NO742282L - - Google Patents

Description

"Carboximides with plant growth regulating effect"

The present invention relates to certain new plant growth regulating carboximides or intermediates for the production of plant growth regulating agents. The invention also applies to methods for producing the compounds.

The carboximides according to the invention are represented by the formula:

where X is CH2 or S,

Z is S, 0 or SO, provided that when Z is 0 X cannot be S,

Y is -COOR^, -CONR^, -CONHNRgR7, -CONHN<+>R6R7R7•halide", CN,

-CONHOH or -COR1Q,

n is 0 or 1,

R^ and R^ both mean alkyl-C^-C^, or when taken together with the carbon atom to which they are attached, cycloalkyl-C4-Cg or methyl substituted cycloalkyl-C^-Cg,

R^ is hydrogen or alkyl-C^-C^,

R^ and Rj. means both hydrogen, alkyl-C^-C^, phenyl, monohalogenophenyl, monoalkyl (C-^-C^)phenyl or mono-alkyl(C^-C4)phenyl,

R 8 and R 7 are alkyl-C^^-^,

Rg is hydrogen, alkyl-C₁-C₁, phenyl, monohalogenophenyl, monoalkyl-(C₁-C₂)phenyl, monoalkyl(C₁-C₂)phenyl, mononitrophenyl or trifluoromethylphenyl,

Rg is hydrogen or alkyl-C₁-C₁,

R^0 is halogen and

means a single or double bond.

These compounds are useful as plant growth regulators and are intermediates for the manufacture of plant growth regulators. Compounds of the above structure, where Y is -COR^Q

and R₂, R₂ and R₂Q as described are primarily useful as intermediates for the preparation of the plant growth regulating agents.

Similarly are compounds of the above formula, where Y is

-COOR^ and R^ are hydrogen, also primarily useful as intermediates. According to the invention, the above-identified titiin- dicarboximide, dithiolandicarboximide, thiapyrandicarboximide and pyrandicarboximide compounds are prepared by reacting the the appropriate α-aminocarboxylic acid with the appropriate dithiinidicarboxylic, dithiolandicarboxylic, thiapyrandicarboxylic or pyrandicarboxylic anhydride, preferably in the presence of an aprotic solvent and a tertiary amine, such as e.g. triethylamine. Among the solvents which are usable in carrying out this reaction are: benzene, toluene, xylene, dimethylformamide and acetic acid. In practice, it will be found that the reaction can be carried out at a temperature between 80 and 225, preferably between 120 and 150°C. Alternatively, the desired product can be prepared by melting the α-amino acid or the α-amino acid derivative and the anhydride at temperatures between 150 and 250, preferably at 180 to 210°C. The reaction can be illustrated as follows:

where X, Y, Z, n, R^, R2, Rg and Rg are as defined above, except that Y cannot be -COR1Qor -CONHN<+>R6R7R7•halide".

In the case where Y is -COOH, the acid thus formed can be converted into the corresponding acid chloride or acid bromide by heating the acid with thionyl chloride, thionyl bromide, phosphorus pentachloride or the like, preferably in the presence of an aprotic solvent, aromatic or chlorinated hydrocarbons such as e.g. benzene, xylene, toluene, methylene chloride, chloroform or dichloroethane. This reaction is shown below, where thionyl halide, i.e. chloride or bromide, represents the halogenating agent used.

where X, Z, n, R1, R2, Rg, Rg and R are as described above.

The thus formed acid chloride or acid bromide can then be converted into the corresponding amide or hydrazide by reacting it with ammonia, hydroxylamine, monoalkylamine, dialkylamine or dialkylhydrazine at a temperature between -20 and +25, preferably

-10 to +15°C. This reaction is preferably carried out by dissolving the acid halide in a solvent such as acetone or a

water-miscible ether such as tetrahydrofuran, dioxane or the like, and bubbling ammonia gas through the thus prepared solution while said solution is stirred or shaken, or by mixing the monoalkylamine, dialkylamine or dialkylhydrazine with the thus prepared solution. Alternatively, the amine, hydroxylamine or hydrazine can be dissolved in the solvent and then added to the acid halide in an aprotic solvent. The reaction can be shown schematically as follows:

where X, Z,n, R2, R4, R5, Rg, R7, Rg and R1Q are as defined above. Alternatively, the dithiene dicarboximido amides, the dithiolane dicarboximido amides, the thiapyrandicarboximido amides and the pyran dicarboximido amides of the formula:

where X, Z, n, R^, , Rg and Rg are as described above, is prepared by reacting the appropriate dithiinidicarboxylic, dithiolandicarboxylic, thiapyrandicarboxylic or pyrandicarboxylic anhydride with the appropriate a,a-disubstituted-a-aminonitrile for to

give the product:

where X, Z, n, R1, R2, Rg and Rg are as defined above. This reaction is carried out at temperatures from 20 to 60°C in an inert solvent such as e.g. ether, tetrahydrofuran, chloroform, methylene chloride, benzene, toluene, acetonitrile and the like. The acid thus formed is then cyclized to the corresponding carboximide either thermally or by heating with a drying agent such as e.g. acetic anhydride, acetyl chloride, thionyl chloride or the like, at temperatures from 0 to 100°C. The resulting product:

where X, Z, n, R^, R2, Rg and R n are as defined above, is converted to the active amide by hydrogenation of the nitrile function. This reaction is preferably carried out with a strong acid such as e.g. sulfuric acid,

preferably in the presence of an immiscible solvent such as

methylene chloride, chloroform or the like, at temperatures from -10 to +30°C.

When a hydrazinium halide is desired, a hydrazide of the formula:

wherein X, Z, n, R^, R2, Rg, R7, Rg and Rg are as defined above, is treated with an alkyl halide in the presence of a solvent such as e.g. tetrahydrofuran, ether, dioxane, benzene, chloroform or the like, at elevated temperature to give the desired corresponding hydrazinium halide.

To obtain the active dicarboximido ester represented by the formula:

where X, Z, n, R^, , Rg and are as defined above and R^ is alkyl-C^-C^, the corresponding acid, i.e. where R^ is hydrogen, is treated with a diazoalkane-C^- C^in the presence of a solvent such as ether. This reaction can be carried out at a temperature between -10 and +30°C.

