NO142122B - NEW RELATIONS WITH PLANT GROWTH REGULATORY EFFECT - Google Patents

Description

The invention relates to new compounds with plant growth-regulating action with the general formula

where n means the number 1 or 2, and X is 0 to 1,

when n is the number 1,

means R<1> sodium; potassium; ammonium; ammonium substituted with one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl; straight or branched chain alkyl, alkenyl or alkynyl of up to 20 carbon atoms; or halo-lower alkyl;

and when n is the number 2, R' means calcium; magnesium or lower alkylene,

R'l' R<l>2' R*3 and R,4 are lower alkyl, as well as enantiomers and racemic mixtures of the compound of formula II, with the proviso that when R' means methyl, ethyl, allyl, sodium or potassium, means R'-^<R>'2» <R*>30<j R<*>4 lower alkyl with more than 1 carbon atom.

ring agents before and after germination and as a herbicide.

A preferred group of compounds are those of the general formula

where n and X have the meanings given in formula II, when n is 1 R^ means ammonium, substituted ammonium, straight-chain or branched alkyl with 3-20 carbon atoms, alkenyl with 2 or 4-20 carbon atoms, or alkynyl with up to 20 carbon atoms , or halo-lower alkyl and, when n is 2, R^ means calcium, magnesium or lower alkylene, enantiomers and racemic

mixtures, and especially by the general formula

where Re means alkyl with 3-12 carbon atoms.

The aforementioned compounds all have L-configuration as they are derived from the naturally occurring ketohexose, L-sorbose. L-sorbose is the only known naturally occurring form of sorbose. However, the corresponding enantiomer of L-sorbose, namely D-sorbose, can be prepared synthetically. In particular, it should be mentioned that the compounds corresponding to L-sorbose can be prepared in an analogous way with D-configuration as well as racemic mixtures of these compounds, by using D-sorbose as starting material instead of L-sorbose, or that one uses a mixture of D- and L-sorbose as starting material when the corresponding racemic mixture is desired....The "preparative methods are exactly the same, regardless of whether one uses a compound as starting material .of the L-form, the D-form or the corresponding racemic mixture. In the same way, all the structural formulas, as indicated in the preceding or the following description, are not to be understood as structural formulas which should describe a particular or an absolute configuration, but these structural formulas shall include all possible configurations, i.e. they include in particular enantiomers and the racemic mixtures.The examples and the rest of the description relate, when nothing else is expressly stated, to the racemic compounds the parts.

The compounds covered by the formula n exhibit plant growth, regulatory activity and herbicidal activity after and/or before germination. However, the growth-regulating effect after germination is considered because most compounds have this effect, and because this activity is suitable for controlling the growth of weeds that appear in the lawn.

The term "plant growth regulator", which is used here, denotes e.g. a compound which either slows down or stimulates the growth of main or secondary branches, resp. plant shoots. Such a compound is capable of influencing (retarding or stimulating) flower development, initiation of flowering, shoot or branch formation, parthenocarpy, fruit and/or leaf drop as well as fruit and/or leaf ripening. Furthermore, there are effects and influences of substance transport inside the plant, e.g. stimulation of latex flow and/or metabolism or e.g. an increase in the sugar content of the plant, etc. In addition, the compounds have a herbicidal effect. When it comes to lawns, e.g. these regulatory agents delay lawn growth, and can further cause further root shoot formation. When it comes to

where shrub plants these regulatory activities cause a delay in growth in height while simultaneously stimulating growth to the side.

The term "lower alkyl" in combinations such as Halogen-lower alkyl refers to straight-chain or branched hydrocarbons, which have up to 7 carbon atoms, such as e.g. methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, etc. The term "halogen-lower alkyl" includes straight-chain or branched alkyl groups with up to 7 carbon atoms, where 1 or more hydrogen atoms are replaced by halogen atoms, which e.g. 2,2,2-tri-chloroethyl, 2,2-dichloroethyl, 2-chloroethyl, 4-chlorobutyl, 2,2,2,-trifluoroethyl, 2-fluoroethyl, 2-bromo-1,1,2,2 -tetrafluoroethyl, 2,2,3,3,4,4,4-heptafluorobutyl, etc. The term ammonium indicates the corresponding salts of 2-keto-gulonic acid derivatives of formula I or II. The term "substituted ammonium" means ammonium residues, where one or two of the hydrogen atoms are replaced by a lower alkyl, lower alkenyl or hydroxyalkyl substituent.

Examples of representatives that can be attributed to formula II and

which have an effect as a plant growth regulator and/or which have a herbicidal effect are: Ammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; Calcium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; Dimethylaronium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; N-ethanolamine 2, 3:4, 6-di-O-isopropylidene-2-keto-L-gulonate; n-butyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3-Chloropropyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-hexyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-heptyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-octyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-nonyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-undecyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2,2-trichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-dodecyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

1-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-decyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-bromomethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-Butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 1-amyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; bis-2,3:4,6-di-O-isopropylidene-2-keto-gulonate-ethylene glycol ester; t-butyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-pentynyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 1-hexin-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3-methyl-1-butyn-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 5-hexenyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 3- <p>ent<y>l-2,3.:A-,.6-di-O-isopropylidene-2-keto-K-gulonate; Dichloromethyl 2,3:4,6-di-O-isopropylideh-2-keto-L-gulonate; 2,2-dichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-chloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 4-chlorobutyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2,2-trifluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-Fluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-bromo-1,1,2,2-tetrafluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,4-heptafluorobutyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,5,5-octafluoropentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate.

