- Synthesis and Enantiodifferentiation of Isomeric 3,5,6,8a-Tetrahydro-2,5,5,8a-tetramethyl-2H-1-benzopyrans (Edulans I and II)
-
The benzopyran derivatives 1a-d were prepared in a biomimetic-type reaction from their natural precursor 3-hydroxy-retro-α-ionol (6) which was available from α-ionol by tert-butyl chromate oxidation, reduction with NaBH4, and subsequent rearrangement of t
- Schmidt, Gertraut,Full, Gerhard,Winterhalter, Peter,Schreier, Peter
-
-
Read Online
- Selective oxygenation of ionones and damascones by fungal peroxygenases
-
Apocarotenoids are among the most highly valued fragrance constituents, being also appreciated as synthetic building blocks. This work shows the ability of unspecific peroxygenases (UPOs, EC1.11.2.1) from several fungi, some of them being described recently, to catalyze the oxyfunctionalization of α- and β-ionones and α- and β-damascones. Enzymatic reactions yielded oxygenated products such as hydroxy, oxo, carboxy, and epoxy derivatives that are interesting compounds for the flavor and fragrance and pharmaceutical industries. Although variable regioselectivity was observed depending on the substrate and enzyme, oxygenation was preferentially produced at the allylic position in the ring, being especially evident in the reaction with α-ionone, forming 3-hydroxy-α-ionone and/or 3-oxo-α-ionone. Noteworthy were the reactions with damascones, in the course of which some UPOs oxygenated the terminal position of the side chain, forming oxygenated derivatives (i.e., the corresponding alcohol, aldehyde, and carboxylic acid) at C-10, which were predominant in the Agrocybe aegerita UPO reactions, and first reported here.
- Aranda, Carmen,Babot, Esteban D.,Del R?o, José C.,Gutiérrez, Ana,Hofrichter, Martin,Kiebist, Jan,Mart?nez, Angel T.,Scheibner, Katrin,Ullrich, René
-
p. 5375 - 5383
(2020/06/08)
-
- Fungi-mediated biotransformation of the isomeric forms of the apocarotenoids ionone, damascone and theaspirane
-
In this work, we describe a study on the biotransformation of seven natural occurring apocarotenoids by means of eleven selected fungal species. The substrates, namely ionone (α-, β- and γ-isomers), 3,4-dehydroionone, damascone (α- and β-isomers) and theaspirane are relevant flavour and fragrances components. We found that most of the investigated biotransformation reactions afforded oxidized products such as hydroxy- keto- or epoxy-derivatives. On the contrary, the reduction of the keto groups or the reduction of the double bond functional groups were observed only for few substrates, where the reduced products are however formed in minor amount. When starting apocarotenoids are isomers of the same chemical compound (e.g., ionone isomers) their biotransformation can give products very different from each other, depending both on the starting substrate and on the fungal species used. Since the majority of the starting apocarotenoids are often available in natural form and the described products are natural compounds, identified in flavours or fragrances, our biotransformation procedures can be regarded as prospective processes for the preparation of high value olfactory active compounds.
- Serra, Stefano,De Simeis, Davide
-
-
- MnO2/TBHP: A Versatile and User-Friendly Combination of Reagents for the Oxidation of Allylic and Benzylic Methylene Functional Groups
-
In the presence of activated MnO2, tert-butyl hydroperoxide (TBHP) in CH2Cl2 is able to oxidize the allylic and benzylic methylene groups of different classes of compounds. I describe a one-pot oxidation protocol based on two sequential steps. In the first step, carried out at low temperature, MnO2 catalyses the oxidation of the methylene group. This is followed by a second step where reaction temperature is increased, allowing MnO2 both to catalyse the decomposition of unreacted TBHP and to oxidize allylic alcohols that could possibly be formed. The proposed oxidation procedure is generally applicable, although its efficiency, regioselectivity, and chemoselectivity are strongly dependent on the structure of the substrate. A simple and user-friendly synthetic procedure for the oxidation of allylic and benzylic methylene groups to the corresponding conjugated carbonyl derivatives is described. The proposed oxidation protocol is based on the combined use of MnO2 and tert-butyl hydroperoxide, and is generally applicable.
- Serra, Stefano
-
p. 6472 - 6478
(2015/10/19)
-
- Co(acac)catalyzed allylic and benzylic oxidation by tert -butyl hydroperoxide
-
Various allylic and benzylic substrates were oxidized to the corresponding enones, arenealdehydes and aryl ketones in good yields with tert-butyl hydroperoxide in the presence of catalytic amounts of Co(acac)under mild conditions. The reactivity, selectivity, and scope of the reaction were investigated. Georg Thieme Verlag Stuttgart. New York.
