanamide group.     

One-pot synthesis of alkyl 3-aryl-2-(4-phenyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-1-yl)propanoates

Reaction of 3-aryl-2-bromopropanoic acids esters, products of the Meerwein arylation, with sodium azide afforded alkyl 2-azido-3-arylpropanoates. The latter react with ethyl acetoacetate and phenylacetylene to form 1,2,3-triazole derivatives. A one-pot method for the synthesis of 3-aryl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)-propanoic acid esters via a tricomponent reaction of alkyl 2-bromo-3-arylpropanoates, sodium azide, and phenylacetylene in the presence of CuI was developed.     

Crystal structure of a new π-complex of AgClO4 with 1-allyl-5-(2-pyridyl)-1H-tetrazole of the composition [Ag2(C9H6N5)2](ClO4)2

By the AgClO₄ interaction with 1-allyl-5-(2-Pyridyl)-1H-tetrazolee (1aPyt) in a methanol solution, an [Ag₂(1aPyt)₂](ClO₄)₂ π-complex is obtained, which is studied using single crystal X-ray diffraction.