The invention discloses compounds of the formula ##STR1## wherein R.sup.1 is selected from the group consisting of alkyl, alkenyl, haloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl; and R.sup.2 is selected from the group consisting of alkenyl, haloalkenyl and ##STR2## wherein R.sup.3 and R.sup.4 are selected from the group consisting of hydrogen and alkyl.

This invention relates to new compositions of matter and more particularly 
relates to new chemical compounds of the formula 
##STR3## 
wherein R.sup.1 is selected from the group consisting of alkyl, alkenyl, 
haloalkyl, alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl; and R.sup.2 
is selected from the group consisting of alkenyl, haloalkenyl and 
##STR4## 
wherein R.sup.3 and R.sup.4 are selected from the group consisting of 
hydrogen and alkyl. 
The compounds of the present invention are unexpectedly useful as 
herbicides. 
In a preferred embodiment of this invention R.sup.1 is selected from the 
group consisting of lower alkyl, lower alkenyl, lower haloalkyl, lower 
alkoxy, lower alkylthio, lower alkylsulfonyl and lower alkylsulfinyl; 
R.sup.2 is lower alkenyl, lower chloroalkenyl, lower bromoalkenyl, and 
##STR5## 
wherein R.sup.3 and R.sup.4 are selected from the group consisting of 
hydrogen and alkyl of up to three carbon atoms. 
The term lower as used herein designates a straight or branched carbon 
chain of up to six carbon atoms. 
The compounds of this invention can be readily prepared by heating a 
compound of the formula 
##STR6## 
wherein R.sup.1 and R.sup.2 are as heretofore described, in a dilute, 
aqueous, acidic reaction medium for a period of about 10 to about 60 
minutes. Temperatures of from about 70.degree. C to the reflux temperature 
of the reaction mixture can be utilized. The reaction medium can comprise 
a dilute aqueous inorganic acid such as hydrochloric acid at a 
concentration of from about 0.5 to about 5 percent. Upon completion of the 
reaction the desired product can be recovered as a precipitate by cooling 
the reaction mixture. This product can be used as such or can be further 
purified by conventional means such as recrystallization and the like. 
The compounds of formula II can be prepared by reacting a molar amount of 
an isocyanate dimer of the formula 
##STR7## 
wherein R.sup.1 is as heretofore described, with about two molar amounts 
of a diethyl acetal of the formula 
##STR8## 
wherein R.sup.2 is as heretofore described. This reaction can be effected 
by heating a mixture of the isocyanate dimer and the acetal in an inert 
organic reaction medium such as benzene at the reflux temperature of the 
reaction mixture. Heating at reflux can be continued for a period of from 
about 2 to about 30 minutes to insure completion of the reaction. After 
this time the desired product can be recovered upon evaporation of the 
reaction medium and can be used as such or can be further purified by 
standard techniques in the art. 
The isocyanate dimer of formula III can be prepared by reacting a 
thiadiazole of the formula 
##STR9## 
wherein R.sup.1 is as heretofore described, with phosgene. This reaction 
can be effected by adding a slurry or solution of the thiadiazole, in a 
suitable organic solvent such as ethyl acetate, to a saturated solution of 
phosgene in an organic solvent such as ethyl acetate. The resulting 
mixture can be stirred at ambient temperatures for a period of from about 
4 to about 24 hours. The reaction mixture can then be purged with nitrogen 
gas to remove unreacted phosgene. The desired product can then be 
recovered by filtration if formed as a precipitate or upon evaporation of 
the organic solvent used if soluble therein. This product can be used as 
such or can be further purified if desired. 
Exemplary thiadiazoles of formula V useful for preparing the compounds of 
the present invention are 5-methyl-2-amino-1,3,4-thiadiazole, 
5-ethyl-2-amino-1,3,4-thiadiazole, 5-propyl-3-amino-1,3,4-thiadiazole, 
5-allyl-2-amino-1,3,4-thiadiazole, 
5-pent-3-enyl-2-amino-1,3,4-thiadiazole, 5-chloromethyl-2-amino-1,3,4-thia 
diazole, 5-.beta.-chloroethyl-2-amino-1,3,4-thiadiazole, 
5-.gamma.-chloropropyl-2-amino-1,3,4-thiadiazole, 
5-trichloromethyl-2-amino-1,3,4-thiadiazole, 
5-methoxy-2-amino-1,3,4-thiadiazole, 5-ethoxy-2-amino-1,3,4-thiadiazole, 
5-propoxy-2-amino-1,3,4-thiadiazole, 5-butyloxy-2-amino-1,3,4-thiadiazole, 
5-hexyloxy-2-amino-1,3,4-thiadiazole, 
5-methylthio-2-amino-1,3,4-thiadiazole, 
5-ethylthio-2-amino-1,3,4-thiadiazole, 
5-propylthio-2-amino-1,3,4-thiadiazole, 
5-butylthio-2-amino-1,3,4-thiadiazole, 
5-methylsulfonyl-2-amino-1,3,4-thiadiazole, 
5-ethylsulfonyl-2-amino-1,3,4-thiadiazole, 
5-butylsulfonyl-2-amino-1,3,4-thiadiazole, 
5-hexylsulfonyl-2-amino-1,3,4-thiadiazole, 
5-methylsulfinyl-2-amino-1,3,4-thiadiazole, 
5-ethylsulfinyl-2-amino-1,3,4-thiadiazole, 
5-propylsulfinyl-2-amino-1,3,4-thiadiazole, 5-butylsulfinyl-2-amino- 
1,3,4-thiadiazole, 5-trifluoromethyl-2-amino-1,3,4-thiadiazole, 
5-t-butyl-2-amino-1,3,4-thiadiazole and the like. 
