DE2639671A1 - CHROME COMPOUNDS, THE PROCESS FOR THEIR PRODUCTION AND THEIR CONTAINING INSECTICIDES ACTING AS ANTIJUVENIL HORMONE - Google Patents

Description

Chromene compounds, processes for their preparation as well as containing the same, acting as an anti-uveni hormone insecticides

The invention relates to chromene compounds which are found to be effective has been shown to inhibit the effects of juvenile hormone in insects.

Among the various chemical compounds that have hitherto been used as insecticides to kill insects, Many proved to be harmful to other animals and humans. In addition, many species of insect pests have it developed a resistance and even immunity to the available insecticides.

Other well-known methods of controlling insects include the use of hormones that stimulate the development of Bugs insects. Although such hormones have the advantage

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sitting, apparently harmless to other animals, is their application to a relatively late point in time in the life cycle of the insect generally limited, namely after the insect already has its undesirable harmful Produced effect.

The endocrine system of insects secretes a certain as Juvenile hormone, a known hormone that works to that the biological activities of metamorphosis, reproduction, diapause and sex attractant production are controlled will. In particular, the juvenile hormone acts to keep the young developing insect in an immature state lasts until it has developed to the point where it is ready to peel or transform into fully grown form is. When the insect begins to mature, the body stops secreting juvenile hormone until after the insect has reached the adult form at which point the secretion of the juvenile hormone begins again to promote the development of the genital organs.

The forms in which juvenile hormone occurs in nature are dealt with in the following publications: Trautmann et al., Z.Naturforsch., 29C, 166-168 (1974) 5 Judy et al., Proc. Nat. Acad. Sci. USA, 70, 1509-1513 (1973); Roller et al., Angew. Chem. Int. Ed.Eng., 6, 179-180 (1967); Meyer et al., Proct. Nat. Acad. Sci., USA, 60, 853-860 (1968); Judy et al. _a Life Sci., 13, 1511-1516 (1973); Jennings et al., Life Sci., 16, 1033-1040 (1975) and Judy et al., Life Sci., 16, 1059-1066 (1975).

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It has now been found that the lipoid extract of the common ' Bedding plant Ageratum contains two active compounds:

(1) 6,7-dimethoxy-2,2-dimethyl-3-chromene and

(2) 7-methoxy-2,2-dimethyl-3-chromene, each being inhibitory acts on the effects of juvenile hormone in insects.

The first connection was made by A.R. Alertsen in the article "Ageratochromene, a Heterocyclic Compound from the Essential Oils of some Ageratum Species" in Acta Chem. Scand. 9 (1955), No. 10, 3 pages 1725-1726. Further publications in this area were made by R. Hüls in the Article "Syntheses De Chromenes Substitues" in Bull. Soc. Chim. BeIg., 67 (1958), pp. 22-32.

According to the invention chromene compounds are provided which proven effective in inhibiting the effects of juvenile hormone proven both during the early development of the insect and after reaching the adult Condition when the genital organs are subject to development. By such inhibition of the effects of juvenile hormone, the maturing insect that is infected with the present invention Compounds that have been treated die within a short time after such treatment. aside from that the ability to reproduce is prevented in a treated insect. It was also found that the invention Compounds disrupt embryogenesis in insect eggs, induce diapause in insects, and sex pheromone secretion prevent insects. The present compounds can be appropriately applied, including topically, orally or in the vapor state as a fumigant.

