- Preparation of two diastereoisomeric decalin synthons and (-)-ambrox
-
Two diastereoisomeric decalins, (2S,4aS,5S,6R)- and (2S,4aS,5R,6R)-5-(2- hydroxyethyl)-1,1,4a,6-tetramethyldecalin-2,6-diol (5 and 6) were prepared from the degradation products of oleanolic acid. Starting from 6, (-)-ambrox (4) was synthesized.
- Xie, Yi-Peng,Li, Bo-Gang,Luo, Ying-Gang,Chen, Xiao-Zhen,Zhang, Guo-Lin
-
-
Read Online
- Manganese-Catalyzed Hydrogenation of Sclareolide to Ambradiol
-
The hydrogenation of (+)-Sclareolide to (?)-ambradiol catalyzed by a manganese pincer complex is reported. The hydrogenation reaction is performed with an air- and moisture-stable manganese catalyst and proceeds under relatively mild reaction conditions at low manganese and base loadings. A range of other esters could be successfully hydrogenated leading to the corresponding alcohols in good to quantitative yields using this easy-to-make catalyst. A scale-up experiment was performed leading to 99.3 % of the isolated yield of (?)-Ambradiol.
- Zubar, Viktoriia,Lichtenberger, Niels,Schelwies, Mathias,Oeser, Thomas,Hashmi, A. Stephen K.,Schaub, Thomas
-
-
- METHOD FOR SYNTHESISING AMBROXIDE FROM AGERATINA JOCOTEPECANA
-
The present invention is related to a process for obtaining the (?)-13,14,15,16-tetranor-8a,12-labdanediol compound from the Ageratina jocotepecana plant, the process comprises the steps of a) obtaining an organic concentrated extract from the Ageratina jocotepecana shoot system; b) subjecting the organic concentrated extract to column chromatography in order to elute a fraction with the (?)-13,14,15,16-tetranor-8a,12-labdanediol compound; c) separating the eluted fractions comprising the (?)-13,14,15,16-tetranor-8a,12-labdanediol compound; and d) evaporating the organic solvent to yield the (?)-13,14,15,16-tetranor-8a,12-labdanediol compound in a solid form.
- -
-
Paragraph 0058; 0059
(2019/02/05)
-
- A SOLID FORM OF (-)-AMBROX FORMED BY A BIOVERVERSION OF HOMOFARNESOL IN THE PRESENCE OF A BIOCATALYST
-
A solid form of (-)-Ambrox formed by a bioconversion process.
- -
-
Page/Page column 39; 40
(2017/11/15)
-
- Synthesis and Applications of Cyclohexenyl Halides Obtained by a Cationic Carbocyclisation Reaction
-
The synthesis of cyclic alkenyl halides (mainly fluorides, chlorides and bromides) from alkynol or enyne derivatives by an acid-mediated cationic cyclisation reaction is disclosed. This high-yielding, scalable and technically simple method complements and challenges conventional methodologies. This study includes the development of biomimetic cationic cyclisation reactions of polyenyne derivatives to give interesting halogen-containing polycyclic compounds. The application of this reaction in the key step of the synthesis of two terpenes, namely austrodoral and pallescensin A, and the potent odorant 9-epi-Ambrox demonstrates the potential of the reaction for natural product synthesis.
- Alonso, Pedro,Pardo, Pilar,Fontaneda, Raquel,Fa?anás, Francisco J.,Rodríguez, Félix
-
p. 13158 - 13163
(2017/09/06)
-
- A drop of the fragrant ether perfuming preparation method
-
The invention discloses a preparation method for ambrox and relates to the technical field of daily use chemicals. According to the preparation method disclosed by the invention, by taking cheap and easily available ferric trichloride as a catalyst, high quality ambrox is prepared by cyclodehydrating ambradiol in an organic solvent. In the reaction, ferric trichloride is taken as the catalyst, so that the reaction temperature is low and the reaction time is short. The method disclosed by the invention further has the advantages of being clean and environmental-friendly, low in cost of product, convenient in post-treatment, more suitable for industrial production and the like.
- -
-
Paragraph 0033-0034
(2017/08/25)
-
- Synthesis method for ambroxide
-
The invention discloses a synthesis method for ambroxide. According to the synthesis method, sclareol is used as a raw material, and under catalysis of phosphomolybdate, ambroxide is synthesized through a one-step reaction by means of peroxide oxidization. Compared with an existing method, the synthesis method includes few process steps and is free of environment pollution.
