Prepn from 1-phenyl-3-methyl-5-pyrazolone and dimethylcarbamoyl chloride: CH 279553 (1952 to Geigy); GB 681376. Anticholinesterase activity: Pulver, Domenjoz, Experientia 7, 306 (1951); Ferguson, Alexander, J. Agric. Food Chem. 1, 888 (1953); Müller, Spindler, Experientia 10, 91 (1954). Toxicity study: E. W. Schafer, Toxicol. Appl. Pharmacol. 21, 315 (1972).