Background Art The horse chestnut leafminer is a new insect pest introduced to Europe around 1985. This tiny moth is a significant pest for the horse chestnut (Aesculus hippocastanum L.), on which the moth's larvae consume the leaf parenchyma during their development stage and form mines. When a massive infestation takes place, frequently during the second pest generation (July), the larvae cause necrosis and then shedding of the leaves. Due to the shortened assimilation period, the trees are weakened and where heavy infestation occurs continuously over several years, the trees can die. A more serious situation can come about when the leafminer larvae shift to another tree host, as we can currently witness on maple. In regions where leafminer infestation has occurred for ca 10 years, the parasitation of leafminer larvae by parasitoids from the genus Chalcidoidea has only reached 30%, an insufficient rate for effective control of the pest populations. The only suggested and useable methods of controlling the pest are the racking and burning of infested horse chestnut leaves [Skuhravy V. Anzeiger fur SchadlirTgskunde Pflanzenschutz Umweltschutz 71,82-84 (1998)] and the spraying of trees with inhibitors of chitin biosynthesis (e. g. diflubenzuron).

Chemical communication serves diverse behavioral and physiological functions in nature. For example, chemicals named"sex pheromones"are used by individuals belonging to same species to find a partner of the opposite sex for mating. Those compounds can be chemically characterized and prepared in laboratory. So far we know the chemical structures of ca 400 sex pheromones of moths [Arn, H., Tóth, M.

1998: List of Sex Pheromones of Lepidoptera and Related Attractants. In Arn H., Tóth M. & Priesner E. (eds): The Pherolist. Internet database (www- pherolist. slu. se)]. At present no pheromone-based methods to protect the horse chestnut trees against the leafminer exist, however, those pheromone-based techniques of protection against other types of moth (the tortrix and pyralid moths) are much more advanced and are successfully used for population monitoring [Ridgeway, R. L., Silverstein, R. M. a May, N. I (Ed.) 1990: Behavior-Modifying Chemicals for Insect Management. Marcel Dekker, Inc. New York, 761 pp.], or to confuse the males, by making it more difficult for males to locate females for mating by increasing the airborne concentrations of synthetic pheromones (Ridgeway et al.

1990). Beside these simple techniques, some more complex ones have been developed, e. g. where males are lured by a synthetic pheromone in proximity to toxic fumigants and/or insecticides (the attract and kill method) (Hofer, D. and Brassel, J, "Attract and kill"to control Cydia pomonella and Pectiophora gossypiella IOBC WPRS'Bull. 1992/XV/5: 36-39), or to viral agents (Czech patent application PV 1680-95), or spores of entomofagous fungus (PV 1680-95) or compounds regulating insect metamorphosis and development (IGR, e. g. juvenoids and their synthetic analogues) (Czech patent application PV 1680-95). Those compounds are toxic both to the attracted males, and also to those females which copulate with the contaminated males and subsequently pass the toxic principle on to their eggs.

Disclosure of Invention Existing methods to control the leafminer C. ohridella are presently unsatisfactory, ecologically unsound (insecticide spraying in inhabited areas), or time consuming and not cost-effective (racking of leaves). This invention, based on the discovery of a sex pheromone and its method of preparation, eliminates these drawbacks, being based on the modification of chemical communication between the sexes by use of an identified and synthesized sex pheromone, with the aim of attracting and trapping males, or confusing them and thus interrupting the reproductive cycle of the leafininer. The subject of the present invention are isomerically pure tetradeca-8,10-dienals of the general formula I

CH3 (CH2) 2-CH=CH-CH=CH- (CH2) 6-C (I=O (I) characterized in that they are preparable by reacting the compound of the general formula II I-CH=CH- (CH2) 7-OX where X is a protection group preferably selected from the group consisting of alkyl, trialkylsilyl, tetrahydropyranyl and the tert-butyl group with 1-pentyne in the presence of an amine, Pd (0) catalyst and cuprous salt to provide an enyne of the general formula III CH3 (CH2) 2-C=C-CH=CH- (CH2) 7-OX (III) which is by catalytic hydrogenation, reduction with an alkali metal dissolved in liquid ammonia or reduction with boranes, allanes or stannanes, transformed to the compound of the general formula IV CH3 (CH2) 2-CH=CH-CH=CH- (CH2) 7-OX (IV) and finally in an acidic environment, preferably by the treatment with a mixture of ether/acetanhydride/ferric chloride and then with potassium hydroxide at 20-50 °C to obtain the compound from general formula V CH3 (CH2) 2-CH=CH-CH=CH- (CH2) 7-OH (V) V) which is finally oxidized, preferably with Cr (VI) compounds, in an appropriate solvent such as dichloromethane to form an aldehyde of the general formula I.