The diethyl acetal of formula IV when not readily available can be prepared 
by reacting an amine of the formula 
##STR10## 
wherein R.sup.2 is as heretofore described with the diethyl acetal of 
.alpha.-bromoacetaldehyde. This reaction can be effected by combining from 
about 1 to about 2 molar amounts of the amine of formula IV with one molar 
amount of the diethyl acetal of .alpha.-bromoacetaldehyde in about 
equimolar proportions in an inert organic reaction medium such as 
methanol. The reaction mixture can then be heated at reflux for a period 
of from about 4 to about 8 hours. After this time the reaction mixture can 
be cooled to room temperature and an alkali metal hydroxide or carbonate 
can be added in an amount sufficient to neutralize the reaction mixture. 
Stirring can be continued at room temperature for a period of up to about 
24 hours to ensure completion of the reaction. After this time the 
reaction mixture can be filtered and the filtrate distilled under reduced 
pressure to yield the desired product. 
Exemplary compounds of formula VI are allylamine, propargylamine, 
2-butenylamine, 3-butenylamine, 3-pentenylamine, 4-pentenylamine, 
5-hexenylamine, 1-methyl-2-propynylamine, 1,1-dimethyl-2-propynylamine, 
1-ethyl-2-propynylamine, 1,1-diethyl-2-propynylamine, 
1-propyl-2-propynylamine, 1,1-dipropyl-2-propynylamine, 
1-chloroallylamine, 1-bromoallylamine, 4-chloro-2-butenylamine, 
6-chloro-4-hexenylamine and the like. 
The manner in which the compounds of the present invention can be prepared 
is more specifically illustrated in the following examples.

EXAMPLE 1 
Preparation of the Diethyl Acetal of 2-Allylaminoacetaldehyde 
Allylamine (60 grams), the diethyl acetal of 2-bromoacetaldehyde (90 grams) 
and methanol (100 ml) were charged into a glass reaction vessel equipped 
with a mechanical stirrer, thermometer and reflux condenser. The reaction 
mixture was heated at reflux with stirring for a period of about 6 hours. 
After this time the reaction mixture was cooled to room temperature and 
sodium hydroxide (20 grams) was added. The reaction mixture was then 
stirred for an additional period of about 16 hours. The mixture was then 
filtered and the filtrate was distilled to yield the desired product the 
diethyl acetal of 2-allylaminoacetaldehyde having a boiling point of 
69.degree. C at 4.0 mm of Hg pressure. 
EXAMPLE 2 
Preparation of 5-t-Butyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) was charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-t-butyl-2-amino-1,3,4-thiadiazole (10 grams) in ethyl acetate (300 ml) 
was added to the reaction vessel and the resulting mixture was stirred for 
a period of about 16 hours resulting in the formation of a precipitate. 
The reaction mixture was then purged with nitrogen gas to remove unreacted 
phosgene. The purged mixture was then filtered to recover the desired 
product 5-t-butyl-1,3,4-thiadiazol-2-yl isocyanate dimer as a solid having 
a melting point of 261.degree. to 263.degree. C. 
EXAMPLE 3 
Preparation of the Diethyl Acetal of 
2-[1-allyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
A mixture of 5-t-butyl-1,3,4-thiadiazol-2yl isocyanate dimer (8.7 grams), 
the diethyl acetal of 2-allylaminoacetaldehyde (8.0 grams) and benzene (50 
ml) was charged into a glass reaction flask equipped with a mechanical 
stirrer and thermometer. The reaction mixture was then warmed with 
stirring until the reactants dissolved. After this time the reaction 
mixture was stripped of benzene to yield an oil. This oil was dissolved in 
an ether-pentane mixture and was treated with diatomaceous earth and 
filtered. The filtrate was then stripped of solvent to yield the desired 
product the diethyl acetal of 
2-[1-allyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde as a 
dark red oil. 
EXAMPLE 4 
Preparation of 
1-(5-t-Butyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-o 
ne 
The diethyl acetal of 
2-[1-allyl-3-(5-t-butyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde prepared 
in Example 3, concentrated hydrochloric acid (10 ml) and water (800 ml) 
were charged into a glass reaction vessel equipped with a mechanical 
stirrer, thermometer and reflux condenser. The reaction mixture was heated 
at reflux for a period of about 15 minutes. The reaction mixture was 
filtered while hot and the filtrate was then cooled, resulting in the 
formation of a precipitate. The precipitate was recovered by filtration, 
dried and was recrystallized from an ethyl acetate-hexane mixture to yield 
the desired product 
1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-o 
ne having a melting point of 106.degree. to 107.degree. C. 
