miun.sePublikasjoner
Endre søk
Begrens søket
123 51 - 100 of 106
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Treff pr side
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
  • Standard (Relevans)
  • Forfatter A-Ø
  • Forfatter Ø-A
  • Tittel A-Ø
  • Tittel Ø-A
  • Type publikasjon A-Ø
  • Type publikasjon Ø-A
  • Eldste først
  • Nyeste først
  • Skapad (Eldste først)
  • Skapad (Nyeste først)
  • Senast uppdaterad (Eldste først)
  • Senast uppdaterad (Nyeste først)
  • Disputationsdatum (tidligste først)
  • Disputationsdatum (siste først)
Merk
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 51.
    Högberg, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Larsson, Michael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diasteroselective Addition to Chiral Racemic 2-Methylaldehydes using Organozinc Reagents.: Poster och Abstrakt, 18:e Organikerdagarna, Mitthögskolan, Sundsvall.2002Konferansepaper (Annet vitenskapelig)
  • 52.
    Högberg, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Larsson, Michael
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pherodip: Third coordination meeting, Freising, Munchen, Germany, deltagande.1997Konferansepaper (Annet vitenskapelig)
  • 53.
    Högberg, Hans-Erik
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Isaksson, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Franssen, M
    Jongejan, H
    Wijnberg, J
    de Groot, A
    Formation of hemiacetal esters in lipase-catalysed reactions of vinyl esters with hindered secondary alcohols2000Inngår i: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 41, nr 17, s. 3193-3196Artikkel i tidsskrift (Fagfellevurdert)
  • 54. Högberg, Hans-Erik
    et al.
    Wennerström, O
    Synthesis of Some Bicyclophanes.1982Inngår i: Acta Chemica Scandinavica, B-Organic chemistry and biochemistry, ISSN 0302-4369, Vol. 36, nr 10, s. 661-667Artikkel i tidsskrift (Fagfellevurdert)
  • 55.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantioselektiv syntes av norterpenen Cryptone: 19:e Organikerdagarna, 14-17 juni, Linköping2004Konferansepaper (Annet vitenskapelig)
  • 56.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantioselektiv syntes av seskviterpenen torreyol och andra kadinenderivat: 20:e Organikerdagarna, 12-15 juni 2006, Kalmar, Poster2006Konferansepaper (Annet vitenskapelig)
  • 57.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark Henriksson, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemiacetal ester formation in lipase catalysed transesterifications of vinyl esters with hindered secondary alcohols: Meeting abstract2003Inngår i: ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 2003Konferansepaper (Fagfellevurdert)
  • 58.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Lindmark-Henriksson, Marica
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hemiacetals and their esters as side-products in lipase catalysed transesterification of vinyl esters with sterically hindered alcohols2004Inngår i: Journal of Molecular Catalysis B: Enzymatic, ISSN 1381-1177, E-ISSN 1873-3158, Vol. 31, nr 1-3, s. 31-37Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hemiacetals and their esters are formed as side-products in lipase catalysed transesterification of vinyl esters with sterically hindered secondary alcohols. Scope and limitations of the reaction as well as the consequences of it for lipase catalysed kinetic resolutions are discussed.

  • 59.
    Isaksson, Dan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantiomerically enriched cryptone by lipase catalysed kinetic resolution2006Inngår i: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 17, nr 2, s. 275-280Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Thiophenol was added to racemic cryptone (4-isopropyl-2-cyclohexene-1-one) and the resulting 1,4-addition products, cis- and trans-4-isopropyl-3-(phenylsulfanyl)cyclohexanone) were separated and the latter reduced to rac-1,3-cis-1,4-trans-4-isopropyl-3-(phenylsulfanyl)cyclo¬he¬xanol which was subjected to lipase catalysed resolution by acylation catalysed by CAL-B (Candida antarctica lipase B). The remaining alcohol was separated from the produced acetate, which was hydrolysed to the alcohol. The enantiomeric alcohols so obtained were oxidised. The initial products, probably sulfoxidoketones spontaneously decomposed to furnish enantiomerically enriched (R)- and (S)-cryptone with up to 76% and 98% ee, respectively.