- -
-
Paragraph 0013
(2016/10/17)
-
- METHOD FOR THE CONVERSION OF ABIENOL TO SCLAREDIOL
-
A method of selective conversion of Abienol, represented by formula 1, to Sclareodial, represented by formula 2 by ozonolysis and subsequent reduction. The ozonolysis is carried out at temperatures above -60 °C, preferably in nonhalogenated solvents. R is selected from H, acetals, aminals, optionally substituted alkyl groups, such as benzyl group, carboxylates such as acetates or formates, carbonates such as methyl or ethyl carbonates, carbamates, and any protecting group which can be attached to 1 and cleaved from 2, R' is selected from CH=CH2, an alkyl moiety with C2-C20, e.g. CH2-CH3, or a cycloalkyl or polycycloalkyl moiety with C3-C20, e.g. cyclopropyl, optionally alkylated, respectively, and the wavy bond is depicting an unspecified configuration of the adjacent double bond between C2 and C3.
- -
-
-
- Preparation of Ambrox from Labdanes of Dysoxylum hongkongense, and the Preparation of New Diterpenoids from Dysoxylum hongkongense
-
The present invention discloses eight new diterpenoids, i.e. Dysongensins A to H, extracted from the leaves and twigs of Dysoxylum hongkongense, wherein AMBROX? which is applicable in the perfume industry is prepared from Dysongensin A via a series of chemical reactions, and the cytotoxicity of Dysongensins A to H against human cancer cell lines and their antiviral and anti-inflammatory activities are determined. Therefore, in the present invention, AMBROX? prepared from Dysongensin A is a new idea for application as an odorous compound in the perfume industry, and the novel diterpenoids can be prepared as a pharmaceutical compositions and/or a drug having antiviral, anti-inflammatory and/or anti-cancer activities.
- -
-
-
- IMPROVEMENTS IN OR RELATING TO ORGANIC COMPOUNDS
-
A process for the hydrogenation of a substrate comprising a carbon heteroatom double bond in the presence of a transition metal complex comprising a tridentate or bisdentate-ligand containing a nitrogen, sulphur and phosphorus atom, of which at least the N- and P- and optionally also the S-atom coordinates with the transition metal.
- -
-
Paragraph 0099
(2016/11/24)
-
- Scalable Synthesis of the Amber Odorant 9-epi-Ambrox through a Biomimetic Cationic Cyclization/Nucleophilic Bromination Reaction
-
A novel biomimetic nucleophilic bromocyclization reaction is used in the key step of a new and straightforward synthesis of 9-epi-Ambrox, an organic compound of high interest and value in the context of fragrances. This strategic reaction allows access to 9-epi-Ambrox on a gram scale from a dienyne derivative, easily available from geraniol, following a sequence of seven steps (35% global yield) with just one purification process. Both enantiomers of the molecule were obtained by a challenging enzymatic resolution.
- Fontaneda, Raquel,Alonso, Pedro,Fa?anás, Francisco J.,Rodríguez, Félix
-
supporting information
p. 4626 - 4629
(2016/09/28)
-
- Diastereoselective Synthesis of (±)-Ambrox by Titanium(III)-Catalyzed Radical Tandem Cyclization
-
A synthesis of (±)-ambrox, a compound with delicious ambergris-type scent, is presented. The key step is a highly diastereoselective titanocene(III)-catalyzed radical tandem cyclization of a farnesol derivative.
- Rosales, Antonio,Foley,Padial, Natalia M.,Muoz-Bascn, Juan,Sancho-Sanz, Iris,Roldan-Molina, Esther,Pozo-Morales, Laura,Iras-lvarez, Adriana,Rodrguez-Maecker, Roman,Rodrguez-Garca, Ignacio,Oltra, J. Enrique
-
p. 369 - 374
(2016/02/09)
-
- Synthesis and antifungal activity of ethers, alcohols, and iodohydrin derivatives of sclareol against phytopathogenic fungi in vitro
-
This study synthesized 20 sclareol derivatives. The antifungal activities of these derivatives were evaluated in vitro against five phytopathogenic fungi using the mycelium growth rate method. Among all the tested compounds, compound 16 with one iodine atom and three hydroxyl groups displayed higher fungicidal activities against all the tested phytopathogenic fungi than precursor sclareol. Compound 16 also showed more pronounced antifungal activities against Curvularia lunata (IC50 = 12.09 μg/mL) and Alternaria brassicae (IC50 = 14.47 μg/mL) than the positive control, a commercial agricultural fungicide thiabendazole.
- Ma, Miaofeng,Feng, Jili,Li, Ruoxin,Chen, Shu-Wei,Xu, Hui
-
p. 2773 - 2777
(2015/06/08)
-
- (3E, 7E)- homo- farnesol improved production method
-
The present invention relates to novel processes for improved preparation of homofarnesol, especially of (3E,7E)-homofarnesol and homofarnesol preparations having an elevated content of (3E,7E)-homofarnesol (also referred to as all-E-homofarnesol).