- Han, Xiaoqiang,Zhou, Ziyuan,Wan, Chuan,Xiao, Yumei,Qin, Zhaohai
-
p. 615 - 620
(2013/03/29)
-
- Regio- and stereoselective hydroxylation of optically active α-ionone enantiomers by engineered cytochrome P450 BM3 mutants
-
The selective hydroxylation of an unactivated C-H bond is a crucial step in the synthesis of fine chemicals such as hydroxylated terpenoids. In the present study, the ability of 40 cytochrome P450 BM3 mutants to perform the regio- and stereoselective hydroxylation of α-ionone has been investigated. Based on their activity and selectivity to produce 3-hydroxy-α-ionone from racemic α-ionone, 6 BM3 mutants were selected. Out of these, 3 mutants (M01 A82W, M11 A82W and M11 V87I) showed high selectivity for trans-3-hydroxy-α- ionone formation while 3 other mutants (M11 L437N, M11 L437S and M11 L437T) formed almost equal amounts of both cis-3-hydroxy- and trans-3-hydroxy-α- ionone. Incubation with individual enantiomers showed that M11 L437N, M11 L437S and M11 L437T exhibited opposite stereoselectivity producing (3S,6S)-hydroxy-α-ionone with the (6S)-enantiomer and (3S,6R)-hydroxy- α-ionone with the (6R)-enantiomer. Thus for the first time, BM3 mutants that can selectively produce diastereomers of 3-hydroxy-α-ionone (>90% de), with high turnover numbers and minimal secondary metabolism, have been identified. Docking studies have been performed to rationalize the basis of the experimentally observed selectivity. In conclusion, engineered P450 BM3s are promising biocatalysts for regio- and stereoselective production of hydroxylated α-ionones for industrial applications. Copyright
- Venkataraman, Harini,Beer, Stephanie B. A. De,Geerke, Daan P.,Vermeulen, Nico P. E.,Commandeur, Jan N. M.
-
p. 2172 - 2184,13
(2012/12/12)
-
- Regio- and stereoselective hydroxylation of optically active α-ionone enantiomers by engineered cytochrome P450 BM3 mutants
-
The selective hydroxylation of an unactivated C-H bond is a crucial step in the synthesis of fine chemicals such as hydroxylated terpenoids. In the present study, the ability of 40 cytochrome P450 BM3 mutants to perform the regio- and stereoselective hydroxylation of α-ionone has been investigated. Based on their activity and selectivity to produce 3-hydroxy-α-ionone from racemic α-ionone, 6 BM3 mutants were selected. Out of these, 3 mutants (M01 A82W, M11 A82W and M11 V87I) showed high selectivity for trans-3-hydroxy-α- ionone formation while 3 other mutants (M11 L437N, M11 L437S and M11 L437T) formed almost equal amounts of both cis-3-hydroxy- and trans-3-hydroxy-α- ionone. Incubation with individual enantiomers showed that M11 L437N, M11 L437S and M11 L437T exhibited opposite stereoselectivity producing (3S,6S)-hydroxy-α-ionone with the (6S)-enantiomer and (3S,6R)-hydroxy- α-ionone with the (6R)-enantiomer. Thus for the first time, BM3 mutants that can selectively produce diastereomers of 3-hydroxy-α-ionone (>90% de), with high turnover numbers and minimal secondary metabolism, have been identified. Docking studies have been performed to rationalize the basis of the experimentally observed selectivity. In conclusion, engineered P450 BM3s are promising biocatalysts for regio- and stereoselective production of hydroxylated α-ionones for industrial applications. Copyright
- Venkataraman, Harini,Beer, Stephanie B. A. De,Geerke, Daan P.,Vermeulen, Nico P. E.,Commandeur, Jan N. M.
-
p. 2172 - 2184
(2013/01/14)
-
- Process for Synthesis of (3R,3'R,6'R)-Lutein and its Stereoisomers
-
(3R,3′R,6′R)-Lutein and (3R,3′R)-zeaxanthin are two dietary carotenoids that are present in most fruits and vegetables commonly consumed in the US. These carotenoids accumulate in the human plasma, major organs, and ocular tissues. In the past decade, numerous epidemiological and experimental studies have shown that lutein and zeaxanthin play an important role in the prevention of age-related macular degeneration (AMD) that is the leading cause of blindness in the U.S. and Western World. The invention provides a process for the synthesis of (3R,3′R,6′R)-lutein and its stereoisomers from commercially available (rac)-α-ionone by a C15+C10+C15 coupling strategy. In addition, the present invention also provides access to the precursors of optically active carotenoids with 3-hydroxy-ε-end group that are otherwise difficult to synthesize. The process developed for the synthesis of lutein and its stereoisomers is straightforward and has potential for commercialization.
