IL44428A - 3-alkyl-1-(5-substituted-1,3,4-thiadiazol-2-yl)-5-hydroxy-2-imidazolidinones - Google Patents

Description

This invention relates to new compositions of matter and more particularly relates to new chemical compounds of the formula .1 wherein R"1" is selected from the group consisting of alkyl up to 4 carbon atoms, Hfck¾M¥& , chloroalkyl, trifluoromethyl , 2 alkoxy, alkylthio, alkylsulfonyl and alkylsulfinyl ; and R is alkyl.

The compounds of the present invention are unexpectedly useful as herbicides.

In a preferred embodiment of this invention R^ is selected from the group consisting of alkyl of up to 4 carbon atoms, ] -¾5e^3a-Ms«a325CSC-K, lower chloroalkyl, trifluoromethyl , lower alkoxy, lower alkylthio, lower alkylsulfonyl and lower alkyl- 2 sulfmyl; and R xs lower alkyl.

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 N- N wherein R and R are as heretofore described, in a dilute, aqueous, acidic reaction medium for a period of about 10 to about ° 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 wherein R is as heretofore described, with about two molar amounts of a dimethyl acetal of the formula wherein R 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 N N R1 - C C - NH.

NS (V) ^ 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-l , 3 , 4-thiadiazole , 5-ethyl-2-amino-1 , 3 , 4-thiadiazole , 5-propyl-2-amino-l , 3 , 4-thiadiazole , &Ha i-3¾ -- 5-chloromethyl-2-amino-l , 3 ,4-thiadiazole , 5-^-chloroethyl-2-amino- 1 , 3 , 4-thiadiazole , , 3 , 4-thiadiazole , 5-trichloromethyl-2-amino-l , 3 , 4-thiadiazole , 5-methoxy-2-amino- 1,3 , 4-thiadiazole , 5-ethoxy-2-amino-l , 3 ,4-thiadiazole , 5-propoxy- 2-amino-1 , 3 , 4-thiadiazole , 5-butyloxy-2-amino-l ,3 ,4-thiadiazole , 5-hexyloxy-2-amino-l , 3 ,4-thiadiazole , 5-methylthio-2-amino-l ,3,4-thiadiazole , 5-ethylthio-2-amino-l , 3 ,4-thiadiazole , 5-propylthio- 2-amino-1 , 3 , 4-thiadiazole , 5-butylthio-2-amino-l , 3 , 4-thiadiazole , sulfinyl 5-methylsulfonyl-2-amino-l , 3 , 4-thiadiazole , 5-ethyl 2-amino-l ,3,4-thiadiazole , 5-butyl-2-amino-l , 3 ,4-thiadiazole , 5-methylsulfinyl- 2-amino-l, 3, 4-thiadiazole, -^¾¾&¾8^0«¾«^^ sulfin l 5-propy]-2-amino-l , 3 , 4-thiadiazole , 5-t-butyl-2-amino-l ,3,4-thiadiazole, 5-trifluoromethyl-2-amino-l , 3 , 4-thiadiazole , and the like.

The manner in which the compounds of the present in-vention can be prepared is more specifically illustrated in the Example 1 Preparation of 5-Methyl-l,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-l , 3 , 4-thia-diazole (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-l , 3 , 4-thiadiazol-2-yl isocyanate dimer.

Example 2 Preparation of the Dimethyl Acetal of 2- :l-Methyl-3- (5-methyl- 1 , 3 , 4-thiadiazol-2-yl) ureidoj acetaldehyde A mixture of 5-methyl-l , 3 , 4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2-methylamirioacetalde-hyde (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 dimethyl acetal of 2- EU-methyl-3- (5-methyl-l , 3 , 4-thiadiazol-2-yl) ureidoj acetaldehyde .

Example 3 Preparation of 1- (5-Methyl-l , 3 , 4-thiadiazol-2-yl) -3- methyl-5-hydroxy-l , 3-imidazolidin-2-one The dimethyl acetal of 2- [.¾-methyl-3- (5-methyl-l , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde (15 grams) , water (400 ml) and h drochloric acid (4 ml) are charged into a glass reaction 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 recrys-tallized to yield the desired product 1- (5-methyl-l , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

Example 4 Preparation of 5-Methoxy-l , 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 Ό a mechanical stirrer. A slurry of 5-methoxy-2-amino-l , 3 , 4-thia-diazole (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-l , 3 ,4-thiadiazol-2-yl isocyanate dimer.

