DE2336980A1 - Fragrant alkoxy- and carbalkoxy-alkenes - prepd. by reacting alkenones with organometallic cpds. via intermediates and opt. hydrolysis - Google Patents

Abstract

Alkoxy- and carbalkoxy-alkenes, having pleasant characteristic odours, of formula CH2=CR1-CH2-(CH2CH2-CR3=CH)-n ch2-chr4-cr5r6-or7 (i) (where n is 0 or 1; R1 and R5 are Me; R2, R3 and R4 are H or Me; R6 is 1-4C alkyl; R7 is 1-6C alkyl or cycloalkyl opt. contg. O as an ether- or keto gp. at C atom adjacent to ether-O) are used in perfumery and cosmetics and for improving odour of industrial prods., e.g. washing powders, glues, plastic dispersions. They are starting matls. for aldehydes used in perfumery. 6-Methoxy-2, 6-dimethyl-1-heptene is used as a starting matl. in the synthetic prepn. of hormone-active insecticide "Endocon" (RTM) by hydroformylation, condensn. of 7-methoxy-3, 7-dimethyl-octan-1-al with acetone and reaction of 10-methoxy-6, 10-dimethyl-oct-3-en-2-one with carbaion of isopropoxy-carbonylmethyl-dialkyl phosphonates. (I) are prepd. by reacting an alkenone with an organo-metallic cpd. and converting the inter. obtd. directly to (I) or opt. hydrolysing the inter. to the alcohol. The alcohol is then alkylated or reacted with an enol ether or acid chloride.

Description

BASF joint stock company

Our reference: O.Z. 30 Oll Rr / Wil 6700 Ludwigshafen, 17-7-1973

Alkoxy and carbalkoxy alkenes and processes for their preparation

The invention relates to alkoxy and carbalkoxy alkenes in general Formula I.

R ¹ R ² R ⁵ R ² · "R ⁵

t t Γ I --ι ti Y-

CH ₂ = O CH4: CH ₂ -CH ₂ -O = CHJ ^ -CH ₂ -CH 0 OR '(i),

R ⁶

in which η = 0 or 1,

R ¹ and R ⁵ methyl,

2 "5 k
R, R ^ and R are hydrogen or methyl,

R ^{6 stands} for alkyl having 1 to 4 carbon atoms and · • γ

R 'for an alkyl or cycloalkyl group with up to 6 carbon atoms, those on the carbon atom adjacent to the ether oxygen May contain oxygen in the form of an ether group or an oxo group,

stands.

The new compounds are distinguished by pleasant, characteristic smells and can therefore be used for a variety of purposes in perfumery and cosmetics and for improving the odor of industrial products such as washing powders, glues, plastic dispersions and the like. They also serve as a starting material for the production of aldehydes that are important for the fragrance industry.

It has been found that the new alkoxy and carbalkoxy alkenes can be prepared in a simple manner and with good yields can, if one alkenones of the general formula II

R ¹ R ² f R ⁴ r5 CH ₂ = O CH- ^ CH ₂ -CH ₂ -C = C ^ ₅ -CH ₂ -CH C = O - (II),

in which η and Rl to R- * have the meaning given above, with an organometallic compound Me-R, in which Me stands for lithium or the magnesium-halogen radical of an original compound and R has the meaning given above for the

^84/73 509809/1171 ^{/ 2}

Intermediate of formula III

R ¹ R ² R ⁵ R ^ R ⁵ lip ii »ι

CH ₂ = O CH- "1-CH ₂ -CH ₂ -O = CHJ ^ -CH ₂ -CH C OMe (III),

R ⁶

1 6
in which η, R to R and Me have the meanings given above, and this intermediate of the formula III is converted into the compounds of the formula I either directly or, if appropriate, after hydrolysis to the corresponding alcohol by generally known methods.

The alkenones of formula II used as starting compounds are known compounds which are prepared by known methods can be. For example, alkenones of the formula II in which η = 0 are obtained by reacting alkenyl ketones with olefins (see German Offenlegungsschrift 2,155,285 and 1 964 405).

