Herbicidal and fungicidal compounds of the formula ##STR1## wherein R.sub.1 is substituted or unsubstituted phenyl or naphthyl and R.sub.2 and R.sub.3 are the same or different and are C.sub.1 -C.sub.5 alkyl or from a five- or six-membered ring.

This invention relates to compounds useful as pesticides. The new compounds 
of the invention are derivatives of 1,2,4-oxadiazolidine-3-one and have 
the formula I 
##STR2## 
wherein R.sub.1 is a phenyl or naphthyl group, unsubstituted or 
substituted with one or two halogens, C.sub.1-4 alkyl, alkoxy or nitro 
groups, R.sub.2 and R.sub.3 are the same or different and represent an 
alkyl group containing 1 to 5 carbon atoms, or form a (CH.sub.2).sub.n 
group together--where n is 4 or 5, forming thus a 5 or 6 membered ring. 
The present invention also provides a process for the preparation of the 
biologically active compounds of the formula I. Five-membered heterocyclic 
compounds containing 2 nitrogens and 1 oxygen in the ring, possessing 
biological activity such as weed killer activity are known from British 
Patent Specifications Nos.: 1,051,322, 1,057,955, 1,063,789, 1,094,:977, 
1,099,101, 1,110,500, 1,142,917, 1,168,721, 1,173,300, 1,198,726, 
1,208,111, 1,208,112, 1,211,556, 1,286,067. 
The compounds of the general formula I are preferably prepared by reacting 
a hydroxy-urea compound of the formula III 
##STR3## 
where R.sub.1 is as defined above--with a ketone of the formula II 
##STR4## 
wherein R.sub.2 and R.sub.3 are identical or different and are as defined 
above. 
The reaction is preferably carried out in an inert solvent or using the 
ketone as a solvent at a temperature ranging from room temperature to the 
boiling point of the solvent or of the ketone, if desired, a water binding 
agent can be used. 
Some of the new compounds of the formula I are phytotoxic and can be thus 
useful as herbicides. Some compounds of the invention display fungicide 
activity and some are useful against insects. The new 
1,2,4-oxadiazolidine-3-one derivatives are solid crystalline substances, 
which can be further worked up to pesticidal compositions in the form of 
wettable powders, emulsion concentrates, aqueous or oily suspensions etc.

The invention is further illustrated with the following non-limiting 
Examples. 
EXAMPLE 1 
4-(3,4-Dichlorophenyl)-5,5-dimethyl-1,2,4-oxazolidine-3-one 
22.1 g (0.1 mole) of N-(3,4-dichlorophenyl)-N'-hydroxy-urea and 130 g. of 
acetone are added to a flask of a volume of 500 ml. The mixture is heated 
under stirring and stirred for 15 minutes under reflux. 
The reaction mixture is then cooled to 0.degree. C. and the precipitated 
crystalline substance is filtered and recrystallized from the mixture of 
acetone and pethroleum ether. 
23.5 g. of crystalline substance are obtained, m.p. 73.degree.-75.degree. 
C. 
Yield: 90% 
Analysis 
Calculated: %C, 46.0; %H, 3.68; %N, 10.73; %Cl, 27.12. Found: %C, 45.84; 
%H, 4.03; %N, 10.42; %Cl, 26.98. 
EXAMPLE 2 
4-(3-Chlorophenyl)-5,5-spiro-pentamethylene-1,2,4-oxadiazolidine-3-one 
18.6 g. (0.1 moles) of N-(3-chlorophenyl)-N'-hydroxy-urea are dissolved in 
the mixture of 60 g. of cyclohexanone and 100 ml. of benzene. The solution 
is stirred for 5 hours on a water bath at reflux temperature. The reaction 
mixture is evaporated and the residue is recrystallized from the mixture 
of methanol and water. 
22.6 g. of crystalline product are obtained, m.p. 125.degree. C. 
Yield: 85%. 
Analysis 
Calculated: %C, 58.54; %H, 5.67; %N, 10.51; %Cl, 13.29. Found: %C, 58.35; 
%H, 5.67; %N, 10.54; %Cl, 13.10. 
EXAMPLE 3 
4-(3-Chlorophenyl)-5,5-dimethyl-1,2,4-oxadiazolidine-3-one 
18.6 g. (0.1 moles) of N-(3-chlorophenyl)-N'-hydroxy-urea are added to 130 
g. of acetone. The mixture is stirred for 15 minutes at the temperature of 
the water bath under reflux. The reaction mixture is then evaporated to 
dryness and the residue is recrystallized from the mixture of acetone and 
water. 
20.8 g. of crystalline substance are obtained, m.p. 84.degree.-85.degree. 
C. 
Yield: 92%. 
Analysis 
Calculated: %C, 52.99; %H, 4.89; %N, 12.36; %Cl, 15.64. Found: %C, 52.63; 
%H, 4.60; %N, 12.28; %Cl, 15.53. 
EXAMPLE 4 
4-(3-Chlorophenyl)-5,5-dimethyl-1,2,4-oxadiazolidine-3-one 
The product is prepared according to the procedure set forth in Example 3, 
but the reaction mixture is stirred at room temperature for 24 hours. 