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2B3BÖ7 I

The invention, for use as an anti-juvenile hormone suitable compounds have the following general formula

Figure I.

wherein R and R are hydrogen, chlorine, bromine or fluorine atom, a straight or branched lower alkyl radical with 1 to 4 carbon atoms or a straight or branched one

p 3 Ii c. Lower alkoxy radical with 1 to 3 carbon atoms, R, R, R and R ^ a hydrogen atom, a straight or branched chain lower alkyl radical with 1 to 6 carbon atoms, a straight or branched lower alkoxy radical with 1 to 6 carbon atoms, one of the Radicals OH, -OCH ₂ OCH, -OC ₂ H ₄ OC ₂ H ₅ , -CO-OCH ₃ , -CO-OCH ₂ CH ₃ ,

0 0 0
-OCH, -OCCH ₃ , -OC-CH ₂ CH ₃ , Cl, Br, F, -SCH ₃ , -SCH ₂ CH ₃ ,

-SCH ₀ CH ₀ CH ,, -NO ₀ or the structure where R ² and

"λ ~ * P π U ¹ S
R ^ or R ^ and R or R and R ^ are linked to a -OCH ₂ O- (methylenedioxy) group or -OCHpCHp- (ethylendloxy) group and Y is 0, S or NH.

The invention also relates to a process for the preparation of the compounds of the above formula, which is characterized is that a compound of the general formula J. '

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263Bb7

where W is OH, SH or NH ₂ and R ² , R ³ , R ^ and R ^{5 have} the meaning given in Figure I, with a compound of the general formula II

R.
t

R ^x -C = CCX

where X is H, OH, Cl, Br or J and R and R have the meaning given in Figure I, in the presence of a Friedel-Crafts catalyst, such as formic acid, AlCl ,, ZnCl ₂ , polyphosphoric acid, SnCl. or other catalysts known in the art. If necessary, a suitable solvent compatible with the Friedel-Crafts catalyst can be used. Such a solvent can be, for example, ether, nitrobenzene or carbon disulfide. The reaction produces a chromanone of the general formula III

R-

.Y R

wherein the substituents have the meaning given in FIG. Heat can be added, for example by

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allowing the reaction to proceed for several hours on a steam bath, however such heating is necessary to obtain the chromanone product not always necessary.

The compounds of the formula III are reduced with any reducing agent known to the person skilled in the art, such as with Lithium aluminum hydride or sodium borohydride, in a suitable solvent such as tetrahydrofuran or ether, where a chromanol of the general formula IV is obtained

wherein the substituents have the meaning given in FIG. If following the reduction that the connections reaction mixture containing the formula IV with a Dilute acid such as hydrochloric acid, toluenesulfonic acid or other similar acids known to the person skilled in the art is carried out the dehydration of the hydroxyl group, giving the chromenes which are directly linked to the compounds of FIG correspond. If the chromanols are isolated,

direct
subsequent treatment with a catalytic amount of an acid such as toluenesulfonic acid in benzene under reflux causes dehydration to chromene.

70981 5/1203

If you compounds of the general formula I with unsaturated aldehydes of the formula II in the presence of Friedel-Crafts catalysts lets react, the desired chromenes are obtained directly.

The following examples serve to further illustrate the invention.

example 1

Synthesis of 6 _> 7-dimethoxy-2,2-dimethyl-3-chromene

10 g of 3, ¹ I-dimethoxyphenol and 7.8 g of 3 »3-dimethylacrylic acid were combined in a 125 ml Erlenmeyer flask and dissolved by addition of UO ml of anhydrous ethyl ether. The ether was removed in vacuo and, while the contents of the flask remained fluid, 50 grams of polyphosphoric acid was added. The flask and contents were placed on a steam bath and heated with stirring for 1 hour. At the end of this one hour, 75 ml of water was added and the ingredients stirred for 5 minutes until dissolved. The solution was allowed to cool and a substantially sticky precipitate formed. The aqueous layer was decanted and extracted with 100 ml of ether * The ether extract was washed successively with 150 ml of water, 100 ml of 5 # sodium carbonate and 100 ml of saturated NaCl solution. The ether extract was dried over anhydrous sodium sulfate. The sticky residue which formed on cooling was dissolved in 300 ml of chloroform and washed successively with 150 ml of water, twice 150 ml of 5% sodium carbonate solution and 150 ml of saturated NaCl solution. The chloroform solution was dried over anhydrous sodium sulfate. The essential and chloro-

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Form extracts were combined and the solvents in vacuo removed, leaving 16.17 g of off-white crystalline chromanone stayed behind.

