DE2652356A1 - 6-OXO-2-METHYL-HEPTA-2,4-DIENIC ACID, THEIR ESTERS AND AMIDES AND A PROCESS FOR PREPARING THE NEW COMPOUNDS - Google Patents

Description

6-Oxo-2-methyl-hepta-2,4-dienoic acid, its esters and amides and a process for the preparation of the new compounds

The invention relates to the new 6-oxo-2-methyl-hepta-2,4-dienoic acid, their esters and amides, which can be used as intermediates for numerous carotenoid syntheses, as well as a Process for their manufacture.

Carotenoid syntheses for the production of vitamins and food colors are of great economic importance. An expansion of the use, in particular corresponding (by Their relationship to vitamin A, which is physiologically harmless) food colors, were the difficult and expensive ones Manufacturing process contrary.

There was therefore the task of using as precursors for the carotenoid syntheses provide usable terpenoid intermediates which can be produced in a technically simple way.

According to the invention, this object was achieved with the provision of the new 6-oxo-2-methyl-hepta-2,4-dienoic acid and its derivatives Formula I explained below, which can be prepared very advantageously from the readily available enol acetates of the formula II.

The new terpenoids have the general formula I.

CH ₃ CH ₃

X - C - C = CH - CH = CH - C = 0 (I),

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in the

X for the radicals -OR ¹ ; -NHR ² or -NR ² R- ³ , wherein

12 " ⁷ I.

R, R and R ^ hydrogen, an aliphatic saturated hydrocarbon radical with 1 to 4 carbon atoms, a cycloaliphatic hydrocarbon radical with 5 to 12 carbon atoms, preferably 5 or 6 carbon atoms, a mononuclear araliphatic hydrocarbon radical with 1 to 6, preferably 1 to 3 carbon atoms in the aliphatic chain mean or else

1 ^! 2
R and / or R denote an aromatic hydrocarbon radical.

Of particular economic importance are compounds of Fo "-" oil I, in dor X for the radicals -OR ¹ ; -NHR ² or -NR ² R ³

12 "5
ntoiit, worm R, R and R- ^ Waooerntoff, Methyl or Ethyl mean-

2
ton and those in which R is a cyclohexyl or phenyl group.

Preferred compounds of the formula I may be mentioned as examples :

6-0xo-2-methyl-hepta-2, ^ - diene acid; 6-0xo-2-methyl-hepta-2,4-diene-acid methyl ester; 6-0xo-2-methyl-hepta-2,4-dienoic acid ethyl ester; 6-0xo-2-methyl-hepta-2,4-diene-acid propyl ester; 6-0xo-2-methyl-hepta-2,4-diene-acid butyl ester; 6-0xo-2-methyl-hepta-2, ⁱ f-diene-acid benzyl ester; 6-0xo-2-methyl-hepta-2,4-diene-acid - ^ - (2-phenyl) ethyl ester; 6-0xo-2-methyl-hepta-2,4-diene-acid-cyclohexylamide; 6-0xo-2-methyl-hepta-2 _i 4-dienoic acid anilide; 6-0xo-2-methyl-hepta-2,4-diene-acid-dimethylamide; 6-0xo-2-methyl-hepta-2,4-diene-acid-diSthylamide.

The new 6-oxo-2-methyl-hepta-2,4-dienoic acid or its derivatives of the formula I are obtained when enol acetates of the general formula II

CH_ CH-

X - C - CH - CH «CH - CH β C - O - CO - CH, (II), it J

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^ 52356

in which X has the meaning given in claim 1, at temperatures from -20 to +50 ⁰ C in water or a mixture of water and a polar organic solvent with a halogenating agent and then the halogenated ketocarboxylic acid derivatives of the general formula III obtained

Cii, CH-,

ι 3, 3

X - C - CH - CH - CH = Ch - C = 0 (III),

0 Y

in which X has the meaning given above and Y is -Cl, -Br or -J, at temperatures of ■
Reacts dehydrohalogenating agent.

or -J stands at temperatures from -20 to +80 ⁰ C with a

Some of the enol acetates of the general formula II required as starting materials are new compounds. Only the enol acetates of the formula II in which X = —OH or —NH — Y J have already been described (cf. J ₀ Chem. Soc. I960 , 1).