Example 5 Preparation of the Dimethyl Acetal of 2- (¾-Ethyl-3- (5-methoxy- 1 , 3 , 4-thiadiazol-2-yl) ureidoj acetaldehyde A mixture of 5-methoxy-l , 3 , 4-thiadiazol-2-yl isocyanate dimer (0.05 mole), the dimethyl acetal of 2-f ethylamino-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 dimethyl acetal of 2- [i-ethyl-3-( 5-methoxy-1 , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde . thiadiazol-2-yl) ureid ] 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-l , 3 ,4-thiadiazol-2-yl) -3-ethyl-5-hydroxy-l , 3-imidazolidin-2-one .

Example 7 Preparation of 5-Methylthio-l , 3 , 4-thiadiaz0l-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-l , 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-l , 3 , 4-thiadiazol-2-yl isocyanate dimer.

Example 8 Preparation of the Dimethyl Acetal of 2- l—Propyl-3- (5-methylthio- 1 , 3 , 4-thiadiazol-2-yl) ureidoll acetaldehyde A mixture of 5-methylthio-l , 3 ,4-thiadiazol-2-yl isocyanate dimer (0.05 mole) , the dimethyl acetal of 2 -prcipylamino-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 (5-methylthio-l , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde .

Example 9 Preparation of 1- (5-Methylthio-l , 3 ,4-thiadiazol-2-yl) -3-propyl- 5-hydroxy-l , 3-imidazolidin-2-one The dimethyl acetal of 2- [l)-propyl-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-propyl-5-hydroxy-l , 3-imidazolidin-2-one.

Example 10 Preparation of 5-Methylsulfonyl-l , 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-l , 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-thia-diazol-2-yl isocyanate dimer.

Example 11 Preparation of the Dimethyl Acetal of 2-Ql-Methyl-3- (5-methyl- sulfonyl-1 , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde aminoacetaldehyde (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 dimethyl acetal of 2- [1; -methyl-3- (5-methylsulfonyl-1 , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde .

Example 12 Preparation of 1- (5-Methylsulfonyl-1 , 3 , 4-thiadiazol-2-yl) -3- methyl-5-hydroxy-l , 3-imidazolidin-2-one The dimethyl acetal of 2- El-methyl-3- (5-methylsulfonyl-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-methylsulfonyl-1 , 3 , 4-thiadiazol-2-y.l) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

Example 13 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-l , 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 hos ene. The ur ed mixture is then filtered to recover Example 14 Preparation of the Dimethyl Acetal of 2- l-Methyl-3- (5-methyl- sulfi 1 ,3,4 ¾udxl?dmy^thiadiazol-2-yl) ureido] acetaldehyde A mixture of 5-methylsulfinyl-l , 3 ,4-thiadiazol-2-yl isocyanate di er (0.05 mole), the dimethyl acetal of 2-methyl-aminoacetaldehyde (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 dimethyl acetal of 2- [l-methyl-3- (5-methylsulfinyl-1 thiadiazol-2-yl) ureido] acetaldehyde .

Example 15 Preparation of 1- (5-Methylsulfinyl-l , 3 , 4-thiadiazol-2-yl) -3- methyl-5-hydroxy-l , 3-imidazolidin-2-one The dimethyl acetal of 2- Dl-methyl-3- (5-methylsulfinyl-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-methylsulfinyl-1 , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

Example 16 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- 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 17 Preparation of the Dimethyl Acetal of 2- [;l-methyl-3- (5-trifluoro- methyl-1 , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde A mixture of 5-trifluoromethyl-1 , 3 , 4 -thiadiazol-2-yl isocyanate dimer (9.5 grams), the dimethyl acetal of 2-methyl-aminoacetaldehyde (5.8 grams) 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. This product is recrystallized from heptane to yield the desired product the dimethyl acetal of 2- l -methy1-3- (5-trifluoromethyl-1 , 3 ,4-thiadiazol-2-yl) ureido acetaldehyde having a melting point of 101 to 102°C.

Example 18 Preparation of 1- (5-Trifluoromethyl-1 , 3 ,4-thiadiazol-2-yl) -3- methyl-5-hydroxy-l , 3-imidazolidin-2-one ^ The dimethyl acetal of 2-[ l-methyl-3- (5-trifluoromethyl-1 , 3 , 4-thiadiazol-2-yl) ureido] acetaldehyde (15 grams) , water (400 ml) and hydrochloric acid (4 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 an ethyl acetate-hexane mixture to yield the desired product l-(5-tri- Example 19 Preparation of 5-t-Butyl-l , 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-l , 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-l , 3 , 4-thia-diazol-2-yl isocyanate dimer as a solid having a melting point of 261 to 263°C.

