1,2,3 triazole trimethylsilyl azide

In this case, the substitution of the TMS group for hydrogen in HN3 imparts a degree of thermal stability to the otherwise unstable azide and also acts as a blocking agent in allowing the direct synthesis of the triazole. Trimethylsilyl azide can be distilled at atmospheric pressure without decomposition (bp 95°C). Similarly, diazomethane, potentially very explosive, is thermally stable when trimethylsilated, (CH3)3SiCHN2 [18107-18-1]. 

In the presence of copper and palladium catalysts, terminal alkynes 1222 react with trimethylsilyl azide and allyl methyl carbonate to provide 2,4-disubstituted 1,2,3-triazoles 1223 in moderate to good yield. Isomerization of the allyl substituent in the presence of a ruthenium catalyst gives 4-substituted 2-(l-propen-l-yl)-2//-l,2,3-triazoles 1224. 

Deprotection of N-2 by ozonolysis furnishes triazoles 1225 (Scheme 202) <2003JA7786>. Finding that 1,3-dipolar cycloaddition of alkynes 1222 to trimethylsilyl azide, carried out in DMF/MeOH in the presence of Cul as a catalyst, leads directly to products 1225 with much higher yields provides a significant progress to the synthesis of N-unsubstituted 1,2,3-triazoles <2004EJO3789>. 

A simple procedure for the synthesis of 4,5-disubstituted 1,2,3-triazoles 1247 involves stirring a mixture of nitroethene 1245 with trimethylsilyl azide and tetrabutylammonium fluoride at 30 °C for 3h. No solvent is needed. Triazoline 1246, which forms in the first step of the reaction, eliminates nitrous acid, and the trimethylsilyl group is cleaved off by the fluoride anion to afford triazole 1247. Various aryl and heteroaryl substituents R are used providing triazoles 1247 in 70-90% yield (Scheme 207) <2005JOC6526>. 

Addition of trimethylsilyl azide to acetylenes gives the 2.ff-isomers directly, and the 1. -isomers are not detected. A very ready migration of the trimethylsilyl group must take place in those triazoles. Similar rearrangements occur in additions of trialkyltin azides. ... 

Gilardi and co-workers reported a synthesis of 4-(trimethylsilyl)-5-nitro-1,2,3-triazole (136) via a cycloaddition between l-nitro-2-(trimethylsilyl)acetylene (134) and trimethylsilyl azide (135). This may provide a route to 4,5-dinitro-l,2,3-triazole via nitrodesilylation or lead to the synthesis of 4-amino-5-nitro-l,2,3-triazole, an isomer of ANTA. 

The monoadduct from norbornadiene and the bulky trimethylsilyl azide is less stable than the bisadduct and spontaneously yields a 1-silylated triazole that isomerizes to a 2-silyltriazole (Scheme 139).104... 

We reported that the palladium-catalyzed three-component coupling reaction of the activated alkynes 41, allyl methyl carbonate 5b, and trimethylsilyl azide 42 gave the 2-allyl-1,2,3-triazoles 43. The reaction proceeds via the [3 + 2] cycloaddition of tt-allylpalladium azide 44 to the alkynes 41, followed by the formation of (-allyl)(r]5-triazoyl)-palladium 45 (Scheme 16) [51]. However, this method was limited only for activated alkynes. Synthesis of the triazoles 47 from the nonactivated terminal alkynes 46 was achieved by the three-... 

Fully substituted triazoles were synthesized via the four-component coupling reaction of the unactivated silylacetylenes 50, two equivalents of allyl carbonates 5b, and trimethylsilyl azide 42 in the presence of a Pd(0)-Cu(I) bimetallic catalyst (Scheme 18) [54], Various trisubstituted 1,2,3-triazoles were obtained in good yields. The reaction most probably proceeds through the formation of alkynylcopper species 52, which on cross-coupling reaction with the 7r-allylpalladium complex 53 gives the products 51. 

Unlike hydrazoic acid, trimethylsilyl azide is thermally quite stable. Even at 200° it decomposes slowly and without explosive violence. Accordingly it is a very convenient and safe substitute for hydrazoic acid in many reactions. A notable example is the cycloaddition of hydrazoic acid to acetylenes which is a general route to substituted triazoles.4 The reaction of trimethylsilyl azide with acetylenes is also a general reaction from which the 2-trimethyIsilyI-1,2,3-triazoles may be obtained in good yield.5 On hydrolysis these adducts are converted under mild conditions to the parent alkyl 1,2,3-triazoles.5... 

