Amination with Alkyl Nitrates

Uses. Tetramethylene sulfone has high solvent power for aromatics and has been used extensively by Olah and co-workers for Friedel-Crafts type nitrations and for studies of the mechanism of nitronium tetrafluoroborate nitration of alkyl-benzenes and halobenzenes in homogeneous solution. It is a superior solvent for quaternization of tertiary amines with alkyl halides, since it has a high dielectric constant and does not enter into side reactions observed with nitrobenzene and dimethylformamide. For example in the synthesis of the acridizinium salt (3), Bradsher and Parham effected quaternization of (1) with benzyl bromide in tetramethylene sulfone at room temperature in excellent yield. Several other salts analagous to (2) were obtained in good yield and in crystalline form with use of tetramethylene sulfone, whereas with other solvents the products were colored... 

From the recent advances the heteroatom-carbon bond formation should be mentioned. As for the other reactions in Chapter 13 the amount of literature produced in less than a decade is overwhelming. Widespread attention has been paid to the formation of carbon-to-nitrogen bonds, carbon-to-oxygen bonds, and carbon-to-sulfur bonds [29], The thermodynamic driving force is smaller in this instance, but excellent conversions have been achieved. Classically, the introduction of amines in aromatics involves nitration, reduction, and alkylation. Nitration can be dangerous and is not environmentally friendly. Phenols are produced via sulfonation and reaction of the sulfonates with alkali hydroxide, or via oxidation of cumene, with acetone as the byproduct. 

The reaction of primary aliphatic amines and nitramines with nitronium salts also leads to deamination and the formation of alkyl nitrates. 

Ordinarily, alkyl nitrate esters will not nitrate amines under neutral conditions. However, Schmitt, Bedford and Bottaro have reported the use of some novel electron-deficient nitrate esters for the direct At-nitration of secondary amines. The most useful of these is 2-(trifluoromethyl)-2-propyl nitrate, which nitrates a range of aliphatic secondary amines to the corresponding nitramines in good to excellent yields. Nitrosamine formation is insignificant in these reactions. 2-(Trifluoromethyl)-2-propyl nitrate cannot be used for the nitration of primary amines, or secondary amines containing ethylenediamine functionality like that in piperazine. Its use is limited with highly hindered amines or amines of diminished nucleophilicity due to inductive or steric effects. 

An important development of the synthesis described above is derived from the observations of Scott, O Donovan and Reilly [159], which were taken up by others [109]. l-Guanyl-3,5-dimethylpyrazole nitrate reacts with alkyl- and aryl-amines in hot water, ethanol, or without solvent to give good yields of guanidines. Use of this pyrazole nitrate or other salt for obtaining guanidines now competes with older methods if yield and ease of isolation of the product are the main considerations [95, 138, 140, 143, 160-164]. 

In certain applications, the quaternary ammonium salts have advantages over tertiary amines for actinide extractions. Quantitative extraction of the transplutonium elements from nitrate media by quaternary ammonium salts can be achieved with a lower aqueous-phase nitrate concentration than is required for tertiary amines thus, aluminum nitrate may be used instead of lithium nitrate. The separation factor between Am and Cm can be as high as three in a quaternary ammonium nitrate system (50). The effect of the length of the alkyl chain on Cm, Am, Bk, Cf, and Es extraction by alkyldioctylammonium nitrates suggests that steric factors substantially influence the extraction selectivity (51). A comparison of the extraction of tetravalent and hexavalent actinides by tetraheptyl ammonium nitrate shows that tetravalent ions are more easily extracted than hexavalent ions e.g.,... 

Alkaline hydrolysis of a variety of organic compounds nitration of chlorobenzene alkylation of benzene with straight-chain olefins reduction of aromatic nitro compounds to corresponding aromatic amines with aqueous NajS or Na2Sj. 

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