Synthesis and Characterisation of New Monomethoxypoly(Ethylene Glycol) (mPEG) Carbonate Ester Surfactants.

New A B and A-B-A carbonate-esters, where A represents the hydrophilic part and B the lipophilic part, comprising monomethoxypoly(ethylene glycol) (mPEG) and a long chain carboxylic acid, have been synthesised. The synthetic approach to these compounds involved the alkylative esterification of aliphatic carboxylic acid as the key step. For the A-B type compounds, the palmitic acid salt reacted chemoselectively with ambident alpha-chloroalkylcarbonates 8 in DMF provided cesium was the counter-ion. With methyl substitution on the alkyl halide the mode of reaction was slightly altered, leading to unravelling of the alkylating agent structure via a presumed interaction with DMF. The decomposition fragments were detected in HPLC and in NMR designed experiments. For the A B-A analogue, the tetrabutylammonium salt of docosanedioic acid was first alkylated with an ethylthio derivative of chloromethyl chloroformate and then converted into the carboyl chloride that was used effectively to acylate mPEG alcohol. These new compounds have been studied to establish their properties as surfactants. Enzymatic hydrolysis studies have shown enhanced degradation of the carbonate ester function in comparison with ordinary esters.