Triazole derivatives could be synthesized from different starting substrates. Various triazoles 155 were synthesized from nonactivated terminal alkynes 152, allyl methyl carbonate 153 and trimethylsilyl azide 154 in a [3 + 2] cycloaddition with the use of the Pd(0)-Cu(I) bimetallic catalyst <03JA7786>. The allyl group of 155 was efficiently deprotected by ruthenium-catalyzed isomerization followed by ozonolysis to give 4-substituted triazoles 156. a-Aminoacetophenones 157 were reacted with hydrazines in acetic acid to give an efficient... 

Furthermore, cycloaddition reactions have been carried out between metal acetylides and azides leading firstly to triazole triazene salts (241). On hydrolysis the corresponding triazole azide (242) is obtained (ssjociosi). The addition of trimethylsilyl azide to alk5oies occurs at higher temperatures, but due to the considerable thermal stability of the azide, good yields of triazoles (243) can be achieved (sommiioi). 

Tetrachlorocyclopropene reacts with trimethylsilyl azide to yield a bicyclic triazole (261) which rearranges to 4,5,6-trichloro-l,2,3-triazine (262) (79CB1529. 81cb1546). 

Trimethylsilyl azide, (CH3)3SiN=N=N. Mol. wt. 115.21, ra.p. 95°. This stable azide can be prepared in 87% yield by reaction of trimethylchlorosilane with sodium azide in THF, filtration from sodium chloride, and distillation. The reagent can be used in place of the explosive hydrazoic acid for the synthesis of 4-phenyl-1,2,3-triazole since the trimethylsilyl group is easily removed by water,... 

Other metal-mediated reactions of azide reagents to terminal alkynes have also been reported. Indium(ll) triflate catalyzed tandem azidation/l,3-dipolar cycloaddition of various (o,(o-dialkoxyalkynes 134 with trimethylsilyl azide yielded fused 1,2,3-triazoles 135 <05TL8639>. A new ruthenium-catalyzed process for the regioselective synthesis of 1,5-disubstituted-1,2,3-triazoles has been developed <05JA15998>. 

A convenient synthesis, which leads toA-hydrogen-l,2,3-triazoles, utilises the stable (and relatively safe) trimethylsilyl azide. Alternatively, by conducting a cycloaddition in the presence of formaldehyde, A-hydroxymethyl-triazoles are formed (mainly the 2-isomer from isomerisation of initially formed 1-hydroxymethyl-triazole) from which AT-unsubstituted heterocycles can be easily obtained using base azidomethanol is formed in situ and is the entity that adds to the alkyne. ... 

It is possible to synthesize 1,2,3-triazoles from acetylenes and hydrazoic acid, but the instability of hydrazoic acid has limited this application. Sodium azide is silylated readily with trimethylchlorosilane to produce trimethylsilyl azide [4648-54-8], (CH3)3SiN3, which reacts with acetylenes to produce... 

For acceptor-substituted alkynes, it is possible to use trimethylsilyl azide as transfer reagent (cyanogen azide does not react). The reaction (2-90) is not regiospecific, but the silylated triazoles 2.225 can be hydrolyzed and deprotonated to the anion 2.226. The latter reacts regiospecifically with cyanogen bromide to form the triazole-carbonitrile 2.227, which is in equilibrium with the a-diazo-A -cy-ano-imine 2.228 (Regitz et al., 1981 b). 

Triazoles are generally prepared by the cycloaddition of an alkyne with an azide, but the hazardous nature of some alkyl azides limits the method in these cases. A convenient synthesis which leads to A-hydrogen 1,2,3-triazoles utilises the stable (and relatively safe) trimethylsilyl azide." For C-unsubstituted 1,2,3-triazoles, ethyne itself would be required but it is much more convenient to use, as starting material, vinyl acetate instead of the gaseous ethyne, or in general, an enamine or an enol ether as alkyne equivalents. 

Kamijo S, Jin T, Yamamoto Y (2004) Four-component coupling reactions of silylacetylenes, allylcarbonates, and trimethylsilyl azide catalyzed by a Pd(0)-Cu(I) bimetallic catalyst. Fully substitued triazole synthesis from seemingly internal alkynes. Tetrahedron Lett 45 689-691... 

Perfluoropropene and perfluorobutene-2 react with benzyl azide at 150 °C to give the [3+2] cycloadducts in 85% and 65% yields, respectively. Trimethylvinylsilane also undergoes the [3+2] cycloaddition reaction with 4-nitrophenyl- and 4-cyanophenyl azide to give the triazolines in high yields. Also, ]V-alkylmaleimides react with trimethylsilyl azide to give the corresponding [3+2] cycloadduct . The reaction of maleimide A -proponic acid and a heterocyclic azide is accelerated by molecular recognition . The palladium-catalyzed reaction of alkenyl bromides with sodium azide in dioxane at 90 °C or DMSO at 110 °C affords the 4-substituted 1,2,3-triazoles 55. ... 

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