Alternatively, the appropriate α-amine ester may:

where R^ and R2 are as defined above and R^ is alkyl-C^-C^, allowed to react with the appropriate dicarboxylic anhydride: where X, Z, n, Rg and Rg are as defined above, to give the corresponding ester:

where R 3 is alkyl-C 1 -C 4 and X, Z, n, R 1 , R 2 , RQ and Rg are as previously indicated. In yet another method, the acid halide, prepared as above, can be treated with a lower C^~C4~ alkanol in the presence of an acid acceptor such as e.g. pyridine, triethylamine, sodium bicarbonate and the like.

The dicarboxymidonitrile:

where R^, R2, Rg, Rg, X, Z and n are as described above, can be obtained by drying the corresponding amide by using titanium tetrachloride, acetic anhydride, phosphorus pentoxide, phosphorus oxychloride or the like, in the presence of a solvent such as . benzene, tetrahydrofuran or the like. This reaction can be carried out at a temperature between 0 and 100°C.

The plant growth-regulating effects achieved by compounds with the structure:

where X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0

cannot X be S, Y is -C00R_, -CONHOH, -CONR.R.-, -CONHNR,R_,

-CONHN R6R7R7*halide" or CN, n is 0 or 1, R-j^ and R2 both mean alkyl-C^-C^, or when taken together with the carbon atom to which they are attached cycloalkyl-C4-C8 or methyl substituted cycloalkyl -C4-Cg,<R>3 is alkyl-C^-C4, R4 and R^ both mean hydrogen, alkyl-C^-C4, phenyl, monohalogenophenyl, monoalkyl(C^-C4)phenyl or monoalkyl(C1~C4)- phenyl, Rg and R7 are alkyl-C^-C^, Rg is hydrogen, alkyl-C^-C4, phenyl, monohalophenyl, monoalkyl(C^-C^)phenyl, monoalkyl(C1-C4)phenyl, mononitrophenyl or trifluoromethylphenyl ,' ;Rg is hydrogen or alkyl-C^-C^ and means a single or double bond, are very remarkable. ;Preferred compounds according to the invention are those represented by the above formula and where X and Z are both sulphur, ;and Y, n, R^, R2, Rg and Rg are as defined above. In particular, preferred compounds are those where n is 1. Another group of preferred compounds are those represented by the above formula and where X is CH2, Z is oxygen and n, Y, R^, R2, Rg and Rg is as described above. ;Another group of preferred compounds is indicated;by the above formula" and where X is CH2, Z is sulfur and n, Y, R^, R2, Rg and Rg are. as. defined above. ;.Another group of preferred compounds is illustrated by the above formula where X is S, Z is SO and n, Y, R^, R^, Rg and Rg are as defined above. Another preferred group of compounds according to the present invention contains the formula: where Y is -COOR3, -CONR^, -CONHNRg R^ , -CONHN+RgR7R7 • halide" , CN or -CORQ, R1 and R2 both mean alkyl-C^-C^or when taken together with the carbon atom to which they are attached to cycloalkyl-C₁-C₂, R₂, R₄ and R₂, are hydrogen or alkyl-C₁-C₂, Rg and R₆ are alkyl-C₂-C₂, the same or different and Rg is halogen. ;A preferred method according to the invention for producing a compound with the formula: ; where Y is -CN and R-j^ and R2 both mean alkyl-C^-C^or when taken together with the carbon atom to which they are attached to cycloalkyl-C4-Cg, ;X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0, X cannot be S, Rg is hydrogen, alkyl-C 1 -C 4 , phenyl, monohalophenyl, monoalkyl-(C 1 -C 4 )phenyl, monoalkoxy(C 1 -C 4 )phenyl, mononitrophenyl or trifluoromethylphenyl , Rg is hydrogen or alkyl-C^-C^, is a double bond or single bond and n is 0 or 1, characterized by addition of a compound with the structure: ; where n, X, Z, Rg and Rg are as defined above, with a compound of the formula: where R 1 and R 2 are as described above, in the presence of an inert solvent at a temperature between 20 and 60°C to form a product with the formula: ; where R^, R2, Rg, Rg, X, Z and n are as described above, after which the product is cyclized by heating. A further method according to the invention includes the production of a compound with the formula: where Y is -CN or -CONH2, X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0, X cannot be S, R^ and R2 both mean alkyl-C1~C4 or taken together therewith carbon atom to which they are attached, cycloalkyl-C4-Cg, n is 0 or 1, Rg is hydrogen, alkyl-C-^C^ phenyl, monohalophenyl, monoalkyl(C1~<C>4)<f>enyl, monoalkoxy(C1 ~C4)-phenyl, mononitrophenyl or trifluoromethylphenyl, Rg is hydrogen or alkyl-C1~C4 and is a double or single bond, characterized by addition of a compound of formula: where X, Z, n, Rg and Rg are as defined above, with a compound of the formula: where and R2 are as described above, in the presence of an inert solvent at a temperature between 20 and 60°C to form a product of the formula: where X, Z, n, R^, , Rg and Rg is as described above, after which the product is cyclised by heating and treating the thus produced product with a strong acid at a temperature between -10 and +30°C. Another preferred method according to the invention comprises the preparation of a compound with the formula: where Y is -CN and R1 and R^ both mean alkyl-C^-C^ or taken together with the carbon atom to which they are attached to cycloalkyl-C4-C8, characterized by addition of a compound of the formula: with a compound of the formula: . .. ; where R^ and R^ are as described above, in the presence of an inert solvent at a temperature between 20 and 60°C to form a product of the formula: where R1 and R2 are as described above, after which the product is cyclized by heating. ;A further preferred method according to the invention comprises the preparation of a compound with the formula: ; where Y is -CN or -CONH2 and R^ and R2 both mean alkyl-C^-^ or taken together with the carbon atom to which they are attached-, cyclo-alkyl-C^-Cg, characterized by addition of a compound of the formula: with a compound of the formula: where R 1 and R 2 are as described above, in the presence of an inert solvent at a temperature between 20 and 60°C to form a product of the formula: ; where R1 and R2 are as described above, after which the product is cyclized by heating and treating the thus formed reaction product with a strong acid at a temperature between -10 and +30°C.; The method for regulating the growth of plants includes; applying an effective plant growth-regulating amount on leaves, roots, stems, seeds, seed pieces or the soil in which the plants are to grow, of a compound with the formula:; where X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0 X cannot be S, Y is -C00R-, -C0NR.Rc, -C0NH0H, -CONHNR,R_, . _ 3 4 5 6 7 -CONHN RgR7R7*halide", -CN or -COR1Q, n is 0 or 1, R1 and R2 are both alkyl-C^-C4 or taken together with the carbon atom they