The chromanone was dissolved in 400 ml of dry ethyl ether, and 2.5 g of lithium aluminum hydride was added in portions. The reaction was refluxed for 2 hours, they were then allowed to cool to room temperature ". The excess lithium aluminum hydride was through dropwise addition of water, and 150 ml of 4N HCl were slowly added to the reaction mixture. Stirring was continued for 15 minutes. The reaction mixture was with Ether extracted and successively with 100 ml of water, 100 ml of 5% sodium carbonate solution and 100 ml of saturated NaCl solution washed. The ether extract was dried over anhydrous sodium sulfate. The removal of the ether in a vacuum yielded 15.6 g of crude chromene.

Distillation at 4 mm gave 10 g of pure 6,7-dimethoxy-2,2-dimethy1-3-chromene, boiling point 142-144 ⁰ C. The residue remaining after the distillation residue was a Magnesiumsilikatadsorbent (Florisil) and eluted with increasing concentrations of Ether eluted in petroleum ether to give 2.2 g of additional pure chromene. The combined yield was 12.2 g or an overall yield of 79 % of the theoretical amount. The purity, determined with the aid of thin-layer and gas / liquid chromatography, was found to be over 99 %. The structure was verified by IR and NMR spectroscopy.

Another synthesis involves the reaction of a corresponding phenol with 3-methyl-2-buten-1-ol or 3-methyl-1-bromo-2-butene or 3-methyl-l-buten-3-ol in the presence of a catalyst

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tors such as formic acid, 85 # polyphosphoric acid, acetic acid or ZnCIp, which gives you the corresponding auroman. The chroman is with a dehydrating agent such as chloranil or DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone) in one suitable solvent such as benzene or xylene treated with the introduction of the double bond and formation of the corresponding Chromens.

Example 2

Synthesis of 6,7-methylenedioxy-2,2-dimethylchromene

5.1 g of 3-methyl-1-bromo-2-butene were combined with 4 g of 3,4-methylenedioxyphenol and dissolved in 50 ml of pentane and 50 ml of benzene. Two grams of anhydrous ZnCl was added and the reaction mixture refluxed for 1 hour and cooled. The mixture was extracted with ether and washed successively with 100 ml of water, 100 ml of 5 # sodium carbonate and 100 ml of saturated saline. After drying the extract over anhydrous sodium sulfate, the solvent was removed in vacuo, leaving 7.4 g of crude chromane. The material was fractionated on a column with magnesium silicate adsorbent (Florisil) and eluted with increasing concentrations of ether in petroleum ether, 4.5 g of pure chromane being obtained.

1 g of the chroman was dissolved in 75 nil benzene and 1.2 g DDQ offset. The reaction mixture was taking for 4 hours Held at reflux, then cooled and filtered. Removal of the solvent from the filtrate gave 1.35 g of the crude product. Chromatography over magnesium silicate gave 0.95 g of pure 6,7-methylenedioxy-2,2-dimethylchromene. Structure and Purity was determined by thin layer and gas / liquid chromatography and NMR spectroscopy.

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Example 3

A complementary synthesis similar to the above involves the reaction of a corresponding phenol with an allyl alcohol in the presence of formic acid, the chroman being obtained in high yield. Subsequent dehydration of this compound with Chloronil or DDQ results in the desired chromene.

