Abstract: The present disclosure provides methods for the separation and quantitation of enantiomers of vitamin E using supercritical fluid chromatography (SFC) or carbon dioxide-based chromatography on chiral columns. The disclosed methods may be used to quantitatively determine the concentration of RRR-?-tocopherol in foods, food ingredients, dietary supplements, vitamin premixes, nutritional formulas, and medicines. Further provided is a method of differentiating the source of ?-tocopherol as natural or synthetic.

Abstract: It discloses an iron-based montmorillonite medicine for treating hyperphosphatemia and iron deficiency anaemia, and the preparation method thereof. The medicine comprises effective ingredient iron-based montmorillonite (Fe-montmorillonite) which is obtained by soaking or eluting the medicinal montmorillonite by water soluble iron salt solution. The effective ingredient is added by pharmaceutic adjuvant or not to make medicanent which is given via gastrointestinal tract. The effective ingredient binds the phosphate in the patients' digestive tract to form insoluble matter which can be excreted from the body via the digestive tract, therefore the phosphate in the patients with chronic renal failure is reduced and the goal of treating hyperphosphatemia is achieved.

Abstract: The present invention is directed to a process for the manufacture of 2,3,5-trimethyl-hydro-p-benzoquinone comprising the following steps: a) hydrogenating 2,6-dimethyl-p-benzoquinone with hydrogen in the presence of a hydrogenation catalyst in an organic solvent to obtain 2,6-dimethyl-hydro-p-benzoquinone; b) reacting 2,6-dimethyl-hydro-p-benzoquinone with a secondary amine and formal-dehyde in an organic solvent to obtain 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone; c) reacting 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone with hydrogen in the presence of a hydrogenolysis catalyst in an organic solvent to obtain 2,3,5-trimethylhydro-p-benzoquinone; wherein the organic solvent in all steps a), b) and c) is independently selected from the group consisting of methyl tert.-butyl ether, ethyl tert.-butyl ether, methyl tert.-amyl ether, methoxycyclopentane and any mixtures thereof. Preferably the organic solvent used in all steps a), b) and c) is the same.

Abstract: The present invention is directed to a process for the manufacture of 3,7-dimethyl-1-octen-3-ol comprising the following steps: a) hydrogenation of 6-methyl-5-hepten-2-on to 6-methyl-2-heptanon in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of carbon, calcium carbonate and aluminum oxide. b) reaction of 6-methyl-2-heptanon with acetylene to 3,7-dimethyl-1-octin-3-ol in the presence of ammonia and potassium hydroxide and in the absence of any additional organic solvent; c) hydrogenation of 3,7-dimethyl-1-octin-3-ol to 3,7-dimethyl-1-octen-3-ol in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of calcium carbonate, aluminum oxide, silica, porous glass, carbon or graphite, and barium sulphate, with the proviso that the catalyst additionally contains lead when the carrier is calcium carbonate.

Abstract: The present invention is directed to a process for the manufacture of 2,3,5-trimethyl-hydro-p-benzoquinone comprising the following steps: a) hydrogenating 2,6-dimethyl-p-benzoquinone with hydrogen in the presence of a hydrogenation catalyst in an organic solvent to obtain 2,6-dimethyl-hydro-p-benzoquinone; b) reacting 2,6-dimethyl-hydro-p-benzoquinone with a secondary amine and formal-dehyde in an organic solvent to obtain 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone; c) reacting 2,6-dimethyl-3-(N,N-disubstituted aminomethyl)-hydro-p-benzoquinone with hydrogen in the presence of a hydrogenolysis catalyst in an organic solvent to obtain 2,3,5-trimethylhydro-p-benzoquinone; wherein the organic solvent in all steps a), b) and c) is independently selected from the group consisting of methyl tert.-butyl ether, ethyl tert.-butyl ether, tert.-amyl ether, methoxycyclopentane and any mixtures thereof. Preferably the organic solvent used in all steps a), b) and c) is the same.

