Thionoesters are isomeric with thioesters.  In a thionoester, sulfur replaces the carbonyl oxygen in an ester. Methyl thionobenzoate is CHC(S)OCH. Such compounds are typically prepared by the reaction of the thioacyl chloride with an alcohol.
They can also be made by the reaction of Lawesson's reagent with esters or by treating pinner salts with hydrogen sulphide. An alternatively, various thionoesters may be prepared through the transesterification of an existing methyl thionoester with an alcohol under base-catalyzed conditions.
Xanthates and thioamides can be transformed to thionoesters under metal-catalyzed cross-coupling conditions.