Thus there were 2 g of 3,4-dimethoxyphenol and 1.9 g of 3-methyl-1-penten-3-ol combined in 10 ml of formic acid with stirring at room temperature for 18 hours. The formic acid was in vacuo removed. The residue dissolved in ether was successively with 100 ml of water, 100 ml of 5J5iger sodium carbonate and 100 ml saturated saline solution. The ether solution was dried over anhydrous sodium sulfate to give 3.5 g of des Crude product after removing the ether in vacuo. Chromatography over magnesium silicate gave 2.5 g of the pure chroman. 0.88 g of the pure chroman was dissolved in 100 ml of benzene and refluxed with 0.9 g of DDQ for 1 hour. To Cooling, filtering and removing the solvent gave the filtrate 1.1 g of the crude product, which on chromatography over magnesium silicate 0.55 g of pure 6,7-dimethoxy-2-methyl-2-ethylchromene revealed. Purity and structure were determined by thin layer and gas / liquid chromatography and by NMR spectroscopy certainly.

Example 4

The synthesis of chromenes which are not substituted in the 2-position are, was carried out by reacting the corresponding phenol with acrylonitrile under basic catalysis, wherein the phenoxypropionitrile was obtained which corresponds to the corresponding

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Phenoxypropionate was converted by treatment with acid. Ring closure to the chromanone was achieved by treatment with polyphosphoric acid and the chromene is effected by reducing the chromanone with a reagent such as lithium aluminum hydride or Sodium borohydride and subsequent treatment with acid for Promote dehydration.

Thus, 5 g of 3> 4-dimethoxy phenol, 6.88 g of acrylonitrile and 0.5 ml of N-benzyltrimethylammonium hydroxide (Triton B _s 40% solution) were combined and treated for 18 hours under reflux. After cooling, the reaction mixture was extracted with chloroform and washed with 5 # sodium hydroxide and saturated saline. After drying over anhydrous sodium sulfate and removing the solvent, the organic layer gave Ί, Ι g of 3> ^ ~ dimethoxyphenoxypropionitrile. 2.2 g of the nitrile were combined with RO ml of water and 80 ml of concentrated hydrochloric acid and treated under reflux for 2 hours. After cooling, the reaction mixture was extracted with ether and washed with water and 5% sodium hydroxide. The basic washing liquid was acidified with 6N hydrochloric acid and extracted twice with ether. The ether extract was washed twice with water and with saturated saline solution. Drying over anhydrous sodium sulfate and removing the solvent in vacuo gave 1.25 g of the crude 3 > ^ -dimethoxyphenoxypropionic acid. The crude product was combined with 5 g of polyphosphoric acid and ^{heated to 85 °} C. for 1 hour. The reaction mixture was extracted with ether and washed with IOS sodium carbonate solution and saturated salt solution. Drying over anhydrous sodium carbonate and removing the solvent gave 0.35 g of the pure 6,7-dirnethoxychromanone. The chromanone was dissolved in 50 ml of dry ether and treated with excess for 1 hour

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Treated lithium aluminum hydride under reflux. After cooling, the reaction was stopped by adding 10 ml of water and then stirred for 15 minutes with 10 ml of 2N hydrochloric acid. The reaction mixture was extracted with ether and washed with water and saturated saline solution, after drying and removing the solvent, 0.31 g pure 6,7-dimethoxychromene obtained. '

Example 5

Table I below provides a flowsheet showing the isolation of the two natural products from Ageratum, including column fractionation and thin-layer chromatography .

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TABEL

Parliamentary group 1-

Petroleum ether inactive

16 mg RF 0.74 compound

AGERATUM HOUSTONIANUM whole plants / 72 g

Homogenized in diethyl ether / acetone

1-1 (v / v)

filtered - quickly evaporated

1.0 g lipoid extract
Column chromatography (Florisil) of 0.7 g of crude lipoid

Elution with diethyl ether / petroleum ether

5% ether / petroleum ether 274 mg, active

Prop.TCL

Petroleum ether / ether / acetic acid 90-10-1

Active gangs

19 mg RF 0.17

I connection

Ether / petroleum ether
mg active

25% ether / petroleum ether inactive

Prop.TCL

Petroleum ether / ether /
acetic acid
90-10-1

1.3 mg * RP 0.17

GED purity 98% mass spectroscopy MG-190 NMR see below

combined - 20.3 mg GLC purity 98 %

Mass spectroscopy M.G. - 220 NMR see below

Comp. 1: NMR (100 MHz _{1 CCIj 1.} ); 1.38 (6Η, δ), 3.69 (3H, δ), 5.31 (lH, d, J = 10) 6.13 (lH, d, J = lO), 6, l8 (lH, 6 ), 6.21 (lH, d, J = 9), 6.7O (lH, d, J = 9)