Alkenones of the formula II in which η = 1 are obtained, for example by reacting the appropriately substituted 1,7-octadien-3-ol with acetoacetic ester (cf. German Offenlegungsschrift 1 768 811).

Preferred starting compounds are alkenones of the formula II, in which η »is 0 or 1,

R ¹ , R ⁵ and R ^{5 are} methyl and

R and R are hydrogen

mean. Examples include 2-methyl-1-hepten-6-one; 2,> - dimethyl-1-hepten-6-one; 2,5-dimethyl-l-hepten-6-one and that Geranylacetone unsaturated in the 1-position.

The organometallic compounds Me-R used are alkyl magnesium chlorides, bromides and iodides with 1 to 4 carbon atoms and alkyl lithium with 1 to 4 carbon atoms. The preparation of the alkylmagnesiuohalide solutions is carried out in a known manner by reacting alkylchloride, -bronide or -iodide with magnesium in ethereal solvents such as diethyl ether, tetrahydrofuran or diethyl glycol dimethyl ether . 0.5 to 5 #, preferably 1 to 2 molar solutions are used.

509809/1171 / 3

The reaction of the Alkylmagnesiumhalogenidlösung will be within the alkenone of the formula II in manner known per se in ethereal solvents at temperatures of -20 to +80 ⁰ C, preferably a complete conversion to obtain the ketone at 35 to 65 ⁰ C., it is advisable in many cases to use about a 10 molar excess of the Grignard compound.

Alkyl lithium is obtained in a manner known per se by reacting an alkyl halide with 2 equivalents of lithium in dry ether. It is generally used in the form of a 0.5 to 5 molar solution. The reaction of the alkyl lithium with ketone II in a conventional manner by the dropwise addition of the ketone to the ethereal solution of the alkyl lithium at 0 to 35 ⁰ C.

The hydrolysis of the magnesium or lithium alcoholates of the formula III formed is carried out in the customary manner by stirring with Water. The work-up is carried out, for example, by filtration and fractional distillation of the organic phase formed.

For the preparation of alkoxyalkenes of the general formula I in which η and R to R have the meanings given above and R 'stands for an alkyl group or cycloalkyl group, the intermediate of the formula III is added to the corresponding one after hydrolysis Alcohol with a common alkylating agent.

Alkyl sulfates or alkyl tosylates, but in particular alkyl halides, may be mentioned as alkylating agents.

The reaction with alkyl halides takes place in the manner of the known Williamson ¹ see ether synthesis, which is described in more detail, for example, in Houben-Weyl, "Methods of Organic Chemistry", 4th Edition, Volume 6/3, pages 26 ff.

It is advantageous to proceed in such a way that the alcohol formed in the hydrolysis of intermediate III is mixed with excess Sodium hydride is converted into the alcoholate and the corresponding alkylating agent is added dropwise to the resulting reaction mixture.

509809/1171

The reaction is carried out at higher temperatures, preferably at temperatures from 80 to HO ^{0 C, especially when using longer-chain alkylating agents.} After the addition of the alkyl halide, the reaction mixture is generally allowed to continue to react for about 4 to 6 hours at temperatures of 80 to HO ⁰ C with stirring.

The alkylating agent is generally used in amounts of from about 1 to 1.25 moles per mole of the alcohol to be alkylated.

For the preparation of carbalkoxyalkenes of the formula I in which η and R to R have the meanings given above and R 'stands for an alkyl or cycloalkyl group with up to 6 carbon atoms, the oxygen in the form of an oxo group on the ether oxygen contains neighboring C-atom, one puts the intermediate

7 product of the formula III with an acid chloride of the formula R-Cl

7 7 7

or an acid anhydride of the formula R'-O-R 'to, where R' in the acid chloride and the acid anhydride has the meaning given above.