- -
-
Page/Page column 6-7; 20
(2009/10/30)
-
- CaCl2- or MgCl2-catalyzed allylic oxidations of ionone-like dienes
-
The allylic oxidation of ionone-like dienes catalyzed by CaCl2 or MgCl2 with TBHP is presented. The method provides a facile method to synthesize dienones derived from ionone-like dienes in good to moderate yields. A plausible mechan
- Yang, Min,Peng, Qian-Rong,Lan, Jing-Bo,Song, Guang-Fu,Xie, Ru-Gang
-
p. 2617 - 2620
(2008/09/16)
-
- 2-Fluoroabscisic acid analogues: Their synthesis and biological activities
-
Fluorine was introduced into the 2-position of the side chain of abscisic acid (ABA) analogues by Wittig reaction of α-ionone derivatives with ethyl triethylphosphono-2-fluoroacetate. The effects of the fluorinated analogues were evaluated on inhibition o
- Kim, Bum Tae,Min, Yong Ki,Asami, Tadao,Park, No Kyun,Kwon, Oh Young,Cho, Kwang Yun,Yoshida, Shigeo
-
p. 313 - 317
(2007/10/03)
-
- Probing for the threshold energy for visual transduction: Red-shifted visual pigment analogs from 3-methoxy-3-dehydroretinal and related compounds
-
While azulenic retinal analogs failed to yield a red-shifted visual pigment analog, the 9-cis isomers of the push-pull polyenals 3-methoxy-3-dehydroretinal and 14F-3-methoxy-3-dehydroretinal yielded iodopsin pigment analogs with absorption maxima at, resp
- Imai, Hiroo,Hirano, Takahiro,Terakita, Akihisa,Shichida, Yoshinori,Muthyala, Rajeev S.,Chen, Rong-Liang,Colmenares, Leticia U.,Liu, Robert S. H.
-
p. 111 - 115
(2007/10/03)
-
- Novel synthesis of degradation products of carotenoids, megastigmatrienone analogues and blumenol-A
-
Synthesis of 4-alkylidene-3,5,5-trimethylcyclohex-2-enones 7 has been achieved utilising 1,4-conjugate dehydrobromination of allylic bromides 5 as a key step. This chemical transformation is applied to the synthesis of degradation products of carotenoids: megastigmatrienones 7e/1-4,4-methylene-3,5,5-trimethylcyclohex-2-enone 7a, 4-(3-hydroxybutylidene)-3,5,5-trimethylcyclohex-2-enone 9,1,3,7,7-tetramethyl-2-oxabicyclo[4.4.0]dec-5-en-9-one 10a-b and 3,4,7,8-tetrahydro-4,4,7-trimethylnaphthalen-2(6H)-one 15. A novel photoisomerisation of 4-[(Z)-3-acetoxybut-2-enyl]-4-hydroxy-3,5,5-trimethylcyclohex-2-enone 19 to 4-[(E)-3-acetoxybut-2-enyl]-4-hydroxy-3,5,5-trimethylcyclohex-2-enone 20 enables us to synthesise blumenol-A 21.
- Ito, Nobuhiko,Etoh, Takeaki,Hagiwara, Hisahiro,Kato, Michiharu
-
p. 1571 - 1579
(2007/10/03)
-
- Reactions of endocyclic linearly conjugated dienolates with Michael acceptors leading to bicyclo[2.2.2] octane derivatives. Application to the synthesis of C13 degradation products of carotenoids
-
The endocyclic linearly conjugated dienolates from substituted cyclohex-2-enones react with but-3-en-2-one, substituted methyl propenoates, but-3-yn-2-one and methyl propiolate to afford bicyclo[2.2.2]-oct-2-en-1-ols 10a-c, 14a-c and bicyclo[2.2.2]octa-2,5-dien-1-ols 15a,b. The AlCl3-catalysed reaction of 3,5,5-trimethyl-Htrimethylsiloxy)cyclohexa-l)3-diene 3 with (E)-4-acetoxy- and (E)-4-methoxy-but-3-en-2-one provides trans-8-acetoxy-7-acetyl-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2- enes 22, 23 and trans-7-acetyl-8-methoxy-3,5,5-trimethyl-1-(trimethylsiloxy)bicyclo[2.2.2]oct-2- enes 24, 25. Starting from these bicyclo[2.2.2]octenes, the C13 degradation products of carotenoids including 3-oxo-α-ionone 20, blumenol-C 27 and 1,3,7,7-tetramethyl-2-oxabicyclo[4.4.0]decan-9-one 29 have been synthesized.
