DE3003980A1 - Gamma-methylene:oxy-substd. butenolide derivs. - with herbicidal activity esp. against parasitic weeds e.g. orobanche or striga species - Google Patents

Abstract

New gamma-substd. butenolide derivs. are cpds. of formula (I). In (I) X is CH2 or a direct bond; R1 and R2 are each H, 1-5C alkyl or opt. substd. aryl, or R1 and R2 together with the adjacent C-atoms form an o-phenylene residue of formula (Ia); when R1 and R2 are H, 1-5C alkyl or aryl, then R' and R" together with the adjacent C-atoms form a divalent residue of formula (Ib), (Ic) or (Id); and when R1 and R2 together form a residue (Ia), then R' and R" are each H, 1-5C alkyl or opt. substd. aryl, or together with the adjacent C-atoms form a divalent residue of (Ib), (Ic), (Id) or (Ie). Y is 2 H-atoms, an additional C-C bond, or an epoxy gp.; R''' is H, 1-5C alkyl or opt. substd. aryl; and the benzene rings A and B opt. carry one or more substituents selected from 1-8C alkyl, 1-8C alkoxy, halogen, aryl and aralkyl, or a fused-on benzene or heterocyclic ring. (I) are herbicides with activity against weeds and parasitic weeds such as Orobauche species (broomrapes) and Striga species. Certain cpds. (I) also have activity as germination stimulants.

Description

Butenolide derivatives Process for their preparation and means for

Control of weeds The invention relates to butenolide derivatives of the formula a process for their preparation and herbicidal compositions containing them. The derivatives are suitable for combating weeds of the Striga and Orobanche genera.

The invention relates to new compounds and methods of preparation such compounds that are used to control certain weeds or parasitic Weeds are suitable. The invention also relates to weed killers which are suitable for this purpose. In particular, the invention relates to new compounds and herbicidal compositions prepared therefrom which are suitable for Control of the weeds Striga hermontica, Striga asiatica (lutea), Orobanche crenata, Orobanche ramosa or Orobanche aegyptiaca, which are parasitic in poor, economical important seeds or crops are, such as sorghum, corn, sugar cane and / or broad beans.

These compounds and compositions also show some Activity against Alectra vogelii, a parasitic plant found in certain African Areas, especially in Tanzania, cowpea infested.

In G2-PS 1 470 097 certain compounds and herbicides Compositions described which contain such compounds and are suitable are for the control of parasitic weeds of the genera Striga and Orobanche. Some of these connections have the disadvantage that sis easily are unstable in the places where they are intended to be used as herbicides.

The present invention is based on the fact that new compounds a have improved stability or more effective herbicidal activity than the Previously known Xerbindungen and these new compounds are suitable for as effective germ stimulants for the seedlings or seeds of Striga hermontica, Striga asiatica, Orobanche crenata, Orobanche ramosa or Orobanche aegyptica too works. They are also effective against Alectra vogelii.

According to the invention, a compound of the formula I provided in which -X- is a direct single bond or a -CH2 bond and in which, if R1 and R2, which can be the same or different, are hydrogen, an alkyl radical having 1 to 5 carbon atoms or an aryl radical, substituted or unsubstituted, R 'and R "together with the adjacent two carbon atoms to form a ring structure of the formula are linked or wherein, if R1 and R2 are linked together with the two adjacent carbon atoms to form a ring structure of the formula R 'and R', which can be identical or different, denote hydrogen, an alkyl radical having 1 to 5 carbon atoms or a tryl radical, substituted or unsubstituted, or they can be bonded together with the two adjacent carbon atoms to form a ring structure of the formula wherein Y represents two hydrogen atoms, an additional bond, or an epoxy group; R "'represents hydrogen, an alkyl radical having 1 to 5 carbon atoms or an aryl radical, substituted or unsubstituted, and the benzene rings A and B can be substituted by one or more substituents, which can be the same or different, or one or both of the benzene rings A. and B may have fused a benzene ring or a heterocyclic ring.

As examples of the compounds according to the invention, compounds corresponding to one of the formulas II, III, IV, V, VI, VII, VIII and IX can be mentioned: wherein R1, R2, Rt, Ril, R "r, X, Y, A and B have the meanings given above.

As a special substituent for the alkyl radical R1, R2, Rt, R "or Ritt can be called a methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl or pentyl group, and of these, methyl is preferred. Of the Substituent R1, R2, Rt, R ″ or Rt lt can be an aryl radical, such as a phenyl or Naphthyl radical, optionally substituted by one or more alkyl, alkoxy or halogen residues. -X- is preferably a direct single bond and -Y- is preferably an additional bond. The benzene rings A and B can be substituted be through one or more substituents selected from alkyl or alkoxy radicals with 1 to 8 carbon atoms, such as methyl, ethyl, propyl, butyl, methoxy, ethoxy, Propoxy or Butozy, halogen, such as chlorine or bromine, aryl, such as phenyl or naphthyl, or aralkyl, w1e benzyl. As stated above, one can or both of the benzene rings A and B can be a benzene ring or a heterocyclic ring Have condensed ring, this benzene ring A or benzene ring B being enlarged becomes a naphthalene ring or a benzo-heterocyclic ring, whereby one a higher molecular weight compound is obtained.