A further subject of the present invention is the (E8, Z10)-tetradeca-8,10- dienal of the formula VI and the method of synthesizing thereof characterized in that the iodide of the formula VII where X represents a protection group X as tert-butyl, 1-tetrahydropyranyl under an inert atmosphere of preferably nitrogen or argon, which is treated with a ca 2-5 fold excess of 1-pentyne in the presence of 1-5 equivalents of an amine preferably piperidine, 1-butylamine, a Pd (0) catalyst preferably tetrakis (trifenylfosphine)- palladium (0) in an amount of 0.5-20 mol % and a cuprous salt preferably cuprous iodide in 1-3 equivalents in an organic aprotic solvent, preferably selected from the group of benzene, toluene, and tetrahydrofuran, in a temperature range of 10-100 °C for 0.1-20 hr to obtain the compound of the formula VIII

which is treated with dialkylborane preferably dicyclohexylborane in 1-3 equivalents for 0.1-5 hrs and the boron compound formed is hydrolyzed with 1-10 equivalents of an acid preferably acetic or propionic acid for 1-40 hrs at 10-80 °C and the protected dienole of formula IX obtained is processed with acid preferably a mixture of ether/acetanhydride/ferric (III) chloride) at 10-40 °C for 1-50 hrs and then with 1-3 equivalents of potassium hydroxide dissolved in aqueous methanol at 20-50 °C for 1-24 hrs to provide the compound of formula X which is finally oxidized, preferably with Cr (VI) compounds selected from pyridinium chlorochromate or pyridinium dichromate in an appropriate solvent such as benzene, chloroform, or dichloromethane at 10-50 °C for 0.1-20 hrs and the resultant compound of formula VI is purified using column chromatography, preferably in a silica gel column and the synthetic pheromone is stored under an inert atmosphere, advantageously under nitrogen or argon, at 0-78 °C either as a neat substance or in the form of solutions in organic solvents, preferably in hexane or benzene.

The present invention further involves a method of using a compound of the general formula I as a specific sex attractant for leafminers of the Gracillariidae (Lepidoptera) genus and a method of population monitoring, of mass trapping, of confusion and of contamination with biocontrol agents of males of the genus Gracillariidae in devices comprising compounds of the general formula I along with a mechanical restraining member, chemical or biological agents.

Further there is involved a method of using a compound of the general formula VI as a specific sex attractant for horse chestnut leafininer males (Cameraria ohridella Deschka et Dimic 1985, Lepidoptera: Gracillariidae) and a method of

population monitoring, of mass trapping, of confusion and of contamination with biocontrol agents of horse chestnut leafminer males in devices comprising compounds described by the general formula VI.

The devices for carrying out the method of population monitoring, of mass trapping, of confusion and of contamination with biocontrol agents of males of the genus Gracillariidae comprising compounds of the general formula I or compound VI along with mechanical restraining member, chemical or biological agents and a pheromone dispenser. The pheromone dispenser being characterized in that the compound described by general formula I or VI is directly, in a solution, as a mixture with antioxidants and/or stabilizers or in a form of appropriate pro-pheromone derivatives applied on a suitable support selected from the group of natural or synthetic rubber polymers, cellulose glass fibers or metal films.

Devices for the contamination of males according to the present invention can contain, beside the attractant described by the general formula I or VI, insecticides, a biocontrol agent, or compounds regulating insect development (IGR-Insect Growth Regulators), in which the attracted males are killed or agents spread into leafminer populations.

The methods of preparation of the sex pheromone, under the terms of this invention, involve the use of easily available starting 1-alkenyliodides [e. g. Svatos A., Saman, D.: Coll. Czech. Chem. Commun. 62,1457-1467 (1997)] with a suitable protection group (e. g. Greene, T. W.: Protective groups in organic synthesis, Wiley 1981). The iodide is coupled with an 1-alkyne in the presence of a catalytic amount of catalyst [Pd (0)] X4 and an oxidative agent (typically a cuprous salt) in a basic solvent (amine) under an inert atmosphere to provide enynes [e. g. Descoins, C., Lethere, M., Linstrumelle, G., Michelot, D. Ratovelomanana V. Syn. Commun. 14,761 (1984)].