- Ito, Nobuhiko,Etoh, Takeaki
-
p. 2397 - 2405
(2007/10/03)
-
- Synthesis and Enantiodifferentiation of Isomeric 2,3,5,6,8,8a-Hexahydro-2,5,5,8a-tetramethyl-7H-1-benzopyran-7-ones(3,4-Dihydro-3-oxoedulans)
-
The benzopyran derivatives 1a-d were prepared in a biomimetic type reaction from their presumed natural precursor 3-oxo-retro-α-ionol, which was available from α-ionone by tert-butyl chromate oxidation, reduction with NaBH4, and subsequent rearrangement o
- Schmidt, Gertraut,Neugebauer, Wolfgang,Winterhalter, Peter,Schreier, Peter
-
p. 1898 - 1902
(2007/10/03)
-
- Norisoprenoids in Vitis vinifera White Wine Grapes and the Identification of a Precursor of Damascenone in These Fruits
-
Twenty-four norisoprenoids, which are either free volatile components of juices of Vitis vinifera cvv.Chardonnay, Semillon and Sauvignon Blanc, or are liberated by glycosidase enzyme, or acid hydrolysis of extracts of these juices, have been identified.Eleven of these norisoprenoids are reported as grape products for the first time.The hypothetical 7-oxomegastigmane precursors, grasshopper ketone (5) and megastigm-5-en-7-yne-3,9-diol (10), as well as the related allene, 9-hydroxymegastigma-4,6,7-trien-3-one (6), have been observed for the first time, cooccurring with damascenone (1), 3-hydroxy-β-damascone (2), 3-oxo-β-damascone (3) and 3-oxo-α-damascone (4).Hydrolytic studies have shown that megastigm-5-en-7-yne-3,9-diol (10) is a precursor of damascenone (1) and 3-hydroxy-β-damascone (2) during wine conservation.
- Sefton, Mark A.,Skouroumounis, George K.,Massy-Westropp, Ralph A.,Williams, Patrick J.
-
p. 2071 - 2084
(2007/10/02)
-
- 3-OXO-α-IONOL, VOMIFOLIOL AND ROSEOSIDE IN VITIS VINIFERA FRUIT
-
Key Word Index - Vitis vinifera; Vitaceae; grapes; 3-oxo-α-ionol; vomifoliol; dehydrovomifoliol; roseoside; hydrolytic studies. 3-Oxo-α-ionol, vomifoliol and dehydrovomifoliol were identified for the first time in fruit from Vitis vinifera.The last named compound was mainly present free in the juice while the others existed predominantly as conjugates.In the case of vomifoliol, the conjugation was with glucose, i.e. as roseoside.Hydrolytic studies on 3-oxo-α-ionol and vomifoliol gave a range of compounds which have been recognized as fruit and plant products.
- Strauss, Christopher R.,Wilson, Bevan,Williams, Patrick J.
-
p. 1995 - 1998
(2007/10/02)
-
- Ionones and &β-Ionylideneacetic Acids: Their Influence on Abscisic Acid Biosynthesis by Cercospora rosicola
-
Several ionones and β-ionylideneacetic acids inhibited absicisic acid (ABA) biosynthesis in Cercospora rosicola at 100 μM.At lower concentrations, α-ionone, 1',2'-dihydroxy-1',2'-dihydro-β-ionone and 4'-keto-α-ionone enhanced ABA biosynthesis.Conversions
- Norman, Shirley M.,Poling, Stephen M.,Maier, V. P.,Nelson, Mary D.
-
p. 2887 - 2892
(2007/10/02)
-
- Technische Verfahren zur Synthese von Carotinoiden und verwandten Verbindungen aus 6-Oxo-isophoron. VI. Synthese von Rhodoxanthin und (3RS,3'RS)-Zeaxanthin; Zugaenge zur C15-Ringkomponente ueber 3-Oxo-jonon-Derivative
-
The C15-ring component 4, key intermediate of a new scheme for the synthesis of rhodoxanthin (1) and (3RS,3'RS)-zeaxanthin (3), has been synthesized starting from 6-oxo-isophorone (7) via 3-oxo-cyclocitral and 3-oxo-ionone derivatives.
- Widmer, Erich,Soukup, Milan,Zell, Reinhard,Broger, Emil,Lohri, Bruno,et. al.
-
p. 944 - 957
(2007/10/02)
-
- Further Synthesis of Zeaxanthin and Rhodoxanthin
-
A modification of a previously reported synthesis of zeaxanthin (1), and routes to both zeaxanthin and rhodoxanthin (2) from α-ionone, are described.
- Ellis, Peter R.,Faruk, Erol A.,Moss, Gerald P.,Weedon, Basil C. L.
-
p. 1092 - 1097
(2007/10/02)
-