BICYCLO 4.1.0]HEPTANE-2,4-DIONE DERIVATIVE, INTERMEDIATE FOR THE SYNTHESIS THEREOF, AND PRODUCTION THEREOF

Abstract: Compounds represented by general formulae (I) and (II), useful as the intermediates for agricultural chemicals, particularly herbicidal compounds, wherein R¹ and R² represent each hydrogen, alkyl or COOR³; R³ represents alkyl; and R⁴ represents alkyl.

Description: FIELD OF THE INVENTION The present invention relates to bicyclo[4,1,0]heptane-2,4-dione derivatives useful as an intermediate, the intermediates for the synthesis thereof and the process for the manufacture thereof. BACKGROUND ART 2-substituted benzoyl-1,3-cyclohexanediones have been known effective as weed killers, and representatives having various substituents and/or chemical structures have been proposed. It is an object of the present invention to provide effective compounds as the intermediates for synthesizing such herbicidal compounds. DISCLOSURE OF THE INVENTION The present invention is directed to compounds represented by the general formula (I): wherein R¹, R² denote each independently hydrogen, alkyl or -COOR³, and R³ denotes alkyl, a process for the manufacture thereof, and a compound represented by the general formula (II): wherein R¹, R² are as defined above, and R⁴ denates alkyl, and a process for the manufacture thereof. "Alkyl" is a straight or branched group having 1-6 carbon atoms. A compound of the general formula (I) is prepared from a compound of the general formula (II) according to the process shown below: wherein R¹, R² and R⁴ are defined above. The reaction shown above is accomplished by reacting a cyclopropane derivative of the general formula (II) in an adequate solvent and in the presence of a base. As the solvent described above, alcohols such as methanol and ethanol can be used, and the sodium alcoholate or potassium alcoholate thereof can be used as the base described above. The reaction can be accomplished at a temperature in a range of from room temperature to 150°C, and preferably at the boiling point of the alcohol used. One to five times the amount in mole of the base relatively to the mole of the cyclopropane derivative used, and preferably 1 to 2 times the amount in mole, is used for the reaction. The cyclopropane derivatives of the general formula (II) can be manufactured by reacting a ketone of the general formula (III) with an ester of the general formula (IV) in the presence of a base according to the process shown below: wherein R¹, R² and R⁴ are defined above, and Hal denotes halogen. The foregoing reaction is normally accomplished in an adequate solvent. As the solvent, benzene, toluene and the like can be used besides alcohols, however, it is most preferable to use an alcoholate as a base in alcohol. In the reaction, bicyclic compounds represented by the general formula (I) can be prepared without isolating cyclopropane derivatives of the formula (II) when more than 2 moles of alcoholate are used. The halogen is preferably chlorine. As shown below, a compound of the general formula (VI) having herbicidal activity can be readily prepared by reacting the bicyclic compound of the general formula (I) with chloride benzoate of the general formula (V): wherein Xn denotes a substituent. It is described in the International Publication No. WO 91/00260 Gazette that the compound represented by the general formula (VI) shows herbicidal activity. The compound specified in this application may have the tautomers as shown below. The chemical structures of the compounds according to the invention and other compounds were determined by using IR, NMR, MS and other analytical apparatuses. BEST MODE FOR CARRYING OUT THE INVENTION Below, the present invention is illustrated by means of Examples and and Practical Examples. Example 1 (2-acetylcyclopropyl)diethyl methylmalonate In 25 ml of ethanol 5.15 g of powdered sodium ethylate was added and then dissolved. To the obtained solution, 13.2 g of diethyl methylmalonate was added at room temperature. Then 9.5 g of 5-chloro-3-pentane-2-on (90% purity) was further fed dropwise thereto for 30 min. at a temperature of from 0°C to 10°C. After reacting the solution for 3 hours at room temperature, ethanol present therein was removed by distillation under reduced pressure. Subsequently an extraction was made with ethyl acetate after pouring the solution into ice water. The extract was dehydrated with magnesium sulfate and then the solvent therein was removed by distillation under reduced pressure, affording 17.3 g of the objective product (98.5% purity). The boiling point of the obtained product was in a range of from 130 to 135°C, and all the amount of the compound obtained was in the trans-form. Example 2 Cis- and trans-5-ethoxycarbonyl-5-methylbicyclo[4,1,0]heptane-2,4-dione (Compound No. 3 and 1). 330.7 g of (2-acetylcyclopropyl)diethyl methylmalonate of the formula (II), wherein R¹ is CH₃, R² is CO₂C₂H₅, and R³ is C₂H₅, was added into 975.6 g of 14% sodium ethylate solution in ethanol, after which the solution was heated to reflux for 3 hours. After cooling the solution, it was poured into a cool aqueous solution of hydrochloric acid and then extracted with ethyl acetate. The extract was then washed with saturated brine. After dehydrating the extract with magnesium sulfate, the solvent was removed by distillation there-from, affording 87.6 g of the trans-form compound of the formula (I), wherein R¹ is CH₃ and R² is CO₂C₂H₅, in whitish crystals by adding ether into the remained solution. The filtered solution was further separated by using silica gel chromatography to obtain 8.1 g of the trans-form compound and 27.8 g of the cis-form compound of the formula (I), wherein R¹ is CO₂C₂H₅ and R² is CH₃. Example 3 Cis- and trans-5-ethoxycarbonyl-5-methylbicyclo[4,1,0]heptane-2,4-dione (Compound No. 3 and 1). In 20 ml of ethanol was added 3.52 g of powdered sodium ethylate and then dissolved. To the obtained solution, 4.5 g of diethyl methylmalonate was added at room temperature and then 3 g of 5-chloro-3-pentene-2-on (97.5% purity) was further added thereto at a temperature of from 0°C to 10°C. After reacting the solution for 1 hour at room temperature, the solution was heated to reflux for 24 hours. Subsequently the solution was treated according to the procedure in Example 1, affording 1.29 g of the trans-form compound and 0.41 g of the cis-form compound. Representative examples of the compounds according to the present invention including the compound obtained in the Examples described above are illustrated in Table 1. Practical Example Cis-3-(4-chloro-2-nitrobenzoyl)-5-methylbicyclo[4,1,0]heptane-2,4-dione : (1) 5,0 g of trans-5-methyl-5-ethoxycarbonylbicyclo[4,1,0]heptane-2,4-dione of the formula (I), wherein R¹ is CH₃ and R² is CO₂C₂H₅, was dissolved in 50 ml of methylene chloride and then 2.65 g of triethylamine was further added thereto. After cooling the solution to 10°C, 5.24 g of 4-chloro-2-nitrobenzoylchloride was added to the solution and the solution was stirred for 2 hours at room temperature. After washing the reaction solution firstly with diluted hydrochloric acid and subsequently with water, the solution was dehydrated with magnesium sulfate and the solvent therein was removed by distillation under reduced pressure. The residues were dissolved in 50 ml of acetonitrile, after which 0.15 g of potassium cyanide and 2.45 g of triethylamine were added and stirred for one night at room temperature. After removing the solvent therein under reduced pressure, methylene chloride was added thereto. Then the solution was washed firstly with diluted hydrochloric acid and subsequently with water, and dehydrated with magnesium sulfate. After removing the solvent from the solution, 9.7 g of trans-3-(4-chloro-2-nitrobenzoyl)-5-methyl-5-ethoxycarbonylbicyclo[4,1,0]heptane-2,4-dione was obtained. (2) 73 ml of 1N NaOH was added to the compound obtained in (1), after which the solution was stirred for 24 hours at room temperature. After cooling the solution to a temperature range of from 5°C to 10°C, 110 ml of ethyl acetate was added thereto, and 48.4 ml of 1N HCL was further fed dropwise thereto. After stirring the solution for 2 hours, the organic layer was separated and washed with saturated brine, dehydrated with magnesium sulfate, after which the solvent therein was removed by distillation under reduced pressure. To the remained solution was added 15 ml of methanol and after cooling the solution, 4.7 g of the objective product in whitish crystals was obtained. The melting point of the product was in a range of from 104°C to 108°C. FIELD OF INDUSTRIAL USE The compounds according to the present invention are useful as intermediates for the manufacture of agricultural chemicals and the like, and particularly as intermediates for herbicidal compounds.