is bonded to, cycloalkyl-C₁-C₂ or methyl substituted cycloalkyl-C₁-C₂, R₂ is hydrogen or alkyl-C₁-C₂, R₂ and both are hydrogen, alkyl-C₁-C₂, phenyl, monohalophenyl , monoalkyl(C^-C^)phenyl or monoalkoxy(C1~C4)phenyl, Rg and R7 are alkyl-C1~C2, Rg is hydrogen, alkyl-C^-C4, phenyl, monohalophenyl, monohaloalkyl(C^-C4) phenyl, monoalkoxy-(C 1 -C 4 )phenyl or trifluoromethylphenyl, Rg is hydrogen or alkyl-C 1 -C 4 , R 1Q is halogen and means a single or double bond.

A preferred embodiment of this method is

to apply the active compound to the seeds, seed pieces or soil containing the seeds or seed pieces of the plants of which they

is the desired plant growth regulation for. An alternative preferred method is when the compound is applied to the leaves and stem of the plants for which plant growth regulation is desired,

preferably in an amount of 0.67 g/yr to 357 g/yr. Another alternative preferred embodiment is when the compound is applied to the roots of the plants for which plant growth regulation is desired.

The various methods comprise the use of the above compounds for the treatment of plants where the treated plants are agronomic crops and said treatment

yields increased yields, or the treated plants are agronomic crops planted as seeds and said treatment accelerates flowering and seed setting, or the treated plants are leafy plants and said treatment increases leaf size or the treated plants are tuberous plants or root crops and said treatment increases root deposition and/ or root size and weight.

A further preferred method of plant growth regulation is carried out by applying an effective plant growth regulating amount to leaves, roots, stems, seeds, seed pieces or soil in which the plants are to grow, of a compound of the formula:

where Y is -C00R3, -CONR4R5, -C0NHNRgR^ or -C0NHN<+>RgR^Ryhalide<->or CN, R, and R2 both mean alkyl-C^-C4or taken together with the carbon atom to which they are attached, cycloalkyl-C 4 -C 8 , R 4 and R 1 .

means each hydrogen or alkyl-C-^-C^ Rg and R7 are alkyl-C^-C,,,

either similar or different. Some preferred compounds are 1-(5,6-dihydro-p-dithiyne-2,3-dicarboxamido)cyclohexanecarboxamide, 1-(5,6-dihydro-p-dithiyne-2,3-dicarboxamido)cyclopentanecarboxamide or i-(5 ,6-dihydro-p-dithiyne-2,3-dicarboxamide)-N,N-dimethylcyclo-j hexanecarboxamide.

A very surprising aspect of the invention is the discovery that, although the plant growth-regulating action of the compounds within the described class sometimes varies from plant to plant and from compound to compound, said compounds are usually very active in small amounts of application and do not appear to be phytotoxic when applied in relatively large quantities. IN

in practice, it will generally be found desirable to use from 0.6 7 to

357 g/year and preferably 0.67 to 44.6 g/year of the active dicarboximido compound in the treated areas to achieve the desired plant growth regulating effect.

Among the desired effects achieved with the compounds according to the invention are:

A) Increased stem-joint growth in certain plants that show

with longer stem joints with increased dry weight,

B) Increased leaf size in certain plants, which shows

both by increased leaf area and increased dry weight of the leaves, C) Induced flowering and/or seed setting in certain plant varieties,

b) Increased tuber setting in tuberous plants, .

E) Increased height in certain seedlings and growth retardation in

other plant species,

F) Delay in display, especially in flowering plants and

G) Increased viability or improved germination of seeds

which have been obtained from plants treated with the compounds according to the invention.

The advantages that are achieved with increased stem joint length are many.

They include, in addition to a general increase in the overall length and weight of the plant, the opening or spreading of the plant's anthers, which usually makes the plant less vulnerable to disease through better ventilation. Furthermore, increased stem-joint length provides special advantages for plants such as e.g. tobacco, sugar cane, timber and seed corn. Extension of tobacco-stem joints raises the tobacco leaves from the ground sufficiently to prevent their normal destruction by the elements (ie wear, disease, 6.1.).

In sugar cane and timber, greater stem joint length results in larger canes and trees, resulting in greater yields of sugar and timber, while in seed corn, longer stem joint length raises the branched corn tip, i.e. the plant's male organ, so high that it can be removed from all plants in a .field by a single cutting before pollination occurs. Regulated pollination, to obtain a desired hybrid, can then be carried out as desired.

The advantage of increasing leaf size in plants is obvious and of particular importance for those plants where the leaves form the salable crop. Tobacco, pre-plants and leafy vegetables such as spinach, silver beet, lettuce and cabbage are examples of such plants.

Accelerated flowering and seed setting are important for plants

which are grown for seeds, including plants such as lettuce, radish,

sugar beet, beetroot, Brussels sprouts, broccoli and carrots. Accelerated flowering also reduces the time before harvesting, thus increasing the possibility of multiple harvests versus a single harvest.

Increased tuber setting in tuber plants such as e.g. potatoes

is another important advantage of the invention, since the treated plants can develop two to three times as many potatoes as the untreated plants. Furthermore, the potatoes on the treated plants are significantly more uniform in size than on the untreated plants, although they are only medium in size. However, this is an advantage in cases where the potatoes are to be canned. Increased size in certain root crops such as e.g. sugar beet can also be obtained by using the compounds according to the invention.