The reaction with an acid chloride or an acid anhydride is advantageously carried out in such a way that the intermediate product of the Formula III, preferably to an intermediate of the formula III, in which Me stands for the magnesium-halogen radical of a Grignard compound stands, at temperatures of about 0 to 80 ° C, the acid chloride or the acid anhydride slowly adds and the resultant Reaction mixture in the usual way by pouring into ice water, Separating the organic phase, drying and fractionating worked up.

The acid chloride and the acid anhydride are generally used in amounts of 1 to 1.25 moles per mole of intermediate of the formula III.

For the preparation of carbalkoxyalkenes of the formula I in which η and R to R have the meanings given above and R 'stands for an alkyl or cycloalkyl group with up to 6 carbon atoms, the additional oxygen on the carbon atom adjacent to the ether oxygen in the form of an ether group contains, stands, one puts

509809/1171

the intermediate of formula III after hydrolysis to the corresponding one Alcohol, if appropriate in the presence of small amounts of acidic catalysts, reacts with the corresponding enol ether.

The reaction with the corresponding enol ethers is advantageously carried out so that one of a dihydro-4H-pyran or a vinyl ether, preferably the III in the hydrolysis of the intermediate alcohol formed at room temperature or to an elevated to about 50 ⁰ C temperature with the molar amount in Presence of an acidic catalyst, intensively mixed for a short time. An alkali metal hydroxide solution is then added to the reaction mixture, the organic phase is separated from the inorganic phase and the organic phase is fractionated, small amounts of solid alkali metal hydroxide or CaO being added to the mixture to be distilled in order to avoid cleavage due to residues of the acidic catalyst.

The preferred enol ethers are dihydro-4H-pyran and vinyl alkyl ethers with a total of up to 6 carbon atoms.

As acidic catalysts, for example, mineral acids such as hydrochloric acid, hydrogen chloride in ether, sulfuric acid, phosphoric acid, p-toluenesulfonic acid or acidic ion exchangers as well as the salts of strong acids with weak bases, such as tin chloride, Aluminum chloride, phosphoroxy chloride or boron trifluoride can be used.

While the presence of an acidic catalyst is absolutely necessary for the reaction with dihydro-4H-pyran, the Reaction with vinyl alkyl ethers can in many cases also be carried out without the presence of acidic catalysts.

The acidic catalysts are generally used in amounts of from 0.01 to 1% by weight , based on the sum of the reaction components.

The alkoxy and carbalkoxy alkenes according to the invention can be used as fragrances in perfumery and cosmetics as well as for olfactory purposes Use to improve industrial products. Except-

509809/1171 / ⁶

they can then be used as a starting material for the production of aldehydes. For example, it is of particular importance 6-methoxy-2,6-dimethyl-l-heptene as the starting compound for the synthetic production of the horraon-like effect Insecticide Endocon. For the production of the endocone, the 6-methoxy-2,6-dimethyl-l-heptene is hydroformylated 7-methoxy-3,7-dimethyl-octan-1-al obtained in the presence of bases with acetone to give 10-methoxy-6,10-dimethyl-oct-3-en-2-one condenses, which results in a Homer reaction with the carbanion of isopropoxy-carbonylmethyl-dialkylphosphonates can be transferred into the Endocon.

example 1 Preparation of 6-methoxy-2 _J 6-dlmethyl-l-hepten

a solution prepared by reacting 142 g of methyl iodide and magnesium in the usual way 166.3 solution of a) is treated g (1 mole) methylmagnesium iodide in 500 ml ether at 20 ⁰ C gradually with 126 g (1 mol) of 2-methyl-l -hepten-6-one and works the reaction mixture by hydrolysis with water and subsequent fractional distillation of the organic phase »The yield of pure 2,6-dimethyl-l-hepten-6-ol is 91 % of theory.

b) 142 g (1 mol) of the 2,6-dimethyl-l-hepten-6-ol thus obtained are at 90 ^° C. to form a mixture of 31 # 5 g (1 * 05 mol) of an 80% suspension of Na hydride dripped in mineral oil and 300 ml of toluene. The mixture is then ^{stirred at 90 °} C. until no more Hg cleavage occurs. Then, 156.2 g (1.1 mol) of methyl iodide are added dropwise also at 90 ° C and the reaction mixture stirred for 5 hours at 90 ⁰ C. The reaction mixture is worked up by hydrolysis with water and subsequent fractional distillation of the organic phase.

