DE1068707B - Process for the production of Cdo-carotenoids - Google Patents

Description

The subject of German patent 1 046 046 is the production of quaternary phosphonium halides by reacting hydrohalides of tertiary phosphines with alcohols. The Quaternaries available in this way Phosphonium halides can be converted into so-called phosphinylides by removing hydrogen halide and these then for the synthesis of compounds, e.g. B. the carotenoid series can be used.

It has now been found that C ₄₀ -carotenoids are obtained from alcohols and phosphine compounds without having to isolate the phosphinylides which may be formed as intermediates, if geraniol or /? - cyclogeraniol with a hydrosalt of a triarylphosphine or with triarylphosphines and a proton donor and with 2, 6, ll, 15-tetramethylhexadecaheptaen- (2,4,6,8,10, 12,14) -dial- (l, 16) or with 2,6,11,15-tetramethylhexadecahexaen- (2,4,6, 10,12,14) -in- (8) -dial- (l, 16) by means of a proton acceptor. The end products of this novel reaction are lycopene or / J-carotene or their 15,15'-dehydro derivatives.

Inorganic acids, in particular the hydrohalic acids, are primarily suitable as proton donors and the oxo acids of sulfur. In addition, all such acids are suitable as those with triarylphosphines Salts of the type

Method of manufacture
of C4o carotenoids

R- ^ PH

form. R stands for identical or different aromatic radicals, XH stands for the radical of an inorganic or strong organic acid, e.g. B. trichloroacetic acid or benzenesulfonic acid.

Suitable proton acceptors are acid-binding agents, such as alkali and alkaline earth hydroxides, alkali and Alkaline earth imides, alkali and alkaline earth alcoholates, alkali and alkaline earth enolates of ketones, ammonia and strong basic amines; Organometallic compounds can also be used.

The reaction according to this invention proceeds particularly well in solvents; one uses those that do not react with the proton acceptors and proton donors. Freedom from water the solvent is not always necessary. Solvents are, for. B. the ethers, such as tetrahydrofuran, Dimethyltetrahydrofuran, dioxane, the hydrocarbons such as benzene, toluene, xylene, cyclohexane, Cyclooctane, isooctane, the alcohols such as methanol, ethanol, isopropanol, propanol, butanol and benzyl alcohol, called; strongly polar solvents such as dimethylformamide, acetonitrile and N-methylpyrrolidone, are often particularly beneficial.

Applicant:

Aniline & Soda Factory in Baden

Corporation,

Ludwigshafen / Rhine

Dr. Horst Pomnier and Dr. Wilhelm Sarnecki,

Ludwigshafen / Rhine,
have been named as inventors

The reaction temperatures can be varied within wide limits, for example from -50 to + 100.degree. C., and depend, among other things, on the melting or boiling point of the solvent. In general, it is advantageous to work at temperatures between 0 and +50 ⁰ C and in an inert atmosphere, for. B. under nitrogen or argon.

The amounts of the starting materials are usually chosen stoichiometrically, but it can be advantageous to use the To use dioxo component to achieve a smooth implementation on both sides in deficit.

The proton acceptors are also usually added in equivalent amounts, although in excess does not interfere with the smooth course of the reaction, in some solvents it even promotes it.

If you have the new, in its reaction mechanism not yet clarified in all details, in which lycopene or / 3-carotene or their 15,15'-dehydro derivatives are built up according to the scheme C ₁₀ + C ₂₀ + C ₁₀ , with the compares running syntheses according to the same Äufbauschema z. B. in the German patent application H 27327 IVb / 12 ο (German Auslegeschrift 1 017 165), patent 971 986 and in the work of O. Isler and coworkers in HeIv. China. Acta, Vol. 39, 1956, p. 463, the advantages of this invention are readily apparent: The yields achieved with the process according to the invention are between 50 and 60%, while they are significantly lower with the known processes. The new process also requires significantly less effort and leads to better utilization of the geraniol or ß-cyclogeraniol than the known regulations, since these run over several synthesis stages. The invention, which leads from geraniol or / J-cyclogeraniol to lycopene or ^ -carotene practically in one step,

909 648/430

therefore improves the technical synthesis of these substances considerably and thus enriches technology considerably.

Lycopene and / 3-carotene, which are red in nature Pigments are very suitable dyes for food. That /? - carotene - provitamin A - is also a valuable pharmaceutical; It is also used in large quantities as an additive for animal feed used.