Growth inhibition in plants is yet another advantage achieved by the compounds according to the invention and which is of particular importance when treating ornamental plants and shrubs.

Another advantage is the discovery that seeds obtained from

plants treated with the compounds according to the invention are more viable and germinate better than seeds from untreated plants.

A further advantage of the compounds according to the invention

is that they delay the display of plants. This effect is particularly important for flower growers and florists who want to extend the flowering time of plants.

Many of the above plant growth regulatory compounds have been noted to increase yields. Yield increases are also achieved with other crops, such as e.g. soybeans, sugar beet or similar,

either as a result of one or more of the growth-regulating effects mentioned above, or perhaps as a result of a more direct impact on the yield.

Surprisingly, applicants have discovered that the dicarboximido compounds described above provide these advantages.

The applicants have also found that the effectiveness of the compounds according to the invention as plant growth regulators is not limited by the composition of the preparation or by the method of application. The active compounds can be put together as powders, powder concentrates, wettable powders with approx. 80% by weight of a solid

carrier such as e.g. kaoiin. Suitable machines for such production are ribbon mixers and double cone mixers. It is also self-evident that the concentration of active ingredients in powder preparations can be easily varied by adjusting the amount of wettable powder

and carries. Typical powders will usually contain between 1 and 15% by weight of active substance, although higher concentrations can also be used.

An alternative method for producing powders, also powder concentrates, comprises mixing the active dicarboximide derivative with the solid carrier and then passing the uniform mixture through a crushing mill to achieve the desired particle size.

A typical granular preparation can be prepared by mixing a small amount, ie 0.5% by weight, of a vaporized colloid. silicon dioxide with 5.6% by weight of the above-mentioned dithiin derivative and air-grind the mixture to a smooth mixture. silica sand,

85.7% by weight, is then placed in a mixing machine together with 0.7% by weight of calcium sodium lignin sulphonate powder and 4.2% of a 1% aqueous solution of calcium sodium lignin sulphonate. The mixture is mixed and then added: 3.5% by weight synthetic calcium silicate. The mixture continues to be mixed for several minutes until the finished product is evenly coated and free-flowing. It is of course clear that the amount of active substance in the manufactured granular product can be varied within wide limits, preferably between 1 and 15% by weight. This only requires appropriate adjustment of the amount of granular carrier and/or additives. It is also clear that adsorbent, as well as non-absorbent, carriers can be used in the preparation of the granular preparations.

Other preparations, methods, products and advantages according to the invention will be clarified with the help of the examples listed below;

Example 1

Preparation of 5, 6- dihydro- 5-phenyl- p- dithiine- 2, 3- dicarboxylic anhydride

To a stirred suspension of 18.6 g of the disodium salt of 1,2-dicyano-1,2-dimercaptoethylene under nitrogen is added 26.4 g of 1,2-dibromo-1-phenylethane. After stirring at 40°C for half an hour, the mixture is heated under reflux for 1.5 hours, cooled, filtered and the solvent removed under reduced pressure. The residue is crystallized by filtration with carbon tetrachloride to give the product, 2,3-dicyano-5,6-dihydro-5-phenyl-p-dithiyne, as golden-brown crystals, mp 121.5 to 124°C. A purified sample had a melting point of 125-126.5°C.

Hydrolysis of the dinitrile is carried out by stirring 16.0 g of dinitrile in 71 ml of concentrated sulfuric acid and slowly adding 66 ml of water so that the temperature in the mixture reaches approximately 120°C. The mixture is kept at this temperature for 5 hours, after which it is poured onto ice, the resulting precipitate is filtered off, washed with water and air-dried. This solid is recrystallized from chloroform to give the desired anhydride, mp 131 to 133°C. The analytical sample is obtained from methylcyclohexane and has a melting point • 139-139.5°C.

Example 2

Preparation of 5- substituted- 5, 6- dihydro- p-dithiin- 2, 3- dicarboxylic acid anhydrides

Using the procedure outlined in Example 1, but replacing 1,2-dibromo-1-phenylethane with the appropriately substituted 1-phenyl-1,2-dibromoethane or -1,2-dibromopropane, the following 5,6 are prepared -dihydro-p-dithiyne-2,3-dicarboxylic acid anhydrides:

where Rg = CH3- (melting point 173-174°C)

or

Example 3

Preparation of lr-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclohexaricarboxylic acid

A stirred mixture containing 7.3 g of 1-aminocyclohexanecarboxylic acid, 9.4 g of 5,6-dihydro-dithiyne-2,3-dicarboxylic acid-

anhydride and ml of triethylamine in 150 ml of xylene are heated under reflux under a Dean-Stark water separator for 16 hours. The hot solution is filtered and the filtrate is reduced in volume to 50 ml.

The mixture is cooled and the product, 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid, mp 187 to 188.5°C, is removed by filtration and air-dried. The crude product is recrystallized from xylene to an analytically pure sample, melting point 189-190°C.

Analysis:

Calculated for C13H15N04's2: C 49.82, H 4.82, N 4.47

Found: C 50.19, H 4.59, N 4.28.

Example 4

Preparation of 1-(5,6-dihydro-p-dithiin-2>3-dicarboximido)cyclopentacarboxylic acid

By following the procedure described in example 3, however

by replacing 1-aminocyclohexanecarboxylic acid with 1-amino-cyclopentanecarboxylic acid, the product 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarboxylic acid is obtained, which can be recrystallized from toluene, melting point 169-170°C.

Analysis:

Calculated for C12H13N04S2: C 48'15'H 4>38'N 4'68

Found: C 48.52, H 4.25, N 4.64.

Other 5,6-dihydro-p-dithiyne-2,3-dicarboximidocarboxyl-

acids which can be prepared according to the above method, but where

The 1-aminocyclopentanecarboxylic acid is replaced with the appropriate α-aminocarboxylic acid as indicated in Table I below.

Example 5

Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclohexanecarbonyl chloride

A stirred mixture containing 6.0 g of 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid and 1.8 ml of thionyl chloride in 50 ml of benzene is heated under reflux for 3.5 hours. The solvent and excess thionyl chloride are removed under reduced pressure and the residual oil, characterized only by its infrared spectrum, is essentially pure 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)-cyclohexanecarbonyl chloride.