The starting materials of the formula II can be prepared in a simple and very advantageous manner by adding 6-acetoxy-2,6-dimethyl-cyclohexa-2,4-dienone in the presence of nucleophilic reagents such as alcohols, primary and secondary amines, ammonia or water irradiated with UV light. The irradiation in the presence of alcohols leads to the esters of the general formula II (X = OR), in the presence of primary or secondary amines to the corresponding amides of the general formula II (X = WhR,

NR R), in the presence of water to the acid of the general formula II (X = OH) and in the presence of ammonia to the amide of the general formula II (X = NH _p ). For further details on this production process, we refer to J. Chem. Soc. 1960, If.

which serves as the starting material for this process can be easily and with good yields by acetoxylation of 2,6-dimethylphenol with lead tetraacetate (cf. F. V / essely and F. Sinwel ,months.

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1950, SrL, IO55) or by pyrolysis of the 2,6-dimethyl-o-quinol acetate dimer (cf. E. Adler et al, Aota. Chem. Scand. 1960, 14, 1580).

Preferred starting materials of the formula II in the invention Procedures are for example:

ö-AoGtoxy-2-methyl-hepfca-j5j5-dienoic acid; 6-acetoxy-2-methyl-hepta-3,5-diene-acid methyl ester; 6-acetoxy-2-methyl-hepta - ^, 5-dienoic acid ethyl ester; 6-acetoxy-2-methyl-hepta- ^ 5,5-diene-acid-cyclohexylamide; o-acetoxy ^ -methyl-hepta- ^, 5-diene-acid anilide; ö-acetoxy ^ -methyl-hepta- ^ S-diene-acid-dimethylamide; w-acetoxy-2-methyl-hepta-] 5i 5-dienoic acid diethylaraidj 6-acetoxy-2-methyl-hepta - ^, 5-dienoic acid propyl ester; 6-acetoxy-2-methyl-hepta - ^, 5-dienoic acid butyl ester;

6-Acefcoxy-2-methyl-hepta-3i 5-dienoic acid benzyl ester and 6-Acetoxy-2-methyl-hepta-3i5-dienoic acid (2'-phenyl) ethyl ester.

To prepare the compounds of the formula I, the compounds of the formula II in water or in a mixture of water and a polar organic solvent, preferably in one Mixture of water and a polar organic solvent, which is soluble in water, reacted with a halogenating agent and then the halogenated ketocarboxylic acid derivatives formed in the process of formula III dehydrohalogenated with a base.

It is possible to use the intermediates that occur in this reaction sequence of the formula III by evaporation of the organic water-soluble solvent and extraction with an organic, water-immiscible solvents such as methyl chloride, chloroform, diethyl ether, benzene or toluene (see example), The products III are then subsequently treated with a base

In a preferred embodiment, however, the haloketocarboxylic acid derivatives are used III nicM; isolated, but dehydrohalogenated directly by adding bases to the reaction mixture.

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As a halogenating agent required for the conversion of the enol acetates of the formula II into haloketocarboxylic acid derivatives of the formula III are the halogens chlorine, bromine or iodine themselves as well as compounds that under the reaction conditions develop small amounts of chlorine, bromine or iodine, such as N-chlorosuccinimide, N-brorasuccinimide, N-iodosuccinimide, N-bromophthalimide, N-bromoacetamide, N-bromocaprolactam, 1,3-dibromo-5,5-dimethylhydantoin or also phenyltrimethylammonium perbromide and pyridinium hydrobromide perbromide, are suitable. Preferred halogenating agents are: N-bromosuccinimide, N-bromosuccinimide, W-iodosucciniraid, 1,3-dibromo-5,5-dimethylhydantoin.

The components can be used in a stoichiometric ratio for the halogenation of the enol acetates. But you can also use the halogenating agent in an excess of up to 100 % .

As polar organic solvents, for example methylene chloride and chloroform, as those which are soluble in water, for example dioxane, tetrahydrofuran, dimethoxyethane, alcohols or carboxylic acids with 1 to h carbon atoms, preferably 1 or 2 carbon atoms ^ or a combination of two or several of these solvents are in question.