EXAMPLE 5 
Preparation of 5-Trifluoromethyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) was charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-trifluoromethyl-2-amino-1,3,4-thiadiazole (45 grams) in ethyl acetate 
(300 ml) was added to the reaction vessel and the resulting mixture was 
stirred for a period of about 16 hours resulting in the formation of 
precipitate. The reaction mixture was then purged with nitrogen gas to 
remove unreacted phosgene. The purged mixture was filtered to recover 48 
grams of a white solid. This solid was recrystallized from dimethyl 
formamide to yield the desired product 
5-trifluoromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 6 
Preparation of the Diethyl Acetal of 
2-[1-allyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
A mixture of 5-trifluoromethyl-1,3,4-thiadiazol-2-yl isocyanate dimer (9.0 
grams), the diethyl acetal of 2-allylaminoacetaldehyde (8.0 grams) and 
benzene (30 ml) are charged into a glass reaction vessel equipped with a 
mechanical stirrer and thermometer. The reaction mixture was then warmed 
with stirring until the reactants dissolved. After this time the reaction 
mixture was stripped of benzene to yield an oil. This oil was dissolved in 
an ether-pentane mixture and was treated with diatomaceous earth and 
filtered. The filtrate was then stripped of solvent to yield the desired 
product the diethyl acetal of 
2-[1-allyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
as a red oil. 
EXAMPLE 7 
Preparation of 
1-(5-Trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazol 
idin-2-one 
The diethyl acetal of 
2-[1-allyl-3-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
prepared in Example 6, water (800 ml) and hydrochloric acid (10 ml) were 
charged into a glass reaction vessel equipped with a mechanical stirrer, 
thermometer and reflux condenser. The reaction mixture was heated at 
reflux for a period of about 15 minutes. The reaction mixture was then 
filtered while hot and the filtrate was cooled resulting in the formation 
of a precipitate. The precipitate was recovered by filtration, was dried 
and was recrystallized from hexane to yield the desired product 
1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazol 
idin-2-one having a melting point of 92.degree. to 93.degree. C. 
EXAMPLE 8 
Preparation of the Diethyl Acetal of 2-Propargylaminoacetaldehyde 
Propargylamine (2.0 mole), the diethyl acetal of 2-bromoacetaldehyde (1.0 
mole) and methanol (100 ml) are charged into a glass reaction vessel 
equipped with a mechanical stirrer, thermometer and reflux condenser. The 
reaction mixture is heated at reflux with stirring for a period of about 4 
hours. After this time the reaction mixture is cooled to room temperature 
and sodium hydroxide (20 grams) is added. The reaction mixture is then 
stirred for an additional period of about 16 hours. The mixture is then 
filtered and the filtrate is distilled to yield the desired product the 
diethyl acetal of 2-propargylaminoacetaldehyde. 
EXAMPLE 9 
Preparation of 5-Methyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) is charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-methyl-2-amino-1,3,4-thiadiazole (40 grams) in ethyl acetate (300 ml) is 
added to the reaction vessel and the resulting mixture is stirred for a 
period of about 16 hours, resulting in the formation of a precipitate. The 
reaction mixture is then purged with nitrogen gas to remove unreacted 
phosgene. The purged mixture is then filtered to recover the precipitate. 
The precipitate is then recrystallized to yield the desired product 
5-methyl-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 10 
Preparation of the Diethyl Acetal of 
2-[1-Propargyl-3-(5-methyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
A mixture of 5-methyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), 
the diethyl acetal of 2-propargylaminoacetaldehyde (0.1 mole) and benzene 
(60 ml) are charged into a glass reaction vessel equipped with a 
mechanical stirrer and reflux condenser. The reaction mixture is heated at 
reflux for a period of about 15 minutes. After this time the mixture is 
stripped of benzene under reduced pressure to yield a solid product as the 
residue. The residue is then recrystallized to yield the desired product 
the diethyl acetal of 
2-[1-propargyl-3-(5-methyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde. 
EXAMPLE 11 
Preparation of 
1-(5-Methyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolidin- 
2-one 
The diethyl acetal of 
2-[1-propargyl-3-(5-methyl-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde (15 
grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a 
glass reaction vessel equipped with a mechanical stirrer, thermometer and 
reflux condenser. The reaction mixture is heated at reflux for a period of 
about 15 minutes. The reaction mixture is then filtered while hot and the 
filtrate is cooled to form a precipitate. The precipitate is recovered by 
filtration, is dried and is recrystallized to yield the desired product 
1-(5-methyl-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolidin- 
2-one. 
EXAMPLE 12 
Preparation of 5-Methoxy-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) is charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-methoxy-2-amino-1,3,4-thiadiazole (40 grams) in ethyl acetate (300 ml) 
is added to the reaction vessel and the resulting mixture is stirred for a 
period of about 16 hours, resulting in the formation of a precipitate. The 
reaction mixture is then purged with nitrogen gas to remove unreacted 
phosgene. The purged mixture is then filtered to recover the precipitate. 