Example 6

Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclopentanecarbonyl chloride.

By using the method indicated in Example 5, but by replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid with 1-(5,6-dihydro-p-dithiyne-2 ,3-dicarboximido)cyclopentanecarboxylic acid, the product, 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarbonyl chloride is obtained, characterized only by its infrared spectrum.

This procedure is repeated, but replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarboxylic acid with the appropriate acid to give the compounds listed in Table II below.

Example 7

Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximidoicyclohexanecarboxamide

The 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride prepared in Example 5 is dissolved in 100 ml of tetrahydrofuran and cooled to 5°C. Ammonia gas is bubbled through the stirred solution until a small excess has been added. The mixture is filtered to remove inorganic salts, the filtrate is concentrated under reduced pressure and the residue is crystallized from methanol to give 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxamide, mp 188 to 189.5 °C.

Analysis:

Calculated for C13<H>16N2°3S2: C 49'98'H 5'16'N 8'97

Found: C 50.02, H 5.08, N 8.75.

Example 8

Preparation of - 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclopentanecarboxamide

By using the method indicated in Example 7, but by replacing i-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride is replaced by 1-(5,6-dihydro-p-dithiyne- 2,3-dicarboximido)cyclopentanecarbonyl chloride, the product 1-(5,6-dihydro-p-titiin-2,3-dicarboximido)cyclopentanecarboximide is obtained, melting point 195-196°C.

Analysis:

Calculated for c12<H>14<N2>°3<S>2<:>C 48'30'H 4.73, N 9.39.

Found: C 48.44, H 4.72, N 9.46

The carboxamides in Table III below are prepared according to the above procedure, but 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarbonyl chloride is replaced by the appropriate acid chloride.

Example 9

Preparation of 1-(5,6-dihydro-p-di.thiindicarboximido)-NfN-dimethyl-cyclohexanecarboxamide

A solution containing 10 g of 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride in 50 ml of tetrahydrofuran is cooled to 10 to 15<G>C, and, with stirring, gaseous dimethylamine is bubbled into the solution until the is saturated. After a further 5 minutes the mixture is filtered to remove salts and the solvent is removed from the filtrate to give the above product, mp 169-170.5°C.

i Deisi-substituted carboxamides in Table IV below are prepared using essentially the same procedure as described above.

Example 10 l Preparation of 1-(5/S-dihydro-p-dithiin-^/3-dicarboximido)cyclohexanecarboxylic acid-2,2-dimethylhydrazide

Two equivalents of 1,1-dimethylhydrazine are added dropwise to an ice-cold solution of 1-(5,6-dihydro-p-dithiyne-2,3-cyclohexanecarboxylic acid chloride in tetrahydrofuran. After stirring for a further 0.5 hour, the solids are removed by filtration and the solvent removed in vacuo from the filtrate to give the above product, mp 149-150°C.

- Example 11.

Preparation of 2-[1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)-cyclohexylcarbonyl]-1,1,1-trimethylhydrazinium bromide

Excess methyl bromide is added to the dimethylhydrazide prepared as in example 10 and the mixture is stirred in a pressure flask for two days. Excess methyl bromide is removed by evaporation and the above-mentioned quaternary bromide remains, melting point 176-177°C. The bromide can be converted to the corresponding chloride by passing a 50% aqueous ethanol solution of the salt slowly through a column packed with "Ambérlyst A21", an organic ion exchange resin in chloride form, and evaporating the eluent. The residue is crystallized from ethanol-1-ether to give the chloride salt.

Example 12

Preparation of ethyl-1-(5,6-dihydro-p-dithionine-2,3-dicarboximido)-cyclohexancarboxylate

An excess of an ether solution of diazoethane is added to a solution of 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid in ether. After resting for one hour at room temperature, the solution is washed with excess aqueous sodium bicarbonate solution, followed by two water washes. The organic phase is dried and the solvent is evaporated under reduced pressure to give the above product.

Alternatively, this ester can be prepared by the action of ethanol and pyridine on the acid chloride, described in example 5.

Example 13 Preparation of 3-[N-(1-cyanocyclohexyl)carbamoyl]-5,6-dihydro-p-dithiyne-2-carboxylic acid

1.24 g of aminonitrile is added to a stirred suspension of 1.88 g of anhydride in 50 ml of ether. The mixture is heated under reflux for 5 hours. The crystalline product is removed by filtration, washed with acetonitrile and dried to give the title compound, mp 133 to 134°C (dec).

Example 14 Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclohexanecarbonitrile

A suspension of the acid in acetonitrile is heated under reflux for 3 hours. The colorless solid dissolves to give a pale yellow solution. The solvent is removed and the residue is crystallized from methanol to give the title compound, mp 12 3 to 124°C. Analysis:

Calculated for<C>13H14N2°2<S>2<:>C53'04'H 4.79, N 9.52.:

Found: C" 53.31, H 4.94, N 9.58

Example 15

Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclohexanecarboxamide

To 300 mg of the nitrile prepared in example 14 in 5 ml of methylene chloride, 10 drops of concentrated sulfuric acid are added with vigorous stirring. After 0.5 hour, ice and more methylene chloride are added.

The organic phase is separated, washed with water, dried and the solvent is evaporated so that a crystalline residue of the title compound remains, melting point 187-189°C.

Example 16 Preparation of methyl-1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)-cyclohexanecarboxylate

A mixture containing 18.8 g of 5,6-dihydro-p-dithiyne-2,3-dicarboxylic anhydride, 15.7 g of the amino ester and 1.3 ml of triethylamine in 300 ml of xylene is heated with stirring for 6 hours under a Dean-Stark water separator. The solvent is removed, the residue is taken up in ether, filtered and the filtrate is washed with sodium bicarbonate solution. The organic phase is separated, dried and the solvent is removed for

to leave a solid residue of the desired product, mp 96-99°C.

