FR2532941A1 - BRASSINOSTEROIDS, PROCESS FOR THE PREPARATION THEREOF, AND PRODUCTS CONTAINING SUCH COMPOUNDS AND HAVING REGULATORY ACTION ON PLANT GROWTH - Google Patents

Abstract

THE INVENTION CONCERNS NEW BRASSINOSTEROIDS. THEY RESPOND TO THE FORMULA: (CF DRAWING IN BOPI) IN WHICH R REPRESENTS AN ALKYL OR ALCENYL RADICAL, Z REPRESENTS A -CO-O-CH- CO-CH-, AND R AND R ARE DIFFERENT FROM ONE OF THEM. OTHER AND EACH REPRESENT HYDROGEN OR AN ACYL, OR STILL FORM TOGETHER A RADICAL CARBONYL OR A RADICAL (CF DRAWING IN BOPI) IN WHICH X REPRESENTS HYDROGEN OR A RADICAL ALKYL OR ALCOXY AND REPRESENTS HYDROGEN OR A RADICAL IN BOPI , ALCOXY OR ARYL. THESE COMPOUNDS ARE GROWTH SUBSTANCES. THEY WILL BE USED IN PARTICULAR TO ACT ON THE VEGETATIVE OR GENERATIVE DEVELOPMENT OF LEGUMES SUCH AS SOY.

Description

The present invention relates to novel brassins

  steroids, a process for their preparation, and products

  which contain such compounds and which have a regular action

trice on plant growth.

  Rapeseed was isolated from a steroid, brassinolide, which stimulates plant growth and elucidated its structure (see Mo D Grove et al, Nature, 281, 216 (1979)). Regulatory action on the growth that makes

  evidence this compound is however not satisfactory.

  It was therefore necessary to develop - this was the technical problem to be solved for new brassinosteroids having, in comparison with known brassinolide of similar constitution,

  better regulatory properties on plant growth.

  This technical problem is solved according to the invention by means of a product characterized in that it contains at least one compound corresponding to the general formula R 1 n - (I) in which R 17 represents a C 8 alkenyl alkyl radical -C 10, C 8 -C 10 or a radical Z represents one of the groups: CO CH and OC CH, II il X 2 2

O o -

  R 2 and R 3 are different from each other and each represents hydrogen or an acyl radical, or together form a radical C = O or a radical Y in which X represents hydrogen, a C-alkyl 1-C 4 or C 1 -C 3 alkoxy and Y is hydrogen, C 1 -C 4 alkyl, C 1 -C 3 alkoxy

or an aryl.

  The compounds in accordance with the invention are in the form of geometrical isomers, the substituents -OR 2 and -OR 3 having the cis 2a, 3a configuration or the cis 25 configuration,

  The various isomers and their mixtures are also

of the present invention.

  The compounds according to the invention are remarkably well suited to regulate the growth of plants in different cultures. By their field of activity as well as by their tolerance, they surprisingly surpass the product.

  acting in the same sense that was discussed at the beginning.

  The compounds according to the invention make it possible to stimulate the vegetative growth of cultivated plants; in certain intervals of concentrations they also allow

  to inhibit it In addition it is possible, with the help of these

  posed, to obtain, by action on the generative phase,

yields.

  In the case of cultivated plants the new compounds generally act on the membrane system, of which they

  modify the permeability for different substances.

  Under certain conditions they can exert an anti-stress effect.

  Since the compounds according to the invention

  both qualitative and quantitative changes

  in the plant that changes in its metabolism

  they should be included in the category of "growth substances" or "growth regulators", products

  signal by the following application possibilities.

  Inhibition of vegetative growth in the case of woody and herbaceous plants, for example on roadsides, railway installations, etc., with the aim of obstructing too exuberant vegetation Inhibition of growth, to prevent lodging or breakage of the stems in the case of cereals, and to increase the harvest in

the case of cotton.

  Action on the branching of vegetative and generative organs, to increase floral production in the case of ornamental plants and utilitarian plants, or to inhibit the formation of lateral discharges in the case of tobacco

and tomato.

  Improvement of the quality of the products, for example increase of the sugar content in the case of sugar cane, sugar beet or fruits, and greater regularity of the ripening of the product to be harvested, o

better yields.

  Increased resistance to stress, for example against weather effects, such as cold and drought, but also against phytotoxic actions

of chemical agents.

  Action on the latex flow in the case of rubber plants. Parthenocarpic fruit formation, pollen sterility and action on sex are other possibilities

application.

  Mastery of germination of seeds or bud-

  ment. Defoliation or action on abscission of fruits in

the purpose of facilitating the harvest.

  The compounds according to the invention are suitable

  especially when one wishes to act on the vegetative

  tative and generative of certain legumes, such as soybeans.

  Depending on the result we want to obtain, we apply

  doses of active material generally between 0.001 and 1 kg per hectare, but it is also possible to

apply higher doses.

  The timing of the application depends on the purpose we have

  fixed and climatic conditions.