The precipitate is then recrystallized to yield the desired product 
5-methoxy-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 13 
Preparation of the Diethyl Acetal of 2-But-3-enylaminoacetaldehyde 
But-3-enylamine (1.5 mole), the diethyl acetal of 2-bromoacetaldehyde (1.0 
mole) and methanol (100 ml) are charged into a glass reaction vessel 
equipped with a mechanical stirrer, thermometer and reflux condenser. The 
reaction mixture is heated at reflux with stirring for a period of about 6 
hours. After this time the reaction mixture is cooled to room temperature 
and sodium hydroxide (20 grams) is added. The reaction mixture is then 
stirred for an additional period of about 16 hours. The mixture is then 
filtered and the filtrate is distilled to yield the desired product the 
diethyl acetal of 2-but-3-enylaminoacetaldehyde. 
EXAMPLE 14 
Preparation of the Diethyl Acetal of 
2-[1-But-3-enyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
A mixture of 5-methoxy-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 mole), 
the diethyl acetal of 2-but-3-enylaminoacetaldehyde (0.1 mole) and benzene 
(60 ml) are charged into a glass reaction vessel equipped with a 
mechanical stirrer and reflux condenser. The reaction mixture is heated at 
reflux for a period of about 15 minutes. After this time the mixture is 
stripped of benzene under reduced pressure to yield the desired product 
the diethyl acetal of 
2-[1-but-3-enyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde. 
EXAMPLE 15 
Preparation of 
1-(5-Methoxy-1,3,4-thiadiazol-2-yl)-3-but-3-enyl-5-hydroxy-1,3-imidazolidi 
n-2-one 
The diethyl acetal of 
2-[1-but-3-enyl-3-(5-methoxy-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde (15 
grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a 
glass reaction vessel equipped with a mechanical stirrer, thermometer and 
reflux condenser. The reaction mixture is heated at reflux for a period of 
about 15 minutes. The reaction mixture is then filtered while hot and the 
filtrate is cooled to form a precipitate. The precipitate is recovered by 
filtration, is dried and is recrystallized to yield the desired product, 
1-(5-methoxy-1,3,4-thiadiazol-2-yl)-3-but-3-enyl-5-hydroxy-1,3-imidazolidi 
n-2-one. 
EXAMPLE 16 
Preparation of 5-Methylthio-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) is charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-methylthio-2-amino-1,3,4-thiadiazole (45 grams) in ethyl acetate (300 
ml) is added to the reaction vessel and the resulting mixture is stirred 
for a period of about 16 hours, resulting in the formation of a 
precipitate. The reaction mixture is then purged with nitrogen gas to 
remove unreacted phosgene. The purged mixture is then filtered to recover 
the precipitate. The precipitate is then recrystallized to yield the 
desired product 5-methylthio-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 17 
Preparation of the Diethyl Acetal of 2-Hex-4-enylaminoacetaldehyde 
Hex-4-enylamine (2.0 mole), the diethyl acetal of 2-bromoacetaldehyde (1.0 
mole) and methanol (100 ml) are charged into a glass reaction vessel 
equipped with a mechanical stirrer, thermometer and reflux condenser. The 
reaction mixture is heated at reflux with stirring for a period of about 6 
hours. After this time the reaction mixture is cooled to room temperature 
and sodium hydroxide (20 grams) is added. The reaction mixture is then 
stirred for an additional period of about 16 hours. The mixture is then 
filtered and the filtrate is distilled to yield the desired product the 
diethyl acetal of 2-hex-4-enylaminoacetaldehyde. 
EXAMPLE 18 
Preparation of the Diethyl Acetal of 
2-[1-Hex-4-enyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
A mixture of 5-methylthio-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 
mole), the diethyl acetal of 2-hex-4-enylaminoacetaldehyde (0.1 mole) and 
benzene (60 ml) are charged into a glass reaction vessel equipped with a 
mechanical stirrer and reflux condenser. The reaction mixture is heated at 
reflux for a period of about 15 minutes. After this time the mixture is 
stripped of benzene under reduced pressure to yield a solid product as the 
residue. The residue is then recrystallized to yield the desired product 
the diethyl acetal of 
2-[1-hex-4-enyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde. 
EXAMPLE 19 
Preparation of 
1-(5-Methylthio-1,3,4-thiadiazol-2-yl)-3-hex-4-enyl-5-hydroxy-1,3-imidazol 
idin-2-one 
The diethyl acetal of 
2-[1-hex-4-enyl-3-(5-methylthio-1,3,4-thiadiazol-2-yl)ureido]acetaldehyde 
(15 grams), water (400 ml) and hydrochloric acid (4 ml) are charged into a 
glass reaction vessel equipped with a mechanical stirrer, thermometer and 
reflux condenser. The reaction mixture is heated at reflux for a period of 
about 15 minutes. The reaction mixture is then filtered while hot and the 
filtrate is cooled to form a precipitate. The precipitate is recovered by 
filtration, is dried and is recrystallized to yield the desired product 
1-(5-methylthio-1,3,4-thiadiazol-2-yl)-3-hex-4-enyl-5-hydroxy-1,3-imidazol 
idin-2-one. 