Example 17

Preparation of 1-(5,6-dihydro-p-dithiin-2,3-dicarboximido)cyclohexanecarboxamide-5-oxide

2.5 g of a 30% aqueous hydrogen peroxide solution is added to a stirred suspension of 6.25 g of 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxamide in 30 ml of acetic acid. After 16 hours at 25°C, the solvents are removed in vacuo and the residue taken

into chloroform which is dried and evaporated. The crystalline residue

recrystallized from a 1:1 mixture of chloroform and acetonitrile to give the 5-oxide, mp 133 to 136.5°C (dec.).

Example. 18

Preparation of 1-(tetrahydro-p-dithiin-2,3-dicarboximido)cyclohexanecarboxylic acid

By following the procedure described in example 3, but by replacing i-(5,6-dihydro-p-dithiyne-2,3-dicarboxylic acid anhydride with tetrahydro-p-dithiyne-2,3-carboxylic acid anhydride and xylene with benzene as solvent, the product described in the title is obtained, melting point 6 3°C (decomposition).

Example 19

Preparation of 1-(tetrahydro-p-dithiin-2,3-dicarboximido)cyclohexanecarbonyl chloride

Using the procedure outlined in Example 5, but by

replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid with 1-(tetrahydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid, the title compound is obtained, which only is characterized by its infrared spectrum.

Example 20

Preparation of 1-(tetrahydro-p-dithiin-2,3-dicarboxamido)cyclohexanecarboxamide

Using the procedure outlined in Example 7, but replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride with 1-(tetrahydro-p-dithiyne-2,3-dicarboximido )cyclohexanecarbonyl chloride, the title compound is obtained, melting point 188°C.

Example 21

Preparation of 1-(2,2-dimethyl-1,3-dithiolane-4,5-dicarboximido)-cyclohexanecarboxylic acid

A stirred mixture of 10.2 g of 2,2-dimethyl-1,3-dithiolane-4,5-dicarboxylic anhydride and 7.1 g of amino acid in 170 ml of benzene and 0.5 ml of triethylamine is heated under reflux under a Dean-Stark water separator for 48 hours. The solvent is removed and the residue is crystallized from aqueous methanol to give the title product, mp 188 to 189°C.

Other 1,3-dithiolane-4,5-dicarboximidocarboxylic acids which can be prepared according to the above procedure, but by replacing 2,2-dimethyl-1,3-dithiolane-4,5-dicarboxylic anhydride with the appropriate anhydride, are listed below.

Example 22

Preparation of 1-(2,2-dimethyl-1,3-dithiolane-4,5-dicarboximido).-cyclohexanecarbonyl chloride

By using the procedure given in Example 5, but by replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanone-carboxylic acid with 1-(2,2-dimethyl-1,3 -dithiolane-4,5-dicarboximido)-cyclohexanecarboxylic acid, the title compound is obtained, which is only characterized by its infrared spectrum.

By using the appropriate acid described in Example 21, the following carbonyl chlorides are prepared.

Example 2 3

Preparation of 1-(2,2-dimethyl-1,3-dithiolane-4,5-dicarboximido)-cyclohexanecarboxamide

By using the procedure given in Example 7, but by replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride with 1-(2,2-dimethyl-1,3-dithiolane) -4,5-dicarboximido)-cyclohexanecarbonyl chloride, the title compound is obtained, melting point 163 to 164.5°C.

The carboxamides below are prepared according to the above procedure by replacing 1-(2,2-dimethyl-1,3-dithiolane-4,5-dicarboximido)cyclohexanecarbonyl chloride with the appropriate carbonyl chloride from example 22.

Example 24

Preparation of 1-(5,6-dihydro-4H-thiapyran-2,3-dicarboximido)-cyclohexanecarboxylic acid

By applying the procedure described in Example 3, but by replacing 5,6-dihydro-p-dithiyne-2,3-dicarboxylic acid anhydride with 5,6-dihydro-4H-thiapyran-2,3-dicarboxylic acid anhydride, the title compound is obtained as a gum and is only characterized by its infrared spectrum.

Example 2 5

Preparation of 1-(5,6-dihydro-4H-thiapyran-2,3-dicarboximido)-cyclohexanecarbonyl chloride

By using the procedure set out in Example 5, but by replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)-cyclohexanecarboxylic acid with 1-(5,6-dihydro-4H-thiapyran- 2,3-dicarboxy.imido)cyclohexanecarboxylic acid, the title compound is obtained, which is only characterized by its infrared spectrum.

Example 2 6

Preparation of 1-(5,6-dihydro-4H-thiapyran-2,3-dicarboximido)-cyclohexanecarboxamide

By applying the method stated in example 7, but by

replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride with 1-(5,6-dihydro-4H-thiapyran-2,3-dicarboximido)cyclohexanecarbonyl chloride gives the title compound as solid crystals, melting point 178-180.5°C.

Example 2 7 Preparation of 1-(6-methyl-5,6-dihydro-4H-pyran-2,3-dicarboximido)-cyclohexanecarboxylic acid

By following the procedure from example 3, but by replacing 5,6-dihydro-p-dithiyne-2,3-dicarboximidocarboxylic acid anhydride with. 6-methyl-5,6-dihydro-4H-pyran-2', 3-dicarboxylic acid anhydride, the title compound is obtained, a dark colored solid which is identified by its infrared spectrum.

Example 2 8 Preparation of 1-(6-methyl-5,6-dihydro-4H-pyran-2,3-dicarboximido)-cyclohexanecarbonyl chloride

By following the procedure from example 5, but by replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxylic acid with 1-(6-methyl-5,6-dihydro-4H- pyran-2,3-dicarboximido) cyclohexanecarboxylic acid, the title compound is obtained which is characterized only by its infrared spectrum.

Example 2 9

Preparation of 1-(6-methyl-5,6-dihydro-4H-pyran-2,3-dicarboximido)-cyclohexan s ank yearbook s amide

Using the procedure outlined in Example 7, but replacing 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarbonyl chloride with 1-(6-methyl-5,6-dihydro-4H -pyran-2',3-dicarboximido) cyclohexanecarbonyl chloride, the title compound is obtained as a crystalline solid with a melting point of 185.5 to 189°C.

