2- -4-methyl-1,2,4-oxadiazolidine-2,5-dione

The activation of the hydrazines 397 (Scheme 68) with l,l -carbonyldiimidazole (CDI) and reaction with hydroxylamines gave the hydroxy semicarbazides 398, which could be treated with methyl chloroformate in the presence of TEA to give the first examples of 4-amino-substituted l,2,4-oxadiazolidin-3,5-diones 399 <2000HC055>. 

The herbicide methazole, containing an oxadiazolidine ring, can be classed in the azole group. The herbicidal properties of this compound were first described in the 1960s. The composition of the compound, introduced under the code number VCS-438 is 2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-2,5-dione (2) (Furness, 1970). 

N-(2,6-dimethylphenyl)- N- (1 -pyrazol-1 -ylmethyl)acetamide (9cl) 4-chloro-5-(dimethylamino)-2-[(3-trifluoromethyl)phenyl]-3(2//)-pyridazinone N-2-benzothiazolyl- N, iV - dimethylurea 2-(3,4-dichlorophenyl)-4-methyl-l,2,4-oxadiazolidine-3,5-dione N-(3-methoxypropyl)-iV -(l-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine 4 methoxy-3,3 -dimethylbenzophenone N -(4-bromophenyl)- JV-methoxy- N- methylurea 2-chloro- N-(2-ethyl-6-methylphenyl)- N- (2-methoxy-l-methylethyl)acetamide N -(3-chloro-4-methoxyphenyl)-JV,JV-dimethylurea 4-amino-6-(l,l-dimethylethyl)-3-(methylthio)-l,2,4-triazin-5 (4H) -one... 

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