- -
-
Paragraph 0076-0079
(2018/12/12)
-
- IMPROVEMENTS IN OR RELATING TO ORGANIC COMPOUNDS
-
A process for the hydrogenation of a substrate comprising a carbon heteroatom double bond in the presence of a transition metal complex comprising a tridentate or bisdentate- ligand containing a nitrogen, sulphur and phosphorus atom, of which at least the N- and P- and optionally also the S-atom coordinates with the transition metal.
- -
-
Page/Page column 26; 27
(2015/08/06)
-
- Enantioselective access to (-)-Ambrox starting from β-farnesene
-
Starting from inexpensive (E)-β-farnesene (1), an eight-step enantioselective synthesis of the olfactively precious Ambrox ((-)-2a) has been performed. The crucial step is the catalytic asymmetric isomerization of (2E,6E)-N,N-diethylfarnesylamine (3) to t
- Chapuis, Christian
-
p. 197 - 214
(2014/03/21)
-
- Entropy is key to the formation of pentacyclic terpenoids by enzyme-catalyzed polycyclization
-
Polycyclizations constitute a cornerstone of chemistry and biology. Multicyclic scaffolds are generated by terpene cyclase enzymes in nature through a carbocationic polycyclization cascade of a prefolded polyisoprene backbone, for which electrostatic stabilization of transient carbocationic species is believed to drive catalysis. Computational studies and site-directed mutagenesis were used to assess the contribution of entropy to the polycyclization cascade catalyzed by the triterpene cyclase from A. acidocaldarius. Our results show that entropy contributes significantly to the rate enhancement through the release of water molecules through specific channels. A single rational point mutation that results in the disruption of one of these water channels decreased the entropic contribution to catalysis by 60 kcalmol-1. This work demonstrates that entropy is the key to enzyme-catalyzed polycyclizations, which are highly relevant in biology since 90% of all natural products contain a cyclic subunit.
- Syren, Per-Olof,Hammer, Stephan C.,Claasen, Birgit,Hauer, Bernhard
-
supporting information
p. 4845 - 4849
(2014/05/20)
-
- PROCESS FOR THE CYCLODEHYDRATION OF DIOLS AND USE THEREOF FOR THE MANUFACTURING OF AMBRAFURAN AND OTHER CYCLOETHER DERIVATIVES
-
The present invention relates to a process for manufacturing tetrahydrofuran, tetrahydropyran and, more generally, cycloether derivatives through the cyclodehydration of 1,4- or 1,5- diols. More specifically, the process of the invention involves (i) the stereoselective cyclodehydration in water of 1,4- or 1,5- diols comprising at least one chiral tertiary alcohol functional group with retention of the initial chirality, and/or (ii) the cyclodehydration in water of 1,4- or 1,5- diols, said diols being non-miscible with and/or non-soluble in water, into corresponding cycloether derivatives, by bringing the reaction mixture to high temperature water (HTW) conditions and/or by mixing the aqueous reaction mixture with a solid catalyst, such as for example a smectite clay. The present invention further relates to the use of the process of the invention for manufacturing ambrafuran, especially (-)-ambrafuran and other cycloether derivatives.
- -
-
-
- Substrate specificity of a novel squalene-hopene cyclase from Zymomonas mobilis
-
Squalene-hopene cyclases (SHC; EC 5.4.99.17) catalyze the cyclization of triterpenoids via cationic intermediates in one of the most complex reactions known in biochemistry. In this study, we report the functional expression of a novel SHC from the ethanol producing bacterium Zymomonas mobilis (ZmoSHC1; YP-163283.1). Biochemical characterization of ZmoSHC1 uncovered unique substrate activity patterns compared to the previously reported AacSHC from Alicyclobacillus acidocaldarius and ZmoSHC2, the second squalene-hopene cyclase from Z. mobilis. ZmoSHC1 showed cyclization of the non-natural substrates homofarnesol (C16) and citronellal (C10) in addition to hopene formation from squalene (C30). Moreover, ZmoSHC1 turned out to reveal high biocatalytic stability during long-term incubations. Remarkably, ZmoSHC1 exhibited a shift of activity towards substrates of shorter chain lengths, displaying over 50-fold higher conversion of homofarnesol and more than 2-fold higher conversion of citronellal in comparison to squalene conversion.
