In organic chemistry, thiocarbamates (thiourethanes) are a family of organosulfur compounds. As the prefix thio- suggests, they are sulfur analogues of carbamates. There are two isomeric forms of thiocarbamates: O-thiocarbamates, ROC(\dS)NR2 (esters), and S-thiocarbamates, RSC(\dO)NR2 (thioesters).

Synthesis

Thiocarbamates can be synthesised by the reaction of water or alcohols upon thiocyanates (Riemschneider thiocarbamate synthesis): Similar reactions are seen between alcohols and thiocarbamoyl chlorides such as dimethylthiocarbamoyl chloride; as well as between thiols and cyanates. The herbicide Cycloate is produced in this way: Other related thiocarbamate herbicides include vernolate (C3H7)2NCOSC3H7 and triallate ((i\sC3H7)2NCOSCH2CCl\dCCl2. Salts of thiocarbamate arise by the reaction of amines with carbonyl sulfide:

Reactions

In the Newman-Kwart rearrangement O-thiocarbamates can isomerise to S-thiocarbamates. This reaction, which generally requires high temperatures, is an important method for the synthesis of thiophenols.

Occurrence

Goitrin is a cyclic thiocarbamate found in some vegetables.

Uses

Thiocarbamate based herbicides (e.g. prosulfocarb) were introduced in 1957 and in 2017 was a $200,000,000 market.