Example 30 Assessment of plant growth regulators with biologically active compounds

Test solutions are prepared by dissolving the test compound

in a 50/50 acetone/water mixture and add 0.4% polyoxyethylene sorbitan monolaurate as surfactant. A sufficient amount of this solution is then added to seeded pots or to the leaves of test plants to provide from 1.4 to 89 g/yr of the test compound.

Containers used for pre-germination treatment are prepared the day before application of the test compounds. Appropriate amounts of soil are placed in the containers to bring the soil level up to 1.9 cm from the top of the containers. Seeds of plant species are placed on the soil surface after which the seeds are covered with 1.3 cm of soil. A rammer is used to level the soil surface and make the soil firm.

Plant species used for post-sprouting tests are planted

about. 17 days before the treatment in suitable containers, as described for the pre-germination plants.

Treatments

Each compound is applied before germination and after germination on a number of plant species. Containers containing the eight plant species are collected in a galvanized metal vessel (32 cm x 51 cm), one vessel for each dosage of each compound. The treatment consists of spraying the test solution in a quantity of 8 litres/year with a nozzle that moves over the metal vessel at a constant speed.

Untreated plants of each species serve as controls

in each test. Plant species used in pre-germination trials are maize (Dekalb), lima bean (Henderson bush) and soybean (Amsoy). Plant species used in post-sprouting experiments are radish (Cherry Belle), cucumber (Marketer), fescue (Kentucky 31) and rice (Nato).

All plant species are observed daily after treatment for

to determine changes in physiology and morphology compared to the control plants. Growth changes of interest that are included are: 1) Delay or acceleration of leaf or flower vishing.

2) Change of sex in cucumber flowers.

.3) Progress of flowering in dicot species. 4) Increased or decreased bud or root shoot growth. 5) Growth inhibition or growth stimulation in stems and leaves. 6) Progress in germination of species treated with pre-germination application.

7) Toxic effect on all species.

Such effects were noted as they occurred.

Final data or visual observations are made 14 days after treatment for radish and fescue and 25 days after treatment for rice, cucumber, lima beans, soybeans, barley and maize. Table V presents quantitative data and assessments of observable growth effects obtained.

Example 31

Increased stem joint growth and fresh weight in maize plants

In these tests, corn kernels are placed in rows on a soil surface in flat vessels. A spray, 50/50 acetone/water, containing the test compound is applied to the seeds and soil surface in sufficient quantity to provide 11.2, 22.3, 44.6 and 89.3 g/yr of the test compound. The grains are covered with approx. 1.3 cm of untreated soil and then watered. The vessels are placed in greenhouse benches and treated as usual in a greenhouse. Three weeks after the treatment, the tubers are examined and the height and fresh weight of the maize plants cut at the soil surface are determined. The data obtained are reproduced in Table VII below.

Example 32

Increased growth and improved position of the leaves on sugar beets

By following the procedure from Example 30, but replacing corn kernels with sugar beet seeds, it was observed that the sugar beet plants germinated in the same way as untreated plants. But

the plants that were treated with 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxamide and 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarboxamide in a dosage of 11.2

22.3, 44.6 and 89.3 g/yr, all grew faster than the untreated controls. It was also observed that the leaf position on treated plants was more upward and better positioned to receive light energy for the production of food during photosynthesis. The leaves on untreated plants hung down. It was further found that all treated plants set seed. This phenomenon is important and unexpected, since sugar beets usually take two years to set seed. This phenomenon is particularly significant for the farmer who grows sugar beet for seed.

Example 33

Assessment of the test compound effects on plant growth

these tests, containers are filled with greenhouse potting soil

to 1.3 cm from the top and pressed together. The pot is then filled to the top with soil into which seeds of Kentucky 31 fescue have been mixed in in a quantity sufficient to provide approx. 625 fennel seeds in each pot.

To prepare the test compounds, 20 mg of the compound is placed in a 55 ml wide mouth glass bottle and dissolved or dispersed in a 50/50 acetone/water mixture sufficient to make a 1000 ppm solution or suspension.

An addition of 5 ml of the 1000 ppm solution to each cup

is equivalent to 115 g/yr.

Just before application of the compounds, the test pots are carefully watered to prevent the formation of air pockets and channels during application, which would prevent even distribution of the test compound in the soil. The application is carried out by dispensing 5 ml of solution or suspension evenly over the soil surface with a pipette. Three parallels are used for each connection.

Each test comprises 5 ml of 1:1 acetone:water control,

5 ml water control as standard for comparing activity from test to test. The treated plants are benched in the greenhouse and watered in the usual way. Minimum day and night temperatures of 18°C are maintained during cooler parts of the year. Normal daily temperature variations occur during the summer season. Data obtained are listed below.

Data record

Initial observations are made three to five days after treatment for early germination of both test species. Physiological and morphological changes from the norm are noted during the test period. Final observation is done two to three weeks after the treatment (depending on the time of year). At this time measurements of the plants' height are carried out.

Example 34

Assessment of the test compounds when it comes to increasing stem joint length and/or height in plants

The growth-enhancing activity of the compounds according to the invention is exemplified by the following tests in which the seeds of various one- and two-seeded plants are mixed separately with potting soil, and a 1.3 cm thick layer of this seed soil is placed on top of approx. 3.8 cm of potting soil in separate 6.3 cm x 6.3 cm plastic pots.

After planting, the cups are sprayed with a water-acetone solution containing the test compound in sufficient quantity to provide an equivalent of 115 g/yr of the test compound per Cup. The treated cups are then placed in greenhouse benches, watered and cared for according to greenhouse practice. Three or four weeks after treatment, the tests end and each cup is examined and judged. The results are listed below.

