Xylenes nitrosation

Thiadiazolin-2-imines can also be converted to thiadiazolin-2-ones in two steps <2004PS601, 2003HAC421, 2003PS1101>. The nitrosation of the thiadiazol-2-imines 87 with saturated nitrite in acetic acid at 0-5°C gave the iV-nitroso-l,3,4-thiadiazol-2(37/)imines 88 in 72% yield. Thermolysis of the latter in refluxing xylene gave the 1,3,4-thiadiazolin-2-one 89 in 78% yield (Scheme 8) <2003HAC421>. 

C8H7N307 mw 257.18 N16.34% OB to C02 -77.77% cryst mp 107-08°. Prepn is by nitrosation of m-xylene, with subsequent oxidation by the addition ofaliq suspension contg 20% nitrosated m-xylene to 70% nitric add at 45 to 75°. The yield is approx 80%. Ref 3 terms this compd useful as either an expl or propint Refs 1) Beil, not found 2) F.M. Rowe et al, Derivatives of the m-Xylenols... , JSocChem Ind49,469-73T (1930) CA25,930 (1931)... 

The nitrosation of phenol and cresols in buffer solutions involves a diffusion-controlled C-nitrosation followed by rate-limiting proton loss. /r-Crcsol is much less reactive than the other substrates.79 Nitrosation in trifluoroacetic acid or in acetic-sulfuric acid mixtures is regioselective (e.g. 4-nitroso-m-xylene is fonned from m-xylene) and possible non-selective nitrous acid-catalysed nitration can be eliminated by purging reaction solutions with nitric oxide.80... 

L. Garcfa-Rfo, P. Herves, J.C. Mejuto, and P. Rodrfgnez-Dafonte, Nitrosation reactions in water/AOT/xylene microemnlsions, 2006, Ind. Eng. Chem. Res. 45,600-606. 

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