Highly branched carbonic-carboxylic anhydrides (1) have been prepared from 2, 4-dimethyl- 3-pentanol and 2, 3, 4-trimethyl-3-pentanol. Both give p-nitrobenzanilide with aniline. The corresponding carbonicphosphoric anhydrides give urethans with amines. Thiolcarbonic- phosphoric anhydrides (7) have been prepared from t-butyl mercaptan and 2, 4-dimethyl-3- pentanethiol (for which a suitable synthesis has been developed); these anhydrides ...