Selective herbicides for cereals - comprising tetrahydro pyranyl heptahydro or octahydro cyclo hexa or hepta pyrimidine diones

摘要

Pyrimidine diones of formula (I): (where n = 4 or 5) are selective pre- and post-emergence herbicides, suitable for use in cereal crops esp. oats, wheat and barley. The cpds. are more active against weeds, and less toxic to cereals than the known herbicide (I, n = 3).