. Example 20 Preparation of the Dimethyl Acetal of 2- Ci-methyl-3- (5-t-butvl- ■ Γ, 3 , 4-thiadiazpl-2-yl) ureido]acetaldehyde ~ A mixture of 5-t-butyl-l , 3 , 4-thiadiazol-2-yl isocyanate dimer (6 grams) , the dimethyl acetal of 2-methylamino-acetaldehyde (3.9 grams) and benzene (50 ml) was charged into a glass reaction flask equipped with a mechanical stirrer and reflux condenser. The reaction mixture was heated at reflux,, with stirring . for a period of about 5 minutes. After this time the reaction mixture was stripped of benzene to yield an oil which solidified upon standing. The resulting solid was then recrystallized from pentane to yield the desired product the dimethyl acetal of 2-Cl-meth.yl-3- (5-t-butyl-l , 3 , 4-thiadiazol-2-yl) ureidol acetaldehyde having a melting point of 80-82°C.

Example 21 Preparation of 1- (5-t-Butyl-l , 3 , 4-thiadiazol-2-yl) -3-methyl- ■ 5-hydroxy-l , 3-imid.azolidin-2-one The dimethyl acetal of 2- [l-met.hyl-3- (5-t-butyl-l , 3 , 4-thiad'ia zol-2-vl) ureidolacetaldehyde (16 grams), concentrated hydrochloric acid (10 ml) and water (500 ml) were charged into . a glass reac 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 a benzene-hexane mixture to yield the desired product 1- (5-t-butyl-l , 3 ,4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one having a melting point of 133 to 134°C.

Additional compounds within the scope of the present invention which can be prepared by the procedures of the foregoing examples are: 1- ( 5-ethy1-1 , 3 ,4-thiadiazol-2-yl) -3-butyl-5 -hydroxy-1 , 3-imidazolidin-2-one , 1- (5-propyl-l , 3 , 4-thiadiazol-2-yl) -3-pentyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-butylthio-l ,3,4-thiadiazol-2-yl) -3-hexyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-pentylthio-l , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-hexylthio-l , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-1 , 3-imidazolidin-2-one , 1- (5-ethylthio-l , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-ethoxy-1,3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin- 2-one , 1- (5-propoxy-l , 3 , -thiadiazol-2-yl) -3-methyl-5-hydroxy-1 , 3-imidazolidin-2-one , 1- (5-butoxy-l ,3 ,4-thiadiazol-2-yl) - 3-methyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-hexyloxy-l ,3,4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-chloromethyl) 1 , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-1 , 3-imidazolidin-2-one , 1- 2-yl) -3-methyl-5-hydroxy-l butyl-l , 3 , 4-thiadiazol-2-ylj] -3-methyl-5-hydroxy-l , 3-imidazo-lidin-2-one , l-(5-allyl-l,3 , 4-thiadiazol-2-yl) -3-methy1-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5-pent-3-enyl-l , 3 , 4-thia-diazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one , 1- (5- pp n* o.

Pof practical use as herbicides the compounds of 3?or excm le dusts can be prepared by grinding and blending the active compound with a solid inert carrier such as tho talwe, clays, silicas, pyrophyllite, and the like* Granular formulations can bo prepared by impregnating the compound, usually dissolved in a suitable solvent, onto and into granulated carriers such as the attapulgitos or tho vormiculiteSf, usually of a particle size range o from about 0*3 to 1*5 mm* lettable ponders, which can be dispersed invater or oil to any desired concentration of tho active compound, can be prepared by incorporating vetting agents into concentrated dust compositions* In some oases the active compounds are sufficiently soluble in common organic solvents such as kerosene or xylene so that they ca 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 e ulsifiable 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 22 Preparation of a Dust Product of Example 16 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 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 inven but generally the herbicidal compositions will comprise from about 0.05 to about 95 percent by wei-ght 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.