- Seitz, Miriam,Klebensberger, Janosch,Siebenhaller, Sascha,Hauer, Bernhard,Breuer, Michael,Siedenburg, Gabriele,Jendrossek, Dieter
-
p. 72 - 77,6
(2020/08/20)
-
- Synthesis of five-membered cyclic ethers by reaction of 1,4-diols with dimethyl carbonate
-
The reaction of 1,4-diols with dimethyl carbonate in the presence of a base led to selective and high-yielding syntheses of related five-membered cyclic ethers. This synthetic pathway has the potential for a wide range of applications. Distinctive cyclic ethers and industrially relevant compounds were synthesized in quantitative yield. The reaction mechanism for the cyclization was investigated. Notably, the chirality of the starting material was maintained. DFT calculations indicated that the formation of five-membered cyclic ethers was energetically the most favorable pathway. Typically, the selectivity exhibited by these systems could be rationalized on the basis of hard-soft acid-base theory. Such principles were applicable as far as computed energy barriers were concerned, but in practice cyclization reactions were shown to be entropically driven. Copyright
- Aricó, Fabio,Tundo, Pietro,Maranzana, Andrea,Tonachini, Glauco
-
experimental part
p. 1578 - 1586
(2012/10/07)
-
- Bioactive compounds with added value prepared from terpenes contained in solid wastes from the olive oil industry
-
Starting from solid wastes from two-phase olive-oil extraction, the pentacyclic triterpenes oleanolic acid and maslinic acid were isolated. These natural compounds were transformed into methyl olean-12-en-28-oate (5), which then was transformed into several seco-C-ring triterpene compounds by chemical and photolytic modifications. The triene seco-products were fragmented through several oxidative procedures to produce, simultaneously, cis- and trans-decalin derivatives, both potential synthons for bioactive compounds. The chemical behavior of the isolated fragments was investigated, and a suitable approach to several low-molecular-weight terpenes was performed. These are interesting processes for the value-addition to solid waste from the olive-oil industry.
- Parra, Andres,Lopez, Pilar E.,Garcia-Granados, Andres
-
scheme or table
p. 421 - 439
(2010/09/05)
-
- Trans-tetrahydrofurans by OH-assisted Ru-catalyzed isomerization of 2-butene-1,4-diols
-
We herein report a general method for the synthesis of 1,2-annulated trans-tetrahydrofurans by the OH-assisted Ru-catalyzed isomerization of (Z)-2-butene-1,4-diols (using Chaudret's catalyst), followed by reduction of the incipient lactol (using Et3SiH and Amberlyst 15). Alternatively, the lactol can be oxidized to the corresponding lactone (using Ikariya's catalyst). It was shown by labeling experiments that an addition/elimination pathway is (at least to some extent) operative for the isomerization reaction. Only 0.5 mol-% of Chaudret's Ru catalyst is sufficient for the rapid and stereoselective isomerization of enediols of the type shown. This allows ready access to trans-tetrahydrofurans.
- Fehr, Charles,Magpantay, Iris,Saudan, Lionel,Sommer, Horst
-
scheme or table
p. 6153 - 6156
(2010/12/29)
-
- CYCLIC ETHERS
-
A process of preparing cyclic ethers is described. The process involves the reaction of at least one organic compound such as a dioi or a polyol which it has at least one pair of hydroxyl groups separated by 4 or 5 carbon atoms, and which is capable of being converted into an ether linkage, with an organic carbonate in the presence of a base. The base is an alkoxy, a carbonate or a hydroxide base or is a mixture of such bases. At least one of the hydroxyl groups of the organic compound is not a tertiary hydroxyl group.
- -
-
Page/Page column 9; 10; 12; 13
(2009/03/07)
-
- Cerium(IV) ammonium nitrate (CAN): A very efficient reagent for the synthesis of tertiary ethers
-
Treatment of tertiary 1,4- and 1,5-diols with cerium ammonium nitrate at room temperature led to the corresponding tetrahydrofuran and tetrahydropyran derivatives in high yield-and stereoselectivity. Utilizing this methodology, manoyl oxide (25a) and a variety of fragrant compounds, such as linalool oxide (8), caparrapi oxide (12), ambrox (14) and other related amber-gris-type odorants have been synthesized; 16 examples are described. Georg Thieme Verlag Stuttgart.
- Alvarez-Manzaneda,Chaboun,Alvarez,Cabrera,Alvarez-Manzaneda,Haidour,Ramos
-
p. 1829 - 1834
(2008/02/08)
-
- PROCESS FOR THE PREPARATION OF OPTICALLY-ACTIVE COMPOUNDS
-
A method of preparing enatiomerically enriched 3a,6,6,9a-tetramethyl-dodecahydro-naphtho[2,1-b]furan, formula (I), from (E,E)- homofarnesic acid or (E)-monocyclohomofarnesic acid by (a) reacting firstly with a chiral alcohol, (b) reacting the product of (a) with an acid to cause a first cyclisation, (c) producing an alcohol by reacting the product of (b) with a reducing agent and (d) causing a second cyclisation by reacting the product of (c) with an acid. The product of this process gives a mixture of both enantiomers with one in excess.