Comp. 2: NMR (100 MHz ₁ CCl ₄ ); 1.37 (6Η, δ), 3.69 (3Η, δ), 3.74 (3H, δ), 5.52 (1H, d, J = 10), 6, H (IH, d, J = IO), 6.24 (1Η, δ), 6.39 (1Η, δ).

263B67I

Inducing premature development

The chromenes and substituted chromenes were made according to the invention synthesized and caused premature ripening when applied to immature insects. The juvenile hormone (JH) is a natural insect hormone that works to keep the developing insect immature until it is is ready to transform itself into the fully grown form or to shed its skin. When the insect begins to mature,. the insect ceases to produce JH and matures to full-blown form. It was recognized that the invention Compounds stop the action of JH and let the immature insect begin the ripening process. With some insects the induced deficiency of JH causes maturation so rapidly that the immature insect just before or during the Transformation or molting process dies. With other insects the lack of JH causes them to transform themselves into miniature adults or to cut them, whereby the immense The eating potential of the immature states is completely avoided and tiny adult insects are formed are sterile and very fragile and which die soon after skinning. The anti-juvenile hormone effect can be achieved through application by exogenous juvenile hormone, indicating that the anti-juvenile hormone compounds act to disrupt / disrupt the synthesis of juvenile hormones.

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Induction of premature ripening in milkweed beetles by lipoid extract from Ageratum

Raw lipoid extract from prematurely

r
²

p
Ageratum 'concentration of grown insects

jig /

cm

15 100

7 80

k 27.8

2 0

Control 0

Ether-acetone (l: l) extract from disrupted plant tissue e

2)
Twenty nymphs in the second manifestation were continuously exposed to the residue of the extract, which was sprayed over a 9 cm Petri dish containing milkweed seedlin and water. The insects molt into apparently normal third and fourth instar nymphs and then molt prematurely into adult insects.

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Induction of premature ripening in milkweed beetles by pure ageratochromes ^w

^ s prematurely adult

Ageratochromic insects

ug / cm ² % ²⁾

0.7 90

0.4 15

Control 0.0

1)
'Pure synthetic ageratochrome (6,7-dimethoxy-2,2-dimethyl-3-chromene). Twenty nymphs in the second instar were kept in a 9 cm petri dish with the synthetic anti-JH compound prepared according to the invention.

The insects shed their skin for the 3rd and 4th manifestations

and then molt into prematurely grown insects. sterilization

In the normal adult insect, JH (or gonadotropic hormone) is produced again after molting into the adult form and is then required for the development of the insect ovaries. The effect of JH by treatment of adult insects with the novel compounds, as described below _/ has been prevented or stopped, and the Insektenovarien not developed. If the insect ovaries were developed at the time of treatment, they quickly reverted to the undeveloped state. In any case, reproduction was prevented.

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263yb7 I.

Sterilization of insects with anti-juvenile hormone

Concentrations of synthetic ageratochrome required are to ovarian development

to prevent insect

7.0 jig / cm ' adult milkweed beetle

(Oncopeltus fasciatus)

2 2}

7.0 µg / cm · ' red bug

(Dsydercus intermedius)

1.5 ug / cm ^{2 3} ^ apple fly

(Rhagoletis pomonella)

ppm spray preparation 'spotted ladybug

(Epilachna varivestis)

'8 newly hatched adult insects were 48 hours long in a treated 9 cm petri dish. The ovaries were examined for development after 6 days.