Particularly preferred compounds are: 2-propynyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; n-Pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate.

The active compounds are particularly useful in agents for regulating plant growth, and especially the growth of grass and weeds, as well as other unwanted plants, which growths happen to interfere with the deliberately planted plants. The compounds do indeed exhibit a plant growth-regulating effect before germination, but they are, however, particularly useful when they are used as plant growth-regulating agents after germination and as an inducing agent for fruit release. The effect after germination of the active compound is confirmed within the scope of the present invention by controlling the growth of unwanted plants. Thus it was e.g. until now, it has not been possible to carry out a post-irrigation control of Digitaria sanguinalis with a post-emergence herbicide. However, this is successful with the active compounds according to the present invention, as the compounds greatly delay the growth and maturation of this grass, whereby pre-seeding and propagation of this grass is prevented.

In the control of grass lawns, and especially wild grass lawns and industrial lawns (e.g. golf courses), it has been shown that you should strive for a maximum delay, which is shown by a reduction in the height of the grass compared to an untreated control sample, of approx. . 40 - 60%, whereby a delay of grass growth of 50% is preferable. A delay of less than 40% must already be described as ineffective as the necessary aesthetic effect does not appear visually, and because the necessary maintenance of the lawn is not reduced. On the other hand, a delay in growth of more than 60% is also not desired as the lawn will make a barren impression and quickly become overgrown with weeds and other unwanted plants.

The active compounds show herbicidal activity especially against cornflower weeds, such as e.g. Matricaria Species and other weeds, such as Papaver rhoeas, Stellaria media and Capsella bursa pastoris.

The compounds are particularly active in and against the following plants:

a) Grass species, such as Agropyron repens, Bromus inermis, Bromus erectus, Deschampsia flexuosa, Alopecurus pratensis, Arrhena-therum elatius, Dactylis glomerata, Festuca pratensis, Trisetum flavescens, Holcus lanatus, Lolium perenne, Poa annua, Poa neu-moralis, Festuca ovina . and cereals, such as rice, wheat, rye, barley, oats, etc.; b) trees and shrubs, such as fruit trees, such as apple, pear, peach, cherry and citrus as well as cocoa, tea, coffee, banana, rubber, olive and nut trees; c) ornamental plants, such as privet, white beech, white cedar, juniper bushes, roses, azalea, chrysanthemum, poinsettia, alpine violets, pyracanta, forsythia, magnolia, petunia and bromeliaceae; d) agricultural plants, such as cotton, soybeans, peanuts, tobacco, flax, sugar beet and pineapple; . blackberries and currants.

Furthermore, these compounds are useful as they reduce shear

of the vines.

In order to achieve an even distribution of the active compounds in the growth-regulating agents according to the invention, the compound or compounds are mixed with conventional auxiliaries, modifiers, diluents or conditioning agents, common for herbicides, whereby these are further formulated into solutions, emulsions, emulsifiable concentrates, dispersions, dust, granules or wettable powder.

Liquid formulations of the active substance or active substances for direct spraying can e.g. are prepared as aqueous solutions or possibly as solutions in solvent mixtures containing e.g. acetone, methanol, dimethylformamide in the ratio 90:8:2 (Volume)volume).

Emulsifiable concentrates, which contain 25 - 50% or more of active ingredient, depending on its solubility, can be prepared in suitable solvents, e.g. N-methylpyrrolidine, dimethylformamide, etc.. Surfactants, such as e.g. wetting agents, dispersing agents, emulsifying agents, etc., are added in sufficient quantity to achieve a formulation with the intended character-

ristics.

Different applications of the active compounds can be made better for the different areas of application when adding compounds that improve dispersion, adhesion, resistance to rain and penetration, such as fatty acids, waxes, resins, wetting agents, emulsifiers, mineral or vegetable oils, binders, etc. In the same way, the biological spectrum can be extended to these compounds or the agents strongly by adding substances that have bactericidal, herbicidal and fungicidal properties, or by adding fertilisers, chelating agents and other plant growth regulating agents.

The indicated application amounts are based on the results shown here and do not include such wide margins that all possible cases are covered, as numerous factors will affect the application amount. For example, the amount will not only vary for the different plant species but also within a specific species, e.g. depending on factors, such as the size and age of the plant, the particular compound used, the season, the soil and climatic conditions at the time of application, such as air temperature, light intensity, rain and wind. When the compounds or agents are further applied by soaking the field, it is necessary - suitable with higher concentrations, as the plants are indirectly treated with this method of treatment in contrast to a direct treatment or application of the agent or compound to leaves and stems, e.g. by spraying the plant.

The amount of active substance in plant growth regulators therefore varies depending on the plant to be controlled, the necessary amount of application, method of application, the active substance used and how far the control of plant growth is desired. In general, the agents in the ready-to-spray form contain less than 50% active substance.