  Some of the compounds according to the invention are

  especially with regard to action

  described; these include those in formula (I) des-

  which: R 17 represents a 2-methyl-6-heptyl (i.e., 1,5-dimethylhexyl), 2-methyl-3-ethylheptene-4-yl-6 (i.e., dimethyl) radical; 1- (4-ethyl-hexen-2-yl), 2,3-dimethyl-heptene-4-yl-6-methyl-3-ethyl-3-heptyl-6 or 2,3-dimethyl-6-heptyl, Z represents one of the groups : -C-0 C 2 and CO-CH 2 e

0 O

  and R 2 and R 3 are different from each other and represent 2 3 each then a hydrogen atom, a formyl radical,

  a C 2 -C 7 -alkyl-CO radical; a C 2 -C 7 alkoxy radical;

  C 1 -C 3 -alkyl-CO or an aryl-CO- radical, or together form a radical ZC = O or a radical Cy in which X represents hydrogen, a C 1 -C 4 alkyl or a C 1 alkoxy -C 3 and Y represents hydrogen,

  C 1 -C 4 alkyl, C 1 -C 3 alkoxy or aryl.

  Examples of alkyl and alkenyl radicals containing from 8 to 8 carbon atoms are, for example, 2-methyl-6-heptyl, 2-methyl-3-ethyl-3-heptene-6-yl and 2,3-dimethyl-4-heptene-6. 2-methyl-3-ethyl-6-heptyl and 2,3-dimethyl-6-heptyl The acyl radical may in particular be the radical

  formyl, a C 2 -C 7 -alkyl-CO- radical, a C 2 -C 7 alkoxy radical,

  C 1 -C 3 -alkyl-CO or an aryl-CO- radical, for example a radical

  acetoxy, methoxyacetoxy, ethoxyacetoxy, propionyloxy, butyry-

  loxy, valeryloxy (pentanoyloxy), hexanoyloxy, heptanoyloxy,

  dimethylacetoxy, diethylacetoxy, benzoyloxy or phenylacetoxy.

  Examples of C 1 -C 4 alkyl radicals which may be mentioned are methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl and chloromethyl radicals. The methoxy, ethoxy and propoxy radicals are examples of C 1 -C 4 alkoxy radicals. Examples of aryl radicals are: naphthyl, phenyl, 2-chlorophenyl, 3-chlorophenyl, 4-chlorophenyl,

  2,6-dichlorophenyl, 2,4-dichlorophenyl, 3,4-dichlorophenyl

  Nyl, 2,4,6-trichlorophenyl, 4-bromo-phenyl, 2,4-dibromo, phenyl, 2,6-dibromo-phenyl, 2,4,6-tribromo-phenyl, 2-fluoro-phenyl, 3-fluoro-phenyl, 4-fluoro-phenyl, 2,4-difluorophenyl, 2-methylphenyl, methyl-3-phenyl, 4-methylphenyl, 3,4-dimethylphenyl, 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, methylene-dioxy -3,4 phenyl, phenoxy-2

  phenyl, 3-phenoxyphenyl, 2-nitro-phenyl and 3-nitro phenyl.

  The compounds in accordance with the invention may be applied alone, as a mixture with one another or mixed with

  Other active ingredients Depending on the purpose, it may be possible to

  add defoliants, phytosanitary products

  or anti-parasitic products.

  When it is desired to extend the scope of activity, it is also possible to add other biocides. Suitable herbicidal partners are, for example, the active ingredients which are mentioned in Weed Abstracts, volume 31, 1981, under the title "List of Common Names and Abbreviations Employed". In addition, non-phytotoxic products may be used on their own but which, when combined with herbicides and / or growth regulators, may increase the efficacy of herbicides and / or growth regulators. a synergistic effect it will be particularly wetting,

  emulsifiers, solvents and / or oily additives.

  It is good to apply the active ingredients according to

  the invention, or mixtures thereof, in the form of

  such as powders, spreading agents, granules,

  tions, emulsions or suspensions, containing supports or

  liquid and / or solid diluents and possibly wet

  lants, adhesives, emulsifiers and / or dispersants.

  Suitable liquid carriers include, for example,

  aliphatic or aromatic hydrocarbons, such as benzene, toluene and xylenes, cyclohexanone, isophorone, dimethylsulfoxide, dimethylformamide, and the like.

  as fractions of mineral oils.

  The solid supports will for example be mineral soils, such as Tonsil, silica gel, talc,

  kaolin, Attaclay, limestone and silica, or

  vegetable fats, such as flour.

  Examples of surfactants are lignin sulphate.

  Calcium fonate, polyethoxylation products of alkyl-

  phenols, sulphonylenesulphonic acids and their salts,

  phenol-sulphonic acids and their salts,

  densification of formaldehyde, sulphates of fatty alcohols and

  benzenesulphonic acids and their salts.

  The proportion of the active ingredient (s) in the various formulations may vary over extended intervals.

  example, from about 10 to 80% by weight of active ingredient,

  90 to 20% by weight of liquid or solid carriers and,

  optionally, up to 20% by weight of surfactants.

  The spreading of the products can be done in the usual way, for example with water as a carrier in the form of mildew is sprayed at doses of about 1000 liters per hectare It is also possible to apply the produced by the so-called "low volume" process and the so-called "very low volume" process, as well as in the form

micro-granules.

  To prepare the formulations we will use, for example,

the following constituents.

