- Regioselective pinacol rearrangement of unsymmetrical cyclobutane-1,2-diols
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Hydroxy-sulfone 34b, prepared as a mixture of trans and cis isomers by condensing the O-silyl derivative 18c of 2-hydroxy-2-methyl-cyclobutanone 18b-the Norrish II photocyclisation product of 2,3-pentanedione 21- and methyl phenyl sulfone 33 was found to rearrange selectively either to the cyclo-propanic β-ketosulfone 37 or the isomeric methyl ketone 38 by using, respectively, the tosyl fluoride/DBU and the DAST reagent. The potential of this methodology has been illustrated by a synthesis of phytal 1 from geranylacetone 46, and by the preparation from 3,4-hexanedione 51 and prenol 56-via the cyclopropanic β-ketosulfone 54 (X-ray)-of an advanced fragment of the juvenile hormone molecule 59.
- Gembus, Vincent,Karmazin, Lydia,Pira, Sylvain,Uguen, Daniel
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Read Online
- Stepwise hydrogenation of specific isoprenoids
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The present invention relates to a stepwise hydrogenation of specific isoprenoids of formula using a specific catalyst.
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Page/Page column 9
(2016/02/29)
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- PROCESS OF ASYMMETRIC HYDROGENATION OF KETALS AND ACETALS
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The present invention relates to a process of the asymmetric hydrogenation of a ketal of an unsaturated ketone or an acetal of an unsaturated aldehyde by molecular hydrogen in the presence of at least one chiral iridium complex. This process yields chiral compounds in a very efficient way and is very advantageous in that the amount of iridium complex can be remarkably reduced.
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Page/Page column 55; 59
(2014/07/08)
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- Structure-activity relationship of novel juvenile hormone, JHSB 3, isolated from the stink bug, Plautia stali
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The structure-activity relationship of JHSB3 isolated from the pentatomid bug, Plautia stali, was studied. Various synthetic analogs were synthesized and subjected to the juvenilizing activity tests using the last instar nymphs of P. stali. These studies indicated that the coexistence of the ester carbonyl group, two epoxides at C2,3 and C10,11 were proved to be crucial for the potent juvenilizing activity. Among the tested analogs, we found highly potent analogs in which the C6,7 double bond of JHSB3 was saturated (0.1 μg/insect). The methoxy analogs in which the epoxide moiety at C10,11 was substituted with a methoxy group exerted a moderate juvenilizing activity.
- Kaihara, Kanako,Kotaki, Toyomi,Numata, Hideharu,Ohfune, Yasufumi,Shinada, Tetsuro
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scheme or table
p. 106 - 113
(2012/02/15)
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- Cyclization of N,N-diethylgeranylamine N-oxide in one-pot operation: preparation of cyclic terpenoid-aroma chemicals
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Acid promoted cyclization of the geranylamine N-oxide (E)-4 followed by base-catalyzed intramolecular aldol condensation afforded 1-acetyl-4,4-dimethyl-1-cyclohexene (7) in one-pot operation. Reduction of 7, which possess strong fruity odor, followed by lipase-catalyzed kinetic resolution furnished the acetate (R)-26 (>49.9% yield, >99% ee) and the recovered alcohol (S)-25 (>49.9% yield, >99% ee, herbal odor).
- Takabe, Kunihiko,Yamada, Takashi,Miyamoto, Takenori,Mase, Nobuyuki
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scheme or table
p. 6016 - 6018
(2009/04/11)
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- Highly selective hydrogenation of carbon-carbon multiple bonds catalyzed by the cation [(C6Me6)2Ru2(PPh 2)H2]+: Molecular structure of [(C 6Me6)2Ru2(PPh2)(CHCHPh)H] +, a possible intermediate in the case of phenylacetylene hydrogenation
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The dinuclear cation [(C6Me6)2Ru 2(PPh2)H2]+ (1) has been studied as the catalyst for the hydrogenation of carbon-carbon double and triple bonds. In particular, [1][BF4] turned out to be a highly selective hydrogenation catalyst for olefin functions in molecules also containing reducible carbonyl functions, such as acrolein, carvone, and methyljasmonate. The hypothesis of molecular catalysis by dinuclear ruthenium complexes is supported by catalyst-poisoning experiments, the absence of an induction period in the kinetics of cyclohexene hydrogenation, and the isolation and single-crystal X-ray structure analysis of the tetrafluoroborate salt of the cation [(C6Me6)2Ru2(PPh 2)-(CHCHPh)H]+ (2), which can be considered as an intermediate in the case of phenylacetylene hydrogenation. On the basis of these findings, a catalytic cycle is proposed which implies that substrate hydrogenation takes place at the intact diruthenium backbone, with the two ruthenium atoms acting cooperatively in the hydrogen-transfer process.