The yield of pure 6-methoxy-2,6-dimethyl-1-heptene is 77 % of theory.

Bp _16-69 ° to 72 ° C; n ^ ⁵ - 1.4283;

Fragrance note: fruity, reminiscent of pomegranates.

509809/1171 ^/?

Examples 2 to 4

In the manner described in Example 1, the compounds described below are obtained:

Example 2: From 1A2 g of 2,6-dimethyl-l-hepten-6-ol with 31 * 5 g of an 80% sodium hydride suspension in mineral oil and 200 g of n-butyl iodide, 6-n-butyloxy-2, 6-dimethyl-1-heptene. Yield 75 % of theory. Kp ₁₇ = 103 to 107 ⁰ C; njp = 1.4299; Fragrance note: pine wood-like.

Example 3: From 142 g of 2,6-dimethyl-l-hepten-6-ol with 31.5 g of an 8O # Lgen Na hydride suspension in mineral oil and 230 g of n-hexyl iodine, the 6-hexyloxy-2,6- dimethyl-1-heptene. Yield 71 % of theory. Bp ₁₉ = 135 ^° C; τιψ = 1.4347; Fragrance note: Pleasant wood smell.

Example 4: From 211 g of 2,6,10-trimethyl-undeca-l, 6-dien-10-ol with 31.5 g of an 80 # strength sodium hydride suspension in mineral oil and 156.2 g of methyl iodide the 10- Methoxy-2,6,10-trimethyl-undeea-1,6-diene. Yield: 67 % of theory. ^Kp 0.3 ^{s 80 to 8l} ° ^{C; 11} D ⁵ "! Fragrance note: nerolidol-like.

Example 5 Preparation of 6-aoetoxy-2,6-dimethyl-1-heptene

A solution of 166.3 g (1 mol) of methyl magnesium iodide in 500 ml of ether, prepared in the usual way from 142 g of methyl iodide and magnesium in ether, is gradually mixed with 126 g (1 mol) of 2-methyl-l-hepten- 6-on. To the resulting Magnesiumhalogenalkoholat 112 g of acetic anhydride are added dropwise at 80 ° C and after 2 hours, stirred at 8O ⁰ C. It is then cooled to room temperature and carefully hydrolyzed with excess water. The organic phase is separated off and the aqueous phase is extracted several times with ether. The combined organic phases are used twice

509809/1 1 71

shaken with sodium bicarbonate solution, dried and then fractionated. The yield of pure 6-acetoxy-2,6-dimethyl-1-heptene is 84 # of theory.

^{Kp 0.1 =; 58} ° ^{Ci n} D ^{5 =} ! '^ 02; Fragrance note: Pear-like with a green note.

Example 6

In the manner described in Example 5, the 6-l? Ropionoxy-2,6-dimethyl-l- is obtained from 126 g of 2-methyl-l-hepten-6-one with 166.3 g of methylmagnesiurajodid and reacting with 145 g of propionic anhydride hepten in a yield of 77 % of theory. Bp ₁₀ = 92 to 94 ° Ci njp = 1.4315; Fragrance note: fruity, towards apricot.

Example 7

Preparation of (2,6-Dimethyl-1-hepten-6-yl ^ tetrahydro pyranyl ^ '-ether

A mixture of 71 g (0.5 mol) of 2,6-dimethyl-1-hepten-6-ol and 42 g (0.5 mol) of dihydro-4H-pyran is concentrated at 40 ° C under catalysis of a few drops. Sulfuric acid stirred for one hour.

The mixture is made with NaOH solution and then with water shaken out a few times, dried and fractionated over some solid NaOH.

Yield 91 % of theory.

Kp _8-117 bis 119 ° C; njp = 1.4521; Fragrance note: fruity.