  A wettable powders a) 80% by weight of active material,% by weight of kaolin,% by weight of surfactants based on the sodium salt of N-methyl-Noleyl-taurine and the calcium salt of

lignin-sulfonic acid.

  b) 50% by weight of active ingredient,% by weight of clay minerals, 5% by weight of pitch derived from the treatment of cellulose and% by weight of surfactants based on a mixture of the calcium salt of ligninsulfonic acid with

  polyethoxylation products of alkylphenols.

  c) 20% by weight% by weight% by weight% by weight calcium products of active ingredient, clay minerals, pitch cellulosic, and surfactants based on a mixture of the salt of lignin-sulfonic acid with

  polyethoxylation of alkyl phenols.

  d) 5% by weight of active ingredient,% by weight of Tonsil,% by weight of cellulosic pitch, and% by weight of surfactant based on a fatty acid condensation product B Emulsifiable concentrate% by weight of active material, 40% by weight of xylene,% by weight of dimethylsulfoxide, and% by weight of a mixture of a polyethoxylation product of nonylphenol and dodecylbenzenesulfonate

of calcium.

  C Paste 44% by weight of active material,% by weight of sodium aluminosilicate, 15% by weight of 8 mol / ethylene oxide cetylpolyglycol ether, 2% by weight of pin oil ,% by weight of polyethylene glycol, and 23% by weight of water. To prepare the novel compounds which are the subject of the present invention, it is possible for example to hydroxylate compounds of general formula (II) R 17 (II) with tert-butyl hydroperoxide or with N-methyl-morpholine N-oxide, in the presence of osmium tetroxide as a catalyst, so as to obtain compounds of formula

2532 41

  general (III): R 17 HCl (III) H Oil'ljit H or act on compounds of formula (II) acetate

  of silver and iodine in aqueous acetic acid, the reaction

  which then occurs generating compounds of general formula (IV): R

R 2 (IV)

HO / I

  O (in the formulas that have just been shown, the symbols R 2 and R 17 have the meanings given above) that are treated with peracids to form the

searched for products.

  To prepare the compounds of formula (I) one starts from

  sterols, such as cholesterol, stigmasterol,

  cholesterol or 8-sitosterol, and these are reacted, in known manner, to arrive at A oxo-6 steroids of formula

(II) (see Helv 49, 1581 (1966)).

  The subsequent reaction leading to the α-β-brows of formula (III) is carried out according to known methods, namely osmium tetroxide catalyzed hydroxylations and carried out with 80% tert-butyl hydroperoxide ( KB Sharpless JACS 98, 1986 (1976)) or with N-methyl-morpholine N-oxide (V an Rheen, Tetrahedron Lett 1976,

1973) -

  The cis-2 P, 3 B cis or derivatives thereof of formula (IV) are obtained by a Prevost reaction with silver acetate and iodine in aqueous acetic acid (Helv 49,

532 4

1581, (1966)).

  The preparation of the compounds of formula (I), the

  cycle B is a lactone ring, is carried out by an oxy-

  Baeyer-Villiget dation oxo-6 steroids of formula (III) or (IV) by means of peracids such as trifluoroperacetic acid, performic acid, permaleic acid, etc. In the case of compounds containing a C 22 -C 23 double bond

  in the side chain it is necessary, before lactonization,

  This double bond is brominated. After the oxidation of BaeyerVilliger, the double bond can be regenerated.

  medium of zinc in acetic acid.

  The following examples illustrate the preparation of

compounds according to the invention.

EXE 1 PLE 1

  a) 3.56 g of ethyl-24 S 5 α-cholestadiene-2,22 one-6 are dissolved

  in 60 ml of tertiary butanol, 4 ml of a solution of

  at 20% tetraethylammonium hydroxide,

  to 0 C and 12 ml of tert-butyl hydroperoxide are added to

  % and 6 ml of a solution of osmium tetroxide (prepared from 250 mg of Os O 4, 49.75 ml of tertiary butanol and 0.25 ml of 80% tert-butyl hydroperoxide) the reaction solution is stirred for 6 hours at room temperature

  room temperature, it is poured into a 5% solution of hydrogen

  sodium sulphite and extracted with ethyl acetate.

  The extract is washed with water, dried over sodium sulphate and

  After recrystallization in a mixture of chlorine

  of methylene and methanol, 2.3 g of dihydric

  2-hydroxy-2-ethyl-24 S 5-cholesten-22-one-6 Its melting point is 234.5 235.5 Co

  b) 2.2 g of 2α-dihydroxy-3α-ethyl-24,5-a-5-choles are dissolved

  Ten-22-one-6 in 15 ml of pyridine, 8 ml of anhy-

  acetic acid and 220 mg of dimethylamino-4-pyridine and allowed to stand at 20 ° C. for 17 hours. After this, the precipitate is precipitated in ice water, the product is separated by

  spin, wash and dry.

