Nitrones thiolactams

Thiolactams (46) are isolated on addition of carbon disulfide to cyclic nitrones (44) the products are formed in a sequence of [3 + 2] cycloaddition giving (45) and cycloreversion (equation 20). ... 

The nitrones (119) are readily converted into thiolactams (120) by heating under reflux in carbon disulpWde. The reaction presumably involves an initial cycloaddition and subsequent cycloreversion with the loss of carbon oxysulphide. 

Although phenyl isothiocyanate adds to nitrones across its C=N bond giving (121), substituted phenyl isothiocyanates add across both 0=N and C=S bonds giving (122) and (123). The latter compound cycloreverts to the thiolactam (124) and the aryl isocyanate. 

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