The reaction is carried out in the cone at a temperature of -20 to +50 ⁰ C, preferably from 0 to +20 ⁰ C, and stirring is continued until acetate can no longer be detected by IR spectroscopy »

The crude products of the formula III, which are used as mixtures of conformational isomers can occur - e.g. for analytical purposes - by silica gel column chromatography (mobile phase: methylene chloride) or isolated spectroscopically pure by vacuum distillation.

Strong bases such as alkaline earth and alkali hydroxides and tertiary organic amines are suitable as dehydrohalogenating agents,

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2B5 / 35S

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Preferably used tertiary organic amines such as 1, ¹ I-Diasabicyclo [2.2.2] octane, s-collidine (2,4,6-trimethyl-pyridine), lutidine, N, IJ-dimethyl aniline, p- (II, ii-dimethylainino) pyridine, quinoline, Κ, Η-biraethylcyclohexylamine, ii-methylmorpholine, 1,5-diazabicyclo [] 4.3. ti] non-5 ~ en »1,6-diazabicyeloQ). k . ojundec-ö-en, 1,8-bis (dimethylaniino) naphthalene, in particular 1,4-diazabieyelo £ 2.2.2] octane and N-methyl-morpholine.

The dehydrohalogenating agents are expediently used in a stoichiometric amount or in an excess of up to about 200 % ; an excess of about 10 to 100 % is particularly advantageous; excess dehydrohalogenating agent must be removed again during work-up.

The dehydrohalogenation may be carried out to 8O ⁰ C in a temperature range of -20 °; Temperatures between -10 and 30 ^° C. are particularly advantageous.

The reaction mixture is worked up in the usual way Manner, e.g. by distilling off the solvent, distributing the residue between an aqueous phase and a conventional one low-boiling solvent which is poorly or immiscible with water as the organic phase, washing, drying and then Fractionating the organic phase. If haloamides are used as halogenating agents, washing is carried out the organic phase with 1 η NaOH for the purpose of removing the amide, then with 2η HCl to remove the organic base and only then with water.

The compounds of the formula I of the process according to the invention are of exceptional interest as intermediates for carotenoid syntheses. For example, one comes from 6-0xo-2-methylhepta-2,4-dienoic acid derivatives by lengthening the chain by 2 carbon atoms according to Ilüller-Cunradi and Pieroh (e.g. according to US patent 2,165,962, 1939), to 2,6-dimethyl-8-oxo-octa-2,4,6-trienoic acid derivatives.

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Uiasetsung of so obtained C ^ -AlaehycL-carbansäui'ederiva-

JLU

With the technically (e.g. according to ties BbP 1 155 126) easily accessible CRet ± iiyliaeEi) tripiienylphosphoraii one can easily and with very good yields (e.g. according to & L · ϊ /. Schuleter et al, HeIo „Chlci. Acta 1366, 41 -42 page 3 ^ 9) previously difficult to access ß-Äpo-8 * -carotinic acid cierlvates, which are used as food colors _Λ produce. These ß-Apo-S'-carotinic acid derivatives had to be prepared in a random manner by repeated Müller-Cunradi lengthening and 2 or 3 carbon atoms each (cf. O. Isler et al, HeIo. Chim. Acta 1959, 42 , Page 847).

The parts given in the following examples mean Ge-HF real parts. They relate to the volume units xirie kilograms per liter.

example 1

a) Preparation of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester

Its solution of 184.8 parts of 6-acetoxy-2,6-dimethylcyclohexa-2,4-dlenone in 2000 parts by volume of ethanol is irradiated for 5 hours under nitrogen at 0 to 5 C in a Duran glass reactor while stirring with a 900 ¥ high pressure mercury burner . After evaporation of the solvent under reduced pressure, the remaining oil (211.0 parts) is distilled under reduced pressure. L6L obtained, 5 parts of distillate of boiling point Kp ~ _{0 ±} ⁰ 90 to 10Q C.

ii ¥ spectrum in ethanol: H _qv = 233 nm; £ = 20 150.

