Tert-Butyl nitrite

Doyle and Bryker (1979) reported high yields of arenediazonium tetrafluoroborates when aromatic amines were reacted with tert-butyl nitrite and trifluoroboro etherate in CH2C12. It is likely that nitrosyl fluoride is formed as nitrosating reagent by fluoride-alkoxy exchange. 

The Pd°-catalyzed arylations using arenediazonium tetrafluoroborates are limited to those diazonium salts that can be manipulated at room temperature. The reaction can, if necessary, be performed at temperatures up to 50 °C by using a mixture of an arylamine and tert-butyl nitrite in chloroacetic acid or in a mixture of chloroacetic and acetic acid (Kikukawa et al., 1981a). Styrene reacted with fourteen arylamines in the presence of 5 mol-% Pd(dba)2 to give the corresponding substituted stilbenes in yields of 46-97%. It is important for good yields to carry out these reactions in an acidic system. Without acid the yield was low (11%), and diazo tars were also formed. 

With regard to the mechanism of these Pd°-catalyzed reactions, little is known in addition to what is shown in Scheme 10-62. In our opinion, the much higher yields with diazonium tetrafluoroborates compared with the chlorides and bromides, and the low yields and diazo tar formation in the one-pot method using arylamines and tert-butyl nitrites (Kikukawa et al., 1981 a) indicate a heterolytic mechanism for reactions under optimal conditions. The arylpalladium compound is probably a tetra-fluoroborate salt of the cation Ar-Pd+, which dissociates into Ar+ +Pd° before or after addition to the alkene. An aryldiazenido complex of Pd(PPh3)3 (10.25) was obtained together with its dediazoniation product, the corresponding arylpalladium complex 10.26, in the reaction of Scheme 10-64 by Yamashita et al. (1980). Aryldiazenido complexes with compounds of transition metals other than Pd are discussed in the context of metal complexes with diazo compounds (Zollinger, 1995, Sec. 10.1). 

Unsymmetrical 3,4-dihalo-l,2,5-thiadiazoles 118 and 119 were prepared from 3-amino-4-chloro-l,2,5-thiadiazole 117 via a Sandmeyer-like reaction involving successively tert-butyl nitrite and either copper bromide or copper iodide in anhydrous acetonitrile (Scheme 17) <2003H(60)29>. The bromo and iodo thiadiazoles 118 and 119 undergo selective Stille and Suzuki C-C coupling chemistry (see Section 5.09.7.6). 

Compounds of this family (such as tert-butyl nitrite and isoamyl nitrite) are powerful vasodilators and have been used clinically for the relief of the symptoms of angina for over 100 years (Fig. 8.8). 

Many alkyl nitrites are thermally imstable and may readily decompose or explode on heating [1]. Methyl nitrite explodes more violently than ethyl nitrite [2]. Lower alkyl nitrites have been known to decompose and burst the container, even in refrigerated storage [3]. Individually indexed compounds are t Butyl nitrite, 1658 t tert-Butyl nitrite, 1659... 

Indeed, there were those who described the azide coupling method as racemization-free. [15l However, this viewpoint proved to be overly optimistic. In 1970, Sieber reported that during a synthesis of calcitonin M by the azide method, significant epimerization occurred during two of the segment condensation steps in one of these reactions 40% of the epimerized product was observed. 16 There is a crucial detail in the experimental procedure here. The workers used tert-butyl nitrite to convert a peptide hydrazide into a peptide azide, but did not isolate the azide as was typical for research at that time. Instead, they neutralized the active intermediate in situ with DIPEA and added the amino segment for acylation. This demonstrates another important theme in the control of epimerization, the presence of a tertiary amine in the reaction mixture, even if only as a neutralization equivalent, can result in the formation of epimerized products. Indeed, most observations of racemization during... 

An interesting regioselective deaminative fluorination of a purinc-2.6-diamine derivative 12 has been reported. The nucleoside is selectively fluorinated in the 2-position of the purine moiety by treatment with tert-butyl nitrite in 60% hydrogen fluoride/ pyridine at — 20 C for 10 minutes.149 The hydrogen fluoride concentration of the reagent should not be higher than 65% (suitable 45-65%). 