Abstract: The present invention relates to novel processes for the manufacture of chroman derivatives such as ?-tocopherol (TCP) and alkanoates thereof, especially ?-tocopheryl acetate (TCPA), whereby at least one step of the processes is carried out in the presence of a Lewis acid or a mixture of a Lewis acid with a Bronsted acid as the catalyst under pressure, preferably at an absolute pressure of at least 1.1 bar. As starting materials for the manufacture of TCP and its alkanoates either a mixture of 2,3,5-trimethylhydroquinone (TMHQ) or 2,3,6-trimethylhydroquinone-1-alkanoate (TMHQA) and a compound selected from the group consisting of phytol (PH), isophytol (IP) and (iso)phytol derivatives or 2-phytyl-3,5,6-trimethyl-hydroquinone (PTMHQ)/3-phytyl-2,5,6-trimethylhydroquinone-1-alkanoate (PTMHQA) and/or an isomer thereof are used. Suitable Lewis acids are indium(III) salts and scandium(III) salts. Suitable acid mixtures are iron/iron(II) chloride/hydrogen chloride and zinc(II) chloride/hydrogen chloride.

Abstract: The invention relates to a process for the oxidation of mesitol with singlet oxygen, which is released from hydrogen peroxide, this release taking place in the presence of a bismuth compound as catalyst. In the process, 2,4,6-trimethylquinol is formed in high yield and selectivity as product, which can be used in further reactions for the synthesis of vitamins and in particular of vitamin A and vitamin E.

Abstract: The present invention is directed to a process for the manufacture of 3,7-dimethyl-1-octen-3-ol comprising the following steps: a) hydrogenation of 6-methyl-5-hepten-2-on to 6-methyl-2-heptanon in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of carbon, calcium carbonate and aluminum oxide. b) reaction of 6-methyl-2-heptanon with acetylene to 3,7-dimethyl-1-octin-3-ol in the presence of ammonia and potassium hydroxide and in the absence of any additional organic solvent; c) hydrogenation of 3,7-dimethyl-1-octin-3-ol to 3,7-dimethyl-1-octen-3-ol in the presence of hydrogen and a palladium containing catalyst on a carrier selected from the group consisting of calcium carbonate, aluminum oxide, silica, porous glass, carbon or graphite, and barium sulphate, with the proviso that the catalyst additionally contains lead when the carrier is calcium carbonate.

Abstract: The present invention relates to a process for the manufacture of alkenylated aromatic compounds featuring at least one hydroxy group, their ring-closure reactions to 5 chroman derivatives, as well as the acylation of the latter and the aromatic compounds featuring at least one hydroxy group themselves. The present invention relates especially to a process for the manufacture of tocol, tocopherols and their alkanoates such as (x-tocopherol (TCP) and alkanoates (TCPA) thereof, preferably (x-toeopheryl acetate (TCPAc). The processes of the present invention are characterized in that at least one step of the processes is carried out in the presence of an indium salt as the catalyst.

Abstract: The present invention is concerned with a novel process for the manufacture of 4alkanoyloxy-2,3,5-trimethylphenyl (E/Z)-phytyl ethers, precursors of ?-tocopheryl alkanoates, by cross-metathesis reaction of alkenyl ethers of 1-alkanoyloxy-2,3,6-trimethylhydroquinone with 2,6,10,14-tetramethylpentadecene or a phytol derivative, e.g. an ester, an ether or a silyl ether, in the presence of a cross-metathesis catalyst. As the crossmetathesis catalyst especially ruthenium metal carbene complexes are suitable which possess (a) ruthenium metal center(s), have an electron count of 16 or 18 and are penta- or hexa-coordinated. A further object of the invention is a process for the manufacture of ?tocopheryl alkanoates comprising this reaction.

Abstract: The present invention relates to novel processes for the manufacture of chroman derivatives such as ?-tocopherol (TCP) and alkanoates thereof, especially ?-tocopheryl acetate (TCPA), whereby at least one step of the processes is carried out in the presence of a Lewis acid or a mixture of a Lewis acid with a Bronsted acid as the catalyst under pressure, preferably at an absolute pressure of at least 1.1 bar. As starting materials for the manufacture of TCP and its alkanoates either a mixture of 2,3,5-trimethylhydroquinone (TMHQ) or 2,3,6-trimethylhydroquinone-1-alkanoate (TMHQA) and a compound selected from the group consisting of phytol (PH), isophytol (IP) and (iso)phytol derivatives or 2-phytyl-3,5,6-trimethyl-hydroquinone (PTMHQ)/3-phytyl-2,5,6-trimethylhydroquinone-1-alkanoate (PTMHQA) and/or an isomer thereof are used. Suitable Lewis acids are indium(III) salts and scandium(III) salts. Suitable acid mixtures are iron/iron(II) chloride/hydrogen chloride and zinc(II) chloride/hydrogen chloride.

