The invention rela tes to a new process for the pre¬ paration of J-T-aryl-U'-Cmono- or disubstituted) -urβa derivatives having the general formula ( I) ,

E ¹

Aryl - KB - CO - N ( I)

wherein

Aryl is an optionally substituted phenyl group, and

1 and E 2 each stand for an optionally substituted alkyl, cycloalkyl, alkoxy or phenyl group, or

E 1 and E2 may form, together with the adjacent nitrogen atom, a nitrogen-containing he erocyclic group which may contain a further hetero atom, or one of E 1 and E2 may also stand for hydrogen, with the proviso that if one of B 1 and E2 is an optionally substituted phenyl group, the other may represent only ..__- hydrogen atom or an optionally substituted alkyl or alko_zy group. _. _ ._ ; The ^' phenyl group epresen e ^;ι by "Aryl" may bear as optional substituents preferably one or more halogen atoms, nitro group(s), lower alkyl group(s), lower _; alko__y gfoup(s), trihalo-lower alkyl group(s), lower alkylthio group(s) or a phenoxy group optionally substituted with the groups, ; listed in this paragraph.

E 1 and E2 may represent as alkyl or alkozy group preferably a group of 1 to carbon atoms, whereas the cycloalkyl groups represented by E 1 or E2 contain prefer-

ably 5 to 8 carbon atoms. These groups may bear option¬ ally e.g. the following substituents: hydroxy group, carboxy group, alkyl group, alkeπyl group, alkynyl grou alkoxy group, phenyl group, substituted phenyl group or heteroaryl group. Of the nitrogen-containing heterocycl ggrroouuppss rreepp;resented by B 1E2 Η- the orpholino group is preferred.

The compounds of the general formula (I) are biologically active or can be converted into biological active substances.

Some representatives of the compounds having the general formula (I), such as those wherein Aryl is as defined above, B is hydrogen or an optionally sub- stituted alkyl or cycloalkyl group and E is an option- ally substituted alkyl or alkoxy group, exert pesticida primarily herbicidal effects (see e.g. E. Wegler: Chemi der P lanzenschutz- und Schadlingsbekampfungsmittel, Springer Verlag, Berlin-Heidelberg-Hew York, 1970, pp. 241 to 255) • Other compounds of the general formula (I), such as l-( —nitrophenyl^-'-t^'-pyridylmethy^-urea

(pyrinuron) , can be applied as rodenticidal agents. Fur representatives of the compounds having the general formula (I) , such as those wherein one of E 1 and E2 is hydrogen and the other is an optionally substituted phenyl group , are pharmaceutically active or can be applie d as intermediates in the preparation of pharma¬ ceutically active agents.

Preferred representa tives of the compounds having the general formula (I) are as follows : IsT-phenyl-N' jU' -dimeth l-urea (fenuron) , a herbicidal substance , 2-me thylcyclohexyl) -urea ( siduron) , a her¬ bicidal substance ,

N-(4-chlorophenyl)-_T' ,N> -dime thyl-urea (monuron), a her-

^" bicidal substance,

N-(3, -dichlorophenyl)-lT ^, -methyl-l. ^, -butyl-urea (neburon) , a herbicidal substance, N- ( 3, -dichloro he y 1) -ISP , 2sT ^» -dime thyl-urea (diu on) , a herbicidal substance, ^'

__ ^" -( 5- trif luorome thylphenyl) -3ϋP , Η ⁹ -dime thyl-urea (fluo- ethuron), a herbicidal substance,

IT- ( 5-chloro-4-trif luorome thylphenyl) -Ε- ,23 ^" ' -dime thyl-urea , a herbicidal substance,

N-(5-chloro- -me thylphenyl) -IT' ,Η- -dime thyl-urea (chlor- toluron) , a herbicidal substance,

I.-( -isopropylphen l -_^^ ^, ,3?' -dimethyl-urea ( iεoprothuron) , a herbicidal substance, E-(5, -dichloroρhenyl)-carbamoyl-morpholine, a herbi¬ cidal substance,