In principle, the amount of active substance used is chosen in such a way that effective control of plant growth is achieved. As it e.g. as explained above, when controlling the lawn, such an amount of active substance is used, so that the normal growth rate is delayed by 40 - 60%. In a similar way, the choice of the smallest amount of use is determined by the smallest amount of active substance which is able to cause a growth delay which corresponds to the lower desired limit. The choice of the maximum amount of use is correspondingly determined by the amount of active substance that causes a growth delay that corresponds to the desired upper limit, i.e. in the case of grass, which is used as an ornamental lawn, the amount that prevents the ornamental lawn from getting a barren appearance, but which on the other hand, it prevents too rapid grass growth, and so that an unwanted chlorosis (ie the lawn turns yellow) does not occur. When it comes to tomato plants, the criteria for an effective growth delay are different as a dwarf-like plant, which does not mean a loss of fruit quality or fruit quantity, is particularly desired. The parameters for an effective growth-regulating activity for such plants are a delayed longitudinal growth, and an enhanced or not delayed lateral growth as a minimum effect and delayed longitudinal and lateral growth as a maximum effect. The amount of active substance, which complies with these criteria or causes these criteria, e.g. in the case of tomato plants determined taking into account the aforementioned views. To achieve the greatest possible effect for growth regulation after germination, quantities of 0.5 kg to 20 kg or more are used per hectares. These amounts are based on the weight of the active compound. In a similar way, the greatest growth-regulating activity after germination will usually be amounts between 1 - 15 kg or more of active substance per hectares. A preferred dosage amount for spray solutions lies between 10 to 100,000 ppm. depending on the plant species to be treated and the compound used. A particularly preferred dosage amount is usually between 100 and 20,000 ppm.

A further advantage of the use of the active substance according to

the invention is the absence of any lasting effect on the plants or a regulatory effect that remains in the soil. These compounds break down slowly and you thus get a reduction in activity. This effect has advantages due to:

a) that a short-term effect is achieved which can be extended by subsequent further treatment: b) that the normal growth conditions of the plant return to the extent that the activity decreases; and c) no harmful residues remain either on the plant or in the soil.

The duration of the delay effect varies depending on the compound used and other factors, such as the treated plant species, climatic conditions, etc.

Although the compounds according to the invention have a plant growth regulating and herbicidal activity, they are practically non-toxic to animals. The cleavage products, which are initially 2-keto-L-gulonic acid and finally carbohydrates are likewise non-toxic.

It is obvious that not all compounds covered by formula II are active against all plants. However, within the scope of the present invention, each of the active compounds exhibits activity towards a particular plant or particular plants, and this activity is a function of the compound. As will be described in more detail below, it is a particular advantage of the present invention that the growth-regulating agents, when used for the treatment of various plants before and after germination, exhibit growth-regulating activity and herbicidal activity. This means that the spectrum of the relevant plants is very broad. The growth-regulating activity of the active compounds is further confirmed by the subsequent microexperiments for activity determination after germination.

A. Experiments with 2, 3:4, 6-di-O-isopropylidene-2-keto-L-gulonic acid

as well as salts and esters of this compound.

The growth-delayed effect of preferred compounds in connection with grass is shown below in greenhouse experiments, and in particular the effect after emergence for Digitaria sanguinalis and Poa pratensis.

The compound to be examined is dissolved in a solvent mixture consisting of 90 parts by volume of acetone, 8 parts by volume of methanol and 2 parts by volume of dimethylformamide.

The grass (Digitaria sanguinalis) is 10 days old and slightly less than 2.5 cm high. Poa pratensis was also cut to a height of approx. 2.5 cm before the compounds in question were applied.

The compounds were sprayed onto the grass at a rate of 0.5 to 8 kg/hectare. The effect, i.e. the growth delay, is determined by measuring the grass height and grass weight of the cut grass after 11 to 26 days.

In the experiments, 3 standard compounds were included. as a "saffron" test. Maleic hydrazide (6-hydroxy-3-(2H)-pyrridazinone) was used in aqueous solution, i.e. as a water-soluble concentrate (300 g/l). In addition, n-butyl-9-hydroxyfluorene was used -(9)-carboxylate, hereinafter designated IT-3233, and methyl 2-chloro-9-hydroxyflurene-(9)-carboxylate, hereinafter designated IT-3456, in the solvent mixture described above.

Additional reference compounds that can be used are CCC (2-chloroethyltrimethylammonium chloride), Alar (N-dimethylaminosuccinic acid), 2,4-D (2,4-dichlorophenoxyacetic acid), MCPA 82-methyl-4-chlorophenoxyacetic acid), CMPP (2-methyl-4-chlorophenoxypropionic acid), ioxy-nil (3,5-diiodo-4-hydroxy-benzonitrile) and ethrel (2-chloroethyl-phosphoric acid).

The test results are summarized in the following tables

I and II.

As solutions in common solvents are not particularly suitable for practical use, DAG and corresponding derivatives were tested in emulsifiable formulations. (25% active substance, 41% xylene, 2% Atlox 3404, 2% Atlox 3403). Several esters were investigated in the aforementioned solvent mixture. In addition, aqueous solutions of DAG, containing 1% Tween 20 (polyoxysorbitan monostearate) were

and when either unbuffered or buffered at pH 5-7, prepared, Aqueous solutions of salts of DAG, which likewise contain Twenn 20, were included in the investigation.