- -
-
Page/Page column 9-14; 16-17
(2008/06/13)
-
- Internal nucleophilic termination in acid-mediated polyene cyclizations part 3. Synthetic access to didehydro and methyl didehydro analogues of (±)-ambrox
-
Treatment of the unsaturated allenic alcohols (E)-7, (Z)-7, 10, 13, and 19 with an excess of FSO3H in 2-nitropropane at -90° to -30° afforded, in 68-85% yield, diastereoisomer mixtures of racemic tricyclic ethers 14a-d and 20a-d, respectively (Schemes 3 and 5), with high stereoselectivity (see Table and Scheme 6). These stereospecific transformations represent the first reported examples of an acid-mediated polyene cyclization, in which an alkene is the initiating group and an allenic alcohol serves as the internal terminator. In close analogy to our earlier work, a nonsynchronous process is postulated, whereby the stereochemical course of cyclization is directed by the conformational structure of an intermediate cyclohexyl cation (see Schemes 3 and 6). In addition, the organoleptic properties of 14c and 20c, racemic didehydro and methyl didehydro analogues, respectively, of the known odorant Ambrox ((-)-4f), are briefly discussed.
- Snowden, Roger L.,Eichenberger, Jean-Claude,Linder, Simon,Sonnay, Philippe
-
p. 1711 - 1723
(2007/10/03)
-
- Degradation of the side chain of (-)-sclareol: A very short synthesis of nor-ambreinolide and ambrox
-
The synthesis of nor-Ambreinolide (8) from (-)-sclareol (1) was carried out by treatment with KMnO4-Ac2O and further alkaline hydrolysis. 8 was directly transformed into (-)-ambrox (11) by reduction with metal borohydride in the presence of Lewis acids.
- Barrero,Alvarez-Manzaneda,Chahboun,Arteaga
-
p. 3631 - 3643
(2007/10/03)
-
- Enantio- and diastereoselective stepwise cyclization of polyprenoids induced by chiral and achiral LBAs. A new entry to (-)-ambrox, (+)-podocarpa-8,11,13-triene diterpenoids, and (-)-tetracyclic polyprenoid of sedimentary origin
-
An enantio- and diastereoselective stepwise cyclization of polyprenoids induced by Lewis acid-assisted chiral Bronsted acids (chiral LBAs) and achiral LBAs is described. In particular, the absolute stereocontrol in the initial cyclization of polyprenoids to form an A-ring induced by chiral LBAs and the importance of the nucleophilicity of the internal terminator in polyprenoids for the relative stereocontrol in subsequent cyclization are demonstrated. (-)-Ambrox was synthesized via the enantioselective cyclization of (E,E)-homofarnesyl triethyrsily ether with triethylsilyl ether with tin(IV) chloride-coordinated (R)-2-(o-fluorobenzyloxy)-2′-hydroxy-1,1′-binaphthyl ((R)-BINOL-o-FBn) and subsequent diastereoselective cyclization with CF3CO2H·SnCl4 as key steps. Protection of (E,E)-homofarnesol by a triethylsilyl group increased the enantioselectivity of chiral LBA-induced cyclization and both the chemical yield and diastereoselectivity in the subsequent cyclization. The enantioselective cyclization of homo(polyprenyl)arenes possessing an aryl group was also induced by (R)-BINOL-o-FBn·SnCl4. Several optically active podocarpa-8,11,13-triene diterpenoids and (-)-tetracyclic polyprenoid of sedimentary origin were synthesized (75-80% ee) by the enantioselective cyclization of homo(polyprenyl)benzene derivatives induced by (R)-BINOL-o-FBn·SnCl4 and subsequent diastereoselective cyclization induced by BF3-Et2O/EtNO2 or CF3CO2H·SnCl4.
- Ishihara, Kazuaki,Ishibashi, Hideaki,Yamamoto, Hisashi
-
p. 3647 - 3655
(2007/10/03)
-
- Synthesis of Ambrox from labdanolic acid
-
A synthesis of the valuable amber-type odorant Ambrox from labdanolic acid (main diterpenoid of the acid fraction of non-polar extracts of Cistus ladaniferus L.) is reported. The conversion is based on (a) the α,β-dehydrogenation of methyl labdanolate using an organoselenium reagent, (b) subsequent oxidative degradations of the side chain, and (c) final acid-promoted cyclization of the resulting tetranorlabdan-8α,12-diol. The influence of the temperature and solvent in the cyclization of the diol with p-toluenesulfonic acid is also described. Thus, Ambrox has been obtained by a six-step procedure in 33% overall yield from methyl labdanolate.