EXAMPLE 20 
Preparation of 5-Methylsulfonyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) is charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-methylsulfonyl-2-amino-1,3,4-thiadiazole (50 grams) in ethyl acetate 
(300 ml) is added to the reaction vessel and the resulting mixture is 
stirred for a period of about 16 hours, resulting in the formation of a 
precipitate. The reaction mixture is then purged with nitrogen gas to 
remove unreacted phosgene. The purged mixture is then filtered to recover 
the precipitate. The precipitate is then recrystallized to yield the 
desired product 5-methylsulfonyl-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 21 
Preparation of the Diethyl Acetal of 
2-(1,1-Dimethylprop-2-ynylamino)acetaldehyde 
1,1-Dimethylprop-2-ynylamine (2.0 mole), the diethyl acetal of 
2-bromoacetaldehyde (1.0 mole) and methanol (100 ml) are charged into a 
glass reaction vessel equipped with a mechanical stirrer, thermometer and 
reflux condenser. The reaction mixture is heated at reflux with stirring 
for a period of about 6 hours. After this time the reaction mixture is 
cooled to room temperature and sodium hydroxide (20 grams) is added. The 
reaction mixture is then stirred for an additional period of about 16 
hours. The mixture is then filtered and the filtrate is distilled to yield 
the desired product the diethyl acetal of 
2-(1,1-dimethylprop-2-ynylamino)acetaldehyde. 
EXAMPLE 22 
Preparation of the Diethyl Acetal of 
2-[1-(1,1-Dimethylprop-2-ynyl)-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde 
A mixture of 5-methylsulfonyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 
mole), the diethyl acetal of 2-(1,1-dimethylprop-2-ynylamino)acetaldehyde 
(0.1 mole) and benzene (60 ml) are charged into a glass reaction vessel 
equipped with a mechanical stirrer and reflux condenser. The reaction 
mixture is heated at reflux for a period of about 15 minutes. After this 
time the mixture is stripped of benzene under reduced pressure to yield a 
solid product as the residue. The residue is then recrystallized to yield 
the desired product the diethyl acetal of 
2-[1-(1,1-dimethylprop-2-ynyl)-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde. 
EXAMPLE 23 
Preparation of 
1-(5-Methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-(1,1-dimethylprop-2-ynyl)-5-h 
ydroxy-1,3-imidazolidin-2-one 
The diethyl acetal of 
2-[1-(1,1-dimethylprop-2-ynyl)-3-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml) 
are charged into a glass reaction vessel equipped with a mechanical 
stirrer, thermometer and reflux condenser. The reaction mixture is heated 
at reflux for a period of about 15 minutes. The reaction mixture is then 
filtered while hot and the filtrate is cooled to form a precipitate. The 
precipitate is recovered by filtration, is dried and is recrystallized to 
yield the desired product 
1-(5-methylsulfonyl-1,3,4-thiadiazol-2-yl)-3-(1,1-dimethylprop-2-ynyl)-5-h 
ydroxy-1,3-imidazolidin-2-one. 
EXAMPLE 24 
Preparation of 5-Methylsulfinyl-1,3,4-thiadiazol-2-yl Isocyanate Dimer 
A saturated solution of phosgene in ethyl acetate (100 ml) is charged into 
a glass reaction vessel equipped with a mechanical stirrer. A slurry of 
5-methylsulfinyl-2-amino-1,3,4-thiadiazole (50 grams) in ethyl acetate 
(300 ml) is added to the reaction vessel and the resulting mixture is 
stirred for a period of about 16 hours, resulting in the formation of a 
precipitate. The reaction mixture is then purged with nitrogen gas to 
remove unreacted phosgene. The purged mixture is then filtered to recover 
the precipitate. The precipitate is then recrystallized to yield the 
desired product 5-methylsulfinyl-1,3,4-thiadiazol-2-yl isocyanate dimer. 
EXAMPLE 25 
Preparation of the Diethyl Acetal of 
2-(1,1-dipropylprop-2-ynylamino)acetaldehyde 
1,1-Dipropylprop-2-ynylamine (1.6 mole), the diethyl acetal of 
2-bromoacetaldehyde (1.0 mole) and methanol (100 ml) are charged into a 
glass reaction vessel equipped with a mechanical stirrer, thermometer and 
reflux condenser. The reaction mixture is heated at reflux with stirring 
for a period of about 6 hours. After this time the reaction mixture is 
cooled to room temperature and sodium hydroxide (20 grams) is added. The 
reaction mixture is then stirred for an additional period of about 16 
hours. The mixture is then filtered and the filtrate is distilled to yield 
the desired product the diethyl acetal of 
2-(1,1-dipropylprop-2-ynylamino)acetaldehyde. 
EXAMPLE 26 
Preparation of the Diethyl Acetal of 
2-[1-(1,1-Dipropylprop-2-ynyl)-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde 
A mixture of 5-methylsulfinyl-1,3,4-thiadiazol-2-yl isocyanate dimer (0.05 
mole), the diethyl acetal of 2-(1,1-dipropylprop-2-ynylamino)acetaldehyde 
(0.1 mole) and benzene (60 ml) are charged into a glass reaction vessel 
equipped with a mechanical stirrer and reflux condenser. The reaction 
mixture is heated at reflux for a period of about 15 minutes. After this 
time the mixture is stripped of benzene under reduced pressure to yield a 
solid product as the residue. The residue is then recrystallized to yield 
the desired product the diethyl acetal of 
2-[1-(1,1-dipropylprop-2-ynyl)-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde. 
