A pyrazolooxadiazepine that is 7-oxo-1,2,4,5-tetrahydro-7H-pyrazolo[1,2-d][1,4,5]oxadiazepin which is substituted at positions 8 and 9 by 2,6-diethyl-4-methylphenyl and pivaloyloxy groups, respectively. A pro-herbicide (by hydrolysis of the pivalate ester to give the corresponding enol), it is used for control of grass weeds in cereal crops.