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. 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 nontoxic 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 ten pounds or more of 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 ments small plastic greenhouse pots filled with dry soil were seeded with the weed seeds. Twenty-four hours or less after seeding the pots were sprayed with water until the soil was wet and the test compounds formulated as aqueous emulsions of acetone solutions containing emulsifiers were sprayed at the indicated concentrations on the surface of the soil. to After spraying, the soil containers were placed in the greenhouse and provided with supplementary heat as required and daily or more frequent watering. The plants were maintained under these conditions for a period of 27 days, at which time the condition of the plants and the degree -of injury to the plants was 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 effectiveness of these compounds is demonstrated by the data in Table I.

TABLE I Injury Rating Weed Concentration in Lbs/Acre YNSG OAT JSWD WLF JSGR PIGW MU Product of Example 18 5 9 10 10 10 10 10 1 2 9 10 10 10 10 10 1 1 10 10 10 10 10 10 1 ^ Product of -j Example 21 5 9 10 9 10 9 10 1 2 9 10 9 10 9 9 1 1 9 10 10 10 10 10 1 YNSG Yellow Nutsedge MUST Mustard WOAT Wild Oats YFXT Yellow Foxtail JSWD Jimsonweed BYGR Barnyardgrass WLF Velvetleaf CRGR Crabgrass JSGR Johnsongrass CHGR Cheatgrass PIGW Pigweed MNGL Morning glory The herbicidal activity of the compound of this invention was also demonstrated by experiments carried out for the post-emergence control of a variety of weeds. In these experiments the compounds of this invention were formulated as a solution in an inert solvent and sprayed at the indicated dosage on the foliage of the weeds that have attained a prescribed size. After spray- to ing, the plants were placed in a greenhouse and watered daily or more frequently. Water was not applied to the foliage of the treated plants. The severity of the injury was determined 17 days after treatment and was rated on the scale of from 0 to 10 heretofore described. The effectiveness of the compounds is demonstrated by the data in Table II.

TABLE II Injury Rating Weed Species Concentration in Lbs/Acre YNSG WOAT JSWD WLF JSGR PIGW MU Of 18 5 10 10 10 10 10 10 1 2 10 10 10 10 10 10 1 1 10 10 10 10 10 10 1 of I 21 5 10 10 10 10 10 10 1 2 . 10 10 10 10 10 10 1 1 10 10 10 10 10 10 1 Yellow Nutsedge MUST Mustard Wild Oats YFXT Yellow Foxtail Jimsonweed BYGR Barnyardgrass Velvetleaf CRGR Crabgrass Johnsongrass CHGR Cheatgrass Pigweed MNGL Morning glory \ \ pp n. o.

In U.S. Patent 3,773,780 which is of earlier date than the present application, a compound of the general formula 7 has been described vhich at first glance appears to be similar to the compounds claimed and described in the present specification . Applicants have, however, carried out various experiments vith that compound and compared the results to the above related results obtained by the compounds according to the present invention. The test results show beyond doubt that applicants' monohydroxy compound possesses superior herbicidal properties different in kind from the herbicidal properties of the dihydroxy compound disclosed by the said U.S. atent. 19A

Claims (10)

1. A compound of the formulc / wherein is selected from the group consisting of alkyl of up to 4 carbon atoms, as2sfe-Xif$£¾: , chloroalkyl, trifluoromethyl , alkoxy, 2 alkylthio, alkylsulfonyl and alkylsulfinyl ; and R is alkyl.

2. The compound of Claim 1, 1- (5-methyl-l , 3 , 4-thia-diazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

3. The compound of Claim 1, 1- (5-methoxy-l , 3 ,4-thia-diazol-2-yl) -3-ethyl-5-hydroxy-l , 3-imidazolidin-2-one .

4. The compound of Claim 1, 1- (5-methylthio-l , 3 ,4-thiadiazol-2-yl) -3-propyl-5-hydroxy-l , 3-imidazolidin-2-one .

5. The compound .of Claim 1, 1- (5-methylsulfonyl- 1 , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

6. The compound of Claim 1, 1- (5-methylsulfinyl-1 , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolin-2-one .

7. The compound of Claim 1, 1- (5-t-butyl-l , 3 ,4-thia- . diazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

8. The compound of Claim 1, 1- (5-trifluoromethyl-1 , 3 , 4-thiadiazol-2-yl) -3-methyl-5-hydroxy-l , 3-imidazolidin-2-one .

9. A herbicidal composition comprising an inert carrier and, as an essential active ingredient, in a quantity toxic to weeds, a compound of Claim 1.

10. A method of controlling weeds which comprises contacting the weeds with a herbicidal composition comprising an inert carrier and, as an essential active ingredient, in a quantity toxic to weeds, a compound of Claim 1.