EXAMPLE 27 
Preparation of 
1-(5-Methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-(1,1-dipropylprop-2-ynyl)-5-h 
ydroxy-1,3-imidazolidin-2-one 
The diethyl acetal of 
2-[1-(1,1-dipropylprop-2-ynyl)-3-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)u 
reido]acetaldehyde (15 grams), water (400 ml) and hydrochloric acid (4 ml) 
are charged into a glass reaction vessel equipped with a mechanical 
stirrer, thermometer and reflux condenser. The reaction mixture is heated 
at reflux for a period of about 15 minutes. The reaction mixture is then 
filtered while hot and the filtrate is cooled to form a precipitate. The 
precipitate is recovered by filtration, is dried and is recrystallized to 
yield the desired product 
1-(5-methylsulfinyl-1,3,4-thiadiazol-2-yl)-3-(1,1-dipropylprop-2-ynyl)-5-h 
ydroxy-1,3-imidazolidin-2-one. 
Additional compounds within the scope of the present invention which can be 
prepared by the procedures of the foregoing examples are 
1-(5-ethyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one 
, 1-(5-propyl-1,3,4-thiadiazol-2-yl)-3-but-3-enyl-5-hydroxy-1,3-imidazolidi 
n-2-one, 
1-(5-butylthio-1,3,4-thiadiazol-2-yl)-3-propargyl-5-hydroxy-1,3-imidazolid 
in-2-one, 
1-(5-pentylthio-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin- 
2-one, 
1-(5-hexylthio-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2 
-one, 
1-(5-ethylthio-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2 
-one, 
1-(5-ethoxy-1,3,4-thiadiazol-2-yl)-3-hex-5-enyl-5-hydroxy-1,3-imidazolidin 
-2-one, 
1-(5-propoxy-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-o 
ne, 
1-(5-butoxy-1,3,4-thiadiazol-2-yl)-3-(1,1-diethylprop-2-ynyl)-5-hydroxy-1, 
3-imidazolidin-2-one, 
1-(5-hexyloxy-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2- 
one, 
1-(5-chloromethyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidi 
n-2-one, 
1-(5-.beta.-chloroethyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imida 
zolidin-2-one, 
1-(5-.gamma.-chlorobutyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imid 
azolidin-2-one, 
1-(5-allyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one 
, 1-(5-pent-3-enyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidi 
n-2-one, 
1-(5-hex-5-enyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin- 
2-one, 
1-(5-ethylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolid 
in-2-one, 
1-(5-propylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazoli 
din-2-one, 
1-(5-butylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolid 
in-2-one, 
1-(5-hexylsulfonyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolid 
in-2-one, 1-(5-ethylsulfinyl-1,3,4 
-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolidin-2-one, 
1-(5-propylsulfinyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazoli 
din-2-one, 
1-(5-butylsulfinyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolid 
in-2-one, 
1-(5-pentylsulfinyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazoli 
din-2-one, 
1-(5-hexylsulfinyl-1,3,4-thiadiazol-2-yl)-3-allyl-5-hydroxy-1,3-imidazolid 
in-2-one, 
1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-(1-chloroallyl)-5-hydroxy-1,3-imidaz 
olidin-2-one, 
1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-(4-bromopent-2-enyl)-5-hydroxy-1,3-i 
midazolidin-2-one, 
1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-(6-chlorohex-3-enyl)-5-hydroxy-1,3-i 
midazolidin-2-one, 
1-(5-t-butyl-1,3,4-thiadiazol-2-yl)-3-(4,4,4-trichlorobut-2-enyl)-5-hydrox 
y-1,3-imidazolidin-2-one, 
1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-(1-methylprop-2-ynyl)-5-hydr 
oxy-1,3-imidazolidin-2-one, 
1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-(1-ethylprop-2-ynyl)-5-hydro 
xy-1,3-imidazolidin-2-one, 
1-(5-trifluoromethyl-1,3,4-thiadiazol-2-yl)-3-(1-propylprop-2-ynyl)-5-hydr 
oxy-1,3-imidazolidin-2-one and the like. 
For practical use as herbicides the compounds of this invention are 
generally incorporated into herbicidal compositions which comprise an 
inert carrier and a herbicidally toxic amount of such a compound. Such 
herbicidal compositions, which can also be called formulations, enable the 
active compound to be applied conveniently to the site of the weed 
infestation in any desired quantity. These compositions can be solids such 
as dusts, granules, or wettable powders; or they can be liquids such as 
solutions, aerosols, or emulsifiable concentrates. 
