Dithiocarboxylic Acids: An Old Theme Revisited and Augmented by New Preparative, Spectroscopic and Structural Facts

The unstable dithiocarboxylic acids dithioacetic acid, 2‐methyl‐dithiopropionic acid, 2,2‐dimethyl‐dithiopropionic acid and dithiobenzoic acid were synthesized and characterized by NMR spectroscopy and GC/MS. The stable dithiocarboxylic acids 2,4,6‐trimethyl benzoic acid, 2,4,6‐tri‐iso‐propylbenzoic acid and 2,6‐dimesityl benzoic acid were synthesized, isolated and characterized by spectroscopic methods and in parts by mass spectrometry and X‐ray crystallography. The new data were used to re‐evaluate literature data on the synthesis, spectroscopy and structural data of dithiocarboxylic acids as a fundamental class of organic compounds in general. Acids revisited: Although described since more than 150 years, dithiocarboxylic acids remained a scarcely characterized class of compounds; here we describe synthesis and isolation of true free acids and critically review earlier data.