Investigations with regard to growth delay were carried out on a plant spectrum consisting of e.g. Digitaria sanguinalis, soya beans and tomatoes, and with which the plants were treated when they were approx. 2 weeks old. When treating Digitaria sanguinalis approx. 2 cm high, soybean plants, about... 5-6 cm high with the first leaves, and the tomatoes were 3-4 cm. high. and with 3-4 true leaves. One sprayed either with aqueous solutions, solvent mixers or emulsifiable concentrates of the active ingredient.

The results of this investigation with the salts and esters of DAG

in different formulations are indicated in table III, where the delay effect is indicated by numbers. The rating scale is defined as follows:

0 no visible growth retardation

1, 2, 3 - slight delay, the palts exhibit little or over-" -

head no reduction of the growth of the visible plant parts;

4, 5, 6 - Moderate growth delay, the plants show reduced

growth of visible plant parts;

7, 8, 9 - strong delay, the plants show little or

or no growth at all;

10 - no growth.

Experimental data show that the salts and esters of DAG are more active than maleic hydrazide and the reference compound IT 3456, and then as a post-germination growth inhibitor for Digitaria sanguinalis, and only slightly less active than a soybean growth inhibitor after germination.

The following table IV contains experimental data with regard to 12 different useful plants and weeds, whereby the plants were sprayed when they were approx. 2 weeks old. Four representative esters of DAG (2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid) were compared with the standard sample, i.e., maleic hydrazide. The same rating scale as in Table III was used.

In the case of tomato plants, length growth is greatly delayed. Instead of this, you can observe a stimulation of the development of side shoots, so that in total you get a branched, bushy plant. It is remarkable that neither the quantity nor the quality of the fruits changes. In tables III to IV, when dosing the salts, esters and other analogous compounds as well as DAG, no account was taken of the acid equivalent.

Although the main area of application of the compounds according to the invention is in a growth regulator that is used after germination, the active compound of formula I can also be used as a growth regulator before germination. For example the pre-germination herbicidal activity of DAG compounds is shown using the n-propyl ester of DAG. The dosage is sprayed in a dosage quantity of 8 kg/hectare. Very strong growth retardation, (ie little or no growth) for Sorghum halepense, Amaranthus sp. and Digitaria sanguinalis appears after 20 and

27 days.

Further investigations of DAG and its salts were carried out with different grasses, cereals, ornamentals, perennials and vegetables.

The ammonium salt of DAG and the n-butyl ester of DAG were investigated as growth retarders on Brazilian pepper (Schinus terebinthifolius Raddi) and sumac (Rhus spp.). The plant leaves were sprayed for such a long time that a continuous spray coating was obtained. "Maintain CF 125" was used as a reference compound

(a mixture of methyl 2-chloro-9-hydroxyfluorene-9-carboxylate, methyl 9-hydroxyfluorene-9-carboxylate and methyl 2,7-dichloro-9-hydroxyfluorene-9-carboxylate). 4 3 days after spraying, the reduction was the absence of longitudinal growth, leaf waste and the deformation of the leaves investigated. In Table XII, the results are given in numbers. The rating scale is as follows:

0 - no effect

1 - delayed length growth

2 - length growth stopped

3 - longitudinal growth stopped and deformed leaves

4 - complete leaf waste, new leaves are small or deformed.

(s) (s)

"Trinton ^-'B-1956 is a water-dispersible, resin-based surfactant manufactured by Rohm & Haas. "Maintain CF-125" is a mixture of methyl 2-chloro-9-hydroxyfluorene-9-carboxylate, methyl- 9-hydroxyfluorene-9-carboxylate and methyl 2,7-dichloro-9-hydroxyfluorene-9-carboxylate.

The 01je auxiliary substance, which is used in the aforementioned formulation, is standard petroleum which is usually used in herbicide formulations, and especially when the herbicide is to be used for the treatment of tree-like plants. This oil supports the penetration as well as the binding ability of the active substance. "Sun Oil 11E", which is an emulsifiable and non-phyto-toxic s<p>ray oil, was used in the formulations according to table

XII.

Preferred growth-regulating, herbicidal compounds according to the invention are thus the corresponding sodium, potassium, ammonium, calcium and dimethylammonium salt of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid (DAG), as well as the lower alkyl and lower alkynyl esters of DAG, and especially the propargyl ester.

It was further found that a growth regulator containing one of the compounds of the general formula II when sprayed on fruit-bearing trees significantly reduces the force that must be used to separate the fruit from the stem. This is shown by comparison with untreated trees. It could further be established that fruit, which was harvested and which had been treated with the growth regulators according to the invention, were relatively free from damage and decay.

The agents can be applied to the fruit-bearing trees in liquid or solid formulations. The application can take place over roots, trunks, branches, leaves or fruits. E.g. fruit stripping agents according to the present invention can be sprayed or dusted on the trees, or the agents can be placed on the soil under the trees, so that the agents can be absorbed by the roots. A preferred application method, which is also the most effective, consists in applying the agents in the form of an aqueous spray solution. If desired, one can use a formulation which is based on a suitable organic solvent such as e.g. an oil-like spray solution.

In order to achieve the greatest effect when using the normal fruit separation agents according to the present invention, the agent is preferably used one to two weeks (depending on the temperature) before the fruit is harvested. In areas where one has to calculate with rain, and then in time intervals between the application of the agent and the harvest, a common adhesion agent is appropriately added to the formulation. Examples of such adhesion agents include e.g. glue, casein, salts of alginic acid, cellulose gum and similar derivatives, oolyvinylpyrrolidone, invert syrup, corn syrup, etc.