Particularly suitable compounds falling under the above formula I are compounds represented by the formulas IIA, IIIA, IVA, VA, VIA, VIIA, VIllA, IXA and XA, as listed below: Of the compounds shown above, the compounds of the formulas VIA and VIIIA are particularly preferred compounds.

According to a further feature of the invention there is provided a process for the preparation of a compound of Formula I above which consists in using a derivative of an enol compound represented by Formula IA with a suitable butenolide derivative of the formula IB react, in which R1, R2, R ', R "and -X- have the meanings given above and Z represents a halogen atom, a methanesulfonate radical (CH3S020-) or a tosylate radical (CH306E4.S020-).

This enol-form derivative of α-formylbutenolide is preferred a metallic derivative thereof in the form of a salt of the enol such as an alkali metal salt, for example the sodium salt. Suitable salts for use in manufacture of the preferred compounds are the sodium enolate salt of 3-hydroxymethylene-1,4-butyrolactone, the sodium enolate salt of the <t'-lactone of 4-hydroxycyclopentenyl-5- (a-formyl-acetic acid), the sodium enolate salt of the γ-lactone of indan-2-ol-1- (a-formyl acetic acid), the sodium enolate salt of the γ-lactone of indan-1-ol- 2- (a-formyl-acetic acid) and the sodium enolate salt of the q% lactone of 3-cyclopentenyl-4- (α-formyl-acetic acid).

A suitable synthesis for the preparation of the enol compound in the form of its sodium salt, which is used as starting material for the preparation of the compound IVA or VA, is listed below: Suitable syntheses for the preparation of the enol compound in the form of its sodium salt, which is used as starting material for the preparation of the compound VIA, VIIA or XA, are listed below: A suitable synthesis for the preparation of the enol compound in the form of its sodium salt, which is used as the starting material for the preparation of the compound VIIIA or IXA, is given below: DBU (1,5-diazabicyclo [5,4,0] undec-5-en) The butenolide derivative of the formula IB can, as above. found to be in the form of methanesulfonate or a tosylate or in the form of a halogen derivative, such as the chlorine derivative (Z-Ol) or the bromine derivative (Z = Br), Suitable butanol: derivatives for use in the preparation of the preferred compounds are 3-bromophthalide, 5-chloro-3-methylbut-2-enolide, 3-methylbut-2-enolide-5-methanesulfonate, 3-methylbut-2-enolide-5-p-toluenesulfonate and 5-bromo-4-methylbut- 2-enolide.

The process can conveniently be carried out in the presence of a suitable solvent of the diluent, such as an organic solvent or diluents, for example 1,2-dimethoxyethane. The procedure can be expedient be carried out at a temperature in the range from 0 ° C to room temperature, until the reaction is complete and the reaction time can be of the order of magnitude from 10 to 20 hours.

The butenolide derivative of the formula IB can be prepared by customary processes, all of the preparation details being described in the literature. Alternatively, the compound 5-chloro-3-methylbutenolide or 5-bread-3-methylbutenolide can conveniently be prepared by an improved process which leads to 3-methylbutenolide in a one-step process. This important intermediate can now be prepared by heating 3-methyl-ç-butyrolactone with a mixture of bromine and phosphorus to form 3-methylbutenolide, which can then be chlorinated or brominated in the usual way to form 5-chloro-3- methylbutenolide or 5-bromo-3-methylbutenolide according to the reaction scheme wherein Z is chlorine or bromine.

This new process route results in the useful intermediate 3-ethylbutenolide, in a more convenient manner and in a better yield v those previously described in the literature Procedure.

Another process leading to the desired butenolide derivative of Formula IX, e.g., 5-chloro- or 5-bromo-3-butenolide, comprises an alternative improved process for 3-methylbutenolide. The latter can be prepared by reacting a third of pyruvic acid, such as ethyl pyruvate, with a vinyl derivative, such as vinyl acetate, in the presence of a titanium salt, such as titanium tetrachloride, and then cyclizing to form a 5-substituted 3-methylbutenolide, for example 5-ethoxy-3- butenolide. The latter can be converted in the usual way into 5-chloro- or 5-bromo-3-methylbutenolide, for example by heating with thionyl chloride with the formation of It goes without saying that the compounds according to the invention can exist in various stereoisomeric forms. Every compound has an optically active center in the ring structure of its formula on the right. In addition, any compound that has more than one ring in the left-hand ring structure of its formula has a second chiral feature, as illustrated with reference to the structures of compounds IVA and VIA, wherein the centers of asymmetry are shown below. With regard to the cis condensation of the rings, each of the compounds can only exist in two diastereoisomeric forms which can be separated from one another. For example, the compound IVA has been separated into its two diastereoisomeric forms, which are conveniently referred to as the slowest isomer and the fastest isomer, respectively, according to the rate at which each isomer is eluted from a silica column (cf.

the following example 3). In the same way was the connection VIIIA separated into its two diastereoisomeric forms, known as the slow "isomer and identified as a "fast" isomer. Each of these diastereoisomers Shapes of each of these connections can also be in their right-handed D-shape and split into their counter-clockwise L-shape.

It is therefore understood that the compounds according to the invention all possible stereoisomeric forms of each compound.