Abstract: A process for the manufacture of 3-phytyl-2,5,6-trimethylhydroquinone-1-acetate, and optionally therefrom tocopheryl acetate, comprises either C-alkylating 2,3,6-trimethylhydroquinone-1-acetate with isophytol or phytol in the presence of a sulphur(VI) containing catalyst of the formula R1SO2OH, wherein R1 signifies hydroxy, halogen, lower alkyl, halogenated lower alkyl or aryl, in an aprotic organic solvent, or O-alkylating 2,3,6-trimethylhydroquinone-1-acetate with a phytyl halide in a polar aprotic organic solvent in the presence of a base, and subjecting the so-obtained 4-O-phytyl-2,3,6-trimethylhydroquinone-1-acetate to a rearrangement reaction, and in each case optionally submitting the so-obtained 3-phytyl-2,5,6-trimethylhydroquinone-1-acetate to a ring closure reaction to produce tocopheryl acetate.

Abstract: A process for the manufacture of (all-rac)-?-tocopherol by the acid-catalyzed reaction of trimethylhydroquinone with isophytol or phytol is characterized by carrying out the reaction in the presence of methane trisulphonate as the catalyst in an organic solvent. The product of the process is the most active and industrially most important member of the vitamin E group.

Abstract: The present invention is concerned with a novel process for the manufacture of ?-tocopheryl acetate which comprises reacting 2,3,6-trimethylhydroquinone-1-acetate with a compound selected from the group consisting of phytol (formula IV with R?OH), iso-phytol (formula III with R?OH), and (iso) phytol derivatives represented by the following formulae III and IV with R?C2-to C5-alkonoyloxy, benzoyloxy, mesyloxy, bezenesul-fonyloxy or tosyloxy, (IV) in the presence of a catalyst of the formula Mn+(R1SO3?)n, wherein Mn+ is a silver, copper, gallium, hafnium or rare earth metal cation, n is the valence of the cation Mn+, and R1 is fluorine, C1-8-perfluoroalkyl or perfluoroaryl, and, if required, cyclizing any 3-phytyl-2,5,6-trimethylhydroquinone-1-acetate or a double bond isomer thereof obtained as an intermediate reaction product, to produce ?-tocopheryl acetate. In the catalyst Mn+ is preferably Ag+, Cu+, Ga3+, Sc3+, Lu3+, Ho3+, Tm3+, Yb3+ or Hf4+.

Abstract: Intermediate compounds which can be used in the preparation of phytone and Vitamin E, a process for the preparation thereof, and a process for the preparation of phytone and Vitamin E from these intermediate compounds.

Abstract: The invention concerns a novel method for preparing vitamin E. More particularly, it concerns a novel method for the condensation of trimethylhydroquinone and isophytol.

Abstract: A process for the manufacture of (all-rac)-&agr;-tocopherol by the catalyzed reaction of trimethylhydroquinone with isophytol or phytol is characterized by carrying out the reaction in the presence of hydrogen tris(oxalato)phosphate, or an adduct thereof with a solvent, as the catalyst in an organic solvent. The product of the process is the most active and industrially most important member of the vitamin E group.

Abstract: The invention concerns a novel method for preparing vitamin E. More particularly, it concerns a novel method for the condensation of Arimethylhydroquinone and isophytol.

Abstract: The invention provides a method of producing &agr;-tocopherol and &agr;-tocopheryl esters. The method comprises using a biological system to produce farnesol or geranylgeraniol. Then, the farnesol or geranylgernaiol is chemically converted into &agr;-tocopherol or an &agr;-tocopheryl ester.

Abstract: The invention concerns a novel method for preparing vitamin E. More particularly, it concerns a novel method for the condensation of Arimethylhydroquinone and isophytol.

Abstract: A process for the manufacture of (all-rac)-&agr;-tocopherol by the catalyzed reaction of trimethylhydroquinone with isophytol or phytol is characterized by carrying out the reaction in the presence of hydrogen tris(oxalato)phosphate, or an adduct thereof with a solvent, as the catalyst in an organic solvent. The product of the process is the most active and industrially most important member of the vitamin E group.

Abstract: The present invention provides a process for preparing of d,l-&agr;-tocopherol by the catalyzed condensation of trimethylhydroquinone with isophytol. This process includes carrying out the condensation in the presence of bis-(trifluoromethylsulphonyl)amine [HN(SO2CF3)2] or a metal salt thereof of the formula Met (N(SO2CF3)2)n (I) as the catalyst and supercritical carbon dioxide or nitrous oxide as the solvent, wherein Met is a metal atom such as for example boron, magnesium, aluminum, silicon, scandium, titanium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, rhodium, palladium, silver, tin, lanthanum, cerium, neodymium, praseodymium, europium, dysprosium, ytterbium, hafnium, platinum and gold, and n is the corresponding valency (1, 2, 3, or 4) of the metal atom Met. A cosolvent may also be used, which is a lower aliphatic alkanol, ketone or hydrocarbon. The product of the process is the most active member of the vitamin E group.