2 3274 X

  c) 0.28 ml of bromine is added to 2.6 g of the crude diacetate in ml of ether and 30 ml of glacial acetic acid, and the mixture is then stirred for 10 minutes at room temperature. the ether, washed with water until neutral and evaporated under reduced pressure is thus collected 3.2 g of diacetoxy-2a, 3a

  crude dibromo-22,23 ethyl-24,5-cholestanone-6.

  d) 4.5 ml of 30% hydrogen peroxide are suspended in 28 ml of methylene chloride, cooled to -10 ° C. and 27.7 ml of trifluoroacetic anhydride are slowly added dropwise to a speed such that the internal temperature does not rise to more than + 10 Co Then add

  3.2 g of 2,3-diacetoxy-3α-dibromo-22,23 ethyl-24,5-a-choles-

  tanone-6 in the form of a solution in 25 ml of chlorine

  of metylene, and stir for 40 minutes at room temperature.

  This is done, diluted with methylene chloride, washed successively with water, with a solution of 5% sodium carbonate and with water, dried and concentrated under reduced pressure. residue for 1 hour on the steam bath in 100 ml of acetic acid with 5 g of zinc powder The zinc is filtered off, diluted with methylene chloride, washed with water until neutral and evaporated After chromatography on silica gel with toluene and ethyl acetate mixtures of graduated concentrations as eluents and after crystallization in a mixture of acetone and hexane 1.5 g of 2-diacetoxy are obtained. 3-ethyl-24 oxa- 7 B-homo 5α-cholesten-22-one, which melts at 221-223 ° C,

  and 310 g of 2α, 3α-diacetoxy-ethyl-24-oxa-6β-homo 5-choles-

  ten-22 one-7, which melts at 202-204 C.

EXAMPLE 2

  a) To a solution of 2 g of ethyl-2,4-cholestadiene-2,22-one-6 in 270 ml of glacial acetic acid and 3.7 ml of water is added silver and 1.9 g of iodine and heated at 45 ° C. for 3 hours with stirring After the silver salts have been filtered off and washed with chloroform, the filtrate is diluted with chloroform and washed. with water, with sodium thiosulfate and with

  water is dried and concentrated after crystallization.

  In a mixture of acetone and hexane, 1.2 g of acetoxy-25-hydroxy-3-ethyl-24α-cholesten-22-one, which melts at 192 ° -194 ° C., are obtained. A 22 double bond and have carried out the oxidation of Baeyer-Villiger and the reduction by zinc,

  as described in Example 1 under (c) and (d),

  Crude product on silica gel eluting with mixtures of chloroform and acetone forming a

  "concentration gradient" is obtained after recrystallization

  In a mixture of hexane and ether, 2-acetoxy-3-hydroxy-ethyl-24-oxa-7β-homo-α-cholesten-22-one-6 (F = 151-15 ° C) with yield of 75% and 2-acetoxy-8-hydroxy-ethyl-24'-oxa-6-B-homo acholestene-22-one-7

  (Mp 175-176 ° C) with a yield of 10%.

EXAMPLE 3

  a) To 2.2 g of 25-acetoxy-3-hydroxy-ethyl-24-oxa-7-homo-cholesten-22-one-6 in 50 ml of methanol is added a solution of 500 mg of potassium in 10 ml of methanol and stirred at room temperature for minutes Acidified with acetic acid, precipitated in ice water, the precipitate is separated off

  by spinning it is washed and dried.

  in a mixture of chloroform and ether,

  1.7 g of 25-dihydroxy-25,38 ethyl-24 oxa-7 B-homo 5-choles-

  tolene-22 one-6, which melts at 211-213 Co b) Cooled to -10 C 500 mg of dihydroxy-2 e, 3 g ethyl-24 oxa-7 B-homo 5-cholesten-22-one-6 in 4 ml of pyridine, 0.5 ml of acetic anhydride is added and the mixture is stirred for

  3 ½ hours at a temperature of -5 to 0 C o After pre-

  cipitation in ice water, separation of the product by dewatering, washing and drying and recrystallization from a mixture of acetone and hexane o 410 mg of acetoxy-36-hydroxy-2-ethyl-24-oxa-7 B is obtained homo 5-cholestene-22-one-6,

which melts at 182-184 C.

EXAMPLE 4

  1 g of 2-dihydroxy, 3-oxa-7B-homo 5

  cholestanone-6 in 10 ml of pyridine, cooled to 0 ° C. and 1 ml of acetic anhydride is added. The mixture is stirred for 5 hours at a temperature of from 0 ° to 5 ° C., the whole is poured into ice-water and the mixture is separated. solid product by spinning, washed and dried After recrystallization from pentane

  950 g of 2-acetoxy-3-hydroxy-oxa-7-homo 5-a-choles were obtained.

tanone-6, which melts at 165.5-167 C.

  Preparation of the starting material a) Dissolve 25 g of 5-cholesten-2-one in 140 ml of

  tetrahydrofuran, 14 g of N-methyl-N-oxide are added.

  morpholine, 25 ml of water and 50 ml of tertiary butanol and, with stirring, a solution of 250 mg of osmium tetroxide in 50 ml of tetrahydrofuran is introduced. The reaction solution is stirred in the dark, 17 hours at room temperature is then poured into 7 liters of ice water to which 50 ml of 2 N sulfuric acid and 1 g of sodium sulphide have been added, the precipitated product is separated by suction, washed with water, dissolved in chloroform and the solution evaporated under reduced pressure The crude product (30 g) is dissolved in 140 ml of pyridine and, after adding 70 ml of acetic anhydride and 3 g of 4-dimethylaminopyridine, the mixture is left to stand at room temperature for 16 hours After precipitation in water, separation of the product by dewatering, washing with water and drying thereof

  It is chromatographed on silica gel after recrystallization.

