text: There are two oxygen atoms in a carbamate (1), ROC(=O)NR, and either or both of them can be conceptually replaced by sulfur. Analogues of carbamates with only one of the oxygens replaced by sulfur are called thiocarbamates (2 and 3). Carbamates with both oxygens replaced by sulfur are called dithiocarbamates (4), RSC(=S)NR.
  There are two different structurally isomeric types of thiocarbamate:
  *O-thiocarbamates (2), ROC(=S)NR, where the carbonyl group (C=O) is replaced with a thiocarbonyl group (C=S)
  *S-thiocarbamates (3), RSC(=O)NR, where the R–O– group is replaced with an R–S– group
  O-thiocarbamates can isomerise to S-thiocarbamates, for example in the Newman–Kwart rearrangement.