According to a further feature of the invention, a method for Control of at least one of the parasitic weeds Striga hermonthica, Striga asiatica (lutea), Orobanche crenata, Orobanche ramosa and Orobanche aegyptiaca provided, that consists in dormant seeds or seeds thereof with a connection accordingly to bring the formula I into contact, wherein R1, R2 R ', R ", Ritz, X, Y, A and B die Have the meanings given above.

When carrying out the weed control procedure is it is generally preferred that the host plant, i.e. the plant to which the germinating weed seeds themselves become infected and grow, not present in the soil containing the parasitic weed seeds to be treated, or that the host plant has essentially reached its maturity, so that any infestation of the host plant by the parasitic weeds with subsequent germination of whose seeds have a minimal impact on the host plant and the harvest the latter or their natural death at the end of a growing season parasitic weeds prevent the maturity and folglioh etne to prevent re-sowing of it. It should be understood, however, that the procedure expediently also carried out at other times during the life of the host plant can be. It may be useful to carry out the procedure using one of the Compounds according to the invention mixed with a selective herbicidal agent after sowing the host plant or during the active period Growth of the host plant.

It can also be advantageous to seed or sow the orobanche or to give Striga species a pretreatment with a solution of Gibberellic acid before treatment with any of the invention Compounds as a method of controlling these parasitic weeds.

According to the invention, a herbicidal composition is therefore provided, which contains as an active ingredient a compound of formula I wherein R1, R2, R ', R ", R", X, Y, A and B have the meanings indicated above, together with a suitable carrier or diluent therefor.

The compound of formula I is preferably applied to the soil, which contains the dormant parasitic weed seeds, in the form of a composition, containing the active compound in admixture with a suitable carrier or diluent contains. Suitable carriers or diluents are, in particular, finely divided ones solid, inert carriers or diluents such as powdered lime or powdered ones Chalk, powdered clays, or powdered common fertilizers. Appropriate are also liquid carriers or diluents, such as water or an organic one Liquid. Premixes with a relatively high concentration of the active agent can be formulated with a carrier for ease of handling, in particular to facilitate the preparation of the final herbicidal composition based on to be applied to the ground. For example, such a premix in the form of a solution of the active compound in an inert organic solvent assume, with such a solution optionally a surface-active middle which is selected to promote the formation of an aqueous emulsion, if diluted the concentrate with a large volume of water for application to the soil will.

That used in the above weed control method active compound or the above herbicidal compositions is or contain preferably a compound of the formula II, III, IV, V, VI, VII, VIII or IX. One such compound can be applied to the ground, the which contains parasitic weed seeds, in amounts from 100 to 5000 / ha or from 0.01 Up to 0.5 g / m3 of soil and for this purpose, compositions can be used containing from 0.001 to 1000 parts per million of the active compound, the Remainder of such compositions essentially of diluent or carrier, as described above. Too little of the active connection can be too Insufficient germination of the parasitic weed seeds lead to effective To achieve combat. Of course, the temperature and humidity conditions should by making soil suitable for the germination of the parasitic weed seeds.

A more preferred compound for use in combating these Weeds or for use in the herbicidal compositions is a compound of the formula IIA, IIIA, IVA, VA, VIA, VIIA, VIllA, IXA or XA. Of these are the currently preferred the compounds of the formula VIA and VIIIA, which are particularly preferred are effective against Orobanche crenata and Striga hermonthica.

It is known to be a compound of the formula XIA effective as a germination stimulator and can be used as a herbicidal agent in the control of parasitic weeds of the Striga and Orobanche genera. Compared with the known compound XIA, the preferred compounds VIA and YIIIA of the invention show an improvement with respect to the compound XIA as germination stimulators in laboratory tests and it was also found that a comparable improvement or benefit was achieved when the compounds of the invention as Herbicides against Striga and Orobanche weeds were used.

The following examples showing the preparation of compounds of the Formula I describe serve to illustrate the invention without limiting it.

Example 1 Preparation of Compound IIA A mixture of 0.87 g of the sodium enolate salt and 1.07 g of 3-bromophthalide in 20 ml of anhydrous 1,2-dimethoxyethane was stirred at room temperature for 18 hours and then diluted with 80 ml of ice-cold water. The precipitated solid product was collected and recrystallized from a mixture of methylene chloride and hexane. The product, compound IIA, in the form of the mixed diastereoisomers, had a melting point of 212-213 ° Ce Analysis: C16H1205 Calc .: C 67.6 H 4.25% Found: C 67.6 H 4.3% .

Example 2 Preparation of Compound IIIA 1.07 g of 3-bromophthalide were added to a suspension of 0.68 g of the sodium enolate of 3-hydroxymethylene-1,4-butyrolactone in 15 ml of anhydrous 1,2-dimethoxypethane and the mixture was stirred at room temperature for 18 hours. The mixture was then diluted with 100 ml of water and extracted three times 30 ml of dichloromethane. The combined organic extract was washed with 50 ml of water followed by 50 ml of a saturated saline solution, dried over sodium sulfate and evaporated to dryness. The solid residue crystallized from a methylene chloride-eexane mixture with formation of the compound IIIA in the form of colorless needles with a melting point of 185 ° -189 °.

Analysis C13H1005 3rd: C 63.4 H 4.05% - Found: C 63.45 H 4.15% Example 3 Preparation of the compound IVA (i) 2-bromoindan-1-ol This was according to known Procedures made from indene The NMR spectrum in deuterochloroform confirmed that that the product was rans-2-bromoindan-1-ol.