  In an ethanol solution, diacetoxy 2a, 3a-5a-cholestanone-6, which melts at 0-151.5C, and in a proportion of 15% diacetoxy- 2nd,

  3 X 5 a-cholestanone-6 which melts at 183 # 5-185 C.

  b) 26 ml of 30% hydrogen peroxide are suspended in methylene chloride, cooled to -10 ° C. and

  161 ml of trihydric anhydride are slowly added dropwise

  at a rate such that the temperature

  The amount of diacetoxy-2a, 3 to 5u-cholestanone-6 is then increased to 27.2g.

  the form of a solution in 160 ml of methylene chloride

  and then stirred at room temperature for 40 minutes.

  For further treatment, dilute with methylene chloride, wash one by one with water, with 5% sodium carbonate solution and

  water, and concentrate under reduced pressure.

  On silica gel chromatography and recrystallization from a mixture of acetone and hexane, diacetoxy-2α, 3α-oxa-7β-homo-5α-cholestanone-6 was obtained in a yield of 81%. at 183-184 ° C., and in a proportion of 6.2%, diacetoxy-2α, 3α-oxa-6β-homo-5-cholestanone-7, which melts at

245-247 Co.

  c) 28.3 g of 2α-diacetoxy-3α-oxa-7β-homo-5α-choles are dissolved

  tanone-6 in 500 ml of methanol and, after adding a solution of 14 g of potassium hydroxide in 150 ml of

  methanol is stirred for 30 minutes at room temperature.

  This is done, acidified with acetic acid, precipitated in ice water, separated by

  spin, wash it with water and dry it after recreating

  in a mixture of acetone and pentane

  22.4 g (95%) of dihydroxy-2α, 3α-oxa-7β-homo 5-is obtained.

  cholestanone-6 which melts at 138-140 Co

EXAMPLE 5

  a) Using the procedure described in Example 4 (c), 11 μg of 2α-diacetoxy-3-oxa-6β-homo-α-cholestanone-7 are saponified.

  thus obtaining 785 mg of dihydroxy-2α, 3α-oxa-6β-homo

  cholestanone-7, which melts at 216.5 218 C.

  b) 250 mg of 2α-dihydroxy-3α-oxa-6β-homo-5α-choles are dissolved

  tanone-7 in 2 ml of pyridine, cooled to -10 ° C., 0.24 ml of acetic anhydride are added and the mixture is stirred for 4 hours at a temperature of -5 to 0 ° C. After precipitation in ice water, separation the product by spinning, washing and drying it is recrystallized in a

  mixture of acetone and hexane 210 mg of

  toxy-2a-hydroxy-3a-oxo-6-homo 5a-cholestanone-7, which melts

at 199-201 C.

EXAMPLE 6

  By operating as in Example 5 (b), 600 mg of 2α-dihydroxy-3α-methyl-24-oxa-6β-homo-5α-cholesten-22-one were acetylated to give 515 mg of acetoxy-2. a methyl-3-hydroxy-24

  oxa-6 B-homo 5-cholesten-22-one, which melts at 173-174 ° C.

  Preparation of the starting material From the brassicasterol is prepared, by a known method, methyl-24 5-cholestadiene-2,22-one-6 and is made

  react it as described in Example 1.

EXAMPLE 7

  1 g of 2-dihydroxy-B, 3-oxa-7-B-homo-5-a-choline were dissolved

  talone-6 in 100 ml of acetone and 100 ml of tetrahydrofuran

  After cooling to 0 ° C., 0.5 ml of the adduct compound is added.

  diethyl ether-boron trifluoride and stirred for minutes at a temperature of 0 to 5 C. After adding 1 ml of pyridine is concentrated under reduced pressure and recrystallized

  in a mixture of methylene chloride and diisopropylene oxide

  propyl gives 731 mg of isopropylidene-2,3-diox oxa-7

  B-homo 5-cholestanone-6, which melts at 216-217 C.

  Similarly prepared is isopropylidene-dioxy-2a, 3a oxa-7-homo 5-cholestanone-6, which melts at 216-217 C, and

  isopropylidene dioxy-2α, 3α-ethyl-24-oxa-7β-homo-5α-chl

  Lestene-22 one-6, which melts at 157-158 C.

EXAMPLE 8

  900 mg of 2α-dihydroxy-3α-oxa-7β-homo a-cholestanone-6 are dissolved in 10 ml of pyridine, cooled to 0 ° C., 1.8 ml of valeric anhydride are added and the mixture is stirred for 10 hours. at a temperature of 0 ° to 5 ° C. After the further treatment carried out as in Example 4, 950 mg of 2-valeryloxy-3-hydroxy-oxa-7β-homo-acholestanone-6 are obtained,

which melts at 92-94 Co.

EXAMPLE 9

  By operating as in Example 3, the diacetate is saponified.

  toxy-2a, 3a-ethyl-24-oxa-7B-homo 5a-cholesten-22-one-6 and partially acetylated.