Fruit separating agents contain compounds of formula II as active ingredients. If desired, conventional, inert materials, such as are used in agriculture in particular when the agents in question serve to treat trees or when they are used in conjunction with active substances in known fruit separation agents, can be added. Such excipients include e.g. also surface-active compounds, carriers, adhesion agents, stabilizers, etc.

The concentration of active substance with the general formula II in the new fruit separation agents varies, but in order to achieve an optimal effect, it is necessary that a sufficient amount is used. Thus, an aqueous spray solution contains from approx. 0.05% by weight to approx. 1.5% by weight of active substance. The concentration naturally varies depending on the type of fruit and the size of the tree or bush. The dosing amount is what really facilitates harvesting. In the case of spray solutions, the aqueous solution, which contains the fruit separating agent, is sprayed in such a way that the tree is coated with a full coverage spray coating. This requires the use of approx. 3000 to approx. 9,000 liters of a diluted solution (approx. 0.1-1% by weight of active substance) per hectares,

and then depending on the number and size of the trees to be treated.

For the preparation of a preferred spray formulation containing fruit release agents, the active substance or a salt thereof is dispersed or dissolved in a carrier, such as water. The liquid spray solution can be added 0.1 to approx. 0.5% by weight surfactant calculated on the weight of the carrier material. Typical surface-active substances are "Triton^5t-B. 1956", i.e. a water-dispersible and resin-based surface-active agent, which is produced by Rohm & Haas. Furthermore, "X-77 (Chevron-Ortho)", a non-ionic surfactant containing

as basic substances alkylaryl polyoxyethylene glycols, free fatty acids and isopropanol are produced.

The fruit-separating agents effect the separation of the fruits from a multitude of fruit trees. Typical fruits of this species are e.g. oranges, grapefruit, olives, apples, cherries, etc. They also work on other useful plants such as e.g. cotton and soybeans (you get leaf waste here).

As already mentioned, the fruit separation agent is sprayed on the trees in the form of aqueous solutions. 1 in this respect, the invention also covers equivalent amounts of water-soluble salts of compounds of formula II in a similar manner. Such salts include e.g. the ammonium salt, etc. In cases where the compounds used are water-insoluble, emulsifiable concentrates or wettable powder formulations of the active substance are prepared, which can be dispersed in water and thus form a spray solution.

Wettable powder is produced by using an inert diluent, e.g. kaolin. A typical spray solution that is formulated with a wettable powder contains e.g. the active substance, approx. 1 - 5% inert diluent, smaller amounts of dispersing agent, wetting agent and antifoam agent and the corresponding and necessary amount of water.

As oranges can be considered typical fruits that are easier to harvest when treated with chemical fruit peelers, then the effect of the new fruit peelers is illustrated using orange trees.

The sodium salt of 2,3:.4,5-di-0-isopropylidene-2-keto-L-gulonic acid is being investigated as a fruit peeling agent on citrus fruits, e.g. oranges. Aqueous solutions containing -0.05% by weight 0.1, 0.25, 0.5 and 1.0% by weight of this sodium salt and 0.5% "Triton B-1956" are prepared. These solutions are applied to Valencia oranges, seedless swamp grapefruit and red grapefruit trees. One week after spraying, the only observable effect is a slight leaf drop in the trees treated with a higher dose. Two weeks after spraying, most orange and grapefruit fruits have fallen off in the trees that were treated with a dosage of at least 1%. Trees treated with a dose of 0.5% had got rid of approx. half of the fruits, and the remaining fruits hung very loosely.

In addition to the fruit separation effect, the fruits also showed a clear strengthening of the colour, e.g. a significantly deeper and darker color than the untreated fruits.

The sugar content and the total solids content of the treated fruits had also increased compared to the untreated fruits.

Similar results were obtained by spraying e.g. the ammonium salt or the diethylammonium salt or the n-butyl ester of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid.

Used as a fruit separating agent or as a herbicide after or before germination, i.e. as soon as the compounds are used as plant growth regulators, the compounds of formula II can be prepared and formulated as described above and below.

2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid monohydrate is a known commercial preparation and is an intermediate product in the production of L-ascorbic acid (Chemical Abstracts Al_ (1953) 10643 e). It is produced by oxidation of diacetone-L-sorbofuranose in an alkaline or neutral medium. Diacetone-L-sorbofuranose is produced by reacting L-sorbose with acetone in the presence of a strong acid.

The new compounds can be produced by

a) in the presence of a base reacts an acid with the general formula

where R^, R'2, R' and R'4 have that in formula I indicated

importance,

with a compound of the general formula

where X means chlorine, bromine or p-toluenesulfonic acid ester and where

R5 means straight-chain or branched alkyl, alkenyl or alkynyl with up to 20 carbon atoms or halogen-lower alkyl,

or

b) in the case where a compound of formula II is intended where n means the number 2, one reacts in the presence of a base a

acid of formula V with a compound of the general formula

where X.^ and X mean chlorine, bromine or iodine and R,, lower alkvlen,

or

c) in the case where a compound of formula II is intended, and where n means the number 2, one of formula V reacts correspondingly

acid halide with a diol of the general formula

where Rg has the meaning given in formula VII,

or

d) in the case where a salt of formula II is intended, and where n means the number 1 and R' ammonium; ammonium substituted with

one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl brings an acid of the general formula V into contact with a compound of the general formula

where in Rg and Rg means hydrogen, lower alkyl,

lower alkenyl or hydroxy-lower alkyl,

or when n means 2, with calcium hydroxide or magnesium hydroxide.

