| 摘要 |
New 1,3,4-thiadiazole derivs. of formulae (I), (II) and (III): (where X is an N-contg. heterocyclic group opt. contg. other heteroatoms; R is alkyl, alkenyl, alkynyl, alkoxy or alkoxyalkyl; n = 0 or 1; m = 2 or 3; Hal is halogen, pref. Cl). A typical cpd. (I) is 1- 5-(2-chloro-1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl -4,5-dihy- droxy-3-methylimidazolidin-2-one. In an example, this is prepd. by reacting (II; R is Me) with glyoxal hydrate. Cpds. (I) have selective herbicides, esp. useful for preemergence weed control in maize and cotton crops. Cpds. (II) and (III) are intermediates for (I). |
