Patent GB-850137-A (GB)
Title: A process for the manufacture of polyene carboxylic acids and esters thereof and novel polyene carboxylic acids and esters thereof
IPC: C07F9/54
Filed: 1958-08-28
Abstract: The invention comprises polyene carboxylic acids of the general formula:  <FORM:0850137/IV(b)/1> wherein the broken line signifies an optional bond, R2 and R3 alternately signify the methyl group and a hydrogen atom (commencing with the methyl group), R1 signifies a methyl group or a hydrogen atom but must be such that the sequence of R3 (or R3s) R1 and R2 (or R2s) if present is alternately methyl and hydrogen, n signifies the number 0, 1, 2 or 3 and m signifies a number which, when added to n, does not exceed 6-excepting the free acid and methyl ester of the all-ethylenic compound containing 40 carbon atoms and a process for the manufacture of polyene carboxylic acids and esters thereof which comprises converting a phosphonium halide of the general formula:  <FORM:0850137/IV(b)/2> (where n signifies the number 0, 1, 2 or 3, R1 signifies the hydrogen atom, or, where n signifies 0, a hydrogen atom or the methyl group and R2, commencing with the methyl group signifies alternately the methyl group and a hydrogen atom) into the corresponding phosphorane, condensing the latter with and aldehyde of the formula: <FORM:0850137/IV(b)/3> wherein the broken line stands for an optional bond, R3 alternately signifies the methyl group or a hydrogen atom-commencing with the methyl group-and m represents the p  number 2, 4 or 6 when R1 in the second formula above stands for the methyl group on the number 1, 3 or 5 when R1 in the third formula stands for a hydrogen atom and wherein m when added to the n of the third formula above does not exceed 6, splitting off triamyl phosphene from the adduct so formed (by heating the same if desired), partially hydrogenating the product at the triple bond and isomerising same if necessary and, if desired, hydrolysing the resulting ester.  The dots in the above formulae indicate CH3, CH2 or CH groups in carbon atoms according to whether they are associated with one, two, three or four bonds.  Phosphonium halides mentioned are (alkoxy carbonyl methyl), [a -alkoxy-carbonyl ethyl]-, [3-alkoxy carbonyl buten-2-yl-(1)], [5-alkoxycarbonyl-3-methyl-pentadien-(2, 4)-yl-(1)]-and [7-alkoxycarbonyl-3-methyl-octatrien-(2, 4, 6)-yl-(1)]-triaryl-phosphonium halides.  The phosphonium halides are converted to the corresponding phosphoranes by reaction with a metal-organic compound, e.g. phenyl lithium or an alkali metal alcoholate, e.g., sodium methylate preferably in the presence of an inert solvent, e.g., ether or ethanol or in methylene chloride with the exclusion of oxygen, or with an aqueous alkali, e.g., dilute sodium hydroxide.  The condensation of the phosphorane and aldehyde may be carried out in an inert-solvent, e.g. ether, petroleum ether, benzene, methylene chloride, dioxane or tetrahydrofurane and in an inert atmosphere.  Examples are furnished.  The compounds of the general formula given first above have vitamin-A activity. 1-Methoxycarbonyl-3-methyl-5-bromo-pentadien-(1, 3) is obtained by reacting b -acetyl-acrylic acid ethyl ester with lithium acetylide, decomposing the lithium complex, hydrogenating the product and treating the ester obtained with phosphorus trichloride. 2,6-Dimethyl-8-bromo-octatrien-(2,4, 6)-oic-(1) acid methyl ester is obtained by reacting 1-methoxy carbonyl-3-methyl-3-hydroxy pentadien-(1, 4) with dihydropyran hydrogenating the product, treating the ester with lithium aluminium hydride, oxidising the primary alcohol obtained with manganese dioxide to 4-methyl-4-tetrahydropyranyloxy-hexa-dien-(2, 5)-al-(1), reacting the latter with an (a -alkoxycarbonylethylidene)-triphenyl-phosphorane acid converting the product to 2, 6-dimethyl-8-bromooctatrien-(2, 4, 6)-oic-(1) acid methyl ester.  Aldehydes for use as starting are prepared by subjecting to alternate vinyl-alkyl ether- and propenyl-alkyl ether condensations 13-[21, 61, 61-trimethyl-cyclohexen-(11)-yl]-2, 7, 11-trimethyltridecehexaen-(2, 4, 6, 8, 10, 12)-al-(1) or 13-[21, 61, 61-trimethyl-cyclohexen-(11)-yl]-2, 7, 11-trimethyltridecapentaen-(2, 6, 8, 10, 12)-ine-(4)-al-(1) until the desired chain length is achieved.  13-[21, 61, 61-trimethyl-cyclohexen-(11)-yl]-2, 7, 11-trimethyl-tridecapentaen-(2, 6, 8, 10, 12)-ine-(4)-al-(1) is obtained by metal organic condensation of 10-[21, 61, 61-trimethyl-cyclo-hexen-(11)-yl]-4, 8-dimethyl-decatrien-4, 6, 8-ine-(1)-ol-(3) with 3-isopropoxy-2-methyl-propen-(2)-al-(1) and subsequently treating the 13-[21, 61, 61-trimethyl-cyclohexen-(11)-yl]-2, 7, 11-trimethyl-1-isopropoxy-tride caletraen-(1, 7, 9, 11)-ine-(4)-diol-(3, 6) with p-toluene-sulphonic acid. 3-Isopropoxy-2-methyl-propen-(2)-al-(1) is obtained by condensing ethyl orthoformate with propenyl ether to give 1, 1, 3, 3-tetra-ethoxy-2-methyl-propane, converting the latter to methyl malonic dialdehyde and etherifying the latter with isopropyl alcohol. Specification 813,539 is referred to.ALSO:Poultry foods comprise, as additives for pigmentation of the egg yolk, shanks, beak, skin fat and flesh, polyene carboxylic acids and esters thereof of the general formula: <FORM:0850137/I/1> wherein the broken line signifies an optional bond, R2 and R3 alternatively signify the methyl group or a hydrogen atom (commencing with the methyl group), R1 signifies a methyl group or a hydrogen atom but such that the sequence of R3 (or R3s), R1 and R2 (or R2s) if present is alternately methyl and hydrogen, n signifies the number 0, 1, 2, or 3 and m signifies a number, which, when added to n, does not exceed 6 (see Group IV(b)). The dots in the above formula indicate CH3, CH2 or CH groups or carbon atoms according to whether they are associated with one, two or three or four bonds.  Specification 813,539 is referred to.