The salts of DAG are prepared in the usual way. For this purpose, DAG is added under vigorous stirring to an aqueous solution of a base at room temperature. In this work process, the solution is kept at a pH value above 7. After the reaction is finished, excess water is removed in a high vacuum. Anhydrous acetone (about 10 parts by volume) is then added to the syrup obtained and stirred overnight. The white crystalline precipitate that forms is filtered, washed with acetone and dried. In the case of non-volatile bases, equivalent amounts of acids are added. If volatile bases are used, such as ammonium hydroxide or dimethylamine, then an excess of base is used and the used excess is then evaporated away in a vacuum. Then DAG under the usual esterification conditions, such as e.g. in the case of esterification according to Fischer, is not stable, then the new esters of DAG are produced by reacting e.g. the corresponding lower alkyl, lower alkenyl or lower alkynyl halides under basic conditions at room temperature, and by using inert organic solvents, such as dimethylformamide (Df'?F). The esters are insoluble in water but soluble in methanol, acetone, ethanol, chloroform, pentane, benzene, ether, etc.

Furthermore, an acid of formula V can be brought into reaction with

an alcohol of formula IX by reacting these reactants in the presence of an equimolar amount of dicyclohexylcarbodiimide in an inert organic solvent. Preferred solvents are methylene chloride, dimethylformamide, ether, tetrahydrofuran or ethyl acetate (see also Tetrahedron 21, 3531

(1965)).

Solutions consisting of a solvent and a compound according to the invention are indeed suitable for greenhouse experiments, but are not, however, suitable for field experiments. Wettable powders are likewise not generally applicable as the DAG derivatives must be dissolved in order for them to be able to display the necessary activity.

The salts are water-soluble and do not require a special formulation.

The DAG ester is formulated as an emulsifiable concentrate on a xylene base, which is then mixed with water. Emulsions containing 25 to 50% by weight can be prepared from these concentrates. Typical emulsifiable concentrates for the DAG ester are given below.

"Atlox 3403" is a mixture of polyoxyethylene ethers, polyoxyethylene glycerol and alkylaryl sulfonate.

"Atlox 3404" is a mixture of polyoxyethylene alkyl aryl ether and an alkyl aryl sulfonate.

"Emulphor EL 620" is a polyethylated oil.

"Drewmulse GMC-8 is the monoglyceride of a lower molecular weight saturated coconut fatty acid.

In a further form, an equimolar amount of diethanolamine is added to an aqueous solution of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid with stirring. A clear solution is obtained, the pH of which is set to 8 by adding diethanolamine drop by drop.

In a further form, ammonia (25% equimolecular amount) is added while stirring to an aqueous solution of 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonic acid. A clear solution is obtained if the pH is set to 8 by adding ammonia (25%) drop by drop.

The compounds of formula II, where R'^, R'2/R'3 and R'^ have a meaning other than methyl, likewise show growth-regulating action before and after germination. E.g. prevents 2,3:4,6-di-0-butylidene-2-keto-L-gulonic acid in a dosage amount of 8 kg/hectare as a growth regulator before germination the growth of Amaranthus sp. completely after 20 days, and as a growth regulator after germination, the aforementioned acid causes a strong reduction in the growth of red beans. 2,3:4,6-di-O-(3-pentylidene)-2-keto-L-quolic acid is produced in a dosage amount of up to 8 kg/hectare as a growth regulator after germination due to growth delay for Amaranthus sp., Brassita kaber, Ipomoea sp.

and red beans.

Compounds where the 4,6-0-isopropylidene group is replaced by

another group is produced using the so-called "ketal exchange reaction". For this purpose, DAG is dissolved in the desired ketone, aldehyde, ketal and acetal and an acid catalyst is added. These compounds can also be prepared by using a similar ketal exchange reaction, whereby 2,3:4,6-di-O-isopropylidene-α-L-sorbofuranose is used as starting material and by oxidizing the product obtained .

Examples of ketones and aldehydes that can be used in the preparative method are those with the general formula R^g-C<*-> R-]^' where R^Q e.g. means methyl or ethyl, and R.... means methyl or ethyl. Typical compounds of this type are e.g. diethyl ketone or methyl ethyl ketone. Ketones where the two residues R^q and R^ are of equal size do not appear to be particularly qun-rising as these residues are sterically inhibited during the reaction. By using an unsymmetrical aldehyde or ketone, after the course of the reaction the bulky residue will be in the "Exo" position (R'^ in formula II), and is responsible for a new center of asymmetry.

Any strong acid can be used as a catalyst. A preferred catalyst is perchloric acid. Further examples of such acids are sulfuric acid, hydrochloric acid, p<->toluenesulfonic acid, methane-

sulfonic acid and trifluoromethanesulfonic acid.

A preferred temperature range for this reaction is between approx. -20° and approx. 50°, whereby the range between 20° and 30° (room temperature) is particularly preferred. The cleavage point for DAG is also the upper limit to which the reaction mixture can be heated. For this reason, the reaction mixture is not heated above 100°C.