Ten newly hatched adult insects were placed in treated 9 cm petd dishes for 72 hours. The ovaries were examined for development after 13 days.

^ * 45 newly hatched female apple flies were kept for hours in a 9 cm petri dish containing a residue of the test compound. After treatment, the flies were housed in egg-laying cages and examined for ovarian development when the control insects began to lay eggs.

^ 10 newly hatched female spotted ladybugs were sprayed with emulsified ageratochrome while feeding on a bean plant. The ovaries were dissected out and examined for development when the control insects began to lay eggs.

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Ovicidal effect

The control of embryogenesis in insect eggs by juvenile hormone is poorly understood. However, it is known to take place molting and juvenile hormones were found in certain insect eggs extracted from insect eggs, suggesting a putative role of JH during embryogenesis. The compounds according to the invention showed ovicidal effects on contact and on smoking, presumably due to disruption of JH production the insect embryo.

Ovicidal action of an anti-juvenile hormone compound a contact spray preparation on eggs. from the spotted ladybug

% Concentration of% dead

synthetic agerato- .x trained nymphs chrome in the spray preparation 'insects

100 ppm 2.7 100

10 ppm 18.4 76.7

Control 80.0 0.0

1) Four day old eggs on bean leaves were made with ageratochromes sprayed in an emulsion preparation.

Ovicidal effects of an anti-juvenile hormone compound from smoking

Concentration (mg) of synthetic ageratοchromene that is required about the hatching from the egg or the survival of insects of the 1st appearance to prevent insect

0.5 mg milkweed beetles

0.2 mg spotted ladybug

'Freshly hatched eggs were put in watch glasses that covered the Were exposed to damping of the compound located at the edge of the watch glass. A small percentage of nymphs or Larvae sometimes hatched from the eggs, but died within a few hours.

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Induction of diapause

Many insects enter a stage known as diapause in order to survive severe climatic conditions such as winter, hot dry summers, etc. Insects do not eat, mature, or reproduce during diapause. Diapause occurs in many insects when the production of JH ceases. The compounds according to the invention stop the action of JH when they are applied topically and cause the insect to go into diapause. Insects in diapause stop eating and are unable to cause crop damage, and when the diapause is extended ₃ the insects become weak and die. Induction of diapause with these anti-JH chemicals thus becomes a unique method of combating insects.

Induction of diapause in adult Colorado potato beetles

Synthetic ageratochrome topical (ug) '

Insects entering diapause ,, ^

500

250

100

control

40 38

75 0

The insects were topically applied to the abdomen with the anti-juvenile

hormone treated in 1 μζ acetone and put on potato plants growing in soil.

After 21 days it was found that the insects that had remained on the potato plants _{3 had} not entered a diapause. Insects that had fallen on the earth and become motionless were screened from the earth to find that they had entered diapause.

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Induction of premature maturation and sterilization of the milkweed beetle by anti-juvenile hormone compounds

link

1) 2

Concentration 'µg / cm

4.0

1.5

4.0

1.5

0.7

ο.

1)

20 nymphs in the 2nd instar were placed on 9 cm Petri dishes given the residue of anti-juvenile hormone compounds contained, all of which reached adulthood prematurely. Prematurely grown insects were examined for ovarian development after 5 days, which were found to be all sterile.

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Claims (6)