N-(3-chloro- -bromophenyl)-carbamoyl-morpholine, a herbi¬ cidal substance,

_T-(3-chlorophenyl)-carbamoyl-morpholine, a herbicidal substance,

3tf-(_-chlorophenyl)-carbamoyl-morpholine, _ herbicidal substance,

J-.-^-chloro-^-methoxypheEyl)--.' ,_' -dime thyl-urea (metox- uron) , a herbicidal substance, 1T- - ( -chloropb.enoxy) -phenyl7-I. ' ,H' -dimethyl-urea

(chloroxuron) , a herbicidal substance, lT-{-μ- chloropher-y^- '-me h l-lT'-methoxy-urea ( onolin- uron) , a herbicidal substance, -IT'-methyl-N'-met oxy-urea (me obrom- uron) , a herbicidal substance,

N- ( 3, -dichlorophenyl) -N ' -me hyl-K ⁵ -me hoxy-urea ( lin- uron) , a herbicidal substance,

^• _. L- _.

_.-(3-chloro-4-bromophenyl) -u'-me hyl-ΪT'-me thoxy-urea

( chlorbromuron) , a herbicidal substance ,

23 ^' -{3-fl o o- -bromoρhe l)-l<T ^, ,N' -dime thyl-urea , a herbi cidal substance , If- ( 3-fluoro-4-chlorophenyl) -IV -Η* -dime thyl-urea , a herb cidal substance ,

K-{ 3-f luoro-4-chlor ophenyl) -E' -me thyl-IP -me thoxy-urea , a herbicidal substance ,

IT-(3- luoro-^-iodophenylJ-N'-methyl-l-'-methoxy-urea , a herbicidal substance,

3ST- ( 4-chlor ophe nyl) -N ' - ( 3-me thyl- -chlorophenyl) -urea , a herbicidal substance,

!T-( -nitrophenyl)-lS ^r, -(3 ^, -pyridylmethyl)-urea (pyrinuron) a rodenticidal substance, _T-( -chlorophenyl) -_T ^, -(3 _» -dichlorophenyl) -urea (tri- clocarban) , a bacteriostatic agent ,

I -(4-nitrophenyl) -_ ^, -(4-nitrophe_-yl) -urea (niearbazin) , a coccidiostatic agent, and

K- ( 4-chlorophβnyl) -_\f' _.( 3- trif luorome thyl-4-chloroρhenyl ) urea (cloflucarban) , an antiseptic agent.

The most widely applied methods for the prepara tion of the compounds having the general formula (I) are based on the reacti on of isocyanates and amine derivati According to one of these methods isocyanates of the general formula Aryl-UCO are reacted with amines of the general formula MHE 1 E 2 , whereas according to another method isocyana tes of the general formula E -__vCO and amines of the general formula Aryl-HΞo are applied as reactants. In this la tter me thod compounds of the genera p formula (I) wherein £ is hydrogen are formed. A general description of these reactions can be found in Houben- Y/eyl: Methoden der orgenischen Chemie (Georg Thiejne Ver lεg, Stuttgart, 1952, Vol. VIII, pp. 154-156) .

The isocyanates applied as starting substances in the above methods are prepared generally by react¬ ing the appropriate amines with phosgene or by subject¬ ing the appropriate carbamates or urea derivatives to thermal decomposition (see Houben-Weyl: Methoden der organischen Ohemie; Georg Thieme Verlag, Stuttgart, 1952, Vol. VIII, pp. 119-128).

^• It is well known that phosgene is highly detri¬ mental to health, thus reactions utilizing phosgene should be performed under keeping specific security measures. It is a further disadvantage that the reaction involves the formation of hydrochloric acid in great amounts, which is difficult to remove and causes serious corrosion problems. The methods of preparing isocyanates by thermal decomposition are very expensive because of their high demands on material and energy. Thus the pre¬ paration of isocyanates, applied as starting materials in the synthesis of the urea derivatives of the general formula (I), is cumbersome, sophisticated and expensive, and the reaction cannot be performed economically on industrial scale. It is a further disadvantage that isocyanates, owing to their high reactivity, are in- stable compounds and can be stored for a limited period, sometimes for some days only. Thus e.g. 4-nitrophβnyl- isocyanate undergoes water addition and subsequent con¬ densation upon storage, whereby dimers, tri ers and other oligomers are formed which cannot be reacted with amines in the subsequent step (see Ξouben- eyl: Methoden der organischen Chemie, Georg Thieme Verlag, Stuttgart, 1952, Vol. VIII, p. 159).