Abstract: The present invention is a method of making (all-rac)-&agr;-tocopherol in a reaction having the following steps:

Abstract: The present invention provides a process for preparing of d,l-&agr;-tocopherol by the catalyzed condensation of trimethylhydroquinone with isophytol. This process includes carrying out the condensation in the presence of bis-(trifluoromethylsulphonyl)amine [HN(SO2CF3)2] or a metal salt thereof of the formula Met (N(SO2CF3)2)n (I) as the catalyst and supercritical carbon dioxide or nitrous oxide as the solvent, wherein Met is a metal atom such as for example boron, magnesium, aluminum, silicon, scandium, titanium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, rhodium, palladium, silver, tin, lanthanum, cerium, neodymium, praseodymium, europium, dysprosium, ytterbium, hafnium, platinum and gold, and n is the corresponding valency (1, 2, 3, or 4) of the metal atom Met. A cosolvent may also be used, which is a lower aliphatic alkanol, ketone or hydrocarbon. The product of the process is the most active member of the vitamin E group.

Abstract: A process for the production of &agr;-tocopherol acetate in a recirculating process by condensation of trimethylhydroquinone and isophytol in the presence of a catalyst system of a zinc halide and an aqueous protonic acid and, optionally, an elemental metal, in a polar solvent/water mixture extractable or miscible with water, and subsequent acylation of the resultant &agr;-tocopherol and recirculation of the catalyst system.

Abstract: A method of making (all-rac.)-&agr;-tocopherol by the acid-catalyzed condensation of trimethylhydroquinone with isophytol or phytol wherein the condensation is carried out in the presence of a tris(perfluoroalkanesulphonyl or pentafluorobenzenesulphonyl)methane or a metal salt thereof as the catalyst in an organic solvent. In addition to the metal salt, a Bronsted acid, e.g. sulfuric acid, phosphoric acid or p-toluenesulphonic acid, may be used as a co-catalyst. The product of the method of making is the most active member of the vitamin E group.

Abstract: The invention provides processes for producing phytol, isophytol, and certain phytol derivatives by a method of oxidizing or epoxidizing geranylgeraniol or geranylgeraniol derivatives to form epoxygeranylgeraniol derivatives, reducing or hydrogenating the epoxygeranylgeraniol derivatives to produce epoxyphytol derivatives, and then deoxygenating the epoxyphytol derivatives to produce phytol, isophytol, phytene derivatives, isophytene derivatives, or mixtures thereof. The step of deoxygenating is carried out in the presence of deoxygenation catalysts, including rhenium trioxide compounds. The invention also provides methods for the synthesis of certain novel substituted epoxyphytyl compounds and substituted phytene compounds having removable protecting groups.

Abstract: A process is provided for the preparation of .alpha.-tocopherol. According to the process, a condensation reaction between trimethylhydroquinone and a specific phytol derivative or isophytol is conducted in the presence of any one of the following solvents:(i) a carbonate ester;(ii) a lower fatty acid ester represented by the following formula:R.sup.1 COOR.sup.2wherein R.sup.1 means a lower alkyl group having 1-4 carbon atoms and R.sup.2 means a lower alkyl group having 1-5 carbon atoms with the proviso that methyl acetate and ethyl acetate are excluded;(iii) a mixed solvent of a nonpolar solvent and a lower alcohol having 1-5 carbon atoms; and(iv) a mixed solvent of the nonpolar solvent and the lower fatty acid ester.

Abstract: A process for preparing .alpha.-tocopherol or .alpha.-tocopheryl acetate by reacting 2,3,5-trimethylhydroquinone with isophytol or phytol in the presence of a zinc halide condensation catalyst and a proton donor in a solvent with or without subsequent esterification with acetic anhydride, which comprisesA. carrying out the reaction in a nonpolar solvent which is only slightly water-miscible, if at all andB. introducing the required zinc halide into the reaction in the form of a mixture of from 1 to 4 mol of water per mol of zinc halide.The possibility of introducing the zinc halide required in the process according to the invention in the form of a mixture of zinc halide and water which can be readily handled and metered at from 50 to 200.degree. C.

