| 562 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {41} |
| 887 | DF | .~ Carboxylic acid anhydrides (i.e., compounds having the -C(=O)-O-C(=O)- group) {2} |
| 888 | DF | .~.~ Processes of forming the -C(=O)-O-C(=O)- group {7} |
| 897 | | .~.~.~ Carboxylic acid halide reactant |