| 564 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {1} |
| 1 | DF | .~ AMINO NITROGEN CONTAINING (E.G., UREA, SULFONAMIDES, NITROSAMINES, OXYAMINES, ETC., AND SALTS THEREOF) {37} |
| 32 | DF | .~.~ Ureas (i.e., HNH-CO-HNH, wherein substitution may be made for hydrogen only) {9} |
| 63 | DF | .~.~.~ Urea per se or salt thereof {5} |
| 73 | | .~.~.~.~ Purification or recovery |