  %, 2-acetoxy-3-hydroxy-ethyl-24-oxa-7-B-homo 5-a-choles-

  ten-22 one-6, which melts at 158-160 Co.

EXAMPLE 10

  900 mg of 2α-dihydroxy-3α-oxa-7β-homo-6-cholestanone are dissolved in 10 ml of pyridine, cooled to 0 ° C, 1 ml of ethoxyacetic anhydride is added and the mixture is stirred for hours at 0 ° C. -5 Co-After the complementary treatment, carried out

  as in Example 4, and recrystallization from a mixture of

  With hexane and hexane there is obtained 720 mg of 2-ethoxyacetoxy-3-hydroxy-oxa-7β-homo-5-cholestanone-6, which melts at 172 ° -173 ° C.

* EXAMPLE 11 l

  Stirring is carried out at 0.degree. C. for 10 hours at 300.degree.

  2a, 3a-ethyl-24-oxa-7B-homo 5a-cholesten-22-one-6 in 3ml

  of pyridine with 780 mg of phenylacetic anhydride after

  Complementary treatment and recrystallization from a mixture of acetone and hexane gives 210 mg of phenylacetoxy-2-a

  3-hydroxy-ethyl-24 oxa-7β-homo 5α-cholesten-22-one-6,

at 185-186 Co

EXAMPLE 12

  To 500 mg of dihydroxy-2α, 3α-oxa-7β-homo 5α-cholestate

  In a 50 ml portion of benzene, 0.75 ml of triethyl orthoacetate and then 5 mg of p-toluenesulfonic acid are added. The solution is stirred for 20 minutes at room temperature, 3 drops of pyridine are added thereto and it is evaporated under reduced pressure The residue is dissolved in methylene chloride,

  washed with water, dried over sodium sulfate and evaporated.

  605 mg of (ethoxy-1-ethylidene-dioxy) -2α, 3α-oxa-7α-α-cholestanone-6, which melts at 150-154 ° C., are thus obtained.

  1- (3-ethoxy-ethylidene-dioxy) -2,3-oxa-6-homo-5-choles

tanone-7, which melts at 122-124 C,

  1 '(1-ethoxy-propylidene-dioxy) -2-oxa-7b-homo-5-choles-

  tanone-6, which melts at 115-118 ° C, 1- (methoxy-1-methylene-dioxy) -2,3-ethyl-24-oxa-7-homo-c-cholesten-22-one-6, which melts at 96- 98 C, and 1 '(ethoxy-1-ethylene-dioxy) -28,33 ethyl-24 oxa-7B-homo a-cholesten-22-one-6, which melts at 123-125 C.

EXAMPLE 13

  To 500 mg of dihydroxy-2-ae, 3-oxa-7 B-homo 5-cholesta-

  none-6 in 5 ml of tetrahydrofuran is added 1.5 ml of acetone.

  tophenone and 0.1 ml of diethyl ether-boron trifluoride and refluxed for 3 hours then concentrated under reduced pressure, 1 ml of pyridine and evaporated under high vacuum After trituration with hexane on 465 mg of 1-methyl-1-methyl-1-phenyl-1-methylene-dioxy are obtained in the form of a mixture of diastereoisomers which melts at 130.5. 1320 C.

EXAMPLE 14

  500 mg of 2α-dihydroxy-3α-oxa-7β-homo a-cholestanone-6 are dissolved in 15 ml of diethyl carbonate, heated to boiling and, after distilling off 2 ml of diethyl carbonate. 30 ml of sodium methylate are added over a period of 3 minutes. A few mls of the reaction solution are then removed. After cooling, 0.15 ml of glacial acetic acid are added and the mixture is concentrated by evaporation under reduced pressure. The residue is recrystallized from a mixture

  acetone and hexane give 450 mg of carbonyl

  2α-dioxo-3α-oxa-7β-homo-5-cholestanone-6, which melts at 203.5-

205 C.

An analogous preparation is prepared:

  2α, 3α-carbonyldioxy-ethyl-24-oxa-7β-homo-5α-choles-

  ten-22 one-6, which melts at 193-195 ° C, and 23,3-carbonyldioxy-7-oxa-7-homo-cholestanone-6, which

background at 212-214C.

EXAMPLE 15

  300 mg of 2α-dihydroxy-3α-oxa-7β-homo-5-cholestanone-6 are dissolved in 2 ml of benzaldehyde, 0.02 ml of 70% perchloric acid are added and the mixture is stirred for 2 hours at room temperature. The solution is then neutralized with pyridines, diluted with hexane and chromatographed on silica gel with a mixture of hexane and acetate.

  of ethyl at a ratio of 6: 4, 258 mg of benzylidene-dioxygen were

  2a, 3a oxa-7 B-homo 5a-cholestanone-6, which is recrystallized

  in a mixture of ether and pentane Melting point: 137-

139 C.

  Similarly prepared is benzylidene-2α-dioxy-3α-oxa-6β-homo-5-cholestanone-7, which melts at 179-180 ° C, benzylidene-2-dioxy-33 oxa6b- homo 5-cholestanone-7, which melts at 129-131 C, and 2-benzylidenedioxy-B, 3 oxa-7 B-homo 5-cholestanone-6,

which melts at 153-155 Co.

