101
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Tetrahedron reports on organic chemistry. Tetrahedron 2007. [DOI: 10.1016/s0040-4020(07)00205-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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102
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Xu M, Wilderman PR, Morrone D, Xu J, Roy A, Margis-Pinheiro M, Upadhyaya NM, Coates RM, Peters RJ. Functional characterization of the rice kaurene synthase-like gene family. PHYTOCHEMISTRY 2007; 68:312-26. [PMID: 17141283 DOI: 10.1016/j.phytochem.2006.10.016] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2006] [Revised: 09/25/2006] [Accepted: 10/20/2006] [Indexed: 05/09/2023]
Abstract
The rice (Oryza sativa) genome contains a family of kaurene synthase-like genes (OsKSL) presumably involved in diterpenoid biosynthesis. While a number of OsKSL enzymes have been functionally characterized, several have not been previously investigated, and the gene family has not been broadly analyzed. Here we report cloning of several OsKSL genes and functional characterization of the encoded enzymes. In particular, we have verified the expected production of ent-kaur-16-ene by the gibberellin phytohormone biosynthesis associated OsKS1 and demonstrated that OsKSL3 is a pseudo-gene, while OsKSL5 and OsKSL6 produce ent-(iso)kaur-15-ene. Similar to previous reports, we found that our sub-species variant of OsKSL7 produces ent-cassa-12,15-diene, OsKSL10 produces ent-(sandaraco)pimar-8(14),15-diene, and OsKSL8 largely syn-stemar-13-ene, although we also identified syn-stemod-12-ene as an alternative product formed in approximately 20% of the reactions catalyzed by OsKSL8. Along with our previous reports identifying OsKSL4 as a syn-pimara-7,15-diene synthase and OsKSL11 as a syn-stemod-13(17)-ene synthase, this essentially completes biochemical characterization of the OsKSL gene family, enabling broader analyses. For example, because several OsKSL enzymes are involved in phytoalexin biosynthesis and their gene transcription is inducible, promoter analysis was used to identify a pair of specifically conserved motifs that may be involved in transcriptional up-regulation during the rice plant defense response. Also examined is the continuing process of gene evolution in the OsKSL gene family, which is particularly interesting in the context of very recently reported data indicating that a japonica sub-species variant of OsKSL5 produces ent-pimara-8(14),15-diene, rather than the ent-(iso)kaur-15-ene produced by the indica sub-species variant analyzed here.
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Affiliation(s)
- Meimei Xu
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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103
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Yang L, Wang Y, Huang D, Luo G, Dai Y. Preparation of High Performance Adsorbents by Functionalizing Mesostructured Silica Spheres for Selective Adsorption of Organosulfur Compounds. Ind Eng Chem Res 2006. [DOI: 10.1021/ie061174d] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Liming Yang
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Yujun Wang
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Dan Huang
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Guangsheng Luo
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Youyuan Dai
- The State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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104
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Lectka T, Motherwell W. Tetrahedron reports on organic chemistry. Tetrahedron 2006. [DOI: 10.1016/s0040-4020(06)01801-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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105
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Matovic R, Ivkovic A, Manojlovic M, Tokic-Vujosevic Z, Saicic RN. Ring Closing Metathesis/Fragmentation Route to (Z)-Configured Medium Ring Cycloalkenes. Total Synthesis of (±)-Periplanone C. J Org Chem 2006; 71:9411-9. [PMID: 17137368 DOI: 10.1021/jo061790j] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The combination of ring closing metathesis and beta-fragmentation offers an efficient entry into (Z)-configured medium ring cycloalkenes. The fragmentation step can be effected under anionic or radical conditions. The versatility of this method is demonstrated by the total synthesis of (+/-)-periplanone C-a macrocyclic pheromone of Periplaneta americana.
