| abstract |
Benzoxazole and benzothiazole derivs. of formula (I) are new: (where n = 1-4; each R is independently H, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, haloalkylthio, NH2, alkylamino, dialkylamino, NO2, CN or alkoxycarbonyl, or 2 R gps. can form methylenedioxy, dichloromethylenedioxy or difluoromethylenedioxy; R1 is H or alkyl; R2 and R3 are H, opt. substd. alkyl, alkenyl, alkynyl, aralkyl, cycloalkyl, aryl or N-contg. heterocyclyl; or NR2R3 is a mono- or bicyclic ring which is opt. substd., opt. partially unsatd., opt. benzene-fused and opt. contains other heteroatoms; X is O or S). Cpds. nI) are plant growth regulators, esp. herbicides active against broad-leaved and esp. grassy weeds. They can be used as total weedkillers, defoliants, desiccants or germination inhibitors, or for selective weed control (pref. pre-emergence) in beet, soya, cotton, rice and cereal crops. They also have some fungicidal activity, e.g. against Piricularia oryzae on rice. |