It is also known that urea derivatives can be prepared by reacting carbamates with appropriate primary or secondary amines in the presence of a tertiary amine

catalysts see e.g. J. Am. Che . Soc. ___, 4458-4463 ^• (195.17• According to the literature, however, only phenyl carbamates and substituted phenyl carbamates are reactive enough (Houben-Weyl: Methoden der organischen Chemie, Georg Thieme Verlag, Stuttgart, 1952, Vol. VIII pp. 161-162), and if lower alkyl carbamates, which are far more easy to prepare than the respective phenyl or substituted phenyl esters, are applied as starting sub¬ stances, the reaction proceeds with very low yields and requires an extremely long time, or even no reac¬ tion occurs at all. Therefore in large-scale operations lower alkyl carbamates are utilized to prepare urea derivatives only by subjecting them first to thermal de composition, which requires much energy, and then react ing the resulting isocyanates with amines.

It follows from the above that none of the hitherto known methods of producing urea derivatives is completely satisfactory with respect to reaction time, availability of starting substances and security of operations.

The invention aims at the elaboration of a new method for the preparation of urea derivatives having the general formula (I), which requires easily availabl starting substances, provides the end-products with hig yields within a short time, and does not apply substanc detrimental to health.

The invention is based on the recognition that lower alkyl carbamates can be converted into the respec ive urea derivatives directly, i.e. without converting them first into isocyanates, within a short time and with high yields if they are reacted with the respectiv amines in the presence of higher tertiary alklTla ine

Q?._

catalysts instead of the lower tertiary amines (most frequently triethyla ine or pyridine) utilized so far. It has also been observed tha t if phenyl or substituted phenyl carbamates are applied as starting substances in the above reaction and the lower tertiary amine catalyst is replaced by a higher tertiary alkylamine , the re¬ quired end-products are obtained with higher yields. In these latter instances the yield increases sometimes to the double or more ; thus e.g. IT- ( 4- cyano phenyl) —33 ^" * — (3-pyridylme thyl) -urea can be obtained with a yield of 85 to 0 % instead of 43 % attained when operating as described in E-sample 2 of the Hungarian patent specifi¬ cation 1.0. 168 ,295.

Based on the above, the invention relates to a new method of preparing an urea derivative of the general formula ( I) ,

iryl - HH - CO - N . ( I)

E ² wherein Aryl , E 1 and E 2 are as defined above, by reacting a carbamate of the general formula ( II) with an amine of the general formula (III) ,

ΈΪ-R-Ή - CO - X (II)

Aryl-KH ₂ (III) or a carbama te of the general formula ( IV) with an amine of the genera l formula (V) ,

Aryl - KE - CO - X ( IV) wherein E 1, E2 and Aryl are as defined above and X is a lower alkoxy, phenoxy or substituted phenoxy group, in the presence of a tertiary amine catalyst. According to

the invention a tertiary alky la ina containing altogethe at least 6 carbon atoms and minimum one alkyl chain wit at least 4 carbon atoms or a mixture of such tertiary alkylamines is applied as catalyst. As it appears from the above definition, di-.

(C-, 3 alkyl) -butylamines can also be applied as tertiar alkyla ine catalysts, it is more preferred, however, to perform the reaction in the presence of a tertiary amine wherein the highest alkyl chain contains a t least 8, particularly at least 12 carbon atoms. The other two alkyl groups attached to the nitrogen atom may be lower alkyl groups, such as methyl or ethyl group. According to our experiences the catalytic effect of the tertiary alkylamines varies generally parallel with the carbon atom number of the highest alkyl chain, i.e. the great¬ er is the carbon atom number of the highest chain, the shorter is the reaction time and the higher is the yiel of the required urea derivative . Of the tertiary alkyl¬ amine catalysts the following compounds are particularl preferred: trioctylamine , __ ^" ,3_r-dimethyl-n-octyla ine , IT , -dime thyl-n-dodecyla ine , lT,N-dime thyl-n-hexadecyl- a ine and the respective ITjIT-diethyl or H-methyl-l -ethyl compounds. These substances are easily available on the marke t. As mentioned above, mixtures of higher tertiar alkylamines can also be applied as catalysts in the pro¬ cess of the invention. From economical aspects it is pre ferred to utilize such mixtures of technical quality in large-scale operations, since these mixtures are far les expensive than the pure tertiary amines without any appreciable decrease in their catalytic activity. Of the mixtures of higher tertiary alkylamines e.g. the product sold by the firm Hoechst A.G. under the trade name

"Genamin" as well as those sold by the firm Akzo under the trade name "Armeens" are to be mentioned.

