Diisocyano-2,5-dimethylbenzene, p-CN C6H2 CH3 2 NC

Checkers used liquid Diphosgene (Aldrich) with no loss in yield. 

This is a modification of a synthetic method reported by Sahu. This method can be adapted for the synthesis of the isocyanides prepared in Section 6. A. Substitution of triphosgene for phosgene provides a safer alternative for the synthesis of isocyanides, in general. On the other hand, phosgene is less expensive and the phosgene reaction is easier to scale up. p-H2N(CgH2(CH3)2)NH2 is converted to the corresponding formamide by the procedure outlined in Section 6.A. 

A 125-mL round-bottomed flask equipped with a condenser and magnetic stirrer is charged with -H3C0(C6H4)NH2 (12.3 g, 0.10 mol), CHCI3 (10.5 mL, 

Both formamides and solid isocyanides are moderately stable in air but tend to oxidize over time. Consequently, they should be stored under nitrogen at or below 4°C. Accurate percent yields for the isocyanide compounds are not given, since, as previously observed, they are stabilized in the presence of excess starting materials and are generally purified only as needed for further synthesis. 

Characterization of product is confirmed via H NMR, IR, and mass spectra. Mass spectra of all these isocyanides exhibit a parent ion of maximum intensity and characteristic fragmentation peaks. Mass spectroscopy is also a useful tool for detecting unreacted amine or formamide. Isocyanides decompose in acid and are soluble in hexane, THF, toluene, CH2CI2, CH3CN, and alcohols. 

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