Compounds in which both isopronylidene bases are replaced by other groups are prepared starting from sorbose by following those of Reichstein and Griissner, Heiv. Chim. Acta, 17, 311

(1934) specified conditions. In this method, an ene ketone or a suitable aldehyde is reacted with L-sorbose in the presence of a strong """" ~-acid as a catalyst, e.g. sulfuric acid, at or below room temperature. The intermediate product thus obtained is then oxidized in an alkaline or neutral reaction environment.

In the production of di-O-alkylidene sorbofuranose, perchloric acid, hydrochloric acid, p-toluenesulfonic acid etc. are preferably used as acid catalysts, whereby sulfuric acid is particularly preferred.

As the reaction proceeds exothermically, work is carried out at room temperature or below room temperature, whereby a particularly preferred temperature range is between approx. 0° and approx. -20°.

In the subsequent preparation of the acid from the sorbofuranose intermediate, the oxidation is carried out in a neutral or alkaline environment and thereby oxidizing agents are used, such as sodium permanganate, potassium bichromate, potassium permanganate/potassium hydroxide and sodium hypochlorite/Ni<++>. The two latter oxidizing agents are preferred. The oxidation can also be carried out catalytically by using palladium or platinum and oxygen.

A suitable temperature range is between room temperature and 100°, whereby the range between approx. 50° and approx. 60° is preferred.

The following examples shall illustrate the invention.

EXAMPLE 1

Ethyl- 2, 3:4, 6- di- Q- isopropvlidene- 2- keto- L- gulonate.

To a solution of 100 g of anhydrous potassium carbonate in 946 ml of dimethylformamide, 292.2 g of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid monohydrate (DAG monohydrate) and then 205 g of ethyl iodide. Stirring is continued for 2 4 hours at room temperature. The mixture is then filtered to remove inorganic salts and the dimethylformamide is removed by distillation in vacuum (approx. 60°C and approx. 10 mmHg). 200 ml of acetone are added to dissolve the remaining ether. Undissolved inorganic salts are filtered off. The filter cake is washed out with 100 ml of acetone. The filtrate is added to the solution containing the ester and the crude product is isolated by vacuum distillation of the solvent up to an amount of approx. 500 ml and subsequent cooling of this solution to 5°. The crude product is recrystallized in methanol or methanol/acetone

and 284 g of ethyl 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate are obtained, pour temperature: 99 - 100.5°C.

According to this generally applicable regulation,

starting from 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid and 1,2-dibromoethane in a molar ratio of 2:1 of the bis-ester: bis-2,3: The 4,6-di-O-isopropylidene-2-keto-L-gulonate ethylene glycol ester prepd.

EXAMPLE 2

n- butyl- 2, 3:4, 6- di- 0- isopropylidene- 2- keto- L-gulonate While stirring, a suspension of 100 g of anhydrous potassium carbonate in 946 ml of dimethylformamide is added to 2,3:4,6-di- O-isopropylidene-2-keto-L-gulonic acid monohydrate (292.2 g) and then 197 g of n-butyl iodide. The mixture is stirred for 48 hours at room temperature, then filtered and subsequent removal of the inorganic salts. The dimethylformamide is removed by vacuum distillation. 200 ml of acetone is added to the residue and any inorganic salts still present are filtered off. The filter cake is washed with 100 ml of acetone. The filtrate is combined with the ester solution and concentrated in vacuo. Recrystallization of the residue in methanol-acetone gives 172 g of colorless crystals of n-butyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, with a melting point of 53.9 - 56.8 °C.

EXAMPLE 3

n- propyl- 2, 3:4, 6- di- 0- isopropylidene- 2- keto- L-gulonate n- propyl-2,3:4,6-di- 0-isopropylidene-2-keto-L-gulonate is prepared analogously to the work regulations in examples 1 and 2, whereby 200 g of 1-bromopropane is used as halide. Yield 150.6 g, melting point 80 - 81°C.

EXAMPLE 4

n-pentyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate n-pentyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulGnate is prepared analogously to the work regulations in examples 1 and 2, whereby 300 g of 1-bromopentane is used as halide.

Yield 503 g; boiling point 195°C/0.5 mmHg.

EXAMPLE 5

n-dodecyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate N-dodecyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate prepared analogously to the work regulations in examples 1 and 2, yield 75 g, after two recrystallizations in ethanol; m.p. 10.5°C.

EXAMPLE 6

Isopropyl- 2 , 3:4, 6- di- O— isopropylidene- 2- keto- L-. gulonate Isopropyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate is prepared analogously to the working instructions in examples 1 and 2, whereby 250 g of 2-bromopropane is used. Yield 116.8 g, m.p. 107.5 - 109°C.

In a similar manner, further straight-chain and branched, aliphatic hydrocarbyl and halogen-lower alkyl esters can be prepared.