The term "lovwer alkoxy" used in connection with substituent X refers to C-, ^ alkoxy groups, such as meth- oxy, ethoxy, etc. The term "substituted phenoxy" used in connection with group X refers to phenoxy groups which bear one or more substituent(s) inert under the reaction conditions, such as halogen atoms or alkyl, alkoxy, tri- haloalkyl and/or nitro groups. Particularly preferred representatives of the substituents attached to the phen¬ oxy group are electron-attracting groups (e.g. halogen atoms, nitro group), since the phenoxycarbamates with electron-attracting substituents on the aromatic ring are particularly reactive under the conditions according to the invention.

According to the invention the lower alkyl carbamates, regarded so far as substances which cannot be used for the direct industrial preparation of urea derivatives, can be converted directly into the respect- ive ureas within some hours generally with yields of

80 % or more. If phenoxy or substituted phenoxy carbamates are applied as starting substances, the end-product may be obtained with almost quantitative yields in a fast reaction. The starting substances (i.e. the carbamates and the primary or secondary amines) are applied prefer¬ ably in practically equimolar amounts, although any of the reactants may also be used in excess. The higher tertiary alkyla ine catalyst is added to the mixture in an amount of O.O5 to 2 moles, preferably 0.5 to 1.2 moles, calculated for 1 mole of the starting substance present in the lower molar amount. Then a mixture of

higher tertiary amines is applied as catalyst, this ratio relates to the total amount of tertiary amines.

The reaction is performed generally in an inert solvent medium, such as benzene, toluene or xylene, pre- ferably under boiling the reaction mixture. The excess of the higher tertiary alkyla ine may also serve as sol¬ vent, or sometimes the reaction may also be performed in the absence of solvent or diluent.

The urea derivatives of the general formula (I) are generally sparingly soluble in the reaction medium and separate as solids upon cooling the mixture. In such instances the end-products can be separated easily by filtration or centrifugetion. The resulting mother liquor, which contains solvent, higher tertiary alkyl- amine catalyst, minor amounts of unreacted starting sub¬ stances and dissolved end-product, can be utilized re¬ peatedly as reaction medium for further reaction steps. Thereby the specific demand on reactants and catalyst can be decreased substantially. In such instances it is preferred to apply the starting substances in equimolar ratio in order to avoid the accumulation of one of the reactants in the mixture. V/hen the mother liquor is re¬ cycled the yield generally increases, since after the first step no further losses arise owing to the dissolu- tion of the end-product.

It is also preferred to allow distillation of the mixture under boiling, removing thereby the spures of water and the alcohol which forms in the reaction. In this instance it is not necessary to apply anhydrous starting substances and dry solvents.

The end-products which do not precipitate from the reaction mixture upon cooling can be separated from

- li ¬

the mixture by known methods, such as evaporation, preci¬ pitation with non-solvents, etc. In certain fields of application, thus if the urea derivatives are to be used in the agriculture e.g. as pesticidal agents, it is not always necessary to separate them from the reaction mix¬ ture, since this mixture can be applied directly in the preparation of agrochemical compositions (such as spray solutions, impregnated granules, etc.) by admixing it with the necessary additives, if required. The mother liquors obtained after the separation of the solid end- products, which contain certain amount of dissolved urea derivatives, can also be applied for the same purpose. Depending on the field of final utilization, the separat¬ ed crude urea derivatives can be applied either as such or after purification.

The process of the invention can equally be applied for the preparation of symmetrically and asym¬ metrically substituted urea derivatives.

The process of the invention is elucidated in de- tail by the aid of the following non-limiting Examples. It should be noted here that the primary aim of the examples is to illustrate the wide applicability of the new method, thus no effort was made to attain the optimum result in all of the reactions. As an example, the number of recycling the mother liquors given in the examples does not represent the maximum possible value. According to our experiences the mother liquors can be recycled at least 10 times.

