Nitration Nitrosoamides

Notable examples of general synthetic procedures in Volume 47 include the synthesis of aromatic aldehydes (from dichloro-methyl methyl ether), aliphatic aldehydes (from alkyl halides and trimethylamine oxide and by oxidation of alcohols using dimethyl sulfoxide, dicyclohexylcarbodiimide, and pyridinum trifluoro-acetate the latter method is particularly useful since the conditions are so mild), carbethoxycycloalkanones (from sodium hydride, diethyl carbonate, and the cycloalkanone), m-dialkylbenzenes (from the />-isomer by isomerization with hydrogen fluoride and boron trifluoride), and the deamination of amines (by conversion to the nitrosoamide and thermolysis to the ester). Other general methods are represented by the synthesis of 1 J-difluoroolefins (from sodium chlorodifluoroacetate, triphenyl phosphine, and an aldehyde or ketone), the nitration of aromatic rings (with ni-tronium tetrafluoroborate), the reductive methylation of aromatic nitro compounds (with formaldehyde and hydrogen), the synthesis of dialkyl ketones (from carboxylic acids and iron powder), and the preparation of 1-substituted cyclopropanols (from the condensation of a 1,3-dichloro-2-propanol derivative and ethyl-... 

In an attempt to mimic an enzymatic demethylation process, nitroxide photolysis has been used as a method for oxidizing the C-4 jS-methyl group of 4,4-dimethylcholestanone.158 Further applications have been published of the photolysis of jV-nitrosoamides in the presence of oxygen to the synthesis of nitrate esters having functionalized methyl and methylene groups.180... 

The initial rate for the accumulation of C=0 groups of nitrosoamides in the NO concentration range of 4 x 10 - to 4 x 10 mol/1 is proportional to [NO ]", where n 2. This fact confirms the participation of nitrosyl nitrate in PCA conversions. In reaction (Equation 7.42), an unstable intermediate nitrite is initially generated. The latter gives the detectable acylalkylaminoxyl radicals with an anisotropic triplet spectrum (.<4 =1.94 mT, gj, = 2.003) (Figure 7.7). 

Front-side exchange (path (e)) partakes of the character of an add-base reaction in the nitrosoamide decomposition (section a (2) (e)), and in view of the basicity of the incipient hydroxide ion, one would expect extensive exchange of the counter ion in the nitrous add deamination (equation 146, path (e)). In fact, acetate esters are the chief products from deaminations in acetic add (ref. of Table 12), and the alcohol component of the reaction has only rarely been reported (Table 12). In acetic acid runs, the adds present in the medium (HX, equation 146) are HO2CCH3, HONO and HONO2 (the latter from the disproportionation of nitrous add). Acetate esters have invariably been reported as products in deamination and in a few instances nitrite and nitrate estershave been isolated. 

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See also in sourсe #XX -- [ ]

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