Example 8

The catfish described in Example 7 is given "of 2,6-dimethyll-hepten-6-yl (I ¹ -ethoxy-l ^f -ethyl) ether from 71 g of 2,6-dimethyll-hepten-6-ol and 36 g vinyl ethyl ether. The yield is 88 % of theory.

Kp _9-95 ⁰ C; njp = 1.4293; Fragrance note: cypress-like odor.

509809/1171 ^{/ 9}

Claims (5)

Claims 1. Alkoxy and carbalkoxy alkenes of the general formula I R ¹ R ² R ⁵ R ² * R ⁵ CH ₂ = O-CH [CH ₂ -CH ₂ -C = C ^ _n -CH ₂ -CH-C-OR ⁷ '(I), R ⁶ in which η = 0 or 1 1st, R ¹ and R ⁵ methyl, R, Br and R are hydrogen or methyl, R ^{6 stands} for alkyl having 1 to 4 carbon atoms and R 'for an alkyl or cycloalkyl group with 1 to 6 carbon atoms, the additional oxygen on the carbon atom adjacent to the ether oxygen in the form of an ether group or an oxo group may contain, stands. 2. Process for the preparation of alkoxy and carbalkoxy alkenes of the general formula I. R ¹ R ² R ⁵ R ^ R ⁵ CH ₂ = O-CH £ cH ₂ -CH ₂ -C = CHJ ^ -CH ₂ -CiI C-OR ⁷ (I), R ⁶ in which η = 0 or 1, R ¹ and R ⁵ methyl,
ρ -55 Jt R, Br and R are hydrogen or methyl, R ⁶ for alkyl with 1 to. 4 carbon atoms and R 'for an alkyl or cycloalkyl group with 1 to 6 carbon atoms, which is also attached to the carbon atom adjacent to the ether oxygen May contain oxygen in the form of an ether group or an oxo group, characterized in that an alkenone of the general formula II R ¹ R ² . R ⁵ R ⁴ R ⁵ CH ₂ = O- CH- ^ CH ₂ -CH ₂ -C ^ ChJ-jj-CH ^ CH-CO (II), in which η and R to R- * have the meaning given above, with an organometallic compound Me-R, in which Me stands for lithium or the magnesium-halogen radical of an Orlgnard compound and R has the meaning given above, · to the intermediate of the formula III 50980 971171/10 RR ^ R ^ R Β / CH ₂ = O-CH- [CH ₂ -CH ₂ -C = CH] ₁ J-CH ₂ -CH-C-OMe (HI), R ⁶ in which η, R to R and Me are as defined above, and this intermediate of the formula III either directly or, if appropriate, after hydrolysis to the corresponding alcohol by generally known methods converted into the compounds of formula I. 3. The method according to claim 2 for the preparation of alkoxyalkenes of the general formula I, in which η and R to R have the meaning given in claim 2 and R 'stands for a cycloalkyl group or an alkyl group, characterized in that the intermediate of the formula III reacted after hydrolysis to the corresponding alcohol with a customary alkylating agent. 4. The method according to claim 2 for the preparation of carbalkoxyalkenes of the formula I, in which η and R to R have the meaning given in claim 2 and R ^{1 is} an alkyl or cycloalkyl group with up to 6 carbon atoms, the oxygen in the form of a Contains oxo group on the carbon atom adjacent to the ether oxygen, characterized in that the intermediate of the formula III is reacted at temperatures from 0 to 80 ° C with the acid chloride R'-Cl or the acid anhydride R'-OR ^, where R 'in the acid chloride and the acid anhydride has the meaning given above. 5. The method according to claim 2 for the preparation of alkoxyalkenes of the formula I, in which η and R to R have the meaning given in claim 2 and R 'is an alkyl or cycloalkyl group with up to 6 carbon atoms attached to the ether oxygen adjacent carbon atom additionally contains oxygen in the form of an ether group, characterized in that the intermediate product of the formula III after hydrolysis to the corresponding alcohol, optionally in the presence of acidic catalysts, to give the corresponding alcohol. with the corresponding enol ether. Corporation