Alkyl nitrites 2-octyl nitrite

The involvement of an intramolecular hydrogen abstraction in the Barton reaction is not necessarily limited to those molecules with rigid stereochemistry. In fact, simple aliphatic nitrites undergo the Barton reaction with equal ease. Thus, the principal product obtained from the photolysis of ra-octyl nitrite20 in benzene solution is the dimer of 4-nitroso-l-octanol however, photolysis of n-octyl nitrite in n-heptane20 produced a mixture of 7/-nitroso heptanes in addition to 4-nitroso-l-octanol in the ratio l 4.5,f respectively. The formation of y-nitroso heptane obviously results from an attack of the intermediate alkoxy radical on the solvent molecule. The intermediate alkyl radical then collapses, according to eq. 2. For the sake of convenience we have indi-... 

Irradiation of octyl nitrite has already been described Kabasakalian et al. have also studied the behavior of its lower homologs.24 It was observed that primary alkyl nitrites with more than four carbon atoms in a chain produced essentially identical yields (37 to 45%) of nitroso dimer formed by the Barton reaction until the minimum straight-chain length of four carbon atoms was reached. Butyl nitrite underwent internal hydrogen abstraction in poor yield. This is the result of a more difficult abstraction of a primary hydrogen as compared to a secondary hydrogen atom available in compounds with longer chains. Reaction paths 2 and 4 predominated to afford 1-butanol and butanal as the major products. 

Also developed by Hill is a (diotochemical system (equations 41 to 48) based on a polyoxoacid, H3PWi2O40 (P)> The excited state of the acid probably oxidizes the alkane in the first step. The radical can then either attack the solvent to give an iminium radical, wiiich leads to ketone on hydrolysis, or it can be oxidized to the caifaonium ion, in wdiich case attack on the solvent leads instead to the -alkyl-acetamide. If the substrate has two adjacent tertiary C—bonds, then alkenes tend to be formed, llie Barton reaction, normally kmwn as an intramolecular C—activation, can give some intermolecular reaction in some examples. Thus, vdien n-octyl nitrite is rf)otolyzed in heptane, some nitrosoheptane is observed. ... 

Alkyl nitrites. An efficient method for the preparation of 2-octyl nitrite described by Kornblum and Oliveto is as follows. A solution of 0.6 mole of 2-octanol in 240 ml. of pyridine is stirred at 0-10°, and 0.95 mole of nitrosyl chloride is allowed to evaporate into the solution in the course of about 3 hrs. Petroleum ether and water are run into the mixture, and the organic layer is washed, dried, and distilled. Reaction of the alcohol with sodium nitrite and sulfuric acid afforded the ester in only 59% yield. 

There appear to have been no further studies on the thermal decomposition of alkyl nitrites until 1949. Then two more complex nitrites were studied. Komblum and Oliveto (1949) examined the thermal decomposition of optically active 2-octyl nitrite in the liquid phase at 100°C. Optically pure r(-2-octanol was obtained in excellent yield, thus showing that 2-octoxyl radicals were produced, and that these did not racemize. 

Question on stability of the pyrazoline intermediates formed in 1,3-dipolar cycloadditions of alkyl diazoacetates with fullerenes was addressed in subsequent publication [15]. The reaction of glycine ethyl ester hydrochloride (or glycine octyl ester hydrochloride) with sodium nitrite was utilized to prepare ethyl diazoacetate in situ under the HSVM conditions. After 30min of vigorous milling at room temperature, 2-pyrazolines 32a and 32b were formed in 48% and 49% yield, respectively (Scheme 7.8). These pyrazolines were formed via isomerizations of 1-pyrazolines 31a,b which are obtained directly by 1,3-dipolar cycloadditions. 

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