Alkyl nitrites, preparation

Aliphatic nitro compounds. These are isomeric with the alkyl nitrites and may be prepared from the alkyl halide and silver nitrite, for example C,H,aBr + AgNOj — C Hj NO + AgBr... 

Care must be exercised in handling n-amyl and the other alkyl nitrites inhalation of the vapour may cause severe headache and heart excitation. The preparation must therefore be conducted in an efficient fume cupboard. 

As an e.xtension of the oxidative carbonylation with alkyl nitrites, malonate can be prepared by the oxidative carbonylation of ketene (583)[524], Also, the acetonedicarboxylate 585 is prepared by the Pd-catalyzed, alkyl nitrite-mediated oxidative carbonylation of diketene (584)[525],... 

UBE Industries, Ltd. has improved the basic method (32—48). In the UBE process, dialkyl oxalate is prepared by oxidative CO coupling in the presence of alkyl nitrite and a palladium catalyst. 

Nitrous acid or alkyl nitrites react with a number of nitrogen compounds to yield tetrazoles. For example, hydrazidines (87), which can be prepared in situ from the corresponding iminoesters, react with nitrous acid or its derivatives to give 1-substituted tetrazoles (88).150-152 This reaction (Eq. 17), is one of the most extensively used methods for the synthesis of... 

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 esters of nitrous acid are characterised by their high velocities of formation and hydrolysis. They are almost instantaneously decomposed by mineral acids and in the method of preparation given this has been taken into account. The slightest excess of hydrochloric acid must be avoided. Advantage is taken of this property of the alkyl nitrites in all cases where it is desired to liberate nitrous acid in organic solvents (in which metallic nitrites are insoluble). Examples addition of N203 to olefines, preparation of solid diazonium salts (p. 286), production of isonitroso-derivatives from ketones by the action of HN02. This synthesis is often also carried out in the manner of the acetoacetic ester synthesis, with ketone, alkyl nitrite, and sodium ethylate the sodium salt of the isonitrosoketone is formed (cf. in this connexion p. 259) ... 

Diazo esters can also be prepared from glycine esters by treatment with nitrous acid [966] or with alkyl nitrites. Further methods include the oxidation of hydrazones, oximes (Forster reaction), and semicarbazones, the base-induced... 

Aminopyrazolo[3,4-d]pyrimidines 257 were converted into the corresponding 4-aryl substituted derivatives 259 via treatment with alkyl nitrites and boiling in aromatic solvent. The isomer distribution of 259 prepared by these route was that predicted for a radical intermediate (ortho, meta, and para). The structure of isomers was established by H-NMR. Unusual fragmentation products were isolated these probably result from collapse of the radical intermediate 258 (83JOC4605). Methylation of 257 takes place at either N-1 or N-2. Further methylation affords methylamino derivatives structures of the products were established by C-NMR as well as by chemical methods (75JOC1822). 

Alkoxy radicals, 75 peroxyalkyl radicals reaction with, 101 photochemical preparation from alkyl nitrites... 

Cupferron has usually been prepared from a mixture of alkyl nitrite and /3-phenylhydroxylamine in the presence of ammonia in ether or benzene solution,6 but it has also been made by the zinc dust reduction of nitrobenzene in the presence of amyl nitrite and ammonium hydroxide solution.7... 

Alkyl nitrites decompose slowly upon standing and should be kept in a cool place. They should preferably be used within a few days or, at most, within two weeks of their preparation. The decomposition products include water, oxides of nitrogen, the alcohol and polymerisation products of the aldehyde. 

Classically, primary nitroalkanes may be prepared by heating the alkyl bromide (or iodide) but not the chloride, with silver nitrite, frequently in anhydrous ether. The method is not satisfactory with secondary or tertiary halides, when the major products are the alkyl nitrites. 

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