Abstract: A process for the manufacture of d,l-.alpha.-tocopherol by condensing trimethylhydroquinone with isophytol comprises carrying out the condensation in the presence of a polyperfluoroalkylenesulphonic acid as the catalyst and in a solvent, especially an aprotic solvent. The catalyst is preferably a polyperfluoroalkylenesulphonic acid from the Nafion.RTM. series, e.g., Nafion NR 50.RTM. or Nafion 117.RTM..

Abstract: A process is provided for the preparation of .alpha.-tocopherol. According to the process, a condensation reaction between trimethylhydroquinone and a specific phytol derivative or isophytol is conducted in the presence of any one of the following solvents:(i) a carbonate ester,(ii) a lower fatty acid ester represented by the following formula:R.sup.1 COOR.sup.2wherein R.sup.1 means a lower alkyl group having 1-4 carbon atoms and R.sup.2 means a lowe alkyl group having 1-5 carbon atoms with the proviso that methyl acetate and ethyl acetate are excluded;(iii) a mixed solvent of a nonpolar solvent and a lower alcohol having 1-5 carbon atoms; and(iv) a mixed solvent of the nonpolar solvent and the lower fatty acid ester.

Abstract: A process is provided for the preparation of .alpha.-tocopherol. According to the process, a condensation reaction between trimethylhydroquinone and a specific phytol derivative or isophytol is conducted in the presence of any one of the following solvents:(i) a carbonate ester,(ii) a lower fatty acid ester represented by the following formula:R.sup.1 COOR.sup.2wherein R.sup.1 means a lower alkyl group having 1-4 carbon atoms and R.sup.2 means a lower alkyl group having 1-5 carbon atoms with the proviso that methyl acetate and ethyl acetate are excluded;(iii) a mixed solvent of a nonpolar solvent and a lower alcohol having 1-5 carbon atoms; and(iv) a mixed solvent of the nonpolar solvent and the lower fatty acid ester.

Abstract: A process is provided for the preparation of an .alpha.-tocopherol derivatives which are useful as antisterile vitamins, hypolipidemics, blood flow increasing agents, anti-cytosenility agents, antioxidants and the like. Catalysts are also provided.The .alpha.-tocopherol derivatives are represented by the following formula (VII): ##STR1## wherein n stands for 0 or an integer of from 1 to 5. The derivatives can be industrially prepared by employing as catalyst a metal ion-exchanged montmorillonite, metal ion-exchanged bentonite or metal ion-exchanged saponite which is substituted with one metal ion selected from the group consisting of scandium, yttrium, lanthanide element, aluminium, iron, tin, copper, titanium, zinc, nickel, gallium or zirconium.

Abstract: A process is provided for the preparation of an .alpha.-tocopherol derivative represented by the following formula (VII): ##STR1## wherein n stands for 0 or an integer of from 1 to 5. According to the process, trimethylhydroquinone and a particular allyl alcohol derivative or a specific alkenyl alcohol are subjected to a condensation reaction in the presence of a fluorosulfonate [M(RSO.sub.3).sub.3 ], a nitrate [M(NO.sub.3).sub.3 ] or a sulfate [M.sub.2 (SO.sub.4).sub.3 ], wherein M represents a scandium, yttrium or lanthanide atom, and R represents a fluorine atom, a fluorinated lower alkyl group, or an aryl group which may be substituted by one or more fluorine atoms. The lanthanide atom means a lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium atom.

Abstract: A process for preparing .alpha.-tocopherol or tocopheryl acetate by cyclocondensation of trimethylhydroquinone with phytol or isophytol in the presence of an acid catalyst and of a solvent and, where appropriate, subsequent acetylation, which comprises carrying out the cyclocondensation and, where appropriate, the subsequent acetylation in liquid or supercritical carbon dioxide as solvent.

Abstract: A phenol, a formaldehyde and an unsaturated compound having carbon-carbon double bond are reacted in the presence of a secondary amine and an acid at a temperature of 100.degree. to 250.degree. C., to give a chroman.

Abstract: A process for preparing dl-.alpha.-tocopherol or dl-.alpha.-tocopheryl acetate by acid-catalyzed reaction of 2,3,5-trimethylhydroquinone (TMH) with phytol or isophytol in a solvent at elevated temperature, with or without subsequent esterification of the resulting tocopherol with acetic anhydride, entails the reaction being carried out in the presence of a mixture of ortho-boric acid and certain aliphatic di- or tricarboxylic acids, preferably in the presence of a mixture of ortho-boric acid and oxalic acid.