(ii) Trans-indan-2-ol-1-acetic acid This was made by modification the known method. 0.46 g of sodium was stirred in small portions Solution of 3.2 g of diethyl malonate in 15 ml of 1,2-dimethoxyethane added at room temperature (3 hours). The resulting solution was mixed with a solution of 2.15 g of 2-bromo-ndan-1-ol Treated in 12 ml of 1,2-dimethoxyethane and the mixture was over at room temperature Stirred night. Then it was refluxed for 1 hour, cooled and evaporated to dryness.

The mixture of crude diester and excess diethyl malonate was added saponified by boiling with 60 ml of 2N sodium hydroxide for 1.5 hours. The resulting Solution was cooled, washed with twice 30 ml of ethyl acetate, with 6N hydrochloric acid acidified and saturated with salt. By continuously tracing with ether for 24 hours followed by removal of the solvent was obtained a solid product which crystallized from benzene-alcohol when it had a m.p. 116118O.

The hydro-diacid was removed by heating in an oil bath to about 130 ° C decarboxylated with stirring under an atmosphere of nitrogen for 1 hour. The resulting oil solidified on cooling and crystallized from benzene-hezane. It had a melting point of 124-132 °.

Analysis: C11H12O3 13's: C 68.75 H 6.28% Found: C 68.6 R 6.25%.

The NMR spectrum of the compound clearly showed that it was the traded trans-indan-2-ol-1-acetic acid; Double radiation examinations at 220 MHz showed the presence of the CH2-CH-CH-CH2 skeleton associated with the above Structure mapping did not match.

(iii) Lactonization of lrans-indan-2-ol-1-acetic acid 2.5 g of the above Hydroxy acid was dissolved in 65% concentrated sulfuric acid and 10 ml acetic acid and kept at room temperature for 24 hours. It was then broken down to 300 g Poured ice and the aqueous solution was extracted four times with 60 ml of methylene chloride. The combined organic extract was twice 100 ml of water, then with twice with 50 ml of 5% sodium bicarbonate and finally with 30 ml of saturated saline solution washed. After drying over sodium sulfate, the organic solution was filtered and evaporated to give an oil which slowly crystallized. By recrystallization the desired lactone was obtained in the form of a methylene chloride-hexane mixture of colorless needles with a melting point of 73-74 °.

Analysis: C11H1002 Calc .: C 75.8 H 5.7% Found: a 75.85 lI 5.75%.

(iv) Botmylation of the lactone of indan-2-ol-1-acetic acid 0.23 g of sodium were added to a solution of 1.74 g of the above lactone in a mixture of 1.11 g of ethyl formate and 20 ml of ether were added and the mixture was at 18 hours Room temperature stirred. The light tan sodium lmenolate salt was filtered, washed quickly with a small amount of ether and placed in a desiccator overnight dried.

(v) Reaction of the sodium enolate salt with 5-chloro-3-methylbutenolide 0.66 g of 5-chloro-3-methylbutenolide were added to a suspension of 1.12 g of the above sodium enolate salt in 20 ml of anhydrous 1,2-dimethoxyethane, and the mixture was stirred for 16 hours. At the end of this period the mixture was diluted with 50 ml of water and extracted three times with 60 ml of chloroform. The combined chloroform extract was shaken with saturated saline, dried over sodium sulfate, filtered and evaporated to dryness. The remaining light brown solid was crystallized from chloroform-ether to give a compound IVA in the form of a colorless product (mixed isomers) of melting point -200-214 °.

Analysis: C17H1405 Calcd .: C 68.45 H 4.7% Found: C 68.45 H 4.85%.

The product, which was a mixture of diastereoisomers, was separated on a silica column (activity III; 84 x 2.5 cm) below Elute with 2% ethyl acetate in ether.

The "slow" isomer that has the lower Rf value on a silica plate eluted with ethyl acetate-ether mixtures had a melting point of 2050. That "fast" isomers had an mp of 119-1200.

The 5-chloro-3-methylbutenolide used as the starting material above can be prepared from 3-methyl-yt-butyrolactone by heating with bromine and Phosphorus with formation of 3-methyl-3-butenolide, which is then converted into 5-chloro-3-methylbutenolide can be converted by known procedures. Alternatively, the 3-methyl-3-butenolide, if desired, in 5-bromo-3-methylbutenolide by direct bromination, as in the Literature described, are converted, which is also used as the starting material can be used.

Production of 3-methyl-3-butenolide In a 1 liter three-necked round bottom flask equipped with a dropping funnel, magnetic stirrer and an efficient reflux condenser were placed 100 g of 5-mathyl-t-butyrolaoton and 11.6 g of red phosphorus. 168 grams of bromine was added over a 30 minute period while stirring the mixture and cooling with an ice bath. The mixture was warmed to 700 in an oil bath and an additional 168 grams of bromine was added over 30 minutes. After the addition of bromine, the temperature was raised to 800 and the mixture was kept at this temperature for 3 hours. Air was then blown into the colored reaction product until excess bromine and hydrogen bromide were removed (a trap to collect the resulting vapors is beneficial).