- Castro, Juan M,Salido, Sofía,Altarejos, Joaquín,Nogueras, Manuel,Sánchez, Adolfo
-
p. 5941 - 5949
(2007/10/03)
-
- A practical synthesis of ambrox from sclareol using no metallic oxidant
-
The commercial synthesis of Ambrox is modified so that the key intermediate, the sclareolide, results from an indirect Oxidative degradation of sclareol. This method allows to greatly alleviate the waste disposal problem and to raise the overall yield of Ambrox to 75%.
- Moulines,Lamidey,Desvergnes-Breuil
-
p. 749 - 758
(2007/10/03)
-
- The synthesis of (-)-Ambrox starting from labdanolic acid
-
Iododecarboxylation of labdanolic acid (1), followed by dehydrohalogenation led to alkenes 4 and 12. Both compounds were converted into (1R,2R,4aS,8aS)-1-(2-hydroxyethyl)-2,5,5,8a-tetramethyldecahydro-2- naphthalenol (8), which was transformed via cyclization into (-)-Ambrox (9).
- Bolster, Marjon G,Jansen, Ben J.M,De Groot, Aede
-
p. 5657 - 5662
(2007/10/03)
-
- Conversion of Esters and Lactones to Ethers via Thionoesters and Thionolactones Using Reductive Radical Desulfurization
-
Various thionoesters and thionolactones are readily reduced into the corresponding ethers in high isolated yields by radical desulfuurization with organotin hydrides and Et3B under mild reaction conditions.
- Jang, Doo Ok,Song, Seong Ho,Cho, Dae Hyan
-
p. 3479 - 3488
(2007/10/03)
-
- Synthesis of decalin type chiral synthons based on enzymatic functionalisation and their application to the synthesis of (-)-ambrox and (+)-zonarol
-
Stereoselective syntheses of (-)-ambrox 2 and (+)-zonarol 3 were achieved based on the enzymatic syntheses of (8aS)- and (8aR)-decalin-type 1,3-diols 1, respectively. Non-racemic intermediates such as (8aS)-1 and (8aR)-1 were obtained based on the enantioselective hydrolyses of the phenolic acetal derivative (±)-7 by acylase I.
- Akita, Hiroyuki,Nozawa, Masako,Shimizu, Hiroyo
-
p. 1789 - 1799
(2007/10/03)
-
- Resolution of sclareolide as a key intermediate for the synthesis of Ambrox
-
Sclareolide was efficiently resolved by a diastereomeric salt formation method using homochiral erythro-2-amino-1,2-diphenylethanol (ADPE) as a resolving agent.
- Koga, Tsukasa,Aoki, Yoshio,Hirose, Takuji,Nohira, Hiroyuki
-
p. 3819 - 3823
(2007/10/03)
-
- Synthesis of d,l-Norlabdane Oxide and Related Odorants: An Intramolecular Radical Approach
-
A cascade radical approach to d,l-norlabdane oxide and related odorants is reported. Oxidative radical cyclization of polyene 4 with Mn(III) and Cu(II) afforded exclusively bicycle 3, which upon acid treatment gave tricycle 2 possessing the norlabdane oxide skeleton with a modified A-ring system. Tricycle 2 was ultimately converted to d, l-norlabdane oxide 1 and to several new A-ring labdane oxides as potential odorants.
- Zoretic, Phillip A.,Fang, Haiquan,Ribeiro, Anthony A.
-
p. 4779 - 4785
(2007/10/03)
-
- The chemistry of thujone. XX. New enantioselective syntheses of Ambrox and epi-Ambrox
-
The development of a new synthetic approach to (-)-Ambrox (37) and epi-Ambrox (29) using thujone (1) as a chiral synthon, is presented. Thujone (1), a readily available starting material obtained from Western red cedar, can be efficiently converted to β-cyperone (2) and the latter is then chemically elaborated to the key intermediate, the enone 6. A carbonyl transposition of 6 to enone 9 also allows a formal synthesis of (-)-Polywood (18).