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Affiliation(s)
- Radomir Matovic
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000 Belgrade, Serbia
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106
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von Seebach M, Kozhushkov SI, Schill H, Frank D, Boese R, Benet-Buchholz J, Yufit DS, de Meijere A. Stereoselective Preparation of Six Diastereomeric Quatercyclopropanes from Bicyclopropylidene and Some Derivatives. Chemistry 2006; 13:167-77. [PMID: 17024706 DOI: 10.1002/chem.200600799] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Diastereomeric meso- and d,l-bis(bicyclopropylidenyl) (5) were obtained upon oxidation with oxygen of a higher-order cuprate generated from lithiobicyclopropylidene (4) in 50 and 31 % yield, respectively. Their perdeuterated analogues meso-[D(14)]- and d,l-[D(14)]-5 were obtained along the same route from perdeuterated bicyclopropylidene [D(8)]-3 (synthesized in six steps in 7.4 % overall yield from [D(8)]-THF) in 20.5 % yield each. Dehalogenative coupling of 1,1-dibromo-2-cyclopropylcyclopropane (6) gave a mixture of all possible stereoisomers of 1,5-dicyclopropylbicyclopropylidene 16 in 69 % yield, from which (Z)-cis-16 was separated by preparative gas chromatography (26 % yield). The crystal structure of meso-5 looks like a superposition of the crystal structures of two outer bicyclopropylidene units (3) and one inner s-trans-bicyclopropyl unit, whereas the two outer cyclopropyl moieties adopt a gauche orientation with respect to the cyclopropane rings at the inner bicyclopropylidene units in (Z)-cis-16. Birch reduction with lithium in liquid ammonia of meso-5 and d,l-5 gave two pairs of diastereomeric quatercyclopropanes trans,trans-(R*,S*,R*, S*)-17/cis,trans-(R*,S*,R*,R*)-18 and trans,trans-(R*,S*,S*,R*)-19/cis,trans-(R*,S*,S*,S*)-20 in 97 and 76 % yield, respectively, in a ratio 9:1 for every pair. The latter diastereomer was also obtained as the sole product by Birch reduction of (Z)-cis-16 in 96 % yield. Under the same conditions, tetradecadeuterio analogues trans,trans-[D(14)]-(R*,S*,R*,S*)-17/cis,trans-[D(14)]-(R*, S*,R*,R*)-18 (8:1) and trans,trans-[D(14)]-(R*,S*,S*,R*)-19/cis,trans-[D(14)]-(R*,S*,S*,S*)-20 (12:1) were prepared from meso-[D(14)]-5 and d,l-[D(14)]-5 in 37 and 63 % yield, respectively. Reduction of meso-5 with diimine gave the cis,cis-quatercyclopropane (S*,S*,R*,R*)-21 as the main product (58 % yield) along with the cis,trans-diastereomer (S*,S*,R*,S*)-18 (29 % yield). Thus, five of the six possible diastereomeric quatercyclopropanes were obtained from meso-5, d,l-5, and (Z)-cis-16. The X-ray crystal structure analyses of trans,trans-(R*,S*,R*,S*)-17 and cis,cis-(S*,S*,R*,R*)-21 revealed for the both an unusual conformation in which the central bicyclopropyl unit adopts an s-trans-(antiperiplanar) orientation with phi=180.0 degrees , and the two terminal bicyclopropyl moieties adopt a synclinal conformation with phi=49.8 and 72.0 degrees , respectively. In solution the vicinal coupling constants (3)J(H,H) in trans,trans-(R*,S*,R*,S*)-[D(14)]-17, trans,trans-(R*,S*,S*,R*)-[D(14)]-19, trans,cis-(R*,S*,R*,R*)-[D(14)]-18 and trans,cis-(R*,S*,S*,S*)-[D(14)]-20 were found to be 4.1, 4.7, 5.9 and 5.9 Hz, respectively. This indicates a predominance of the all-gauche conformer in (R*,S*,R*,S*)-17 and a decreasing fraction of it in this sequence of the other diastereomers.
