Isocyanates, Thiocyanates, Isothiocyanates, Selenocyanates

Syntheses of isocyanates from carboxylic acids/ and by the thermolysis of N-substituted 4-hydroxy-2-oxazolidones have recently appeared. In the latter method, the oxazolidones are prepared from amines and the overall reaction thus represents a conversion of amines to isocyanates without the use of phosgene. 

The photochemical rearrangement of 2-aminopyrrolin-5-ones to amino-cyclopropyl isocyanates, and of bis(aminopyrrolinones) to bis-isocyanates has been published.  

1-Haloethylcarbamoyl chlorides react with a-pinene to give a mixture of vinyl isocyanate and the hitherto unknown 1-haloethyl isocyanates (39), probably via mono- and bis-dehydrohalogenation, respectively.  

The synthesis and reactions of carbonyl isocyanate, isothiocyanate and di-isothiocyanate have been reported. 

A series of papers detailing a continuation of the study of the synthesis and reactions of uic-iodothiocyanates and -iodoisothiocyanates has been published.Similarly, the treatment of alkenes with thiocyanogen bromide [from equimolar quantitites of bromine and thallium(i) thiocyanate] gives moder-ate-to-high yields of uic-bromothiocyanates. Unlike the analogous vic-iodothiocyanates, the bromo-compounds are not readily isomerized to the corresponding isothiocyanates. 

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