- Tschan, Mathieu J.-L.,Suess-Fink, Georg,Cherioux, Frederic,Therrien, Bruno
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p. 292 - 299
(2007/10/03)
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- CLEAVAGE OF ALKYNEDIOLS
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The present invention relates to a process for the manufacture of a mixture of ketones of the formula I and II, wherein R1, R2, R3 and R4 are independently from each other C1-30-alkyl, by reacting an alkynediol of the formula III in the presence of a catalyst at a temperature of at least 500C and/or at a pressure of at most atmospheric pressure. In preferred embodiments of the invention the ketones of the formulae I and II are identical. Preferably the catalyst is a basic catalyst, most preferably selected from the group consisting of aqueous NaOH and aqueous KOH solutions, and KF on alu minium oxide. The alkynediol is most preferably selected from the group consisting of 2,6,9,13- tetramethyl-tetradeca-2, 12-dien-7-yne-6,9-diol, 2,6, 10, 13 , 17,21 -hexamethyl-docos- 11-yne-10,13-diol, 2,6,10,14,17,21,25,29-octamethyl-triacont-15-yne-14,17-diol, 3,7,10,14-tetramethyl-hexadeca-3,13-dien-8-yne-7,10-diol, 3,6-dimethyl-oct-4-yne-3,6-diol and 2,5-dimethyl-hex-3-yne-2,5-diol. Advantegeously the process of the present invention may be used in the processes for the manufacture of dehydrolinalool or dehydroisophytol to recycle at least one of the starting materials.
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Page/Page column 14
(2008/06/13)
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- ASYMMETRIC HYDROGENATION OF ALKENNES USING CHIRAL IRIDIUM COMPLEXES
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The invention relates to the (stereoselective) hydrogenation of carbon-carbon double bonds in compounds having at least one such bond, e.g., isoprenoids, non-cyclic sesquiterpenes, tocomonoenols, tocodienols, tocotrienols or derivatives thereof, as well as to the (stereoselective) hydrogenation of parts/extracts of plant oils containing such tocotrienols or derivatives thereof, in the presence of a chiral Ir complex as the catalyst, whereby preferably one stereoisomer is manufactured in an excess.
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Page/Page column 15-16; 18
(2008/06/13)
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- PROCESS FOR THE PREPARATION OF SATURATED ALIPHATIC KETONES
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Saturated aliphatic ketones, e.g. hexahydropseudoionone, may be prepared by hydrogenating an olefinically unsaturated ketone, e.g. pseudoionone in a continuous fixed-bed mode in the absence of a solvent in the presence of a catalyst comprising a noble metal deposited on a carrier.
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Page/Page column 3
(2008/06/13)
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- METHOD FOR THE PRODUCTION OF TETRAHYDROGERANYLACETONE
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The invention relates to a method for the production of tetrahydrogeranylacetone (tetrahydropseudoionone) by means of aldolcondensation of citral with acetone and subsequent hydrogenation. The invention also relates to the utilization of the tetrahydrogeranylacetone thus obtained for the production of phytol, isophytol, tocopherol and/or tocopherol derivatives. The invention further relates to methods for the production of tocopherols and/or tocopherol derivatives.
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Page/Page column 13; 14
(2008/06/13)
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- METHOD FOR THE PRODUCTION OF TETRAHYDROGERANYLACETONE
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A method for the production of tetrahydrogeranylacetone is disclosed, whereby pseudoionone, geranylacetone and/or dihydrogeranylacetone in the liquid phase, in which particles of a catalyst, for the preferential hydrogenation of carbon-carbon double bonds before carbon-oxygen double bonds, are suspended, is fed through a device along in the presence of a gas comprising hydrogen, said device preventing the transport of the catalyst particles.
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Page/Page column 7
(2008/06/13)
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- Synthesis of vitamin E analogues: Possible active forms of vitamin E
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We synthesized several vitamin E analogues containing oxygenated functional groups in place of the 8-methyl group which is common to all the natural vitamin E congeners, based on the hypothesis that the methyl group might be metabolically oxidized to produce active forms which might have specific functions other than the antioxidant function. All the vitamin E analogues examined had antioxidant activity. 8-[6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman]meth anol (1d) and 2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-6-ol (4d) showed similar activity to α-tocopherol. 6-Hydroxy-2,5,7-trimethyl-2(4,8,12-trimethyltridecanyl)chroman-8-carba ldehyde (2d) and 6-hydroxy-2,5,7-trimethyl-2-(4,8,12-trimethyltridecanyl)chroman-8-carb oxylic acid (3d) showed weaker activity than α-tocopherol, but their duration of action, especially that of 3d was considerably longer.
- Fujishima, Toshie,Kagechika, Hiroyuki,Shudo, Koichi
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- Process for preparing tertiary alkynols
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Processes for synthesizing tertiary alkynols by reacting carbonyl-group-containing compounds with alkynes in the presence of a basic catalyst are disclosed. Preferred products are 6,10,14-trimethyl-4-pentadecyn-6-ol compounds having the structure: STR1 A preferred, novel compound, 6,10,14-trimethyl-4-pentadecyne-2,6-diol, can be used in the synthesis of Vitamin E or Vitamin K1.
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- Unusually Facile Oxathioacetal Transfer Reaction: an Efficient, Highly Selective Catalytic Deprotection Protocol
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CF3SO3SiMe3-catalysed one-to-one exchange of oxathioacetals to carbonyl compounds in the presence of 4-nitrobenzaldehyde is performed efficiently at room temperature, the protocol developed provides selective and effective deprotection of oxathiolanes in the presence of thioacetals.