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Affiliation(s)
- Malte von Seebach
- Institut für Organische und Biomolekulare Chemie der Georg-August-Universität Göttingen, Tammannstrasse 2, 37077 Göttingen, Germany
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107
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Chavan SP, Kharul RK, Kamat SK, Kalkote UR, Kale RR. A Simple, Concise, Stereocontrolled Synthesis of (8E,10Z)‐Pentadecadien‐1‐ol Acetate. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-200051715] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Subhash P. Chavan
- a Division of Organic Chemistry: Technology , National Chemical Laboratory , Pune, India
| | - Rajendra K. Kharul
- a Division of Organic Chemistry: Technology , National Chemical Laboratory , Pune, India
| | - Subhash K. Kamat
- a Division of Organic Chemistry: Technology , National Chemical Laboratory , Pune, India
| | - Uttam R. Kalkote
- a Division of Organic Chemistry: Technology , National Chemical Laboratory , Pune, India
| | - Ramesh R. Kale
- a Division of Organic Chemistry: Technology , National Chemical Laboratory , Pune, India
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108
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Lectka T, Motherwell W. Tetrahedron reports on organic chemistry. Tetrahedron 2006. [DOI: 10.1016/s0040-4020(06)00771-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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109
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Cottam JR, Steel PJ. X-ray crystal structures of discrete and polymeric chiral silver complexes of monoterpenoid alkenes. J Organomet Chem 2006. [DOI: 10.1016/j.jorganchem.2005.11.046] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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110
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Burgess J, Cottam JRA, Steel PJ. The Silver - Alkene Interaction as a Supramolecular Synthon: Divinylbenzene-Based Assemblies. Aust J Chem 2006. [DOI: 10.1071/ch06147] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The interaction of silver(i) salts with alkenes is shown to be a useful synthon for the assembly of both discrete and polymeric metallosupramolecular architectures. The three isomers of divinylbenzene lead to a diverse range of adducts, seven of which have been structurally characterized by X-ray crystallography.
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111
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Black PJ, Cami-Kobeci G, Edwards MG, Slatford PA, Whittlesey MK, Williams JMJ. Borrowing hydrogen: iridium-catalysed reactions for the formation of C–C bonds from alcohols. Org Biomol Chem 2006; 4:116-25. [PMID: 16358005 DOI: 10.1039/b511053j] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Alcohols have been employed as substrates for C-C bond-forming reactions which involve initial activation by the temporary removal of hydrogen to form an aldehyde. The intermediate aldehyde is converted into an alkene via a Horner-Wadsworth-Emmons reaction, nitroaldol and aldol reactions. The 'borrowed hydrogen' is then returned to the alkene to form a C-C bond.
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Affiliation(s)
- Phillip J Black
- Department of Chemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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112
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Anagnostopoulos D, Chatgilialoglu C, Ferreri C, Samadi A, Siafaka-Kapadai A. Synthesis of all-trans arachidonic acid and its effect on rabbit platelet aggregation. Bioorg Med Chem Lett 2005; 15:2766-70. [PMID: 15876534 DOI: 10.1016/j.bmcl.2005.03.109] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2005] [Revised: 03/21/2005] [Accepted: 03/29/2005] [Indexed: 11/17/2022]
Abstract
A simple and high-yielding method to convert natural all-cis PUFA derivatives to the corresponding all-trans geometrical isomers is described. The method is based on the thiyl radical-catalyzed cis-trans isomerization. The all-trans isomer of arachidonic acid was found to cause rabbit platelet aggregation at concentrations higher than 0.1 mM and inhibition of PAF-induced platelet aggregation in a concentration dependent manner with an IC(50) in the micromolar range.
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113
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Thompson RQ, Phinney KW, Sander LC, Welch MJ. Reversed-phase liquid chromatography and argentation chromatography of the minor capsaicinoids. Anal Bioanal Chem 2005; 381:1432-40. [PMID: 15803310 DOI: 10.1007/s00216-005-3098-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2004] [Revised: 01/03/2005] [Accepted: 01/14/2005] [Indexed: 10/25/2022]
Abstract
An investigation of the liquid chromatography of the minor capsaicinoids in a commercial capsaicinoid mixture is reported. Twelve stationary phases including C8, C18, C30, phenyl, and cation-exchange chemistries were examined in combination with isocratic aqueous methanol and aqueous acetonitrile mobile phases. A phenyl stationary phase and aqueous acetonitrile mobile phase baseline-resolved 7 of 11 capsaicinoids, and selected ion chromatograms (LC-ESI-MS) demonstrated this was the most effective reversed-phase separation. Argentation chromatography with an alkyl or phenyl column and aqueous silver nitrate-methanol mobile phase revealed the presence of the 6-ene-8-methyl and 6-ene-9-methyl homocapsaicin isomers and the absence of 7-ene-9-methyl homocapsaicin. A mixed phenyl-cation-exchange stationary phase (charged with silver ion) enabled unique and useful separations of the capsaicinoids.