The layer chromatographic analyses referred to in the examples were performed on Merck Eieselgel 60 _pπ μ. plates. The melting points are uncorrβcted valueso

Example I

Preparation of N-(4-nitrophenyl)-I. ^, -(5-pyridyl- methyl)-urea

4.22 g (O.O2 mole) of ethyl J-T-(4-nitrophenyl)- ^• carbamate, 1.80 g (O.O167 mole) of 3-aminomethyl-pyridine and 3.18 g (O.O173 mole) of tributyla ine are dissolved in 25 ml of dry toluene, and the mixture is boiled for 5 hours. The separated product is filtered off, washed twice with 10 ml of acetone, each, and dried. 4.33 S (85.1 %) of I- ^" -(4-nitrophenyl)-N ^, -(3-pyridylmethyl)-urea are obtained; m.p«: 222-224°C (the authentic sample melts at 223-225°C) .

The above reaction is repeated with the difference that 1.72 g (O.O175 mole) of trie hyla ine are applied as catalyst. The end-product starts to separate only after about 4 hours of boiling. The mixture is boiled for 36 hours, thereafter the separated product is fil¬ tered off and washed twice with 10 ml of acetone, each. 3 _* 3 g (64.9 %) of l-(4-nitrophenyl)--_ ^■ '-(3-pyridylmethyl)- urea are obtained; .p.: 222-224°C.

Example 2

Preparation of IT- (4-nitrophenτl) -IT'- ( 3-pyr idyl- methyl) -urea

196.13 g ( 1 mole ) of methyl H-(4-nitrophenyl)-car- bamate , 108.14 g (1 mole) of 3- ^s mino ethyl-pyridine end 106.7 g (O.5 mole) of ITjlT-dimethyl-n-dodecyla ine are dissolved in 3 litres of xylene . The reaction mixture is refluxed, and the spures of water present are removed from the mixture together with the alcohol formed in a Dean-Stark trap. The end-product starts to separate from the mixture within 15-20 minutes from the beginning of boiling. The mixture is boiled for 4 hours, thereafter

G

the suspension is filtered at about 1OO to 110°C. The filter cake is washed twice with 1OO ml of hot xylene , each, and wi h a small amount of acetone , and then dried in vacuo . 218.6 g (80.3 ) of H-(4-nitrophenyl) - _7 ^, -(3-pyridylmethyl) -urea are obtained; m.p. : 221-223°C.

Example 3

Preparation of Η- (4-nitropheny 1) -__. ^» -( 3-pyr idyl- methyl) -urea

One proceeds as described in Example 2 with the difference that O.5 mole of _T,_T-dimethyl-n-hexadecyl- amine is applied as catalyst. 240.67 g ( 88.4 %) of lT-(4- nitrophenyl)-IT ^, -(3-pyridylmet_ιyl)-urea are obtained; .p. : 222-224°C .

Example ^* 4 Preparation of _T-(4-nitrophenyl) -_F-{ 5-:pyridyl- methyl)-urea

A mixture of 5.88 g (O.O3 mole) of methyl U-(4- nitrophenyl) -carbamate, 2.70 g (O.O25 mole) of 3-amino- me thy 1-pyri dine , 9»6 ml of Gemamim CS 3O2D (a mixture of !T,3_ ^" -dimethyl-C-, _Q __-, g alkylamines sold by the firm

Hoechst AG) and 50 ml of xylene is filled into a flask equipped with a 20 cm Vigreux column and a Dean-Stark trap, and the mixture is boiled for 2 hours. During this period 6 ml of a mixture of water, me thanol and xylene accumulate in the trap. The mixture is filtered when hot , the crystalline end-product is washed twice with 5 ml of hot xylene , each, and then with a few amount of ace¬ tone and dried. 6.0 g ( 88.2 %) of 2 -(4-nitrophenyl) -N'- (3-py^idylmethyl) -urea are obtained; m.p. : 223-225°C .