- Kutney, James P.,Cirera, Carles
-
p. 1136 - 1150
(2007/10/03)
-
- Oxidative degradation of the sclareol side chain: hemisyntheses of ambergris derivatives using in the key steps palladium complexes or ruthenium tetroxide generated in situ
-
We report the hemisyntheses of various ambergris-type derivatives: ambraoxide 4, Ambrox 8, 13-methylambraoxide 13, ambraketal 14, norambraketal 15, non-norambraketal 16 and dioxepane 53.Sclareol 12 is used as starting material because it is currently available from Salvia sclarea.The key steps involve an oxidative degradation of the sclareol 12 side chain, using either palladium complexes or ruthenium tetroxide generated in situ. - Keywords: sclareol; Ambrox; ambraoxide; 13-methylambraoxide; ambraketal; norambraketal; nor-norambraketal; farnesylic aldehyde; palladium complex; ruthenium tetroxide generated in situ; oxidative degradation
- Zahra, Jean-Pierre,Chauvet, Frederic,Coste-Maniere, Ivan,Martres, Paul,Perfetti, Patricia,Waegell, Bernard
-
p. 1001 - 1024
(2007/10/03)
-
- Practical synthesis of Ambrox from farnesyl acetate involving lipase catalyzed resolution
-
Enantiomerically pure Ambrox was synthesized from (-)-13,14,15,16- tetranor-8α,12-labdanediol, which was prepared by lipase catalyzed kinetic resolution of (±)-drimane-8,11-diol.
- Tanimoto, Hisahide,Oritani, Takayuki
-
p. 1695 - 1704
(2007/10/03)
-
- The chemistry of thujone. XVII. The synthesis of ambergris fragrances and related analogues
-
A strategy to utilize the thujone-derived enone 1 for the development of a synthetic route to ambergris fragrances is presented.Thujone (8) is transformed to the tricyclic enone 9, via the Robinson annulation reaction, and the latter is then elaborated to the cis-fused tricyclic intermediates 10, 11, and 12.Extrusion of the isopropyl side chain in 12 is achieved through an initial ozonation reaction and the resulting ketone 14 is then treated with m-CPBA to afford 16.Cyclopropyl ring opening in 16 is performed via initial saponification to the alcohol 17 and the latter is then reacted with FeCl3 and sodium acetate to enone 1.The necessary elaboration of a tetrahydrofuran ring attached to ring B of 1 is achieved through reaction of 1 with vinylmagnesium bromide, alkylation, hydroboration, and final acid-catalyzed ring closure of the 1,5-diol 4.The route affords the opportunity of synthesizing a variety of analogues within the Ambrox series.
- Kutney, James P.,Chen, Yong-Huang
-
p. 1570 - 1581
(2007/10/02)
-
- Total Synthesis of (-)-Ambrox from S-(+)-Carvone (part 6)
-
Conjugate addition of cyanide and allyl nucleophiles to S-(+)-carvone followed by annulation with methyl vinyl ketone gave the substituted decalones 2 and 3 stereoselectively.Both decalones were transformed into (-)-Ambrox via modification of the sidechain, methylation, conversion of the isopropenyl group and cyclization.
- Verstegen-Haaksma, Anja A.,Swarts, Henk J.,Jansen, Ben J. M.,Groot, Aede de
-
p. 10095 - 10106
(2007/10/02)
-
- Amber-type odorants from communic acids
-
A mixture of the methyl esters of communic acids (3b, 4b, 5b) was used in the synthesis of the ambergris-type odorants Ambrox (1) and ambracetal (2). Both syntheses involve methyl ketone 7 as the key intermediate.
- Barrero, Alejandro F.,Altarejos, Joaquin,Alvarez-Manzaneda, Enrique J.,Ramos, Jose M.,Salido, Sofia
-
p. 9525 - 9534
(2007/10/02)
-
- Synthesis of Ambrox from communic acids
-
Two routes for preparing Ambrox (1) from the methyl esters of trans-communic acid (2b) and/or cis-communic acid (3b), via selective degradation of their side chains, stereoselective formation of the tetrahydrofurane ring, and reduction of the axial methoxycarbonyl group, are described.
- Barrero, Alejandro F.,Altarejos, Joaquin,Alvarez-Manzaneda, Enrique J.,Ramos, Jose M.,Salido, Sofia
-
p. 6251 - 6262
(2007/10/02)
-
- Synthesis of Ambrox from (-)-sclareol and (+)-cis-abienol
-
Short and efficient syntheses of (-)-Ambrox (12) from (-)-sclareol (1) and (+)-cis-abienol (11) are described.In contrast to previously described procedures, the transformation of 1 to 12, involving in the key step, an oxidative degradation by catalytic osmium tetroxide, in the presence of sodium periodate, has the advantage of using the more suitable sodium borohydride, as the reducing agent.The isolation and characterization of some reaction intermediates allowed us to confirm the degradation mechanism.
- Barrero, Alejandro F.,Alvarez-Manzaneda, Enrique J.,Altarejos, Joaquin,Salido, Sofia,Ramos, Jose M.