- Ravindranathan, T.,Chavan, Subhash P.,Varghese, Jos P.,Dantale, Shubhada W.,Tejwani, Rajkumar B.
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p. 1937 - 1938
(2007/10/02)
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- Method of preparing C-18 ketones used in the manufacture of Vitamins E and K
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Methods of forming unsaturated C-18 ketones which can be used in the synthesis of Vitamins E and K1 are disclosed. One procedure involves coupling a C-9 primary allylic halide to a carbonyl-group-containing C-9 terminal alkyne. A second, two-step procedure employs a C-4 bis allylic halide (molar excess) and a carbonyl-group-containing C-9 terminal alkyne to form a C-13 primary allylic halide. The C-13 primary allylic halide can then be converted to the desired C-18 ketone by reaction with 2-methyl-3-butyn-2-ol. Novel C-18 ketones (e.g., 14-hydroxy-6,14-dimethyl-10-methylene-5-pentadecen-7,12-diyn-2-one), C-13 allylic halides (e.g., 10-chloromethyl-6-methyl-5,10-undecadien-7-yn-2-one) and C-9 allylic halides (e.g., 6-chloromethyl-2-methyl-6-hepten-3-yn-2-ol) are formed in the process.
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- Synthesis of Phytone Using Acetylbutyrolactone
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The Grignard reagent (II) from 2-(3'-chloropropyl)-2-methyl-1,3-dioxolane on reaction with methylheptenone (I) gives the tertiary alcohol (III), which on dehydration followed by hydrogenation gives hexahydropseudoionone (V).Repetition of the same sequence of reaction on V and IV gives phytone (VII) in quantitative yield.
- Kulkarni, Sheshgiri N.,Phadke, A. S.
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p. 685 - 686
(2007/10/02)
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- A NOVEL C10 TERPENE SYNTHON : 2-METHYL-6-METHYLENE-1,3E,7-OCTATRIENE
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The reaction of a hydroxylated base with 3-chloro-2-methyl-6-methylene-1,7-octadiene in the presence of a palladium complex and a quaternary ammonium salt gives a novel tetraene : 2-methyl-6-methylene-1,3E,7-octatriene, which is a new C10 terpene synthon.A novel access to pseudo-ionone is also described.
- Mignani, G.,Morel, D.,Colleuille, Y.,Mercier, C.
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p. 2591 - 2594
(2007/10/02)
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- SILVER MEDIATED ACETYLENIC OXY COPE REARRANGEMENT
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Electrophile initiated acetylenic oxy Cope rearrangement of diversely substituted 5-Hexen-1-yn-3-ols leads to the corresponding αδ-diethylenic aldehydes or ketones in good yields with mainly the E configuration for both double bonds.Silver nitrate and Silver trifluoromethanesulfonate appear to be most suitable electrophiles for this purpose and can be used either stoichiometrically (AgTf) or catalytically (AgNO3).
- Bluthe, Norbert,Gore, Jacques,Malacria, Max
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p. 1333 - 1344
(2007/10/02)
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- Process for the preparation of α,δ-diethylenic carbonyl compounds
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α,δ-Diethylenic carbonyl compounds of the formula STR1 are made by an oxy-Cope rearrangement of an acetylenic alcohol of the formula STR2 in the presence of a catalyst based on a metal of Group Ib of the periodic table or palladium. In the formulae (I) and (II), R1, R2, R3 and R4, which may be identical or different, each denote a hydrogen atom or a hydrocarbon radical R2 and R3 being capable together of forming an alkylene radical (--CH2 --)n in which one or more carbon atoms may be substituted by one or more alkyl radicals containing 1 to 4 carbon atoms, n is 3 to 20 inclusively and R5 denotes a hydrogen atom.
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- Isolation and Structural Elucidation of Zoapatanol and Montanol, Novel Oxepane Diterpenoids from the Mexican Plant Zoapatle (Montanoa tomentosa)
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Two novel biologically active oxepane diterpenoids, zoapatanol (1) and montanol (2), have been isolated from the leaves of zoapatle (Montanoa tomentosa).A tea prepared from the plant has been used in Mexico for the past four centuries to induce menses and labor.The isolation of 1 and 2 via a variety of chromatographic and chemical procedures is described.The two title diterpenoids and related oxepanes were characterized by a variety of spectroscopic methods and chemical degradation.The structure of the major component 1 was confirmed by X-ray analysis ofa 3,8-dioxabicyclooctane derivative.
- Kanojia, Ramesh M.,Wachter, Michael P.,Levine, Seymour D.,Adams, Richard E.,Chen, R.,et al.
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p. 1310 - 1319
(2007/10/02)
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- Preparation of squalane by hydrogenolysis
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Novel 2,6,10,15,19,23-hexamethyltetracosane-10,15-diol derivatives. Such derivatives are prepared by hydrogenation of 2,6,10,15,19,23-hexamethyltetracosa-11,13-diyne-10,15-diol derivatives and used as starting materials for preparing squalane.
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