The present invention concerns novel N,N'-diphenyl-N-(N"-alkylcarbamoyl)formamidine derivatives of the formula: ##EQU1## wherein R.sub.1 is hydrogen or alkyl, R.sub.2 is alkyl and Ar.sub.1 and Ar.sub.2 are each phenyl or a substituted phenyl, which compounds are useful as herbicides.The present invention relates to N,N'-diphenyl-N-(N"-alkylcarbamoyl)formamidine derivatives.The present invention provides compounds of formula I, ##EQU2## wherein R.sub.1 is hydrogen or alkyl of 1 to 4 carbon atoms,R.sub.2 is alkyl of 1 to 4 carbon atoms, and eitherAr.sub.1 and Ar.sub.2 are the same, and are each phenyl or a substituted phenyl group selected from ##SPC1##WhereinR.sub.3 is chlorine, bromine, methyl, methoxy, or dimethyl or diethylsulphonamide andR.sub.4 is chlorine, bromine, methyl, methoxy or trifluoromethyl, orAr.sub.2 is phenyl andAr.sub.1 is a substituted phenyl group selected from ##SPC2##WhereinR.sub.3 ' is chlorine or methyl andR.sub.4 ' is chlorine, methyl or trifluoromethyl,With the proviso that Ar.sub.1 and Ar.sub.2 are other than ##SPC3##When R.sub.1 or R.sub.2 is alkyl, this is preferably of 1 to 3 carbon atoms, e.g. methyl, ethyl, n-propyl or i-propyl, and more preferably is methyl.The present invention also provides a process for the production of a compound of formula I which comprisesA. REACTING A COMPOUND OF FORMULA IIa ##EQU3## wherein Ar.sub.1 and Ar.sub.2 are as defined above andM is a salt forming atom or group, preferably an alkali metal, especially sodium,With a compound of formula III, ##EQU4## wherein R.sub.1 and R.sub.2 are as defined above, orB. REACTING A COMPOUND OF FORMULA IIb,wherein Ar.sub.1 and Ar.sub.2 are as defined above, with a compound of formula IV,wherein R.sub.2 is as defined above, to product a compound of formula Ia, ##EQU5## wherein Ar.sub.1, Ar.sub.2 and R.sub.2 are as defined above.The process of the invention, in accordance with variant (a) above, may be effected as follows:A compound of formula IIa may be dissolved or suspended in an inert solvent or suspension medium and a compound of formula III, which may also be dissolved or suspended in an inert solvent or suspension medium, added thereto. Examples of suitable solvents or suspension media are hexamethyl phosphoric triamide or benzene. The reaction may conveniently be effected at room temperature, preferably over a prolonged period e.g. 12 hours, and conveniently with stirring. Working up may be effected in conventional manner.In a preferred modification of the process variant described above, the compound of formula IIa is produced in situ and without isolation, from a compound of formula IIb, by reaction with a strong base, e.g. sodium hydride. The process may be effected by adding a compound of formula III, which may be dissolved or suspended in a suitable solvent or suspension medium to a mixture of a compound of formula IIb and a strong base, in an inert solvent or suspension medium. Examples of suitable solvents or suspension media are hexamethyl phosphoric triamide or benzene. The reaction may then be effected as described above. With respect to the working up of the reaction mixture, excess of the strong base, e.g. sodium hydride, is carefully decomposed, for example, by the addition of water while cooling with ice. In the case where a water immiscible solvent or suspension medium is employed, addition of water may be continued until well separated phases have been obtained. Further working up may be effected in conventional manner.The process of the invention in accordance with variant (b) above, may be effected as follows:A compound of formula IV is added to a compound of formula IIb in an inert solvent, such as absolute toluene, and the mixture is reacted at an elevated temperature, e.g. 80.degree.C, and at an elevated pressure. The mixture may be allowed to react over a prolonged period, e.g. 60 hours. The reaction is preferably effected in an autoclave. Working up is effected in conventional manner.The compounds of formula I are, in general, colourless crystalline substances. Purification may be effected by recrystallisation from suitable solvents, e.g. ethyl acetate or an ethyl acetate/hexane mixture.The compounds of formula IIa, employed as starting material in process variant (a), may be obtained as described above, from a compound of formula IIb, by reaction with a strong base, e.g. sodium hydride.The compounds of formula IIb, employed as starting material in process variant (b), and also in the production of a compound of formula IIa, may be obtained in manner known per se,a' by reacting a compound of formula VwhereinAr.sub.1 is as defined above andR.sub.5 is alkyl of 1 to 4 carbon atoms, preferably ethyl,with a compound of formula VI,wherein Ar.sub.2 is as defined above, orb' by reacting two equivalents of a compound of formula VI with one equivalent of a compound of formula VII,whereinR.sub.6 is alkyl is 1 to 3 carbon atoms, preferably ethyl,to produce a compound of formula IIb'wherein Ar.sub.1 ' and Ar.sub.2 ' have the same significances as Ar.sub.1 and Ar.sub.2 respectively, defined above, with the proviso that Ar.sub.1 ' is the same as Ar.sub.2 '.The compounds of formulae III, IV, V, VI and VIII are either known or, insofar as they are not known, they may be produced in analogous manner to the processes for the production of the known compounds.The compounds of formula I are useful because