Max

IR spectrum (film): I76O, 1735 »I665, 1375, 1225, 1165, 915 cm ~ ^x ,

b) Preparation of 6-oxo-2-methyl-hepta-2,4-dienoic acid ethyl ester

To a solution of 124 parts of the obtained 6-acetoxy-2-methylhepta-3 _{t of} 5-dlenic acid ethyl ester in 1300 parts by volume of a mixture of dimethoxyethane and water (1: 1) is added at room temperature

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temperature with cooling 86.4 parts of 5 »5-diethyl-1,3-dibromohydantoin and stir in the reaction mixture for 9 hours at room temperature Exclusion of light.

212 parts of N-methylmorpholine are then added to the solution with cooling, and the reaction mixture is then stirred for 6 hours at room temperature. For working up, pulls the dimethoxyethane off on a rotary evaporator and ate aqueous residue extracted four times with 300 parts by volume of methylene chloride. The combined organic phases are shaken twice with 100 parts by volume of 1NKOH each time, twice with 200 parts by volume of 2N HCl each time and finally washed neutral with water over Na ^ SO. dried and evaporated under reduced pressure. The clear oil that remains (101.56 parts) is distilled over a VIgreux column. Yield: 90.94 parts (corresponding to 91 % of theory). ^Kp 0.05 ^{= 86 to 100} ° ^c

IR spectrum (film): 1710, 1670, 1630, 1370, 1230, 1195, 990 cm " ¹ .

UV spectrum in C ₂ H ₅ OH: S _max = 281 nm; ^ = 26,600. Example 2

a) 6-Acetoxy-2-methyl-hepta-3,5-dienoic acid methyl ester

If you work as described in Example la), but if 6-acetoxy-2,6-dimethylcyclohexa-2,4-dienone is exposed in methanol instead of ethanol, 6-acetoxy-2-diethyl-hepta-3 is obtained , 5-dienoic acid methyl ester,
Yield: 69 % of theory

UV spectrum in ethanol: J> = 238 nm; £ = 24,500.

max s,

IR spectrum (film: 1755, 17 ^ 0, 1670 cm.

b) 6-0xo-2-methyl-hepta-2,4-dienoic acid methyl ester

If you work as described in Example 1 b), but instead of 124 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester II 6 parts of 6-acetoxy-2-methyl-hepta-3 _> 5-dienoic acid methyl

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ester, one 6-oxo-2-methyl-hepta-2 receives, ^i-l diensäuremethylester, bp "= 76 to 84 ⁰ C in a yield of 78% of theory IR spectrum (film): 1715, 1695, 1675, 1625, 1595 cm " ^1. UV spectrum in C _o H _c 0H: >>" - 282 nmj ^ = 26,200.

in the % Χ «Cl A

Example 3

a) 6-acetoxy-2-methyl-hepta-3,5-dienoic acid

If the procedure is as described in Example 1 a), but 6-acetoxy-2,6-dimethylcyclohexa-2, ^1- t-dienone is irradiated in dimethoxyethane-water instead of ethanol, 6-acetoxy-2-methyl is obtained -hepta-3,5-dienoic acid. Yield: 51 % of theory

UV spectrum in ethanol: fr _ev = 238 nmj £ = 17,350

IUcLX

(partly contains HOOC-C = CH-CH, -CH = C-OCOCH,)

ι ^ά ι J CH ₃ CHL

IR spectrum (film): 3 ^ 00 to 25ΟΟ, 1755, 1710, 1670 cm " ¹ .

b) 6-oxo-2-methyl-hepta-2,4-dienoic acid

If the procedure is as described in Example 1 b), but instead of 124 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester, 109 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid are used and the product is purified instead of distillation by column chromatography over silica gel (mobile phase toluene-methanol 99: 1), 6-oxo-2-methylhepta-2,4-dienoic acid is obtained in a yield of 1 O % of theory. IR spectrum (film): broad band at 3500-2500 cm "¹; 1715, 163Ο cm" ¹ .

Example 4

If one works as described in Example 1 a), however, the irradiation leads of 6-acetoxy-2,6-dimethylcyclohexa-2,4-dienone in dimethoxyethane-cyclohexylamide instead of ethanol, 6-acetoxy-2-methyl-hepta-3,5-dienoic acid-N-cyclohexylamide is obtained.

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265? 356

ü.z. 32 295

Yield: 52 % U ₀ Th.

UV spectrum in ethanol: ^ _max = 238 nm; ^ = 23,320,

IR spectrum (film): 3325, 1750, 1675, 1640, 1620, 1550 cm " ¹ .