-
p. 10405 - 10412
(2007/10/02)
-
- A Short and Efficient Synthesis of (-)-Ambrox from (-)-Sclareol using a Ruthenium Oxide Catalyzed Key Step
-
(-)-Ambrox 5 has been synthesized in 3 steps from natural (-)-sclareol 1.Depending on the reoxidizing agents and the reaction conditions used in the ruthenium oxide catalyzed key step, overall yields of 79percent (NaIO4/RuO4) or 48percent (Ca(OCl)2/RuO4) were observed.Key Words: Ambrox, sclareol, ruthenium tetroxide.
- Martres, Paul,Perfetti, Patricia,Zahra, Jean-Pierre,Waegell, B.,Giraudi, Edouard,Petrzilka, Martin
-
p. 629 - 632
(2007/10/02)
-
- Process for the stereoselective preparation of 8α, 12-oxido-13, 14,15, 16-tetranorlabdane
-
The invention relates to a process for the stereo-selective preparation of 8α,12-oxido-13,14,15,16-tetranorlabdane by dehydration of 8α,12-dihydroxy-13,14,15,16-tetranorlabdane with acid-charged aluminium oxides.
- -
-
-
- STUDIES TOWARD THE TOTAL SYNTHESIS OF POLYOXYGENATED LABDANES: PRELIMINARY APPROACHES
-
Using the keto-ester 3 as a starting material, methods are developed for the successive introduction of hydroxy groups at C-6, C-7 and C-8 of a decalin system, as well as for elaboration of a C-9 pentadiene chain in preliminary approach to the total synthesis of trihydroxylabdadienes.
- Herlem, Denyse,Kervagoret, Jocelyne,Dahai, Yu,Khuong-Huu, Francoise,Kende, Andrew S.
-
p. 607 - 618
(2007/10/02)
-
- Internal Nucleophilic Termination in Biomimetic Acid Mediated polyene Cyclizations: Stereochemical and Mechanistic Implications. Synthesis of (+/-)-Ambrox and Its Diastereoisomers
-
Treatment of 10 structurally releted trienols and dienols 5-8 with an excess of fluorosulfonic acid in 2-nitropropane at -90 deg C afforded, in 74-87percent yield, diastereoisomeric mixtures of the odoriferous norlabdane oxides 9-15 ((-)-9 (Ambrox) is a naturally occuring ambergris odorant).These tranformations represent examples of efficientbiomimetic acid-mediated cyclizations in which the hydroxyl group serves as the internal nucleophilic terminator.The stereochemical outcome of these kinetically controlled processes has been analysed in detail, and mechanistic hypotheses consistent with the results have been proposed.For the four acyclic trienols 5, the major reaction pathway can be rationalized by a totally synchronous process involving three internal anti additions via chair or skew-boat conformations of the nascent cyclohexane rings.An alternative explanation postulates a nonsynchronous process in which ring closure to an intermediate cyclohexyl cation is followed by rapid cyclization, directed by a strong kinetic preference for equatorial C-C and C-O bond formation.In contrast, for the monocyclic dienols 6-8 only a nonsynchronous process, involving prior protonation of the cyclohexenyl bond, is fully consisitent with the results.In the nonsynchronous processes, the orientation of the side chain vicinal to the cyclohexyl cation directs the stereochemical course of the cyclization.For the acyclic trienols, this factor is predetermined by the configuration of the C(7)=C(8) bond, whereas, for the monocyclic dienols, this orientation is determined by the stereoselective axial protonation of the cyclohexenyl bond in 6, or by the distribution of cyclohexene and cyclohexane conformers in 7 and 8, respectively.In the cases studied, it is clear that conformational inversion of the six-membered ring is slower than cyclization and thus ensures that an equatorial side chain leads to a trans A/B ring junction in the cyclization product, whereas an axial side chain affords a cis A/B ring junction.
- Snowden, Roger L.,Eichenberger, Jean-Claude,Linder, Simon M.,Sonnay, Philippe,Vial, Christian,Schulte-Elte, Karl H.
-
p. 955 - 960
(2007/10/02)
-
- Configuration-Odor Relationship in 5β-Ambrox
-
The four possible A/B cis-fused diastereomers of Ambrox have been synthesized and their configurations and conformations established by X-ray and NMR analysis.Only 5β-ambrox (=1,2,3a,4,5,5aβ,6,7,8,9,9a,9bα-dodecahydro-3aβ,6,6,9aβ-tetramethylnaphthofuran; 5) has an odor quality comparable to Ambrox.The 1,3-synperiplanar/diaxial conformation of the substituents at C(8) (=C(3a)) and C(10) (=C(9a)) has thus been confirmed to be a compulsory structure element for the particular odor.
- Escher, Sina,Giersch, Wolfgang,Niclass, Yvan,Bernardinelli, Gerald,Ohloff, Guenther
-
p. 1935 - 1947
(2007/10/02)
-