N Monosubstituted thioureas from

Michael reaction, A1<9) octalone, 45, 82 N Mono- and N,N disubstitdted UREAS AND THIOUREAS 45, 69 N Monosubstituted thioureas from primary amines and silicon tetra-lsothiocyanate, 45, 69 N Monosubstituted ureas from primary amines and silicon tetraisocyan-ate, 46, 69... 

With R] different from R2 two isomeric compounds (138 and 139) are possible, depending on the direction of ring closure (86). However, only one form is generally obtained. Finally, the trisubstituted thioureas such as N,N,N -trimethylthiourea react with chloroacetone to give a thiazolium salt, in a reaction identical to that of the N-monosubstituted thioamides (Scheme 67). 

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