For example, dusts can be prepared by grinding and blending the active 
compound with a solid inert carrier such as the talcs, clays, silicas, 
pyrophyllite, and the like. Granular formulations can be prepared by 
impregnating the compound, usually dissolved in a suitable solvent, onto 
and into granulated carriers such as the attapulgites or the vermiculites, 
usually of a particle size range of from about 0.3 to 1.5 mm. Wettable 
powders, which can be dispersed in water or oil to any desired 
concentration of the active compound, can be prepared by incorporating 
wetting agents into concentrated dust compositions. 
In some cases the active compounds are sufficiently soluble in common 
organic solvents such as kerosene or xylene so that they can be used 
directly as solutions in these solvents. Frequently, solutions of 
herbicides can be dispersed under super-atmospheric pressure as aerosols. 
However, preferred liquid herbicidal compositions are emulsifiable 
concentrates, which comprise an active compound according to this 
invention and as the inert carrier, a solvent and an emulsifier. Such 
emulsifiable concentrates can be extended with water and/or oil to any 
desired concentration of active compound for application as sprays to the 
site of the weed infestation. The emulsifiers most commonly used in these 
concentrates are nonionic or mixtures of nonionic with anionic 
surface-active agents. With the use of some emulsifier systems an inverted 
emulsion (water in oil) can be prepared for direct application to weed 
infestations. 
A typical herbicidal composition according to this invention is illustrated 
by the following example, in which the quantities are in parts by weight. 
EXAMPLE 28 
Preparation of a Dust 
Product of Example 4: 10 
Powdered Talc: 90 
The above ingredients are mixed in a mechanical grinder-blender and are 
ground until a homogeneous, free-flowing dust of the desired particle size 
is obtained. This dust is suitable for direct application to the site of 
the weed infestation. 
The compounds of this invention can be applied as herbicides in any manner 
recognized by the art. One method for the control of weeds comprises 
contacting the locus of said weeds with a herbicidal composition 
comprising an inert carrier and as an essential active ingredient, in a 
quantity which is herbicidally toxic to said weeds, a compound of the 
present invention. The concentration of the new compounds of this 
invention in the herbicidal compositions will vary greatly with the type 
of formulation and the purpose for which it is designed, but generally the 
herbicidal compositions will comprise from about 0.05 to about 95 percent 
by weight of the active compounds of this invention. In a preferred 
embodiment of this invention, the herbicidal compositions will comprise 
from about 5 to about 75 percent by weight of the active compound. The 
compositions can also comprise such additional substances as other 
pesticides, such as insecticides, nematocides, fungicides, and the like; 
stabilizers, spreaders, deactivators, adhesives, stickers, fertilizers, 
activators, synergists, and the like. 
The compounds of the present invention are also useful when combined with 
other herbicides and/or defoliants, dessicants, growth inhibitors, and the 
like in the herbicidal compositions heretofore described. These other 
materials can comprise from about 5% to about 95% of the active 
ingredients in the herbicidal compositions. Use of combinations of these 
other herbicides and/or defoliants, dessicants, etc. with the compounds of 
the present invention provide herbicidal compositions which are more 
effective in controlling weeds and often provide results unattainable with 
separate compositions of the individual herbicides. The other herbicides, 
defoliants, dessicants and plant growth inhibitors, with which the 
compounds of this invention can be used in the herbicidal compositions to 
control weeds, can include chlorophenoxy herbicides such as 2,4-D, 
2,4,5-T, MCPA, MCPB, 4(2,4-DB), 2,4-DEB, 4-CPB, 4-CPA, 4-CPP, 2,4,5-TB, 
2,4,5-TES, 3,4-DA, silvex and the like; carbamate herbicides such as IPC, 
CIPC, swep, barban, BCPC, CEPC, CPPC, and the like; thiocarbamate and 
dithiocarbamate herbicides such as CDEC, metham sodium, EPTC, diallate, 
PEBC, perbulate, vernolate and the like; substituted urea herbicides such 
as norea, siduron, dichloral urea, chloroxuron, cycluron, fenuron, 
monuron, monuron TCA, diuron, linuron, monolinuron, neburon, buturon, 
trimeturon and the like; symmetrical triazine herbicides such as simazine, 
chlorazine, atraone, desmetryne, norazine, ipazine, prometryn, atazine, 
trietazine, simetone, prometone, propazine, ametryne and the like; 
chloroacetamide herbicides such as 4-(chloroacetyl)morpholine, 
1-(chloroacetyl)piperidine and the like; chlorinated aliphatic acid 
herbicides such as TCA, dalapon, 2,3-dichloropropionic acid, 2,2,3-TPA and 
the like; chlorinated benzoic acid and phenylacetic acid herbicides such 
as 2,3,6-TBA, 2,3,5,6-TBA, dicamba, tricamba, amiben, fenac, PBA, 
2-methoxy-3,6-dichlorophenylacetic acid, 
3-methoxy-2,6-dichlorophenylacetic acid, 
2-methoxy-3,5,6-trichlorophenylacetic acid, 2,4-dichloro-3-nitrobenzoic 
acid and the like; and such compounds as aminotriazole, maleic hydrazide, 
phenyl mercuric acetate, endothal, biuret, technical chlordane, dimethyl 
2,3,5,6-tetrachloroterephthalate, diquat, erbon, DNC, DNBP, dichlobenil, 
DPA, diphenamid, dipropalin, trifluralin, solan, dicryl, merphos, DMPA, 
DSMA, MSMA, potassium azide, acrolein, benefin, bensulide, AMS, bromacil, 
2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione, 
bromoxynil, cacodylic acid, CMA, CPMF, cypromid, DCB, DCPA, dichlone, 
diphenatril, DMTT, DNAP, EBEP, EXD, HCA, ioxynil, IPX, isocil, potassium 
cyanate, MAA, MAMA, MCPES, MCPP, MH, molinate, NPA, OCH, paraquat, PCP, 
picloram, DPA, PCA, pyrichlor, sesone, terbacil, terbutol, TCBA, brominil, 
CP-50144, H-176-1, H-732, M-2901, planavin, sodium tetraborate, calcium 
cyanamid, DEF, ethyl xanthogen disulfide, sindone, sindone B, propanil and 
the like. 
