Unsymmetrical bifunctional trithiocarbonate as unexpected by-product in the synthesis of a dithioester RAFT agent

摘要

The trithiocarbonate 2-(benzylsulfanylthiocarbo-nylsulfanyl)propanoic acid is formed as minor by-product in the synthesis of the dithioester 2-((2-phenylthioacetyl)sulfanyl)propanoic acid via the Grignard route.The mechanism for this side reaction is not clear.The isolated trithiocarbonate may act as unsymmetrical but bifunctional RAFT agent in the aqueous polymerization of N,N-dimethyl acrylamide.Therefore,it is important to separate it completely from the dithioester before engaging the latter in controlled free radical polymerization to guarantee a maximum control.