Example 5

Preparation of _Nf- (4-nitrophenyl) -IT*- ( 3-pyr idyl- methyl) -urea

11.77 g ( O.O6 mole) of methyl U-(4-nitrophenyl) - carba ate , 5. g ( O.O5 mole) of 3-aminomethyl-pyridine , 18.7 S (0.065 mole) of Gena in SH 302 D (a mixture of ff,3>T-dimethyl-C. _j g__- g alkylamines sold by the firm Hoechs AG) and 200 ml of toluene are introduced into the apparatus described in Example 4, and the mixture is boiled for 4 hours. During this period 15 ml of a mix¬ ture of water, methanol and toluene accumulate in the trap. The separated solid is filtered off , washed twice with 10 ml of hot toluene , each, the filtrate is com¬ bined with the wash, and the resulting mixture is used as reaction medium in the above reaction. The mother liquor is recycled 10 times. The results of the indi¬ vidual cycles are summarized in Table 1.

ITumber of n d - p r o d u c t the cycle Weight, g M.p. °C Yield, %

1 10.85 221-223 79.72

2 12.95 223-225 95.15

3 11.95 222-224 87.80

4 10.65 221-223 78.25

5 11.OO 222-224 80.82

6 11.82 224-225 86.84

7 12.65 224-226 92.94

8 10.50 223-225 77.14

9 11.OO 222-224 80.82

10 13.28 224-226 97.57 average 11.66 85.70

Example 6

Preparation of N, iff* -bis(4-nitrophenyl) -urea

9.81 g (50 mmoles) of methyl H-(4-nitrophenyl)- carbamate , 6.9 g ( 50 mmoles) of 4-nitroaniline , 140 ml of xylene and 11.8 g ( about 50 mmoles) of Genamin CS

302 D (a mixture of J jl - imeth l-Cn _Q i g alkylamines sold by the firm Hoechst AG) ace introduced into a flask equipped with a reflux condenser, and the mixture is boiled. The yellow crystals of the end-product appear already in the 3rd minute of boiling, and the amount of the crystalline precipitate rapidly increases. After 0.5 hours of boiling the thick, orange crystal suspen¬ sion is filtered in vacuo when hot , the filter cake is washed twice with 20 ml of hot xylene , each, and then with acetone , finally the product is dried in vacuo .

12.78 g (85.2 %) .of J ,IT ^» -bis(4-nitrophenyl)-urea are ob¬ tained. The product is uniform when examined by layer chroma tography utilizing a 3:1 mixture of n-hexane and acetone as solvent , and the chroma togra phi c appearance of the product is identical with that of the authentic sample •

Example 7

Preparation of _T,IT*-bis(4-nitrophenyl)-urea

One proceeds as described in Example 6 with the difference that ^a , diεtiliating column is attached to the flask, the mixture is maintained in gentle boiling and methanol is removed continuously from the mixture. After 2 hours of reaction the end-product is filtered off, 50 mmoles of methyl 3T-(4-nitrophenyl)-carbamate and 0 mmoles of 4-nitroaniline are added to the filtrate, and the reaction is repeated. The results of four sub¬ sequent cycles are summarized in Table 2.

Table 2

Number of E n d - p r d u c t the cycle Weight, g Yield, % Chromatographic appearance

1 13.36 89.1 uniform

2 14.30 95.3 uniform

3 13.58 90.5 uniform

4 14.75 98.3 uniform

Eemark:. The quality of the end-product cannot be cha¬ racterized appropriately on the basis of its melting point , since the compound starts to sublime directly after melting.

Example 8 Preparation of 3T- (4-chlorophenyl) -carbamoyI- morpholine

A mixture of 9.28 g (50 mmoles) of methyl IT- (4- chlorophenyl)-carbamate , 4.36 g (50 mmole s) of morpholi lOO ml of xylene and 10.6 g (50 mmoles) of N,IT-dimethyl tetradecyla ine is boiled gently for 6 hours, and methanol is continuously removed from the mixture by distillation. Thereafter heating is stopped and the mixture is allowed to cool and stand overnight . The separated crystals are filtered off and dried. 9.1 S ( 75.6 %) of N-(4-chlorophe__yl) -carbamoyl-morpholinβ are obtaine d; m.p. : 196-2OO°C ( the a uthentic sample melts at 196-2OO°C) .