Such herbicides can also be used in the methods and compositions of this 
invention in the form of their salts, esters, amides, and other 
derivatives whenever applicable to the particular parent compounds. 
Weeds are undesirable plants growing where they are not wanted, having no 
economic value, and interfering with the production of cultivated crops, 
with the growing of ornamental plants, or with the welfare of livestock. 
Many types of weeds are known, including annuals such as pigweed, 
lambsquarters, foxtail, crabgrass, wild mustard, field pennycress, 
ryegrass, goose grass, chickweed, wild oats, velvet-leaf, purslane, 
barnyardgrass, smartweed, knotweed, cocklebur, wild buckwheat, kochia, 
medic, corn cockle, ragweed, sow-thistle, coffeeweed, croton, cuphea, 
dodder, fumitory, groundsel, hemp nettle, knawel, spurge, spurry, emex, 
jungle rice, pondweed, dog fennel, carpetweed, moringglory, bedstraw, 
ducksalad, naiad, cheatgrass, fall panicum, jimsonweed, witchgrass, 
switchgrass, watergrass, teaweed, wild turnip and sprangletop; biennials 
such as wild carrot, matricaria, wild barley, campion, chamomile, burdock, 
mullein, roundleaved mallow, bull thistle, hounds-tongue, moth mullein and 
purple star thistle; or perennials such as white cockle, perennial 
ryegrass, quackgrass, Johnson grass, Canada thistle, hedge bindweed, 
Bermuda grass, sheep sorrel, curly dock, nutgrass, field chickweed, 
dandelion, campanula, field bindweed, Russian knapweed, mesquite, 
toadflax, yarrow, aster, gromwell, horsetail, ironweed, sesbania, bulrush, 
cattail, wintercress, horsenettle, nutsedge, milkweed and sicklepod. 
Similarly, such weeds can be classified as broadleaf or grassy weeds. It is 
economically desirable to control the growth of such weeds without 
damaging beneficial plants or livestock. 
The new compounds of this invention are particularly valuable for weed 
control because they are toxic to many species and groups of weeds while 
they are relatively non-toxic to many beneficial plants. The exact amount 
of compound required will depend on a variety of factors, including the 
hardiness of the particular weed species, weather, type of soil, method of 
application, the kind of beneficial plants in the same area, and the like. 
Thus, while the application of up to only about one or two ounces of 
active compound per acre may be sufficient for good control of a light 
infestation of weeds growing under adverse conditions, the application of 
10 pounds or more of an active compound per acre may be required for good 
control of a dense infestation of hardy perennial weeds growing under 
favorable conditions. 
The herbicidal toxicity of the new compounds of this invention can be 
demonstrated by the following established testing techniques known to the 
art, pre- and post-emergence testing. 
The herbicidal activity of the compounds of this invention can be 
demonstrated by experiments carried out for the pre-emergence control of a 
variety of weeds. In these experiments small plastic greenhouse pots 
filled with dry soil are seeded with the various weed seeds. Twenty-four 
hours or less after seeding the pots are sprayed with water until the soil 
is wet and a test compound formulated as an aqueous emulsion of an acetone 
solution containing emulsifiers is sprayed at the desired concentrations 
on the surface of the soil. 
After spraying, the soil containers are placed in the greenhouse and 
provided with supplementary heat as required and daily or more frequent 
watering. The plants are maintained under these conditions for a period of 
from 15 to 21 days, at which time the condition of the plants and the 
degree of injury to the plants is rated on a scale of from 0 to 10, as 
follows: 0 = no injury, 1,2 = slight injury, 3,4 = moderate injury, 5,6 = 
moderately severe injury, 7,8,9 = severe injury and 10 = death. 
The herbicidal activity of the compounds of this invention can also be 
demonstrated by experiments carried out for the post-emergence control of 
a variety of weeds. In these experiments the compounds to be tested are 
formulated as aqueous emulsions and sprayed at the desired dosage on the 
foliage of the weeds that have attained a prescribed size. After spraying 
the plants are placed in a greenhouse and watered daily or more 
frequently. Water is not applied to the foliage of the treated plants. The 
severity of the injury is determined 10 to 15 days after treatment and is 
rated on the scale of from 0 to 10 heretofore described.