The enyne can be stereospecifically reduced to a diene by dialkylboranes with subsequent hydrogenolysis of the alkenylboranes thus obtained [e. g. Brown, H. C., Mandal, A. K., Kulkarni, S. U. R Org. Chem. 42,1392 (1977)]. The protection group can be cleaved off in several ways (e. g. Greene, T. W.: Protective groups in organic synthesis, Wiley 1981), however, mild conditions are preferred to limit any possible isomerisation of the conjugated diene. Thus prepared alcohol is oxidized to an

aldehyde by the action of various oxidation reagents, preferentially with pyridinium chlorochromate and pyridinium dichromate in an aprotic solvent [Corey, E. J., Suggs, J. W. : Tetrahedron Let. 31,2647 (1975)]. The synthetic sex pheromone obtained is further purified in a silica gel column. Given the sensitivity of both the synthetic intermediates and the final product to oxidation and/or isomerisation of the double bonds, they should be kept under an inert atmosphere and at a low temperature (-20°C). The synthetic route as described is extremely favorable, despite its multi-step design, as high isomeric purity and chemical yields are easily obtainable and require no special qualification, unusual reagents or complicated production apparatus.

The biological activity of the title compound was proved by wind tunnel bioassays and field tests. The compound described by formula VI is then used for the preparation of lures or dispensers which are further employed in monitoring and trapping devices e. g. Czech patent No.: 257503 from 20.2.1990 (Czech patent app.

No. PV 419-85), and in traps to enable the contamination of attracted males with insect killing agents, see Czech patent..... (Patent application No. PV 1680-95).

The subject of the invention is supported by the examples of preparation and use described herein, however they do not limit it in any sense.

Examples Example 1 (F)-14- (tert-butoxy) tetradec-6-en-4-yne [VIII] Tetrakis (triphenylphosphine) palladium (0.60 g, 0.5 mmol) was added at 20 °C to a solution of iodide 4 (3.24 g, 10.0 mmol) in benzene (25 ml). The mixture was stirred for an additional 60 min. A solution of pent-1-yne (1.66 g, 15.0 mmol) in anhydrous butylamine (7.34 g, 100 mmol) and copper iodide (0.37 g, 2.0 mmol) was added.

After 2 h at room temperature, the mixture was diluted with ether (150 ml) and subsequently poured into saturated aqueous ammonium chloride (100 ml). The organic layer was washed with 20% aqueous ammonia (3 x 100 ml), brine (2 x 100 ml), water (2 x 100 ml), and dried over anhydrous MgSO4. Removal of the solvents in vacuo and purification of the residue by PMPLC (0.5-1.5% of ethyl acetate in

hexane) gave 2.38 g (90%) ofenyne 5. 'H NMR (CDCI3): 0.98 t (3 H, J= 7.5, CH3CH2-) ; 1.18 s (9 H, 3 x CH3); 1.25-1.39 m (8 H, 4 x CHz); 1.50 m (2 H, CH3CH2-); 1.52 m (2 H,-CH2CH2OR); 2.07 dq (2 H, J= 1.5,3 x 7.1,-CH=CHCH2- ); 2.26 dt (2 H, J= 1.2,2 x (2 H, J= 6.7,-CH20R) ; 5.45 m (1 H, J = 4 x 1.7,15.8,-CH=CH-); 6.03 m (1 H, J= 4 x 1.7,15.8,-CH=CH-).

Example 2 (4Z, 6E)-14-(tert-Butoxy) tetradeca-4,6-diene (6) A dicyclohexylborane suspension was prepared in THF (30 ml) from borane-dimethyl sulfide complex (10 M, 0.97 ml) and cyclohexene (1.59 g, 19.4 mmol). The white suspension obtained was treated at 0 °C with a solution of enyne 5 (2.33 g, 8.8 mmol) in THF (10 ml). The mixture was warmed to room temperature, and stirred for 4 h.

The vinylborane formed was hydrolyzed with glacial acetic acid (10 ml) at 20 °C for 12 h, the reaction mixture was neutralized with NaOH (20%, 20 ml), and carefully treated with aqueous H2O2 (30%, 10 ml). The product was extracted with hexane (4 x 75 ml). Chromatography (PMPLC) of the hexane yielded protected dienol 6 (1.61 g, 69%) of 97.8% isomeric purity (GC). tH NMR (CDCI3): 0.92 t (3 H, J= 7.4, CH3CH2-); 1.18 s (9 H, 3 x CH3); 1.24-1.36 m (8 H, 4 x CH2); 1.40 m (2 H, J= 5 x 7.4, CH3CH2-); 1.51 m (2 H,-CH2CH20R); 2.09 bdq (2 H, J= 1.5,3 x 7.5,- CH=CHCH2-); 2.14 dq (2 H, 7= 1.5,3 x 7.5,-CH2CH=CH-) ; 3. 32 t (2 H, J= 6 7,- CH20R); 5.30 bdt (1 H, J = 2 x 7.5,10.8,-CH=CH-CH=CH-); 5.65 bdt (1 H, J = 3 x 7.3,15.0,-CH=CH-CH=CH-); 5.95 dtt (1 H, J = 0.8,2 x 1.5,2 x 10. 9,-CH=CH- CH=CH-); 6.29 ddq (1 H, J = 3 x 0,15.0,-CH=CH-CH=CH-).