Example 9

Preparation of _T-(4-chiorophenτl)-IT*-i3.4-di- chlorophenyl)-urea

A mixture of 4.61 g (25 mmoles) of methyl IT-(4- chlorophenyl)-carbamate, 4.07 g (25 mmoles) of 3,4-di-

G-.I

chloroaniline , lOO ml of toluene and 4.7 g ( 25 mmoles) ^" of NjϊT-dimethyl-dodβeylamins is reacted for 20 hours as described in Example 8, and then the mixture is allowed to cool. 4.60 g (58.4 %) of IT-(4-chlorophenyl) -_T ^» -(3,4- dichlorophenyl)-urea separa te from the mixture as a crystalline substance .

Example 10

Preparation of IT-(3-4-dichlorophenyl)-carbamoyl- morpholine A mixture of 5.50 g ( 25 mmoles) of methyl N-{3,4- dichlorophenyl) -carbamate , -2.18 g (25 mmoles) of morpho¬ line , 1OO ml of xylene and 4.7 g (25 mmoles) of ΪT,N-di- ethyl-dodecylaminβ is reacted for 12 hours as described in Example 8. The crystalline substance which separates upon cooling is filtered off , 25 mmoles of methyl IT-( 3,4- dichlorophenyl) -carbamate and 25 mmoles of morpholine are added to the filtrate , and the reaction is repeated. In the first reaction 5.0 ( 72,7 %) of ΪT-(3, 4-dichlorophenyl) - carbamoyl- orpholine are obtained, whereas 6.35 S (92.3 ^c /°) of the same compound are separated in the second reaction. Both compound fractions melt at 152-155°C ( the authentic sample melts at 157-158°C) .

The above reaction is repeated so that 25 mmoles of triethylemine are added to the- mixture instead of 3T,lT-dimethyl-dodecylamine . 3 _* 05 g (44.3 %) of the desired end-product are obtained after 24 hours of reaction.

Example 11

Preparation of _T-( 3 -4-dic__.lorophenyl) -I ^: . ^} - me hyl-I * -butyl- urea A mixture of 5.5O g ( 25 mmoles) of methyl 3T-(3,4- dichlorophenylj-carbamate , 2.18 g ( 25 mmoles) of IT-butyl- methyla ine , 4.7 g ( 25 mmoles) of lT,I -dimethyl-dodecyl-

amine and 1OO ml of light petrol is reacted for 3 hour -as described in Example 8. The separated solid is fil¬ tered off , 25 mmoles of methyl _T-(3 _» 4-dichlorophe__yl)- carba ate and 2.18 g ( 25 mmoles) of IT-butyl-methyla in are added to the filtrate , and the reaction is repeate In the first reaction 3. 0 g (53.8 %) of 3T-(3,4-dichlo phenyl) -IT* -me hyl -IT* -butyl-urea are obtained, whereas 5 _* 05 S ( 73 _* 4 %) of the same compound are separated in the second reaction. Both compound fractions melt at 108-110°C ( the authentic sample melts at 116-117°C) .

Example 12

Preparation of IT-( 3.4-dichlorophenyl) -IT*-met__y T* -butyl-urea

One proceeds as described in Example 11 with the difference that lOO ml of xylene are applied as solvent , and the progress of the reaction is monitored by layer chroma tography. When the reaction has pro¬ ceeded to about 90 %, as indicated by the chroma togra , the mixture is evaporated in vacuo . A yellowish, vis- cous residue is obtained, which is well soluble in common organic solvents, such as acetone or methyl-eth ketone , and can be applied in the preparation of a herbicidal spray solution.

Example 15 Preparation of IT- (4-chlorophenyl -IT * , T' -di¬ me th l-urea

A mixture of 12.8 g (O.l mole) of 4-chloroani- line , 10.3 g (O.l mole) of methyl EjIT-dimeth l-carbama 20 ml of dime thy 1-hexadecylamine and 1OO ml of high boiling pe troleum fractions (bp. : 16O-18O°C) . is react¬ ed as described in Example 12. When the reaction has proceeded to about 90 ._ , as indicated by the chromato-

i c

gram, the reaction is terminated. A solution of IT-(4- chlorophθnyl) -ΪT* ,N ^» -dime thyl-urea ( monuron) is obtained, which can be applied directly in the preparation of herbicidal compositions , such as spray liquids or im¬ pregnated granules.