Patent claims: Insect control agents containing one or more chromene compounds of the general formula wherein R and RH, a straight or branched lower alkyl radical with 1 to H carbon atoms, a straight or branched lower alkoxy radical with 1 to 3 carbon atoms, Cl, Br or P ,. R, R · ⁵ , R and B? H, a straight or branched chain lower alkyl radical with 1 to 6 carbon atoms, a straight or branched chain lower alkoxy radical with 1 to 6 carbon atoms, -CO-OCH ₃ , one of the radicals OH, -OCH ₂ OCH ₃ , -C η ή Ο -CO-OCH ₂ CH, -OCH, -OCCH, -OC-CH ₂ CH ₃ , Cl, Br, F, -SCH, -SCH ₀ CH- ^, -SCH ₀ CH ₀ CH, -NO ₀ or the structure where R ^ and or R ^ and R ⁴ or and with a - or -OCHpCHp-O- group and Y mean 0, S or NH as active ingredient. 2. Means according to claim 1, characterized in that it contains 6,7-dimethoxy-2,2-dimethyl-2-chromene as an active ingredient, 709 8 15/1203 2639b7i 3 · Process for the preparation of a chromene of the general formula R ⁵ wherein R and RH, a straight or branched chain Lower alkyl radical with 1 to 4 carbon atoms, a straight or branched chain lower alkoxy radical with 1 to 3 carbon atoms, Cl, Br or F, 2 * z hc R, R, R and Br H, a straight or branched chain lower alkyl radical with 1 to 6 carbon atoms, a straight or branched chain lower alkoxy radical with 1 to 6 carbon atoms, one of the radicals OH, -OCH ₂ OCH ,, -OC ₂ H ₁₁ OC ₂ H ₅ , -CO-OCH ₅ , , 9 S -S
-CO-OCH ₂ CH, -OCH, -OCCH, -OC-CH ₂ CH ₃ , Cl, Br, F, -SCH ,, -SCH ₀ CH ,, -SCH-CH-CH ,, -N0_ or the structure where R ^ 2, 3, 2 2 5 du t- and R- ⁷ or R- * and R ⁴ or R and R ^ are connected to a -OCH ₂ O- or -OCHpCH ₂ -O group and Y is 0, S or NH, characterized in that one (a) a compound of the general formula 7 0 9 3 15/1203 263967 wherein W is OH, SH or NH and R,. R ^, R and R ^. have the preceding meaning with a Compound of the general formula,, R 0 t Il R-C = C-C-X II wherein X is H, OH, Cl, Br or J and R and R have the preceding meaning, in the presence of one Friedel-Crafts catalyst implements, (b) the resulting chromanone of the general formula III 1 ¹ ^
wherein R and R to R ^{3 have the} preceding meaning and Y is 0, S or NH, reacts with a reducing agent and (c) the resulting chromanol is treated with a dilute acid. 4. The method according to claim 3, characterized in that in Step (a) 3> ^ - Dimethoxyphenol with 3,3-dimethylacrylic acid is implemented. 5 _.; Chromene of the general formula 7 0 9 8 1 B / 1 2 0 3 263967! wherein R and R H, a straight or branched chain lower alkyl radical with 1 to 4 carbon atoms, a straight or branched chain lower alkoxy radical with 1 to 3 carbon atoms, Cl, Br or 2 3 ^ p
R} R, R and R ^ H, a straight or branched chain lower alkyl radical with 1 to 6 carbon atoms, a straight or branched chain lower alkoxy radical with 1 to 6 carbon atoms, one of the radicals OH, -OCH ₂ OCH ₃ , - OC ₂ H ₁₁ OC ₂ H ₅ , -CO-OCH ₃ , 0 0 0 -CO-OCH ₂ CH ₃ , -OCH, -OCCH ₃ , -OC-CH ₂ CH ₃ , Cl, Br, F, -SCH ₃ , -SCH ₂ CH ₃ , SCH ₂ CH ₂ CH, -NO ₂ or the Structure where R ² and R ⁵ or R ⁵ and R or R and R ⁵ with a -OCH ₂ O- or -OCH ₀ CH ₀ -O-GrUPPe are connected and Y denotes 0, S, or NH, where R, ^J and R are not both Methoxy when R ² and R ^{5 are} H, R and R ^{1 are} methyl and Y mean. 6. Chromene according to claim 5, wherein R is not methoxy when R ^{5 is} H. t 7 Π 9 R 1 5/1 ? 0 3