Alkyl nitrites primary process

The reaction of alkyl halides with metal nitrites is one of the most important methods for the preparation of nitroalkanes. As a metal nitrite, silver nitrite (Victor-Meyer reaction), potassium nitrite, or sodium nitrite (Kornblum reaction) have been frequently used. The products are usually a mixture of nitroalkanes and alkyl nitrites, which are readily separated by distillation (Eq. 2.47). The synthesis of nitro compounds by this process is well documented in the reviews, and some typical cases are listed in Table 2.3.92a Primary and secondary alkyl iodides and bromides as well as sulfonate esters give the corresponding nitro compounds in 50-70% yields on treatment with NaN02 in DMF or DMSO. Some of them are described precisely in vol 4 of Organic Synthesis. For example, 1,4-dinitrobutane is prepared in 41 -46% yield by the reaction of 1,4-diiodobutane with silver nitrite in diethyl ether.92b 1-Nitrooctane is prepared by the reaction with silver nitrite in 75-80% yield. The reaction of silver nitrite with secondary halides gives yields of nitroalkanes of about 15%, whereas with tertiary halides the yields are 0-5%.92c Ethyl a-nitrobutyrate is prepared by the reaction of ethyl a-bromobutyrate in 68-75% yield with sodium nitrite in DMF.92d Sodium nitrite is considerably more soluble in DMSO than in DMF as a consequence, with DMSO, much more concentrated solutions can be employed and this makes shorter reaction times possible.926... 

The formation of alkyl nitrites, CD3OD, and dimethyl ether as well as the appearance of the alkoxyl radicals indicates the importance of the primary process 72, whereas the low HD content of the hydrogen formed from CH OD seems to favor reaction 73, which... 

Simple nitroalkanes absorb below 350 nm and are excited to the lowest singlet n,n state, which efficiently intersystem crosses to Homolytic photocleavage is the principal primary process in both the gas phase and solution to produce alkyl radicals and NO2 (Scheme 6.186).1187 Apart from subsequent recombination of the radical intermediates to form nitrites (Section 6.4.2), competing hydrogen abstraction (photoreduction) involving an excited nitro compound and a hydrogen-atom donor may take place. 

Kabaskalian and Townley (1962a) also showed that the primary process gave RO + NO in a series of alkyl nitrites photolyzed in benzene solution. They deduced this from the products formed which were aldehydes and alcohols, the products expected om the disproportionation of RO radicals. For RO radicals... 

The photodecomposition of the various oxidation products of the alkanes, alkenes, and the aromatic hydrocarbons play important roles in the chemistry of the urban, mral, and remote atmospheres. These processes provide radical and other reachve products that help drive the chemistry that leads to ozone generation and other important chemistty in the troposphere. In this chapter, we have reviewed the evidence for the nature of the primary processes that occur in the aldehydes, ketones, alkyl nitrites, nittoalkanes, alkyl nitrates, peroxyacyl nitrates, alkyl peroxides, and some representative, ttopospheric, sunlight-absorbing aromatic compounds. Where sufficient data exist, estimates have been made of the rate of the photolytic processes that occur in these molecules by calculation of the photolysis frequencies ory-values. These rate coefficients allow estimation of the photochemical lifetimes of the various compounds in the atmosphere as well as the rates at which various reactive products are formed through photolysis. 

McMiUan, G.R. (1963), Photolysis of alkyl nitrites. The primary process in f-hutyl nitrite at 3660 A, J. Phys. Chem., 67, 931-932. 

Alkyl halides can be converted into nitro compounds by treatment with metal nitrites (for a review see Kornblum146). The older directions almost all prescribe silver nitrite at elevated temperatures (ca. 80-110°). However, because of the numerous side reactions it is only for the simplest primary iodides (up to about C5) that this reaction gives satisfactory yields (about 50%). Only in a few cases can bromides be used.643 Recently, however, the process has been made economic by using considerably milder conditions. It is advisable... 

Naked cyanide has been demonstrated to be a synthetically useful reagent in a wide variety of substitution, elimination and addition processes [119]. The reaction of naked nitrite with primary alkyl halides yields nitro compounds as major products, with nitrite esters as the principal byproducts [140]. The use of crown ethers also permits the transformation of organic alkyl halides into the corresponding dialkyl peroxides [141] through the generation of naked peroxide from KO2 or Na02. 

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