Claims: A compound represented by the formula (I) wherein R¹ and R² denote - each independently - hydrogen, alkyl or -COOR³, wherein R³ denotes alkyl. A process for preparing a compound represented by the formula (I): wherein R¹ and R² are as defined in claim 1, characterized in that the compound is prepared by forming a ring closure in a compound represented by the formula (II): wherein R¹ and R² are as defined above and R⁴ denotes alkyl. A compound represented by the formula (II): wherein R¹, R² and R⁴ are as defined in claim 1. A process for preparing a compound represented by the formula (II): wherein R¹, R² and R⁴ are as defined above, characterized in that the compound is prepared by reacting a ketone represented by the general formula (III): wherein Hal denotes a halogen atom, and an ester represented by the general formula (IV): wherein R¹, R² and R⁴ are as defined in claim 1, in the presence of a base.

Inventors: HATANO MASAMI, IMAIZUMI SHINICHI, SUZUKI JUNJI, HATANO, MASAMI, IMAIZUMI, SHINICHI, SUZUKI, JUNJI, HATANO, MASAMI ODAWARA RESEARCH CENTER, IMAIZUMI, SHINICHI ODAWARA RESEARCH CENTER, SUZUKI, JUNJI TAKAOKA PLANT
Applicants: NIPPON SODA CO, NIPPON SODA CO., LTD.
Application year: 1992
Main classification: C07C49
IPC codes: C07C67, C07C45, C07C69, C07C49, C07C205