Abstract: A process for manufacturing an optically active saturated compound of the general formula (25): ##STR1## wherein R.sub.20 represents a group for protecting a hydroxy group, R.sub.21, R.sub.22, and R.sub.23 independently represent a hydrogen atom or a lower alkyl group having 1 to 4 carbon atoms, is disclosed.

Abstract: The invention relates to a process for the manufacture of vinylchromanes. This process is concerned with the manufacture of the compounds having the formula ##STR1## wherein R.sup.o is hydrogen or a cleavable protecting group, and comprises cyclizing a compound having the formula ##STR2## wherein R.sup.o is defined above and R.sup.1 is--CH.sub.2 --CH.sub.2 --C(W)(CH.sub.3)--CH.dbd.CH.sub.2 or--CH.sub.2 --CH.sub.2 C(CH.sub.3).dbd.CH--CH.sub.2 --Wwhere W is a leaving group,by means of a chiral transition metal-diphosphine complex.The compounds of formula I are useful intermediates, e.g. in the manufacture of (R,R,R)-.alpha.-tocopherol.

Abstract: An asymmetric synthesis for Vitamin E in an optically active pure form for 4-(2,5-diloweralkanoyloxy)-3,4,6-trimethylphenyl-butan-2-one and intermediates therein.

Abstract: The present invention is directed to a novel process for producing chromane derivatives, which are suitable as intermediates for the manufacture of d-.alpha.-tocopherol (natural vitamin E), and with a process for producing d-.alpha.-tocopherol itself.

Abstract: D,1-alpha-tocopherol can be prepared by reacting trimethylhydroquinone and a phytyl derivative such as phytol or isophytol in the presence of a Lewis acid, a strong acid and an amine.

Abstract: Tocopherol derivatives of the formula: ##STR1## in which X and X.sub.1, which may be identical or different, each represent hydrogen or chlorine and their acetates are useful in the synthesis of vitamin E.

Abstract: D,1-alpha-tocopherol can be prepared by reacting trimethylhydroquinone and a phytyl derivative such as phytol or isophytol in the presence of a Lewis acid, a strong acid and an amine salt of a non-oxidizing protic acid.

Abstract: A catalytic synthesis of chromans in racemic or optically active forms, including intermediates thereto; the synthesis employs an asymmetric palladium (II) catalyzed oxidative cyclization of a 2-homoallylphenol and provides intermediates useful in making chromans, especially vitamin E in racemic or optically active forms.

Abstract: There is provided a class of novel 3,4-dihydro-2H-benzopyran derivatives which either have excellent inhibitory activity against unfavorable effects of heat, light and oxidative factors or are of use as precursors of compounds having such activity, and methods for producing these derivatives. Also provided are methods of using such 3,4-dihydro-2H-benzopyran derivatives as stabilizers for organic materials sensitive to heat, light or/and oxidative factors, and organic compositions containing such stabilizers.

Abstract: Chroman derivatives of the general formula I ##STR1## where A--B is --CH.sub.2 --CH.sub.2 --(Ia), --CH.dbd.CH--(Ib), --CHOH--CH.sub.2 --(Ic) or --CO--CH.sub.2 --(Id), R.sup.1 is --CH.sub.2 --O--R' or ##STR2## where R' is C.sub.1 -C.sub.4 -alkyl or arylmethyl and R" and R'" are each C.sub.1 -C.sub.4 -alkyl, which can also be bonded to form a five-membered or six-membered cyclic acetal, R.sup.2 is C.sub.1 -C.sub.4 -alkyl and R.sup.3 is H or a protective group.

Abstract: Optically active alpha-tocopherol is synthesized by a multi-step process using phytol as a starting material. The process does not require an optical resolution step.

Abstract: A process for producing chroman, a compound of the formula, ##STR1## or an optically active compound thereof wherein R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group, which comprises reacting a compound of the formula, ##STR2## or an optically active compound thereof wherein A is an aryl group and R.sub.5 is a C.sub.1 -C.sub.4 alkyl group, with a compound of the formula, ##STR3## wherein R.sub.1 is a C.sub.1 -C.sub.3 alkyl group, X is a halogen atom and R.sub.2, R.sub.3 and R.sub.4 are as defined above, to obtain a compound of the formula, ##STR4## or an optically active compound thereof wherein A, R.sub.1, R.sub.2, R.sub.3 and R.sub.