Ferf-butyl nitrite

Nitrosomethane (1) is known to be less stable than its isomer formaldoxime 2 and original attempts to isolate this species failed owing to its facile isomerization to the oxime 2. Already Bamberger and Seligman considered in 1903 that it would be difficult to isolate nitrosomethane after oxidation of methylamine due to its rapid isomerization to 2. Hence, 2 is always present in the synthesis of the nitrosomethane. Nitrosomethane is produced in the pyrolysis or photolysis of tcrf-butyl nitrite and by the reaction of methyl radicals with nitric oxide. Early results were confusing since the final product obtained is dimeric nitrosomethane. It was first isolated in 1948 by Coe and Doumani from the photolysis of gaseous ferf-butyl nitrite according to the overall reaction shown in equation 2. 

For the photolysis of ferf-butyl nitrite a possible reaction mechanism (Scheme 6) consists of the production of ferf-butoxy radicals (equation 3), followed by their decomposition to give acetone and methyl radicals (equation 4). The latter are trapped by the nitric oxide liberated in the first step (equation 5). However, the absence of ethane production in the actual experiments suggested that an intramolecular formation of nitrosomethane is unlikely ". ... 

Butyl 4-methylbenzenesulfonate, see Butyl toluenesulfonate, 3403 f Butyl methyl ether, 2004 f turf-Butyl methyl ether, 2005 Butyl nitrate, 1656 f Butyl nitrite, 1653 f ferf-Butyl nitrite, 1654... 

Many alkyl nitrites are thermally unstable 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 f ferf-Butyl nitrite, 1654 f Butyl nitrite, 1653 Decyl nitrite, 3358 f Ethyl nitrite, 0863 f Isopentyl nitrite, 1990 f Isopropyl nitrite, 1258 f Methyl nitrite, 0454 f Pentyl nitrite, 1992 f Propyl nitrite, 1261... 

Lavi, R., Schwartz-Lavi, D., Bar, I. and Rosenwaks, S. (1987). Directional properties in photodissociation A probe for the symmetry and geometry of excited states of dimethylnitrosamine and ferf-butyl nitrite, J. Phys. Chem., 91, 5398-5402. 

More recently another modification for the preparation of peptide azides was introduced by Alfeeva et al-f l using tetrabutylammonium nitrite as auxiliary reagent. In contrast to the alkyl nitrites which are relatively unstable and therefore have to be purified prior to use by distillation, tetrabutylammonium nitrite is a crystalline and stable compound, which is soluble in anhydrous dipolar aprotic solvents. Moreover, in this procedure the acidity of the reaction mixture is adjusted with anhydrous p-toluenesulfonic acid instead of HCl in anhydrous organic solvents. These conditions are experimentally convenient and more easily controlled than those of the Honzl-Rudinger method. Comparative model reactions performed with ferf-butyl nitrite and tetrabutylammonium nitrite produced nearly identical peptide yields. To date, there are no reports of the condensation of larger fragments and peptide cyclization by this azide procedure. 

A protected serine hydrazide was condensed by the azide method to an S-protected tripeptide H-Asn-Cys-Tyr-NHNH-Cbz to form a protected tetrapeptide Boc-Ser-Asn-Cys-Tyr-NHNH-Cbz 1.02 g of N-. ert-butoxycarbonyiserine hydrazide (Boc-Ser-NH-NHj) in DMF containing HQ in dioxane was mixed at -20 °C with ferf-butyl nitrite. This mixture containing the azide Boc-Ser-N, was neutralized with triethylamine, and a solution of 3.4 g asparagmyI-S-(ethylcarbamoyl)cysteinyI-tyrosinyl 2-(benzytoxy-carbonyl)hydrazide trifluoroacetate was added. After 72 hours at 4 °C a simple work-up procedure and precipitation from methanol-petroleum ether yielded 3 g of impure protected tetrapeptide hydrazide. It... 

Doyle and Bryker reported high yields of arenediazonium tetrafluoroborates when aromatic amines were reacted with ferf-butyl nitrite and trifluoroboro etherate in CH2CI2. It is likely that nitrosyl fluoride is formed as nitrosating reagent by fluoride-alkoxy exchange. 

Figure IX-H-14. Quantum yields of the acetone product formed in the photodecomposition of ferf-butyl nitrite ( 15 Torr) with added NO ( 15Torr) as a function of wavelength (McMillan, 1962 McMillan et al. 1971).

Marchand and co-workers reported a synthetic route to TNAZ (18) involving a novel electrophilic addition of NO+ NO2 across the highly strained C(3)-N bond of 3-(bromomethyl)-l-azabicyclo[1.1.0]butane (21), the latter prepared as a nonisolatable intermediate from the reaction of the bromide salt of tris(bromomethyl)methylamine (20) with aqueous sodium hydroxide under reduced pressure. The product of this reaction, A-nitroso-3-bromomethyl-3-nitroazetidine (22), is formed in 10% yield but is also accompanied by A-nitroso-3-bromomethyl-3-hydroxyazetidine as a by-product. Isolation of (22) from this mixture, followed by treatment with a solution of nitric acid in trifluoroacetic anhydride, leads to nitrolysis of the ferf-butyl group and yields (23). Treatment of (23) with sodium bicarbonate and sodium iodide in DMSO leads to hydrolysis of the bromomethyl group and the formation of (24). The synthesis of TNAZ (18) is completed by deformylation of (24), followed by oxidative nitration, both processes achieved in one pot with an alkaline solution of sodium nitrite, potassium ferricyanide and sodium persulfate. This route to TNAZ gives a low overall yield and is not suitable for large scale manufacture. 

This procedure is the first example of a catalytic transformation of 52 into 54 under relatively mild conditions (at 80 °C for 2 h). In this process the majority of 53 is converted into tcrt-butyl alcohol (see below). Since tcrt-butyl alcohol is known to react with NO2 or with sodium nitrite to produce 53, reagent 53 may be regenerated from the ferf-butyl alcohol formed (Scheme 32). 

Chloroethyl ethyl ether Butyl nitrite Butyl alcohol sec-Butyl alcohol ferf-Butyl alcohol... 

The reaction could be quenched by radical quenchers like 2,4,6-tii-rerr-butyl-phenol, which indicates that a radical pathway is involved. Initially, the homolysis of fert-butyl nitrite leads to the addition of ferf-butyl oxy radical and nitroso radical to alkyne. Species 119 then cyclizes and gives a reactive four-membered ring 120 [153]. Then 120 undergoes proton abstraction, and isobutylene extmsion. Ring-opening of 121 by the elimination of formic acid finally gives the nitrile product. This reaction is the first example of metal-free condition and the use of fert-butyl nitrite in nitrogenation of alkynes (Scheme 4.48). 

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