Example 3 (7)(8E,10Z)-Tetradeca-8,10-dien-1-ol Acetic anhydride (2 ml), and then anhydrous FeCI3 (65 mg, 0.40 mmol) were added to a solution of protected dienol 6 (1.07 g; 4.0 mmol) in ether (20 ml). The dark brown solution was stirred for 20 h at room temperature. A saturated aqueous solution of Na2HPO4 (15 ml) was added, and the mixture was stirred for 2 h. The solid FeP04 was filtered off, and the aqueous layer was extracted with ether (3 x 40 ml). The

collected organic phases were dried over anhydrous MgS04, and then concentrated.

The red oily residue (1.03 g) was dissolved in methanol (10 ml) and an aqueous solution of NaOH (0.60 g in 4 ml of water) was added. The mixture was stirred at 20 °C for 16 h, poured into water (75 ml), and extracted with hexane-ether (3 : 2,4 x 25 ml). The combined extracts were dried (anhydrous K2CO3), evaporated, and the dark residue (0.98 g) was purified by PMPLC. The chromatography (10% ethyl acetate in hexane) gave 0.69 g (82%) of E, Z-dienol 7.'H NMR (CDCl3) : 0.92 t (3 H, J= 7.4, CH3CH2-); 1.25-1.39 m (8 H, 4 x CH2); CH3CH2-); 1.57 m (2 H,-CH2CH20R); 2.09 bdq (2 H, J = 1.5,3 x 2.14 dq (2 H, J = 1.6,3 x 3.65 t (2 H, J = dtt (1 H, J = 2 x 0.7,2x7.5,10.8,-CH=CH-CH=CH-); 2 x 7.1, 15.1,-CH=CH-CH=CH-); 5.96 dtt (1 H, J= 0.9,2 x 1.6,2 x 10.9,-CH=CH- CH=CH-); 6. 30 ddq (1 H, J = 3 x 1.5,11.0,15.1,-=CH-CH=CH-).

Example 4 (8E, (1a)Tetradeca-8,10-dienal Dienol 7 (210 mg, 1 mmol) was injected into a stirred suspension of pyridinium chlorochromate (PCC; 258 mg, 1.2 mmol) and anhydrous sodium acetate (20 mg) in dichloromethane (2 ml). The mixture was stirred for 90 min at room temperature, then poured into 50 ml of ether and filtered through a combined layer of neutral alumina/charcoal/Celite. A subsequent evaporation of the solvents and PMPLC (0.3% triethylamine in benzene-hexane/1: 1) afforded 151 mg (72%) of the pure (96%, GC) target compound, dienal la.'H NMR (CDCI3): 0.92 t (3 H, J = 7.4, CH3CH2-); 1.27-1.38 m (6 H, 3 x CH2); 1.40 m (2 H, J= 5 x 7.4, CH3CH2-); 1.63 m (2 H,-CH2CH2CHO); 2.09 bdq (2 H, J = 1.5,3 x 2.14 dq (2 H, J = 1.6,3 x dt (2 H, J = 2 x 6. 5, -CH2CHO) ; 5.31 dtt (1 H, J = 2 x 0.7,2 x 7.5,10.8,-CH=CH-CH=CH-); 5.65 dtt (1 H, J = 2 x 0.8,2 x 7.0, 15.1,-CH=CH-CH=CH-); 5.95 dtt (1 H, J = 0.9,2 x 1.6,2 x 10.9,-CH=CH- CH=CH-); 6.30 ddq (1 H, J = 3 x 9.76 t (1 H, J = 1.8,-CHO). EI-MS, mlz (rel. %): 39 (11), 41 (33), 54 (23), 55 (27), 67 (100), 68

(18), 79 (33), 80 (13), 81 (50), 82 (21), 91 (16), 93 (14), 95 (26), 96 (18), 98 (19), 109 (14), 208 (9, M-').

Example5 Pheromone dispenser Compound VI is dissolved in hexane of benzene to form a 10 mg/l solution, 10 microliters of which is applied onto rubber septum (that is 100 ng/dispenser). The solvent is left to evaporate and the pheromone dispenser thus prepared is stored in a glass vial at-20 °C.

Example 6 Usage of compound VI in a field test The pheromone dispenser (example 5) and a sticky insert covered with Tanglefoot glue is introduced into Delta trap (25 x 10 cm) and this monitoring device is suspended ca 2.5-3 m above ground near horse chestnut trees and the number of males caught is periodically recorded. Some results are presented in the Table 1.

Table 1. Catches of horse chestnut males in traps according to example 6 Lure males caught/day control 0 3 caged horse chestnut leafminer females 65 compound of structure VI 50