If the procedure is as described in Example 1 b), but instead of 124 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester, 154 parts of 6-acetoxy-2-methylhepta-3,5-dienoic acid-iJ-cyclohexylamide are used and instead of purifying by distillation by crystallization from ether, 6-oxo-2-methyl-hepta-2,4-dienoic acid-H-cyclohexylamide is obtained in a yield of 45 % of theory. Mp. 99 to 101 ⁰ C.
IR spectrum (Nujol): 3270, 1670, 1665, 1625, 160 cm " ¹ .

UV spectrum in C ₀ H-OH: Λ _Qv = 284 ran; £ = 24,000.

c. υ max

Example 5

If you work as described in Example 1 a), however, the irradiation of 6-acetoxy-2,6-dimethylcyclohexa-2,4-dienone leads to Dimethoxyethane-diethylamine instead of ethanol gives 6-acetoxy-2-methyl-hepta-3,5-dienoic acid-N, N-diethylamide.

Yield: 41 % of theory

UV spectrum in ethanol: h = 240 nrnj £ = 24,750

Πία, Χ ^

IR spectrum (film): 176Ο, 1645 cm.

If the procedure is as described in Example 1 b), but instead of 124 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester, 139 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid-N are used , N-diethylamide and purifies instead of distillation by column chromatography on silica (eluent toluene-ethyl acetate 90:10), 6-oxo-2-methyl-hepta-2,4-dienoic acid-N, N-diethylamide is obtained in one yield of 70 % of the total IR spectrum (film): 1695, I67O, I630, 127Ο cm " ^1. UV spectrum in C Ii-OIi: ^ = 282 nmj & = I5 500.

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Example 6

a) Production of o-Oxo ^ -bromo ^ -methyl-hepta - ^ - ensaureathylester

To a solution of 11.3 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester 9.8 parts of N-bromosuccinimide are added in 350 parts by volume of dioxane-water (1: 1) at room temperature and the mixture is stirred the reaction mixture for 4 hours at room temperature with exclusion of light.

The reaction mixture is then extracted several times with methylene chloride; the organic phase is washed with water, dried and concentrated. Isolated after filtration through silica gel (5 parts) 12 g of 6-oxo-3-bromo-2-methyl-hepta-4-enoic acid ethyl ester as a yellow oil.

Yield: 12 parts (91 % of theory)
IR (film): 1720, 1670, 16000, 1175, 975 cm " ^1. UMR (COCl ₇ ): 2 diastereoisomers.

b) Preparation of 6-oxo-2-methyl-hepta-2,4-dienoic acid ethyl ester

A solution of 10 parts of 6-oxo-3-bromo-2-methyl-hepta-4-enoic acid ethyl ester and 3.2 parts of sodium hydroxide in 100 parts by volume of ethanol is stirred for 5 hours at room temperature and then for 30 minutes at 50.degree. After concentrating the solvent on a rotary evaporator, the inorganic part of the residue is dissolved in water and the crude keto ester is extracted with methylene chloride. The combined organic phases are washed neutral with water, dried and concentrated.
Yield: 6.4 parts (93 % of theory).

Example 7

6-Oxo-2-methylhepta-2,4-dienoic acid ethyl ester

To a solution of 38.0 parts of 6-acetoxy-2-methyl-hepta-3, i3-

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ethyl dienate in 400 parts by volume of dioxane-water (1: 1) 32.9 parts of N-bromosuccinimide are stirred at room temperature with cooling and the reaction mixture is stirred for a further 10 hours at room temperature with exclusion of light.

37.7 parts of 1,4-diazabicyclo2.2.2joctane are then added to the solution with cooling, the reaction mixture is stirred for 6 hours at room temperature and then extracted with 500 parts by volume of methylene chloride; the organic phase is shaken twice with 100 parts by volume of In KOH, twice with 100 parts by volume of In HCl, washed neutral with water _{, dried over Na 2} SO ₂ and evaporated under reduced pressure. The red-brown oil that remains (30.3 parts) is distilled over a Vigreux column.

Yield: 25.8 parts (84.5 % of theory)
Bp: B2 to 95 ° C / 0.05 mm Hg.