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Affiliation(s)
- Robert Q Thompson
- Department of Chemistry, Oberlin College, 119 Woodland Street, Oberlin, OH 44074, USA
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114
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Cunha RL, Diego DG, Simonelli F, Comasseto JV. Selectivity aspects of the ring opening reaction of 2-alkenyl aziridines by carbon nucleophiles. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.02.089] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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115
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Khairallah GN, O'Hair RAJ. Gas-Phase Synthesis of [Ag4H]+ and Its Mediation of the C?C Coupling of Allyl Bromide. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200461328] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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116
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Khairallah GN, O'Hair RAJ. Gas-Phase Synthesis of [Ag4H]+ and Its Mediation of the C?C Coupling of Allyl Bromide. Angew Chem Int Ed Engl 2005; 44:728-31. [PMID: 15619256 DOI: 10.1002/anie.200461328] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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117
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Clarke PA, Grist M, Ebden M, Wilson C, Blake AJ. Synthetic studies on the DEF-rings of FR182877 and hexacyclinic acid. Tetrahedron 2005. [DOI: 10.1016/j.tet.2004.10.095] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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118
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2004. [DOI: 10.1016/s0040-4020(04)01396-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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119
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Tallman KA, Roschek B, Porter NA. Factors Influencing the Autoxidation of Fatty Acids: Effect of Olefin Geometry of the Nonconjugated Diene. J Am Chem Soc 2004; 126:9240-7. [PMID: 15281813 DOI: 10.1021/ja049104q] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Autoxidations of cis,cis, cis,trans, and trans,trans nonconjugated octadecadienoates and pentadecadienes were carried out in the presence of alpha-tocopherol to investigate the effect of olefin geometry on this oxidation process and provide insight into the factors that influence the autoxidation of fatty acids. We have found that as the trans character of the diene increases, the amount of O(2) trapping at the central (bis-allylic) position of the pentadienyl radical also increases. In addition, the rate constant for beta-fragmentation (k(beta) approximately 10(6) s(-1)) of the bis-allylic peroxyl radical decreased on going from the cis,cis to the trans,trans diene. We have also found that for the cis,trans nonconjugated dienes, there is a preference for trapping of the pentadienyl radical by O(2) at the transoid end, generating the cis,trans conjugated hydroperoxide as the major product.
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Affiliation(s)
- Keri A Tallman
- Department of Chemistry and Center in Molecular Toxicology, Vanderbilt University, Nashville, Tennessee 37235, USA
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120
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Ferreri C, Samadi A, Sassatelli F, Landi L, Chatgilialoglu C. Regioselective cis-trans isomerization of arachidonic double bonds by thiyl radicals: the influence of phospholipid supramolecular organization. J Am Chem Soc 2004; 126:1063-72. [PMID: 14746474 DOI: 10.1021/ja038072o] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Trans unsaturated fatty acids in humans may be originated by two different contributions. The exogenous track is due to dietary supplementation of trans fats and the endogenous path deals with free-radical-catalyzed cis-trans isomerization of fatty acids. Arachidonic acid residue (5c,8c,11c,14c-20:4), which has only two out of the four double bonds deriving from the diet, was used to differentiate the two paths and to assess the importance of a radical reaction. A detailed study on the formation of trans phospholipids catalyzed by the HOCH2CH2S* radical was carried out on L-alpha-phosphatidylcholine from egg lecithin and 1-stearoyl-2-arachidonoyl-L-alpha-phosphatidylcholine (SAPC) in homogeneous solution or in large unilamellar vesicles (LUVET). Thiyl radicals were generated from the corresponding thiol by either gamma-irradiation or UV photolysis, and the reaction course was followed by GC, Ag/TLC, and 13C NMR analyses. The isomerization was found to be independent of cis double bond location (random process) in i-PrOH solution. In the case of vesicles, the supramolecular organization of lipids produced a dramatic change of the isomerization outcome: (i) in egg lecithin, the reactivity of arachidonate moieties is higher than that of oleate and linoleate residues, (ii) in the linoleate residues of egg lecithin, the 9t,12c-18:2 isomer prevailed on the 9c,12t-18:2 isomer (3:1 ratio), and (iii) a regioselective isomerization of SAPC arachidonate residues occurred in the 5 and 8 positions. This effect of "positional preference" indicates that thiyl radicals entering the hydrophobic region of the membrane bilayer start to isomerize polyunsaturated fatty acid residues having the double bonds nearest to the membrane surfaces. We propose that arachidonic acid and its trans isomers can function as biomarkers in membranes for distinguishing the two trans fatty acid-forming pathways.
