Methylnitrosolic acid

Wieland was the first who studied nitrosolic acids . He was especially interested in the simplest member of this group, the methylnitrosolic acid, ON—C(H)=NOH (10), because he already thought of the dioxime of carbon dioxide, HO—N=C=N—OH, which is an intriguing isomer of methylnitrosolic acid. Wieland tried first the reaction sequence in... 

Since the direct oxidation failed, Wieland used Nef s methods to synthesize oxy-isuretin (formoxyamidoxime), which is generated in situ when formamidoxime, HC(=N0H)NH2, is gently heated with hydroxylamine hydrochloride in methanol (Scheme 10). Oxyisuretin is only stable in solution and gives methylnitrosolic acid and formamidoxime (Scheme 11) upon treatment with an alcoholic solution of KOH. 

Protonation of DNM might lead to three different tautomers (i) dinitrosomethane (H2C(NO)2) when the protonation occurs at the carbon (ketonic isomer) , (ii) methylnitrosolic acid (10) when one of the oxygen atoms of the nitroso groups forms an oxime (enolic isomer) and (iii) a dioxime (HON=C=NOH) of CO2 if a 1,3-hydrogen shift... 

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