The aerated reaction mixture was then placed in an oil bath on 800 and 20 ml of water were carefully added with stirring. Upon termination an additional 300 ml of water was added to the reaction (which took about 30 minutes) and the mixture was refluxed vigorously for 4 hours (using a Feizmantels) heated. The product was cooled, 50 ml of water was added and then the aqueous SchSc was saturated with sodium chloride and four times 100 ml of methylene chloride extracted. The combined extracts were dried (sodium sulfate) and the solvent was removed under reduced pressure. Of the. resulting a dark red residue was distilled under reduced pressure to give 52 g (53%) 3-methyl-3-butenolide, b.p. 520 / 1.5 mm; 320/7 mm; 97.98.60 / 20 mm.

The 5-chloro-3-methylbutenolide used as starting material can also be conveniently prepared in a three-stage process by reacting ethyl pyruvate with vinyl acetate in the presence of titanium tetrachloride, followed by ring closure and subjecting the 5-ethoxy-3-methylbutenolide thus obtained to a chlorination with Thionyl chloride as follows: 8.1 g (43 mmol of freshly distilled) titanium tetrachloride in 60 ml of methylene chloride (dried over molecular sieves) were cooled and stirred in an ice bath and then a solution of 4.94 g (43 mmol) of ethyl pyruvate and 3.66 g (43 mmol ) Vinyl acetate in 30 ml of dry methylene chloride was added dropwise to the cooled and stirred reaction mixture over the course of 2 hours. The mixture was stirred at 0 ° for a further 2 hours. 40 ml of water was then added, the layers were separated and the aqueous layer was extracted with an additional two times 30 ml of methylene chloride. The combined methylene chloride extracts were washed with 3 ml of water, dried over sodium sulfate and evaporated to give 7.50 g of a colorless oil which had NMR signals (CDC at 1.40 g (s, tertiary Me), 6.63 (m) and showed 2.00 and 2.08 (uastereomeric acetates).

The resulting crude colorless oil (7.12 g) was dissolved in 80 ml of absolute Ethanol dissolved, 4 ml of concentrated hydrochloric acid was added and the The mixture was refluxed for 4 hours. 100 ml of water were then added was added and the ethanol was removed by distillation and the residue was removed refluxed for a further 45 minutes. The reaction mixture was then extracted with three times 50 ml of ethyl acetate and the extract was over sodium sulfate dried and evaporated. The product was a yellow-brown rubbery material (2.39 g), the NXR signals (CDC13) at # 1.90 (Vinyl Me) and 6.00 and 6.38 (2x m, each 1 ^ proton) showed.

The crude, yellow-brown gummy substance was mixed with 20 ml of thionyl chloride Heated under reflux for 1 hour and then excess reagent was passed through Distilling away. The residue was distilled under reduced pressure with the formation of 1.4 g of a colorless mobile oil with a bp 620/2 mm.

It was identified as 5-chloro-5-methylbutenolide.

Example 4 0.7 g of bromophthalide was added to a suspension of 0.75 g of the above sodium enolate salt, prepared as for compound IVA in Example 3 above, in 15 ml of anhydrous 1,2-dimethoxyethane, and the mixture was stirred for 18 hours. At the end of this period the mixture was poured into 50 g of ice and the solid product was filtered and dried in the desiccator.

Another crop of product was obtained by extraction the above aqueous mother liquor with three times 30 ml of chloroform, the extract dried over sodium sulfate, filtered and evaporated to dryness. By Crystallization from methylene chloride-hexane mixture gave the compound VA as a crystalline product (mixed diastereoisomers) of melting point = 161-168 °.

Analysis: C20H1505 Calc .: C 71.85 H 4.19% Found: o 71.55 lI 4.28%.

Example 5 Preparation of the compound, VIA Bactonizing trans-indan-1-ol-2-acetic acid 3.4 g of tralls-indan-1-ol-2-acetic acid were dissolved in 25 ml of 25% strength aqueous sulfuric acid dissolved and 150 ml of ether was added and the mixture became vigorous for 18 hours stirred at room temperature. The ethereal layer was separated, saturated with 25 ml Shaken brine and dried over sodium sulfate. By filtering and removing of the solvent in vacuo gave an oily product which crystallized on standing.

Obtained by recrystallization from ether-petroleum ether (b.p. 60-80 °) the desired cis-lactone in the form of colorless needles with a melting point of 6465O.

Formylation of the lactone of cis-indan-1-ol-2-acetic acid 2.61 g of des The above cis-lactones were added to a suspension of 0.345 g of sodium in 50 ml anhydrous ether added, followed by 1.8 g of ethyl formate and 1.0 ml of anhydrous Ethanol. The mixture was left at room temperature under nitrogen for 18 hours touched. The precipitated sodium enolate salt was filtered, quickly with 25 ml of dry Washed with ether and dried in a vacuum desiccator overnight.

Reaction of the sodium enolate salt with 5-chloro-3-methylbutenolide 0.663 g of 5-chloro-3-methylbutenolide were added to a suspension of 1.12 g of the above sodium enolate salt in 20 ml of anhydrous 1,2-dimethovethane and the mixture was stirred for 19 hours. 40 g of broken ice was then added and the aqueous solution was extracted four times with 60 ml of chloroform.

The combined chloroform extract was mixed with 20 ml of a saturated saline solution washed, dried over sodium sulfate, filtered and evaporated to dryness in vacuo. The crystalline solid thus obtained was recrystallized from methylene chloride-hexane and gave compound VIA (mixed diastereoisomers) as colorless Needles of mp = 116-124 °.