Claims (21)

1. Carboximides with plant growth-regulating action, characterized in that they have the formula: where X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0, X cannot be S, Y is -C00R3 , -CONR4 R5 , -C0NH0H, -CONHNRgR^, -C0NHN+RgR?R7•halide? CN or -C0R1Q, n is 0 or 1, R^ and R2 both mean alkyl-C^-C^ , or taken together with the carbon atom to which they are attached, cycloalkyl-C^-Cg or methyl-substituted cycloalkyl-C4-C9 , R 1 is hydrogen or alkyl-C 1 -C 4 , R 4 and R 1 , both mean hydrogen, alkyl-C 1 -C 4 , phenyl, monohalophenyl, monoalkyl (C 1 -C 4 ) phenyl or monoalkyl (C 1 -C 4 ) phenyl, R 6 and R 7 are alkyl-C 2 , Rg is hydrogen, alkyl-C 1 -C 4 , phenyl, monohalogenophenyl, monoalkyl-(C 1 -C 4 )phenyl, monoalkoxy(C 1 -C 4 )phenyl or trifluoromethylphenyl, R 8 is hydrogen or alkyl-C 2 R1Q is halogen, and means a single or double bond. 2. Connection according to claim 1, characterized in that it has the formula: where Y is -C00R-,, -CONR.R,-, -CONHNRgR_, -C0NHN+RcR_R_ • halide", CN ' J 4 o bl car or CORg, R 1 and R 2 both mean alkyl-C 1 -C 2 or taken together with the carbon atom to which they are attached, cycloalkyl-C 2 -C 8 , R 1 , R 1 and R 5 all mean hydrogen or alkyl-C 1 -C 2 , Rg and R^ are alkyl-C-C-C^, either the same or different and Rg is halogen. 3. Connection according to claim 1, characterized in that X and Z are both sulfur and Y, n, R^, R2, Rg and Rg are as defined in claim 1. 4. Connection according to claim 1, characterized in that X is CH2 , Z is oxygen and n, Y, R^ , R2 , Rg and RgFer as defined in claim 1. 5. Connection according to claim 1, characterized in that X is CH2 , Z is sulfur and N, Y, R^ , R2 , Rg and Rg are as defined in claim 1. 6. ' Connection according to Hcrav 1, characterized in that X is S, Z is SO and n, Y, R^ , R2 , Rg and Rg are as defined in claim i. 7. Connection according to claim 3, characterized in that '™ is a double bond. 8. Connection according to claim 3, characterized by being a single bond. 9. Connection according to claim 7, characterized in that Y is -C0NR4 .Rb-. 10. Connection according to claim 7, characterized in that Y is -COOR^ . 11. Connection according to claim 7, characterized in that Y is -CONHNRg R^. 12. Compound according to claim 7, characterized in that Y is -CONHN Rg* halide. 13. Connection according to claim 7, characterized in that Y is -C0R1Q. 14. Connection according to claim 9, characterized in that it is 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclohexanecarboxamide. 15. Connection according to claim 9, characterized in that it is 1-(5,6-dihydro-p-dithiyne-2,3-dicarboximido)cyclopentanecarboxamide. 16. Connection according to claim 9, characterized in that it is 1-(5,6-dihydro-p-dithiin- 2,3-dicarboximido)-N,N-dimethylcyclohexanecarboxamide. 17. Connection according to claim 9, characterized in that it is 1-(5,6-dihydro-4H-thiapyran-2,3-dicarboximido)cyclohexanecarboxamide. 18. Procedure for producing a compound with the form property: where Y is -CN, R 1 and R 2 both mean alkyl-C 1 -C 4 or, taken together with the carbon atom to which they are attached, cycloalkyl-C 1 -C 8 , X is CH2 or S, Z is S, 0 or SO, provided that when Z is 0 X cannot be S, Rg is hydrogen, alkyl-C1~C4 , phenyl, monohalophenyl, monoalkyl-(C1~C4 )phenyl, monoalkoxy(C1~C4)phenyl, mononitrophenyl or trifluoromethylphenyl, R g is hydrogen or alkyl-C-3-C4 is a single or double bond and n is 0, or 1, characterized in that a compound with the formula: where n, X, Z, RQ and R_ are as defined, are reacted with a compound of the formula: where and R2 are as described above, in the presence of an inert solvent at a temperature between 20°C and 60°C to form a product with the formula: where R^, R2, Rg, Rg, X, Z and n are as described above, after which the product is cyclized by heating. 19. Method for preparing a compound of the formula: where Y is -CN or -C0NH2, X is CH2 or.S, Z is S, 0 or SO, provided that when Z is 0 X cannot be S, R 1 and R 2 both mean alkyl-C 4 -C 4 or when taken together with the carbon atom to which they are attached, cycloalkyl-C 4 -C 8 , n is 0 or 1, Rg is hydrogen, alkyl-C1 -C4 , phenyl, monohalogenophenyl, monoalkyl-{C^-C^)phenyl, mono-alkoxy(C-^-C^phenyl, mononitrophenyl or trifluoromethylphenyl, R 8 is hydrogen or alkyl-C 1 -C 4 and is a double or single bond, characterized in that a compound with the formula: where X, Z, n, Rg and Rg are as defined above, is reacted with a compound of the formula': where R 1 and R 2 are as described above in the presence of an inert solvent at a temperature between 20 and 60°C to form a product of the formula: where X, Z, n, R^, R2, Rg and Rg are as described above and where R^ and R2 are as described above, after which the product is cyclized by heating and treating the thus formed reaction product with a strong acid at a temperature between -10 and +30°C. 20. Method for preparing a compound of the formula: where Y is -CN and R1 and R2 both mean alkyl-C^ -^ or, when taken together with the carbon atom to which they are attached, cycloalkyl-C^ -Cg, characterized in that a compound of the formula: is reacted with a compound with the formula: where R. and R.sub.2 are as described above in the presence of an inert solvent at a temperature between 20 and 60°C to form a product of the formula: where R1 and R2 are as described above, after which the product is cyclized by heating to produce the desired compound. 21. Process for preparing a compound of the formula: where Y is -CN or -CONH2 and R^ and R2 both mean alkyl-C-^C^ or, when taken together with the carbon atom to which they are attached, cycloalkyl-C^-Cg, characterized in that a compound of the formula: is reacted with a compound with the formula: hlvøosnr ingsmog idl ed as a betesmkpreevreatt uor vmenelfolor m in 20 næorvg ær 60°aC w efot r inå edratnne et product with the formula: where R^ and R2 are as described above, after which the product is cyclized by heating and treating the thus formed reaction product with a strong acid at a temperature between -10 and +30°C to form the desired product.