they possess biological activity in plants. In particular the compounds of formula I are useful as herbicidal agents, as indicated in the following test viz:Test 1The compounds were applied to cultures of the weed speciesAmaranthus retroflexus,Capsella bursa pastoris,Chenopodium album,Galium aparine,Stellaria media,Senecio vulgaris,Echinochloa crus-galli,Alopecurus myosuroidesand Agrostis albapost emergence, at concentrations of 21/2 and 3 kg/hectare. The cultures were examined 14 days after application. A significant herbicidal effect was observed against each of the weeds at the concentrations tested.In addition, the compounds of formula Ib, ##EQU6## wherein Ar.sub.1 " and Ar.sub.2 " are the same and are each a substituted phenyl group selected from ##SPC4##wherein R.sub.3 " and R.sub.4 " are each chlorine, bromine or methyl, and the compounds of formula Ic, ##EQU7## wherein Ar.sub.1 '" and Ar.sub.2 '" are the same and are each a substituted phenyl group selected from ##SPC5##are further useful as selective herbicidal agents in combating weeds in cotton and potato cultures respectively, as indicated by the following tests:Test 2In the case of the compounds N,N'-di-(4-chlorophenyl)-N-(N"-methylcarbamoyl)-formamidine and N,N'-di-(3,4-dichlorophenyl)-N-(N"-methylcarbamoyl)-formamidine, Test 1 was conducted in a potato culture containing the abovementioned weeds, post emergence, at a concentration of 3 kg/hectare of the compounds. No significant effect on the potatoes was observed at the concentration tested whereas a significant effect was observed against the weeds.Test 3Compounds of formula Ib, were tested in cotton cultures (Gossypium hirsutum) containing the following weeds speciesSida spinosa,Echinochloa crus galli,Amaranthus retroflexus,Ipomoea rubra,Digitaria sanguinalis,Chenopodium album,Sisymbrium irioand Postulaca oleracea.The compounds were applied at a concentration of 3 kg/hectare pre-emergence and 21/2 kg/hectare post emergence. In both cases, a significant herbicidal effect against the weed species was observed with no significant effect on the cotton crop.The preferred compounds of formula I are the compounds of formulae Ib and Ic. Particularly interesting compounds of formula Ib are the compoundsN-n'-di-(3-chlorophenyl)-N-(N"-dimethylcarbamoyl)-formamidine,N,n'-di-(4-chlorophenyl)-N-(N"-dimethylcarbamoyl)-formamidine,N,n'-di-(4-bromophenyl)-N-(N"-dimethylcarbamoyl)-formamidine,N,n'-di-(3-methylphenyl)-N-(N"-dimethylcarbamoyl)-formamidine andN,n'-di-(4-methylphenyl)-N-(N"-dimethylcarbamoyl)-formamidine.However, other groups of compounds falling within the scope of formula I may also be mentioned as having interesting properties, e.g. the compounds of formula Id, ##EQU8## wherein R.sub.1.sup.IV is alkyl of 1 to 4 carbon atoms,R.sub.2.sup.iv is alkyl of 1 to 4 carbon atoms andAr.sub.1.sup.IV and Ar.sub.2.sup.IV are the same and are each phenyl or a substituted phenyl group selected from ##SPC6##whereinR.sub.3.sup.iv is chlorine, methoxy or diethylsulphonamide andR.sub.4.sup.iv is chlorine, methoxy or trifluoromethylwith the proviso that Ar.sub.1.sup.IV and Ar.sub.2.sup.IV are other than ##SPC7##and the compounds of formula Ie, ##EQU9## wherein R.sub.1.sup.V is alkyl of 1 to 4 carbon atoms,R.sub.2.sup.v is alkyl of 1 to 4 carbon atoms,Ar.sub.2.sup.V is phenyl andAr.sub.1.sup.V is a substituted phenyl group selected from ##SPC8##whereinR.sub.3.sup.v is chlorine or methyl andR.sub.4.sup.v is chlorine or methyl.For the abovementioned uses, the amount of compound to be applied to a weed infested locus will vary depending on the particular compound employed, mode of application, ambient conditions, the weeds species to be combated and the cultivated crop, if any, involved. However, in general, a suitable amount to be applied to a locus is between 1 and 10 kg/hectare of the compound, the application to be repeated as required.The compounds may be employed as herbicidal compositions in association with herbicide carriers or diluents. Such compositions also form part of the present invention.Herbicidal compositions may be employed in either solid or liquid application forms. Solid forms, e.g. dusting forms and granulates, may be produced by mixing or impregnating solid herbicide carriers such as diatomaceous earth, kaolin, talc, chalk, limestone and cellulose powder, with the compounds.Additives may be employed in the herbicidal composition. Typical of such additives are wetting and dispersing agents, e.g. the condensation product of formaldehyde with naphthalene sulphonate, and alkyl benzene sulphonates, adhesion imparting agents, e.g. dextrin, and emulsion stabilizers, e.g. ammonium caseinate. Such additives are suitable for incorporation into, e.g. a wettable powder form of composition.the herbicidal compositions may contain, aside from a compound of formula I as active agent, other active agents, such as herbicides, e.g. of the urea class, halogen benzonitriles, carbamates and triazines.Concentrate forms of composition generally contain between 2 and 80%, preferably between 2 and 50%, by weight of a compound of formula I as active agent.Application forms of composition generally contain between 0.01 and 10%, by weight of a compound of formula I as active agent.

common chickweed/сечовина

N,N'-diphenyl-N-(N"-alkylcarbamoyl)formamidines

Найповніша база даних про лікарські трави, підкріплена наукою