  The compounds according to the invention are presented

  usually in the form of crystallized substances,

  lores and odorless, which dissolve poorly in water, have limited solubility in aliphatic hydrocarbons, such as petroleum ether, hexane, pentane and cyclohexane, and are very soluble in halogenated hydrocarbons, such as

  chloroform, methylene chloride and tetrachloro-

  carbon, in aromatic hydrocarbons, such as benzene, toluene and xylenes, in ethers, such as diethyl ether, tetrahydrofuran and dioxane, in carbonitriles, such as acetonitrile, in ketones, such as acetone, in alcohols, such as

  methanol and ethanol in carboxamides, such as dimethyl

  thylformamide, and in sulfoxides, such as dimethyl

sulfoxide.

  The following examples illustrate the possibilities of application of the compounds according to the invention, which are used in the form of compositions which have been

described above.

EXAMPLE 16

  Stimulation of growth in the kidney bean In an air-conditioned chamber with a temperature of 250 ° C and a hygrometric degree of air of 90%, dwarf beans of the variety "Pinto" are cultivated under the action of a light at high intensity proportion in the 660 nm region

  and a very small proportion in the region of 730 nm.

  After 6 days of culture apply 10 pg and 20 pg

  compounds to be studied, dissolved in solvents, on the

  xth developing node.

  Three days after the application we measure the extension

  internodes and the elongation in% is determined by

to the witness.

  The following table contains the results of this test.

  Compound according to the invention Stimulation in% plg 50 μg 2-acetoxy-3α-hydroxy-B-homooxa-7α-cholestatin-6,292

  Carbonyldioxy-2α, 3α-homooxa-7α-cholestate

none-6 190,304

  2-acetoxy-3-hydroxy-B-homooxa-6-Sa-cholestate

  N-7 162 125 (Ethoxy-ethylidene-dioxy) 2 L, 3a B-homo-oxa-7-acholestanone-6,165,162 (1-Methyl-1-phenyl-methylene-dioxy) -2.0.3Homo oxa-7 A-cholestanone-6 152 342 Comparative compound: 2-C-tetrahydroxy, 3 to 22 S, 23 S ethyl-24 B-homooxa-7 u-cholestanone-6 89 114 (3-indolyl) butyric acid 51 100 100 These results show that the compounds according to the invention cause, under the experimental conditions indicated, a greater elongation than in the case of

  comparison compounds and the control.

  Comparative compounds, on the other hand, cause only a more or less marked stimulation of growth in thickness, which sometimes leads sometimes to a shortening

internodes.

EXAMPLE 17

  Stimulation of root growth in Mung beans

  In greenhouse conditions, hairs are germinated

  Mung costs in aqueous emulsions of the compounds to be studied,

  which are present in a concentration of 0.01% by weight.

  After 6 days the length of the

cines sprouted plants.

  The following table contains the results of the test

in the form of percentages.

EXAMPLE 18

  Increasing the resistance of culture plants The culture plants mentioned in the table are pre-emergent treated with aqueous emulsions of the compounds to be studied or mixtures of such compounds. One week after the treatment, the results of this test are evaluated. according to a scale of notes ranging from 0 to 10, the value O corresponding to a destruction

  total (100%) and the value 10 at no damage.

  Compound according to the invention Stimulation in%

  2-acetoxy-hydroxy L 3a B-homo oxa-7 50-cholestate

none-6 180

  Carbonyldioxy-2α, 3α-homooxa-7α-cholestate

none-6 160

  2-acetoxy-3α-hydroxy-B-homooxa-6α-cholestate

  160 (1-Ethoxy-ethylene-dioxy) -2α, 3α-homo-oxa-7α-cholestanone, 200 (1-methyl-1-phenyl-methylene-dioxy) -2α, 3α-B-homooxa; Ccholestanone-6 150 Comparison Compound Giberellic acid (GA 3) 80 Control 100 G It is seen that the compound according to the invention gives the plants a greater resistance against the known herbicide.

Components I Dose-

  Composants Doen Tomato Cucumber Wheat Soy But Rave in kg Acetoxy-2a hydroxy-3a

B-homo oxa-7-

  a-cholestanone-6 (I) 0.02 4-Chloro-4-methylamino-5- (3-trifluoromethylphenyl) -2-pyridazinone 0.34 3 5 9 5 (norflurazone) (II) 3 , 0 1 1 1 4 2 1

(1) + (TI) 0.3

() + t 8 7 10 10 9 7 0.02 3.0

(I) + (II) + 6 5 8 10 7 7

0.02 Control 10 10 10 10 10 10

Claims (9)