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Affiliation(s)
- Carla Ferreri
- I.S.O.F., Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy.
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121
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Ivkovic A, Matovic R, Saicic RN. Ring-Closing Metathesis/Fragmentation Route to Geometrically Defined Medium-Ring Cycloalkenes: Total Synthesis of (±)-Periplanone C. Org Lett 2004; 6:1221-4. [PMID: 15070302 DOI: 10.1021/ol049875z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The combination of alkene metathesis and beta-fragmentation offers an efficient entry into (Z)-configured medium-ring cycloalkenes. The versatility of this method is demonstrated by the total synthesis of Periplanone C, a semiochemical of Periplaneta americana. [reaction: see text]
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Affiliation(s)
- Aleksandar Ivkovic
- Faculty of Chemistry, University of Belgrade, Studentski trg 16, P.O. Box 158, 11000 Belgrade, Serbia and Montenegro
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122
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Tetrahedron reports on organic chemistry. Tetrahedron 2004. [DOI: 10.1016/s0040-4020(04)00315-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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123
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01884-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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124
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Braun NA, Meier M, Kohlenberg B, Valder C, Neugebauer M. Santalum spicatum(R. Br.) A. DC. (Santalaceae)—nor-Helifolenal and Acorenol Isomers: Isolation and Biogenetic Considerations. JOURNAL OF ESSENTIAL OIL RESEARCH 2003. [DOI: 10.1080/10412905.2003.9698617] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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125
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01130-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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126
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Posner PG, Motherwell PW. Tetrahedron reports on organic chemistry. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00841-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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127
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Valder C, Neugebauer M, Meier M, Kohlenberg B, Hammerschmidt FJ, Braun NA. Western Australian Sandalwood Oil—New Constituents ofSantalum spicatum(R. Br.) A. DC. (Santalaceae). JOURNAL OF ESSENTIAL OIL RESEARCH 2003. [DOI: 10.1080/10412905.2003.9712106] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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128
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Tetrahedron reports on organic chemistry. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)00323-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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129
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Braun NA, Meier M, Pickenhagen W. Isolation and Chiral GC Analysis of β-Bisabolols—Trace Constituents from the Essential Oil ofSantalum albumL. (Santalaceae). JOURNAL OF ESSENTIAL OIL RESEARCH 2003. [DOI: 10.1080/10412905.2003.9712064] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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130
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Ferreri C, Faraone Mennella MR, Formisano C, Landi L, Chatgilialoglu C. Arachidonate geometrical isomers generated by thiyl radicals: the relationship with trans lipids detected in biological samples. Free Radic Biol Med 2002; 33:1516-26. [PMID: 12446209 DOI: 10.1016/s0891-5849(02)01083-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The presence of trans fatty acids in mammalians is attributed to exogenous sources; nevertheless, trans isomers could be easily formed by free radical-catalyzed isomerization processes in vivo. The isomerization of methyl arachidonate (all-cis isomer) catalyzed by thiyl radical is proposed as a methodology applicable in biochemical laboratories, which produces mono- and di-trans isomers. Carbon-13 nuclear magnetic resonance spectroscopy shows that the carbon atom in position 15 is characteristic for each mono- and di-trans isomer. Antioxidants, such as alpha-tocopherol and all-trans-retinol acetate, inhibited the isomerization process. Trans phospholipids are formed in erythrocyte membranes by exposing blood to gamma-irradiation in the presence of thiols, which is in contradiction with the known role of these compounds as radioprotectors. Trans isomers are also analyzed in tissues harvested from breast cancer patients and compared to the adipose breast tissue taken a few centimeters from the edge of the tumor from the same patient. This work is generally aimed at contributing to the debate on trans fatty acids and stimulating a reconsideration of the current view on the exclusive presence of cis double bonds in cell membranes by studying radical processes that could affect or protect this natural configuration.
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Affiliation(s)
- Carla Ferreri
- ISOF, Consiglio Nazionale delle Ricerche, Bologna, Italy.