After recrystallization 20.3 g. of the product are obtained, m.p. 
84.degree.-85.degree. C. 
Yield: 81%. 
Analysis is identical with that of Example 3. 
EXAMPLE 5 
4-(3-Chlorophenyl)-5,5-diethyl-1,2,4-oxadiazolidine-3-one 
18.7 g. of N-(3-chlorophenyl)-N'-hydroxy-urea are added to 116 g. of 
diethyl ketone. The reaction is stirred at 90.degree. C. for 1 hour. The 
reaction mixture is then evaporated to dryness and the residue is 
recrystallized from a mixture of methanol and water. 
22.7 g. of crystalline substance are obtained, m.p. 82.degree. C. 
Yield: 89%. 
Analysis 
Calculated: %C, 56.59; %H, 5.94; %N, 11.00; %Cl, 13.92. Found: %C, 56.61; 
%H, 6.07; %N, 11.27; %Cl, 13.60. 
Similarly the following compounds of the present invention were prepared: 
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No. Compound m.p. Yield: 
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6. 4-Phenyl-5,5-dimethyl-1,2,4- 
109 81.5 
oxadiazolidine-3-one 
7. 4-(2-Chlorphenyl)-5,5-dimethyl- 
82 78.0 
1,2,4-oxadiazolidine-3-one 
8. 4-(4-Chlorphenyl)-5,5-dimethyl- 
116 86.0 
1,2,4-oxadiazolidine-3-one 
9. 4-(4-Bromphenyl)-5,5-dimethyl- 
135 91.5 
1,2,4-oxadiazolidine-3-one 
10. 4-(2-Methylphenyl)-5,5-dimethyl- 
75 79.5 
1,2,4-oxadiazolidine-3-one 
11. 4-(4-Methylphenyl)-5,5-dimethyl- 
112 87.5 
1,2,4-oxadiazolidine-3-one 
______________________________________ 
The compounds of the invention are all crystalline substances, easy to 
grind and mix and to work up to pesticide compositions. Thus, for example, 
50 kg. of a compound of the formula I can be admixed with 40 kg. of 
Ultrasil (trademark for amorphous silicon oxide) i.e. with a solid 
carrier, with 4 kg. of Totanin B (trademark for sulfite waste liquor 
powder) and with 2 kg. of Tenciofix LX Special (trademark for purified 
sulfite waste liquor powder) i.e. a dispersing agent, and with 4 kg. of 
Tensopol SP-USP (trademark for lauryl alcohol sulfate) i.e. a wetting 
powder, and the mixture is ground and the product is obtained in the form 
of a wettable powder. 
EXAMPLE 12 
The fungicidal activity of the new 1,2,4-oxazolidine-3-one derivatives was 
tested. 4-(3-chlorophenyl)-5,5-dimethyl-1,2,4-oxazolidine-3-one (Example 
3), 4-(4-chlorophenyl)-5,5-dimethyl-1,2,4-oxazolidine-3-one (Example 8) 
and 4-(4-methylphenyl)-5,5-dimethyl-1,2,4-oxadiazolidine-3-one are 
dissolved in dimethylsulfoxide and a 1% solution is prepared. By diluting 
the solution the minimal inhibiting concentration was determined. 
The tested fungi were as follows: 
Alternaria tenuis 
Fusarium culmorum 
Botrytis allii 
The test was conducted in Petri plates using agar diffusion method and as 
minimal concentration that dilution concentration was considered, at which 
the inhibited zone did not change during 72 hours. 
According to our observations the product Example 3 inhibited the growth of 
Alternaria tenuis even at a concentration of 40 ppm., the compound of 
Example 8 inhibited the growth of Botrytis allii at 100 ppm., the growth 
of Fusarium culmorum at 20 ppm., the compound of Example 11 inhibited the 
growth of Fusarium culmorum at 50 ppm., and the growth of Alternaria 
tenuis at 100 ppm. 
EXAMPLE 13 
The herbicidal activity of the 1,2,4-oxadiazolidine-3-one derivatives on 
monocotyledons and dicotyledons was tested during a preemergent and 
postemergent treatment. 
A 50% wettable powder was prepared from the new derivatives, and the 
treatment was carried out in the form of an aqueous suspension by applying 
a quantity corresponding to 3 kg./ha. each time. 
The following weeds were tested: 
Monocotyledons: 
Echinocloa crus-galli 
Setaria viridis 
Dicotyledons: 
Amaranthus retroflexus 
Chenopodium album 
The preemergent treatment was carried out before sprouting and the 
postemergent treatment was carried out in a 3-4 leaves state. The 
effectivity was evaluated 28 days after treatment and the numbers 1-5 have 
the following meaning: 
1: 0-20% activity 
2: 21-40% activity 
3: 41-60% activity 
4: 61-80% activity 
5: 81-activity 
The results of the experiments were summarized in the following table: 
______________________________________ 
Activity 
Monocotyledons Dicotyledons 
Compound of 
pre- post- pre- post- 
Example emergent emergent emergent 
emergent 
______________________________________ 
1 4 2 3 1 
2 5 2 4 2 
6 3 1 5 1 
9 4 2 3 1 
10 4 2 4 1 
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