To a dry three-neck 250-mL round-bottom flask equipped with a 100-mL addition funnel and nitrogen inlet is added boron trifluoride etherate (8.14 mL, 66.2 mmol) (Scheme 12). The flask is then chilled to -15°C in an ice-acetone bath. The aryl amine (4.5 g, 16.54 mmol) is dissolved in THF and added slowly over 20 min. tert-Butyl nitrite (6.9 mL, 57.9 mmol) in THF is then added to the mixture over 30 min. The reaction is stirred another 10 min at -15°C and then warmed to 5°C over 20 min. Hexane is added (300 mL) to the mixture upon which a solid precipitates. The solid is removed by filtration and washed with cold ether and dried in vacuo to give... 

Goodman and Chorev 75 found that the required a-aminoacyl azides 14 are best prepared by reaction of the mixed anhydride of the amino acid with sodium azide. This method led to slightly better yields than the nitrosylation of TV-formylaminoacyl hydrazide. Curtius rearrangement of the a-aminoacyl azide 14 yielded the isocyanate 16, which was subsequently trapped as 17 or 18 as shown in Scheme 2. Comparable yields were obtained by nitrosylation with tert-butyl nitrite. 76 Other methods of acyl azide formation have rarely been employed for PMRI-peptide synthesis. Only Fincham et al. 11 reported the use of trimethylsilyl azide to synthesize an acyl azide en route to a PMRI-peptide. 

Few examples of the preparation of hydrazines or hydroxylamines on insoluble supports have been reported (Table 10.17). Hydrazines have been prepared by the reduction of aromatic diazonium salts or /V-nitroso amines (prepared from secondary amines by treatment with tert-butyl nitrite [340]), and by the N-amination of support-bound amines (Entry 3, Table 10.17). The direct reduction of hydrazones with borane to yield hydrazines on solid phase has not been reported, and appears to be difficult because of the ease with which the N-N bond of hydrazines is cleaved by reducing agents [340]. 

Nitrosyl chloride [55], nitrosyl fluoride-hydrogen fluoride liquid complexes (NOF3HF, NOF 6HF) [56], nitrous acid-hydrogen fluoride solutions [57, 5 ] nitrogen trioxide (prepared in situ from nitric oxide and oxygen) [59] and tert-butyl nitrite-hydrogen fluoride-pyridine [60] have been substituted for sodium nitrite in the diazotization step... 

One-pot diazotization/fluorodediazoniation of aniline derivatives has been reported using potassium fluoride-hydrogen fluoride salts, in various stoichiometric amounts, as reagents together with tert-butyl nitrite (TBN) or sodium nitrite (Table 6).50 The best result is obtained when 6 mmol of potassium hydrogen fluoride (KHF2) and 4 mmol of silicon tetrafluoride are used with 1 mmol of aniline (entry 3). 

C4H9N02 tert-butyl nitrite 540-80-7 336.15 28.394 1,2 3877 C4H10OS 4-mercapto-1 -butanol 14970-83-3 457.15 39.783 2... 

Replacement of an amino group is possible. When aniline derivatives were treated with aUyl bromide and tert-butyl nitrite (t-BuONO), the aryl-allyl coupling product was formed (Ar NH2 Ar-CH2CH=CH2). ... 

Mixed anhydrides of carboxylic acids (RCO2H) and thiohydroxamic acid react with Sb(SPh)3 in the presence of O2 and water to give alcohols (ROH) via RSb(SPh)2 intermediates (Scheme 14.7) [28]. Both thioethers and sulfoxides bearing a hydrogen atoms are converted to a-fluorothioethers by treatment wifh (diefhylamino)sulfur trifluoride under Sb(.T, catalysis (Scheme 14.8) [29]. Treatment of 2-amino-6-halo nucleosides with tert-butyl nitrite in the presence of SbCls affords the 2-chloro-6-halopurine nucleosides (Scheme 14.9) [30]. 

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