  1 Brassinosterols having the general formula (I): R 1 R 3_ () H   in which: R 17 represents a C 8 -C 10 alkyl radical or a C 8 -C 10 alkenyl radical; Z represents one of the groups: C O CH and -O CH - he 2 1 2 O O   R 2 and R 3 are different from each other and each represents hydrogen or an acyl radical, or form X   cx together a radical C = O or a radical / C wherein X is hydrogen, C 1 -C 4 alkyl or C 1 -C 3 alkoxy and Y is hydrogen,   C 1 -C 4 alkyl, C 1 -C 3 alkoxy or aryl.   2 Brassinosteroids according to claim 1, in which: R 17 represents a 2-methyl-6-heptyl, 2-methyl-3-ethyl-heptene-4-yl6 radical, 2,3-dimethyl-4-heptene-6-methyl-2-methyl-3-ethyl-3-methyl heptyl-6 or 2,3-dimethyl-6-heptyl, Z represents one of the groups: -C O CH and O C CH- 2 O O   R 2 and R 3 are different from each other and each represents hydrogen, a formyl radical, a radical   C 2 -C 7 -alkyl-CO-, a C 2 -C 7 -alkoxy-C 1 -C 3 -alkyl-CO- radical   or an aryl-CO- radical, or together form an O or unradical radical C in which X is hydrogen, a CC 4 alkyl or a C 3 alkoxy and Y is hydrogen, C 1 alkyl or alkoxy in or an aryl. 3. A brassinosteroid according to claim 1, taken from the group consisting of 2-diacetoxy-3-ethyl-24-oxa-7β-homo-5-chlorethene-22-one, 2-diacetoxy-3α-ethyl-24 oxa = 6 B-homo 5 ca-cholestene 22 one-7,   2-acetoxy-3-hydroxy-ethyl-24-oxa-7-homo-5-a-choles ten-22 one-6,   2-acetoxy-3-hydroxy-ethyl-24-oxa-6β-homo 5-choles- ten-22 one-7,   3-acetoxy-2-hydroxyethyl-24-oxa-7-B-homo 5-a-choies   6-ene-2-one, 2-acetoxy-3-hydroxy-oxa-7β-homo-5α-cholestanone-6, 2-acoxy-3α-hydroxy-6α-oxa-6-homo cholestanone 7,   2-acetoxy-3-hydroxy-methyl-24-oxa-6β-homo 5-choles-   1-isopropylidene-2-dioxy-2-oxo-7-iso-1-oxo-6-iso-1-oxo-6-dioxo-3-iso-3-oxo-7-diol 6   IIisopropylidene-dioxy- = 2 EO, 3-ethyl-24 oxa-7 B-homo 5 a-chomo   22-ene-one-6, 2-valeryloxy-3-hydroxy-oxa-7β-homo-acholestanone-6,   2-acetoxy-3α-hydroxy-ethyl-24-oxa-7β-homo 5-choles-   2-ethoxyacetogly-2-hydoxy-3-oxa-7β-homo-5α, 6-cholestanone,   2-phenylacetoxy-3α-hydroxy-ethyl-24-oxa-7β-homo-5α-chl lestene-22 one-6,   (2-ethoxy-ethylidene-dioxy) -2a, 3a oxa-7B-homo 50-7 choles- tanone-6,   1 (Ethoxy-1-ethylidene-dioxy) -2α, 3α-hexa-6β-homo-Sa-choies tanone-7   1 (1-ethoxy-propylidene-dioxy) -2α, 3-oxa-7 β-homo 5 to 7 choles-   6-tanone, 1- (1-methoxy-methylene-dioxy) -L, 3-ethyl-24-oxa-7-aH-α-cholestene-22-one-6,1'-ethoxy-1-ethiylidene-dioxy) -2,3-ethyl-24-oxa-7β-homo-cholesten-22-one-6, (1-methyl-1-phenyl-1-methylene-dioxy) -2α, 3-oxa-7β-homo-ca-cholestanone 6-carbonyldioxy-2α, 3-oxa-7β-homo-ca-cholestanone-6,   carbonyl-2-dioxy-ca, 3-ethyl-24-oxa-7β-homo 5-choles-   22-carbon-2-one-6-carbonyl-2α-dioxy-oxa-7β-homo-5-cholestanone-6, benzylidene-2α-dioxy-3α-oxa-7β-homo-5α-cholestanone; 6, benzylidene-2-dioxy-ca, 3-oxa-6β-homo-ca-cholestanone-7, benzylidene-2α-dioxy-3,3-oxa-6β-homo-55α-cholestanone-7 and benzylidene. 2-oxo-3,3-oxa-7 B-homo 5 ct-cholestanone-6, 4 Process for the preparation of brassinosteroids according to   any of claims 1 to 3, characterized   in that hydroxyl OH compounds of the general formula (II) I (1 in the presence of osmium tetroxide as a catalyst, with   tert-butyl hydroperoxide or with N-methyl-N-oxide   muorpholine, a reaction which leads to compounds of the general formula (III) H, where the silver acetate and the iodine in aqueous acetic acid are reacted with compounds (II), which leads to compounds of general formula (IV) R 17 R O (IV)   and the compounds obtained are treated with peracids to form the desired products (in the preceding formulas, R 2 and R 17 have the meanings given in claim 1). Products having a regulating action on the   growth of plants, products characterized in that they   hold at least one compound according to any one of the 1 to 3.   Products having a regulating action on the growth of plants, according to claim 5, characterized in that they also contain supports and / or adjuvants.   7 Application of the products according to one of the   tions 5 and 6 to act on the vegetative and genera-   legumes, especially soya.   8 Products having regulatory action on growth   plant material according to claim 5, characterized in that   they contain at least one compound that has been prepared   by the method of claim 4.