Examples 8-15

To a solution of 66 parts of 6-acetoxy-2-methyl-hepta-3,5-dienoic acid ethyl ester 57.2 parts of N-bromosuccinimide and 140 parts by volume of dioxane-water (1: 1) are added at room temperature with cooling stir the reaction mixture for another 4 1/2 hours, at room temperature with exclusion of light.

The reaction mixture is then divided into 8 equal parts and each part with the amount shown in the following table of the organic amine given in the table and then stirred for 1 1/2 hours at room temperature.

Working up is carried out as described in Example 1 b). The raw product is analyzed by gas chromatography; the results are summarized in the following table.

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example Amine . 2 ~ j octane Amine amount *
yield Parts η
/ 0 8th 1,4-diazabicyclo А2. 2 N, N-dimethylcyclohexylamine 8.17 approx 95 9 N-methylmorpholine 2,6-lutidine 7.40 approx 95 10 H, N-dimethylaniline 9.27 90 11 Quinoline 7.84 40 12th s-collidine 8.84 50 13th Sodium hydroxide 9.45 50 14th 8.84 50 15th 2.92 90

of 6-oxo-2-methyl-hepta-2,4-dienoic acid ethyl ester area %. according to GC (10 ^ iges silicone oil SE 30 via Chromosorb W)

Example Io
6-Oxo-2-methyl-hepta-2,4-dienoic acid ethyl ester

To a solution of 46.4 parts (86% strength) of 6-acetoxy-2-methyl-hepta-3,5-diensäureäthylester in 15ΟΟ parts by volume of dioxane-water (1: 1) at 0 ⁰ C is added a solution of 28 , 4 parts of bromine in 370 parts by volume of carbon tetrachloride and the reaction mixture is stirred for a further 1 hour with the exclusion of light.

Thereafter, the two-phase mixture 14.4 is grounded. Parts of solid sodium hydroxide added. Subsequently, 3 hrs. At 0 ⁰ C and then for 8 hours. Gerünrt at room temperature. The aqueous phase is extracted four times with 700 volumes of ei η methylene chloride each time; the combined, organic phases are washed neutral with water, dried and concentrated. Residue: 27.6 parts,

Purification by column chromatography (silica gel) removes unur: Starting material (C-acetoxy-2-methyl-hepta-3,5-diene-

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ethyl acid ester) and 11.3 parts of 6-oxo-2-methyl-hepta-2,4-dienoic acid ethyl ester isolated. Yield: 11.3 parts (35 % of theory)

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Claims (3)

-ψ- ο.ζ. 32 2 & 6523S6 patent claims 1. 6-Oxo-2-ffiethyl-hepta-2 _s 4-dienoic acid and derivatives of the general formula I. CH ₃ CH ₃ X - C - C = CH - CH = CH - C = 0 (I), It in which X stands for the radicals -OR ¹ , -NHR ² or -NR ² R ³ , in which R, R and R are hydrogen, an aliphatic radical having 1 to 4 carbon atoms, a cycloaliphatic radical having 5 to 12 carbon atoms, a mononuclear araliphatic Radical with 1 to 6 carbon atoms in the aliphatic chain
mean. 1 2 see chain and R and / or R an aromatic radical 2. Compounds according to formula I in claim 1, in which X is a Means hydroxyl, methoxy or ethoxy group. 3. A process for the preparation of 6-oxo-2-methyl-hepta-2, ⁱ l-dienoic acid or its derivatives of the formula I according to claim 1, characterized in that enol acetates of the general formula II CH CH X - C - CH - CH = CH - CH = C - O - C - CH, (II), ti Il J O O , has in the X as defined in claim 1 to + 5O ⁰ C in water or a mixture of water and a polar organic solvent at temperatures from -20 with a halogenating agent and then the thus obtained halogenated ketocarboxylic acid derivatives of the general formula III - 16 809820/0513 CH ₃ ~ CH ₃ " ^Ζ · ⁵² ^ 52356 t, X - CO - CH - CH - CH = CH - C = O (III), I V in which X has the meaning given in claim 1 and Y is -Cl, Br or I, at temperatures of -20 to +80 ⁰ C with a dehydrohalogenating agent. BASF Aktiengesellschaft 8098 20 / OS 1 3