Tetra-n-butylammonium azide

A final observation consistent with rate-determining cycli-zation is that the reaction rate is relatively insensitive to added electrolyte. Addition of 0.5 equivalents of tetra-n-butylammonium chloride or tetra-n-butylammonium azide to chloroform solutions of... 

Our first synthesis of a polymer-bound anomeric amine involved a trisaccharide model system (Scheme 2.20).45 Disaccharide 66 was extended in standard fashion to trisaccharide 67 and fully protected to give 68. This latter compound was treated with anthracenesulfonamide and Jt.vy/u-coll )2C104 to form the intermediate 69. Reaction of the iodosulfonamide 69 with tetra-n-butylammonium azide followed by acetylation provided the anomeric azide 70. 

The synthesis of aryloxysulphonyl azides, which can be used as precursors for sulphamates, is improved by the use of tetra-n-butylammonium azide under homogeneous conditions in place of an alkali metal azide [ 1 ]. A stoichiometric amount of the ammonium azide is used and no attempts appear to have been made to conduct the reaction under solid liquid phase-transfer catalytic conditions. 

Aryloxysulphonyl azides are obtained in good yield from the reaction of the sulphonyl chloride with tetra-n-butylammonium azide [11]. 

The Curtius rearrangement of acid chlorides to isocyanates (60-70%) is conveniently conducted under mild conditions using preformed tetra-n-butylammonium azide [4, 5]. 

The uniquely distinguished axial alcohol at C5 was activated by triflation and the resultant triflate was displaced by the action of tetra n-butylammonium azide in benzene at room temperature. Compound 25 was thus available in 86% yield from alcohol 24. Hydrogenolysis ((H24 d(OH)2C) followed by acetylation afforded compound 26 in 96% yield. TTie richly detailed NMR spectrum (490 MHz) of 26 was identical in every respect with that of the L-antipode derived from reaction of NeuSAc, first with acidic methanol and then with benzoyl chloride under the influence of DMAP. The infrared and mass spectra, as well as the chromatographic characteristics of the two materials, were identical. 

Tetra-n-butylammonium azide, (n-C4H9)4NN3. This hygroscopic salt (1) is prepared by reaction of (n-C4H4)4NOH with NaN3 in CH2C12 ... 

Tetra-n-butylammonium azide, 563-564 Tetra-n-butylammonium borohydride,... 

The direct formation of A-substituted phthalimides from phthalic anhydride and alkyl azides, via the intermediate RN=PPh, compound, is catalysed by the presence of tetra-n-butylammonium cyanide [34],... 

The reaction of sodium azide with N-aryl chloroimines, obtained from benzanilides and thionyl chloride, to form 1,5-disubstituted tetrazoles is catalysed by tetra-n-butyl-ammonium bromide (Scheme 5.26, Table 5.40) [18] in variable yields, but generally <85%. 5-Butyl-2,3-diphenyltetrazolium salts have also been used as catalysts [18, 19]. 1,5-Disubstituted tetrazoles are also obtained from a one-pot sequential reaction of carbodimides with sodium azide and an aroyl chloride in the presence of tetra-n-butylammonium chloride [20]. 5-Chlorotetrazoles are obtained from the catalysed reaction of aryldichloroisocyanides with sodium azide (Scheme 5.26) [21],... 

Onium salts, such as tetraethylammonium bromide (TEAB) and tetra-n-butylammonium bromide (TBAB), were also tested as PTCs immobilized on clay. In particular, Montmorillonite KIO modified with TBAB efficiently catalyzed the substitution reaction of a-tosyloxyketones with azide to a-azidoketones, in a biphasic CHCI3/water system (Figure 6.13). ° The transformation is a PTC reaction, where the reagents get transferred from the hquid to the solid phase. The authors dubbed the PTC-modified catalyst system surfactant pillared clay that formed a thin membrane-hke film at the interface of the chloroform in water emulsion, that is, a third liquid phase with a high affinity for the clay. The advantages over traditional nucleophilic substitution conditions were that the product obtained was very pure under these conditions and could be easily recovered without the need for dangerous distillation steps. 

Cyclic a-diazo ketonesDiazo transfer can be conducted under phase-transfer conditions (tetra-n-butylammonium bromide or 18-crown-6) wth this arylsulfonyl azide. Other arylsulfonyl azides (mesityl, tosyl) are unsatisfactory. The method may not offer significant advantages with simple ketones, but is the most satisfactory route to hindered diazo ketones. Isolated yields in five cases were 48-84%. 

Phenyl[2-(trimethylsilyl)phenyl]iodonium triflate (226) has emerged as a superior benzyne precursor i.e., admixture of 226 with tetra-n-butylammonium fluoride (TBAF) enables the generation of benzyne in dichloromethane at room temperature (95JCS(CC)983). When organo azides or -nitrones are available in the reaction medium, high yields of the benzotriazoles 227 or benzisoxazolines 228 are obtained (Scheme 62) (98HC205). 

Acyl chlorides may be replaced with imidazolides, which react with sodium azide to give acyl azides. In the reaction shown in equation (34), 2-trimethylsilylethanol is used for trapping the isocyanate. The resulting 2-trimethylsilylethyl ester is easily cleaved with tetra-n-butylammonium fluoride. 

This relatively safe azide has been prepared from hydrazoic acid and tetra-n-butylammonium hydroxide. It is conveniently prepared in quantitative yield from a mixture of tetra-n-butylammonium hydroxide and sodium azide con-... 

Sodium azide I tetra-n-butylammonium bromide N Subst. phosphoromonoamidates from bromides... 

Hendrickson synthesized allyl triflones using tetrabutylam-monium triflinate. The quaternary ammonium system is more soluble and 20-40 times more reactive than the conventional potassium triflinate. Tetra-n-butylammonlum azide (6) prepared from tetra-/3-butylammonium hydroxide and sodium azide reacts with triflic anhydride in chloroform at —78°C to give a 1 1 mixture of tetrabutylammonium triflinate (7) and tetrabutyl-ammonium triflate (8). Treatment of this mixture with allyl bromide gives the corresponding allyl triflone (5) in almost quantitative yield. The water-soluble triflate coproduct (8) in the reaction mixture does not interfere with the formation of (5), which is readily Isolated (eq 4). 

In addition to above reagent systems, Saito and co-workers disclosed that tetra-n-butylammonium iodide (TBAI) can efficiently catalyze direct azidation of aldehyde C-H bonds with thermally stable azidoiodinane reagent I (Scheme 6.24a) [78]. The transformation proceeds with moderate to good yields under mild... 

Shinomoto Y, Yoshimura A, Shimizu H, Yamazaki M, Zhdankin VV, Saito A (2015) Tetra-n-butylammonium iodide eatalyzed C-H azidation of aldehydes with thermally stable azidobenziodoxolon. Org Lett 17(21) 5212-5215... 

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