Analysis: C17H1405 3rd: a 68.45 H 5.05% Found: C 68.45 H 4.7%.

Example 6 Preparation of Compound VIIIL A mixture of 0.75 g of the sodium enolate salt, prepared as described for the compound VIA in Example 5 above, and 0.71 g of 3-bromophthalide in 10 ml of anhydrous 1,2-dimethoxyethane was stirred at room temperature for 19 hours. 20 g of ice were added and the crystalline solid thus obtained was separated off and dried. The product was the compound VIIA (mixed 1) iastereoisomers) with a melting point of 163-173 °.

Example 7 Preparation of the compound VIIIA Indolactonization of cyclopent-2-enyl-1-esic acid. A solution of 30 g of iodine and 50 g of potassium iodide in 200 ml of water was added to a mixture of 12.6 g of cyolopent-2-enyl-1-acetic acid in 400 ml of 0.5M sodium bicarbonate and 300 ml of chloroform were added and the mixture was stirred vigorously at room temperature in the dark for 2 days. At the end of this period the chloroform layer was separated, washed with a solution of 10% sodium thiosulfate and then with a saturated solution of sodium chloride. The resulting chloroform solution was dried over sodium sulfate, filtered and evaporated to dryness to give a thick yellow oil which crystallized on standing. This gave 23.8 g of the desired compound with the structure: Preparation of Ccloaent-3-en-2-ol - acetic acid lactone A mixture of 22.66 g of the above indolactone and 13.69 g of 1,5-diazabicyclo [5: 4: 0] undec-5-en (DBU) in 200 ml of anhydrous tetrahydrofuran was stirred at 500 ° for 2 hours and heated under reflux for 1 1/2 hours. It was then cooled to room temperature, diluted with 100 ml of water and extracted three times with 60 ml of ethylene chloride. The combined organic extracts were shaken with saturated brine, dried over sodium sulfate, filtered and concentrated to give 10.3 g of Cylcopent-3-en-2-ol-1-acetic acid, which was dissolved by distillation at 690 / 0.4 mm has been cleaned.

Analysis: C7H8O2 3rd: C 67.74 H 6.45% Found: C 68.08 H 6.51%.

Fermylation of the lactone of CycloDe: nt-3-en-2-oacetic acid 0.46 g Sodium was added to a solution of 2.48 g of the above lactone in a mixture of 2.22 g of ethyl formate and 25 ml of ether added and the reaction was 18 hours stirred at room temperature. The light tan sodium salt was filtered with a small amount of anhydrous ether and washed overnight in a desiccator dried.

Reaction of the sodium salt with 5-chloro-3-meth: zlbutenolide 1.33 g of 5-chloro-3-methylbutenolide were added to a suspension of 1.74 g of the above sodium salt in 20 ml of anhydrous 1,2-dimethoxyethane and the mixture was stirred at 50 for 16 hours. It was then diluted with 20 g of cold water and extracted three times with 25 ml of methylene chloride. The combined methylene chloride extract was shaken with saturated brine, dried over sodium sulfate, filtered and evaporated to dryness to give a viscous oil which solidified on standing. Crystallization from ether gave a colorless crystalline product with a melting point of 140 ° -188 ° (mixed diastereoisomers), which was identified as compound VIIIA.

Analysis: C13H1205 Calc .: o 62.90 H 4.84% Found: C 62.8t H 4.89%.

Example 8 Preparation of Compound IXA 1.07 g of 3-bromophthalide were added to a suspension of 0.87 g of the sodium salt, prepared as described for the compound VIIIA in Example 7; added in 20 ml of anhydrous 1,2-dimethoxyethane and the mixture was stirred for 18 hours at room temperature. It was then diluted with ice-cold water and extracted three times with 25 ml of methylene chloride. The combined methylene chloride extract was shaken with saturated saline, dried over sodium sulfate, filtered and evaporated to dryness to give 1.45 g of a solid which crystallized from ether. The product was a colorless, crystalline solid, melting point = 178-200 ° (decomp.) (Mixed diastereosorbers) and was identified as compound IXA.

Analysis: C16H1205 3rd: C 67.61 H 4.23% Found: C 67.47 H 4.28%.

Example 9 Preparation of Compound XA A mixture of the sodium enolate salt (prepared as for the compound VIA in Example 5, but using 4 g of lactone and 5 g of 5-bromo-4-methyl-3-butenolide in 100 ml of dry tetrahydrofuran was stirred overnight in a nitrogen atmosphere at room temperature Most of the solvent was removed under reduced pressure at room temperature and the residue was poured into water and extracted several times with methylene chloride. The combined extracts were washed with saturated sodium chloride solution and then with aqueous sodium bicarbonate and water. After removal of the solvent from the dried Solution, the residue was crystallized from ether-chloroform to give the product in the form of colorless crystals, m.p. 188-1890, which were identified as Compound XA The NMR spectrum was consistent with the structure given for Compound XA.

To demonstrate the activity of the compounds to promote the Germination of seeds of Striga hermonthica, Striga asiatica, Orobanche aegyptiaca, The following procedure was used for Orobanche crenata and Orobanche ramosa. Seeds of the parasitic weeds were first washed with a 1% aqueous sodium hypochlorite solution sterilized for 10 to 15 minutes and then with distilled water washed until free of sodium hypochlorite.