EXAMPLE 7

Sodium- 2, 3- 0- isopropylidene- 4, 6- 0- ethylidene- 2- keto- L-gulonate

48 g of 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonic acid (DAG) are dissolved in 250 g of paraldehyde. Five drops of 70% perchloric acid are added and then the reaction is allowed to continue for 12 days at room temperature under constant control using thin-layer chromatography or gas-liquid chromatography until it is finished. The solution is then added with vigorous stirring to 16.8 g of sodium bicarbonate, which was suspended in 100 ml of water. Surplus-

end paraldehyde and excess water distill from in vacuo. The residue is crystallized in alcohol/water and 50.4 g of sodium 2,3-0-isopropylidene-4,6-0-ethylidene-2-keto-L-gulonate is obtained. Physico-chemical data (nuclear resonance spectrum, mass spectrum, infrared spectrum) show the following structure:

In the same way as described above, other 2,3-0-isopropylidene-4,6-0-(R1~R2)-2-keto-L-gulonic acid (structure II), where the R'^ and R'2~ substituents means straight chain or branched, aliphatic lower hydrocarbyl or halogen-lower alkyl.

EXAMPLE 8

2- chloroethyl- 2, 3:4, 6- di- 0- isopropylidene- 2- keto- L-gulonate 6 g 2,3:4,6-di- 0-isopropylidene-2-keto-L-gulonic acid (anhydrous ) is dissolved in 14 ml of pyridine and 3.2 ml of methylene chloride and added dropwise with stirring and ice-cooling with 3.2 ml of thionyl chloride. After 3 hours at room temperature, the reaction solution with 5.9 ml of 2-chloroethanol is added and then stirred for a further 3 hours. The reaction solution is then taken up in methylene chloride and washed in sequence with ice-cold 2-n hydrochloric acid, 2-n caustic soda and water, the organic phase is dried over sodium sulphate and evaporated. The residue is purified on a silica gel column and then distilled. 5 g of an oily product is obtained, kg.: 88°C/0.01 mmHa.

Analogous to the previous examples, especially examples 1, 2 and 8, the following compounds are prepared: ammonium 2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, pour temperature: 177.5 - 178, 5°C; calcium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 265 - 267°C; Dimethylammonium 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 155 - 165°C. N-ethanolammonium 2,3:4,5-di-O-isopropylidene-2-keto-L-gulonate, pour point: 208 - 209°C; n-butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 54 - 57°C; 3-Chloropropyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, boiling point: 130°C/0.005 mmHg; 25 n-hexyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, nD : 1.4544; n-heptyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate > bp: 102 - 103°C/0.01 mmHg; n-octyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, n 25: 1.4538; n-nonyl-2,3:4,6-di-0-isonropvlidene-2-keto-L-gulonate, n 25: 1.4548: 25 n-undecyl-2,3:4,6-di-0- isopropylidene-2-keto-L-gulonate, wn • : 1.4555;

2,2,2-trichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 65 - 66°C;

n-dodecyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 10.5°C;

n-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 80 - 81°C;

1-propyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour temperature: 107.5 - 109°C;

n-decyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, bp: 193°C/0.5 mmHg;

2-bromomethyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp.:

about. 157°C/0.1 torr; 2-Butyl-2,3:4,6-di-O-isopropylidene-2-keto-L-aulonate, pour point: 95.5 - 96.5°C; 1- amyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp.: approx. 135°C/0.1mmHg; bis-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate-ethylene glycol ester, pour point: 150 - 151°C; t-butyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-pentynyl-2,3:4,6:di-O-isopropylidene-2-keto-L-gulonate; 1-hexin-3-yl-2,3:4,6-di-O-isopropylidene<1>2-keto-L-gulonate; 3-methyl-1-butyn-3-yl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

5-hexenyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

3-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; dichloromethyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2-dichloroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-Chloroethyl-2,3:4,6-di-O-iso<p>ropylidene-2-keto-L-gulonate; 4-chlorobutyl 2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2,2,2-trifluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-Fluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate; 2-bromo-1,1,2,2-tetrafluoroethyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,4-heptafluorobutyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2,2,3,3,4,4,5,5-octafluoropentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate;

2-propynyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate, pour point: 91.5 - 92.5°C;

n-pentyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate, bp.: approx. 195°C/0.1mmHg;

Claims (7)

1. Compound with plant growth regulating effect, characterized in that it is covered by the general formula where n means the number 1 or 2 and X is 0 to 1, and when n is the number 1 R' means sodium; potassium; ammonium; ammonium substituted with one or more lower alkyl, lower alkenyl or hydroxy-lower alkyl groups; a straight or branched chain alkyl, alkenyl or alkynyl group of up to 20 carbon atoms; or a halogen-lower alkyl group; and when n is the number 2, R' means calcium; magnesium or lower alkylene, R'1' R<<>2' R,3 and R<1>4 ketyr a lower alkyl group; as well as enantiomers and racemic mixtures of the compound of formula II, with the proviso that when R" means a methyl, ethyl, allyl group, sodium or potassium.,. means R'^, R<l>2' R' ^ ° <J R'4 a lower alkyl group with more than 1 carbon atom. 2. Compound according to claim 1, characterized in that it is n-butyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate. 3. Compound according to claim 1, characterized in that it is n-pentyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate. 4. Compound according to claim 1, characterized in that it is bis-2,3:4,6-di-0-isopropylidene-2-keto-gulonate-ethylene glycol ester. 5. Compound according to claim 1, characterized in that it is n-ethanolammonium-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate. 6. Compound according to claim 1, characterized in that it is iso-propyl-2,3:4,6-di-0-isopropylidene-2-keto-L-gulonate. 7. Compound according to claim 1, characterized in that it is 2-propargyl-2,3:4,6-di-O-isopropylidene-2-keto-L-gulonate.