The parts mentioned in the examples are parts by weight. Volume parts relate to these like milliliters to grams.

example 1

30 parts of geraniol are dissolved in 250 parts by volume of dimethylformamide and 70 parts of triphenylphosphine hydrochloride are added. After stirring for 24 hours at room temperature, 18 parts of 2,6,11.15-tetramethylhexadecaheptaen- (2,4,6,8,10,12,14) -dial- (1,16) are introduced, the mixture is stirred until a clear solution is obtained and cools it down to + 10 ° C. Without further cooling, 37 parts by volume of a 30 "/ own methanolic sodium methylate solution are quickly added. The reaction mixture is stirred for a further 2 hours at room temperature and adjusted with acetic acid to a pn value of 7. After 300 parts by volume of methanol have been added dropwise, the lycopene is precipitated 20 parts of lycopene are obtained after reprecipitating twice from methylene chloride-methanol in the form of very fine red crystal needles, _{mp 170 ° C., 2 maa} . (cyclohexane) 451πιμ, ε = 110,000; 476 ηιμ, ε = 165,000; 507 ΐημ , ε = 115,000.

Example 2

30 parts of geraniol are dissolved in 250 parts of dimethylformamide and 70 parts of triphenylphosphine hydrobromide are added. After stirring for 12 hours at room temperature, 18 parts of 2,6,11,15-tetramethylhexadecahexaen- (2,4,6,10,12,14) -in- (8) -dial- (l, 16) are introduced and the mixture is stirred Mix until a clear solution. 37 parts by volume of a 30% strength methanolic sodium methylate solution are now quickly added to the dark red solution without cooling. The reaction mixture is stirred for a further 2 hours at room temperature, adjusted to pn value 7 with acetic acid and the 15,15'-dehydrolycopene is completely precipitated by adding 300 parts by volume of methanol. 18 parts are obtained. After repeated recrystallization from benzene-methanol, powder-fine, red needles are obtained. F. 185 to 186 ° C, λ max (cyclohexane) 454 and 483 ΐημ.

Example 3

30 parts of 3-cyclogeraniol are dissolved in 250 parts by volume of dimethylformamide and 70 parts of triphenylphosphine hydrobromide are added. After stirring for 12 hours at room temperature, 12 parts of 2,6,11,15-tetramethylhexadecaheptaen- (2,4,6,8,10,12,14) -dial- (1.16) are introduced and the mixture is stirred until it is clear Solution. Without cooling, is then added 37 parts by volume of 30 ° / ₀ methanolic sodium methylate solution quickly. The mixture is stirred for 1 hour at room temperature and adjusted with acetic acid to a _pH value. 7 After stirring for 1 hour at 0 ° C., the /? - carotene is completely precipitated with 250 parts by volume of methanol and then filtered off with suction. 11 parts of all-trans - /? - carotene are obtained; it is pure melting point after falling once from benzene-methanol; F. 179 to 180 ° C, l _max (cyclohexane) 454 and 482 ηιμ.

Claims (5)

Claims: 20 1. A process for the preparation of C ₄₀ carotenoids, characterized in that geraniol or /? - Cyclogeraniol with a hydrosalt of a triarylphosphine or with a triarylphosphine in counter- ^a 5 was from proton donors and with 2,6,11,15-tetramethylhexadecaheptaen- (2,4,6,8,10,12,14) -dial- (1,16) or 2,6,11,15-tetramethylhexadecahexaene - (2,4,6,10, 12,14) -in- (8) -dial- (l, 16) by means of a proton acceptor, expediently in the presence of a further organic solvent, at about -50 to + 100 ° C and the resulting reaction products lycopene or / 3-carotene or their 15,15'-dehydro derivatives isolated in a conventional manner. 2. The method according to claim 1, characterized in that one carries out the reaction in dimethylformamide undertakes. 3. The method according to claim 1 and 2, characterized in that the proton donor is inorganic Acids used. 4. The method according to claim 1 to 3, characterized in that the proton acceptor alkali and alkaline earth alcoholates or hydroxides are used. 5. The method according to claim 1, 2 and 4, characterized characterized in that triphenylphosphine hydrochloride is used as the triarylphosphine hydro salt. Legacy Patents Considered:
German Patent No. 1 046 046.