The Striga and Orobanche seeds were pretreated by incubation at 2300 under moist conditions, e.g. in a moist glass fiber filter paper during 10-14 days. Usually about 25 seeds were placed on 10 mm disks of the filter paper used.

Discs bearing the pre-treated seeds of Striga or Orobanche, were blotted to remove excess moisture. Two discs were made then added to each of two propagation trays, so that 4 slices per treatment templates that carried a total of about 100 seeds. The compounds to be examined were dissolved in ethanol and distilled to the desired concentration Water thins. The amount of ethanol in the final solution was never greater than 0.5% v / v

Freshly prepared solutions were always used. To every son two 16 μl drops of the test solution were added. It could be a dilution of the Test solutions enter through moisture in the discs, so that the specified Concentrations Final concentrations are. Germination was after 2 days at 34 ° C in the case of Striga and after 5 days at 23 ° C in the case of Orobanche counted.

Table I Germination tests on Striga hermonthica Concentration (ppm)% germination Connection connection IIA IIIA 100 1 32 33 50 X 43 39 10 35 25 5 38 17 1 29 1 0.5 30 6 0.1 0 16 Control (distilled water): 6% germination It can be seen that both compounds are active and compound IIA is more active than compound IIIA. Table II Germination tests on Orobanche ramosa Concentration% germination (ppm) Connection connection connection connection IIA IIIA IVA VA 100 0 0 1 1 10 0 1 2 2 1 2 0 0 2 0.1 0 0 0 3 0.01 50 42 55 10 0.001 13 34 50 46 0.0001 30 21 50 9 Control (distilled water): 9% germination It can be seen that all four compounds are active and that compound IVA is the most active compound of the four compounds examined.

Table III Germination tests on Orobanche crenata Concentration% germination (ppm) Connection IVA connection IVA connection ("slow" isome- ("narrow" XIA res) isomer) 1 50 66 49 O, l 18 39 14 O, Oi 9 8 '0 Control (distilled water): 0% germination It can be seen that there is no significant difference between the unresolved DL pairs of diastereoisomers (the slow and fast isomers) of compound IVA. Each of these isomers is superior to compound XIA in its activity.

Table IV Germination tests on Orobanche crenata Concentration% germination (ppm) Connection connection connection VIA VIIA XIA 100 27 18 24 10 37 3 18 1 42 2 5 0.1 14 5 3 0.01 8 6 1 O, OOl 3 16 1 0.0001 1. 5 0 Control (distilled water): 1% germination Each of the compounds VIA and VIIA is superior in its activity to the compound XIA in the lower concentration range.

Table V ========= Keiraung tests on Striga hermonthica Concentration% germination (ppm) Connection IVA connection IVA connection ("slow" Iso- ("fast" XIA mere) tsomere) 100 9 1 1 50 17 3 7 10 10 9 8 5 50 44 23 1 60 28 24 0.5 44 10 18 0.1 7 19 12 0.05 8 20 28 0.01 10 22 21 control (aestillized water: 2% germination 21 Both "slow" isomers and "fast" isomers of compound IVA show a distinct one. Effectiveness. Each of these isomers is superior to compound XIA in certain concentration ranges in terms of its effectiveness.

During the Kharif (second) rainy season, demonstrations were held in Hyderabad, that VIIIA was effective at 10 ppm and 1 ppm potency Reduction of Striga asiatica on a test field with black soil, namely 39 and 36% more effective than a control treatment. In addition, was showed that compounds VIA and VIIIA are active in the Germination of Orobanche ramosa seeds in vitro at concentrations of 0.1 to 1.0 ppm, resulting in about 80 to 90% germination 12 days after treatment. Even Compound VIIIA was shown to be active in stimulating orobanche germination ramosa seeds carried out on glass fiber paper disks and applied to the surface: of sterilized sandy loam soil in glass cups or when burying in 5 cm Depth in this soil or when working into this soil. So the results show that compound VIIIA is as active in sterilized mode as it is in vitro.

Claims (32)