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131
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Posner G, Motherwell W. Tetrahedron reports on organic chemistry. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)01503-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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132
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Hoskovec M, Luxová A, Svatoš A, Boland W. Biosynthesis of sex pheromones in moths: stereochemistry of fatty alcohol oxidation in Manduca sexta. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)01199-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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133
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Shan H, Wilson WK. Ternary gradient elution markedly improves silver-ion high performance liquid chromatography of unsaturated sterols. Steroids 2002; 67:917-23. [PMID: 12234627 DOI: 10.1016/s0039-128x(02)00056-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A wide variety of unsaturated sterols can accumulate in eukaryotic cells as a consequence of normal metabolism, genetic disorders, and actions of enzyme inhibitors. Resolving these sterol mixtures into individual components by conventional chromatographic methods is inefficient because unsaturated sterols differ little in polarity, hydrophobicity, and volatility. Although sterol mixtures are well-resolved by silver-ion high performance liquid chromatography (Ag(+)-HPLC), existing methods require derivatization to acetates for best results, and the isocratic mobile phases lead to long analysis times and low sensitivity for late-eluting sterols. We show that these problems can be overcome with ternary gradient elution using acetone, hexanes, and acetonitrile. Separation of a mixture of 20 underivatized sterols gave dramatically shortened analysis times, with good peak shapes for both early- and late-eluting components. In a similar separation of blood sterols from a patient with Smith-Lemli-Opitz syndrome, the band for 7-dehydrocholesterol was much narrower than with isocratic elution. Column re-equilibration was rapid, and the separations could be monitored with ultraviolet spectroscopy at 210 nm, which affords universal, non-destructive detection of unsaturated sterols. Also discussed are retention mechanisms and reproducibility of Ag(+)-HPLC separations. The overall results represent a major advance in chromatographic methods for resolving mixtures of unsaturated sterols differing in the number and position of olefinic bonds.
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Affiliation(s)
- Hui Shan
- Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street, Houston, TX 77005-1892, USA
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134
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Santangelo EM, Coracini M, Witzgall P, Correa AG, Unelius CR. Identification, syntheses, and characterization of the geometric isomers of 9,11-hexadecadienal from female pheromone glands of the sugar cane borer Diatraea saccharalis. JOURNAL OF NATURAL PRODUCTS 2002; 65:909-915. [PMID: 12088437 DOI: 10.1021/np010551i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Chemical analysis of the pheromone glands of the sugar cane borer Diatraea saccharalis has shown the presence of the four geometric isomers of 9,11-hexadecadienal (1-4), in addition to hexadecanal and (Z)-hexadec-11-enal. We here report the syntheses and characterization of compounds 1-4. One starting material, 9-decen-1-ol, has been used to obtain all of them via divergent synthetic routes.
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Affiliation(s)
- Ellen M Santangelo
- Department of Chemistry, Organic Chemistry, The Royal Institute of Technology, SE-10044 Stockholm, Sweden
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136
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van Beek TA, Wintermans MS. Preparative isolation and dual column high-performance liquid chromatography of ginkgolic acids from Ginkgo biloba. J Chromatogr A 2001; 930:109-17. [PMID: 11681568 DOI: 10.1016/s0021-9673(01)01194-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A chromatographic procedure for the preparative isolation of six different 6-alkylsalicylic acids (syn. ginkgolic acids) with as alkyl substituents C13:0, C15:0, C15:1, C17:1, C17:2 and, tentatively C17:3 from Ginkgo biloba leaves was developed. The procedure consisted of a combination of normal-phase, reversed-phase and argentation chromatography. The compounds were characterised by means of UV, 1H-NMR and 13C-NMR spectroscopy, and mass spectrometry after silylation. A 15 cm C18 RP-HPLC column connected in series with a 20 cm silver(I) loaded cation exchanger HPLC column in combination with the solvent methanol-water (93:7) acidified with 0.1% formic acid was capable of separating the ginkgolic acids C13:0, C15:1, C17:2, C15:0 and C17:1 within 21 min on an analytical scale. The separation is based on a combination of reversed-phase mechanisms and double bond complexation. Detection took place by UV at 311 nm. The separation is a good starting point for the development of a quantitative procedure for the five major ginkgolic acids in Ginkgo leaves and standardised extracts.
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Affiliation(s)
- T A van Beek
- Laboratory of Organic Chemistry, Phytochemical Section, Wageningen University, The Netherlands.
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