Pat entansprü che Üi.¼ compound of the formula I: in which -X- is a direct single bond or a -CH2 bond and in which, if R1 and R2, which can be identical or different, denote hydrogen, an alkyl radical having 1 to 5 carbon atoms or an aryl radical, substituted or unsubstituted, R ' and R "are joined together with the two adjacent carbon atoms to form a ring structure of the formula or, if R1 and R2 together with the two adjacent carbon atoms, are linked to one another to form a ring structure of the formula R 'and RtZ, which can be identical or different, represent hydrogen, an alkyl radical having 1-5 carbon atoms or an aryl radical, substituted or unsubstituted, or can be linked together with the two adjacent carbon atoms to form a ring structure of the formula wherein Y 2 represents hydrogen atoms, another bond or an epoxy group; R! "Represents hydrogen, an alkyl radical with 1 to 5 carbon atoms or an aryl radical, substituted or unsubstituted, and the benzene rings A and B can be substituted by one or more substituents, which can be the same or different, selected from alkyl or alkoxy radicals with 1 to 8 carbon atoms, halogen, aryl and aralkyl radicals, it being possible for one or both of the benzene rings A and B to have a benzene ring or a heterocyclic ring fused thereto. 2. Compound according to claim 1, represented by one of the formulas II, III, IV, V, VI, VII, VIII and IX: wherein R1, R2, R !, R ", R"', X, Y, A and B have the meanings given in claim 1. 3. A compound according to claim 1 or 2, wherein one or more of the Alkyl radicals R1, R2, R ', R "and R' '' are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl or pentyl radical or are. 4. A compound according to claim 1 or 2, wherein one or more of the Alkyl radicals R1, R2, Rt, R "and R" 'represent a methyl radical. 5. A compound according to claim 1 or 2, wherein one or more of the Substituents R1, R2, R ', R "or R"' denote a phenyl or naphthyl radical, optionally substituted by one or more alkyl, Alko2y or halogen radicals. 6. Compound according to one of the preceding claims, wherein -X- a means direct single bond. 7. Compound according to one of the preceding Xnsprtche, wherein -Y- a represents additional bond. 8. A compound according to any one of the preceding claims, wherein one oter both of the benzene rings A and B are substituted or are by one or more substituents selected from ALkylE or alkoxy radicals having 1 to 8 carbon atoms, halogen, aryl and aralkyl radicals. 9. A compound according to any one of the preceding claims, wherein one or both of the benzene rings A and B is substituted or are by one or more substituents selected from methyl, Ethyl, propyl, butyl, methoxy, ethoxy, propoxy, butoxy, chlorine, bromine, phenyl, Naphthyl and bensyl residues. 10. A compound according to claim 1, represented by one of the formulas IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IXA and XA as follows: 11. The compound of claim 1 represented by the formula VIA. 12. The compound of claim 1 represented by the formula VIllA. 13. A process for the preparation of a compound of the formula I according to claim 1, characterized in that a derivative of an enol compound represented by the formula IA: with a suitable butenolide derivative of the formula IB: wherein R1, R2, R ', R "and -X- have the meanings given in claim t and Z is a halogen atom, a methanesulfonate radical (CHDS020-) or a tosylate radical (cH306H4.So2o-). 14. The method according to claim 13, characterized in that as Enol compound, a metal derivative thereof in the form of a salt of the enol compound is used. 15. The method according to claim 14, characterized in that as Metal derivative uses a sodium salt. 16. The method according to claim 13, characterized in that the Derivative of the enol compound selected from the sodium enolate salt of 3-hydroxymethylene-1,4-butyrolactone, the sodium enolate salt of the <t-lactone of 4-hydroxycyclopentenyl-5- (a-formyl acetic acid), the sodium enolate salt of the lactone of indan-2-ol-1- (a-formyl-acetic acid), the sodium enolate salt of the f-lactone of indan-1-ol-2-ta-formyl-acetic acid) and the sodium enolate salt of % Lactones of 3-hydroxycyclopentenyl-4- (α-formyl-acetic acid). 17. The method according to any one of claims 13 to 16, characterized in that that the butenolide derivative of the formula 13 is in the form of the chlorine derivative (Z = Cl) or the bromine derivative (Z = Br) is used. 18. The method according to any one of claims 13 to 16, characterized in that that the butenolide derivative is 3-bromophthalide, 5-chloro-3-methylbut-2-enolide, 3-methylbut-2-enolide-5-methanesulfonate, 3-methylbut-2-enolide-5-p-toluenesulfonate or 5-bromo-4-methylbut-2-enolide are used. 19. The method according to any one of claims 13 to 18, characterized in, that one works in the presence of a solvent or diluent. 20. The method according to claim 19, characterized in that man 1,2-dimetzoxyethane is used as a solvent or diluent. 21. The method according to any one of claims 13 to 20, characterized in that that the reaction is carried out at a temperature from OOC to room temperature. 22. The method according to any one of claims 13 to 21, characterized in that that the reaction time is on the order of 10 to 20 hours. parasitic 23. Methods of combating at least one of the Weeds Striga hermonthica, Striga asiatica (lutea), Orobanche orenata, Orobanche ramosa and Orobanche aegyptaca, characterized in that the dormant seeds thereof with a compound of the formula I in contact, in which R1, R2, R ', R ", R "c, X, Y, A and B have the meanings given in claim 1. 24. The method according to claim 23, characterized gekennzeiohnet that one Compound used with the formula VIA. 25. The method according to claim 23, characterized in that one Compound of Formula VIIIA used. 26. Herbicidal composition containing as an active ingredient a compound of the formula I in which R1, R2, R ', R ", R", X, Y, A and B are in claim I have given meanings, together with a suitable carrier or diluent Therefore. 27. The composition of claim 26, wherein the carrier or diluent is a finely divided solid, inert carrier or a liquid carrier. 28. The composition of claim 26, wherein the carrier or diluent powdered lime, powdered alumina, powdered common fertilizer, is an aqueous medium or an organic liquid. 29. The composition of claim 26 in which the carrier or diluent Is water that contains traces of acetone or methanol. 30. Composition according to any one of claims 26 to 29, in which the active ingredient is a compound represented by one of the formulas selected from the formulas II, III, IV, V, VI, VII, VIII and IX. 31. Composition according to any one of claims 26 to 29, in which the active ingredient is a compound represented by one of the formulas selected from the formulas, IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IXA and XA. 32. Composition according to any one of claims 26 to 29, in which the active ingredient a compound represented by the formulas VIA or VIIIA, is.