  • 60. Ivarsson, P
    et al.
    Tittiger, C
    Blomquist, C
    Borgeson, C
    Seybold, S
    Blomquist, G
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pheromone precursor synthesis is localized in the metathorax of Ips paraconfusus Lanier (Coleoptera : Scolytidae)1998Inngår i: Naturwissenschaften, ISSN 0028-1042, Vol. 85, nr 10, s. 507-511Artikkel i tidsskrift (Fagfellevurdert)
  • 61. Johansson, Björn
    et al.
    Anderbrant, Olle
    Simandl, Jiri
    Avtzis, Nikolaos
    Salvadori, Christina
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Edlund, Helen
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Release Rates for Pine Sawfly Pheromones from Two Types of Dispensers and Phenology of Neodiprion sertifer2001Inngår i: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561, Vol. 27, nr 4, s. 733-745Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Comparisons of release rates, duration in the field, and catch efficiency of polyethylene and cotton roll dispensers for the sex pheromones of sawflies (Hymenoptera: Diprionidae) were conducted. The release rates of the Neodiprion sertifer (Geoffr.) and Diprion pini (L.) sex pheromones, the acetates of pentadecanol and (2S,3S,7S)-3,7-dimethyl (2S,3R,7R)-3,7-dimethyl-2-tridecanol from polyethylene dispensers were measured at different temperatures in the laboratory. The release rates for the substances depended on both the temperature and initial load in the vials. The catch from cotton rolls baited with 100 μg of the acetate or propionate of 3,7-dimethyl-2-pentadecanol was compared to the catch from regularly renewed cotton rolls baited with 10 μg of the same acetate. The catch was higher for the 100-μg cotton rolls for, at most, 45 days, and there was no significant difference in catch between the acetate and the propionate. The catch in traps baited with polyethylene or cotton roll dispensers loaded with the acetate of 3,7-dimethyl-2-pentadecanol was compared and showed that cotton roll traps mirrored the decreasing release of the substance rather than the actual flight activity. The length of the flight period of N. sertifer in Sweden, the Czech Republic, Italy, and Greece did not exceed 100 days in any of the countries. By adjusting the initial pheromone load of the polyethylene vials to the expected temperatures, it should be possible to get a constant and sufficiently high release rate during the entire flight period.

  • 62.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Han, F
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Caldirola, P
    trans-3,4-Disubtituted Pyrrolidines by 1,3-Dipolar Cycloaddition: Enantioselective Approaches and their Limitations1999Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 10, nr 13, s. 2605-2616Artikkel i tidsskrift (Fagfellevurdert)
  • 63.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Asymmetric 1,3-dipolar cycloadditions for the construction of enantiomerically pure heterocycles. A review2001Inngår i: Organic preparations and procedures international, ISSN 0030-4948, E-ISSN 1945-5453, Vol. 33, nr 2-3, s. 105-172Artikkel, forskningsoversikt (Fagfellevurdert)
  • 64.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Catalytic enantioselective 1,3-dipolar cycloaddition of nitrones to cyclopent-1-enecarbaldehyde2002Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 13, nr 9, s. 923-926Artikkel i tidsskrift (Fagfellevurdert)
  • 65.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective addition of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries2001Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, nr 14, s. 1975-1976Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloadditions of chiral azomethine ylides to cinnamoyl moieties, attached to chiral auxiliaries, were investigated. The resulting trans-3,4-disubstituted pyrrolidines were obtained in diastereomeric ratios of up to 78:22. The influence on this ratio by the constitution of the chiral ylide was found to be rather small.

  • 66.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective addition of chiral azomethine ylides to cyclic alpha,beta-unsaturated N-enoylbornanesultams2002Inngår i: Journal of the Chemical Society. Perkin Transactions 1, ISSN 1472-7781, Vol. 2002, nr 8, s. 1076-1081Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Doubly diastereoselective 1,3-dipolar cycloaddition reactions of chiral non-racemic azomethine ylides to cyclic five-and six-membered α,β-unsaturated N-enoylbornanesultams were carried out. When suitable solvents were used, the fused bicyclic adducts formed were obtained in good diastereoselectivity. Moreover, a change of the absolute configuration of the starting ylide precursor reversed the diastereoselectivity of some such reactions. Cleavage of the chiral auxiliary of the cycloadducts furnished amino alcohols and a β-amino ester. The latter was transformed into a known precursor of an antibacterial compound.

  • 67.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantiomerically pure trans-3,4-disubstituted tetrahydrothiophenes from diastereoselective thiocarbonyl ylide addition to chiral alpha,beta-unsaturated amides1999Inngår i: Organic Letters, ISSN 1523-7060, Vol. 1, nr 10, s. 1667-1669Artikkel i tidsskrift (Fagfellevurdert)
  • 68.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Organocatalysts Promote Enantioselective 1,3-Dipolar Cycloadditions of Nitrones with 1-Cycloalkene-1-carboxaldehydes2003Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2003, nr 15, s. 2782-2791Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the presence of enantiopure organocatalysts, 1-cycloalkene-1-carboxaldehydes and various nitrones furnished fused isoxazolidines. Thus, some chiral pyrrolidinium salts catalyzed the formation of such cycloadducts in high diastereo- and enantioselectivity (up to 92% ee). The predominant diastereomer, the exo one, was mostly obtained in excellent diastereoselectivity (> 99:1 dr). Furthermore, after recrystallization of one of the cycloadducts, this was obtained enantiomerically pure (> 99% ee). The absolute configuration of one of the cycloadducts was determined. 

  • 69.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Pheromones of Pine Sawflies: Synthesis of a Pure (2S,3R)-3-Methylalkan-2-ol Stereoisomer via an Asymmetric 1,3-Dipolar Cycloaddition; Preparation of a Pheromone Component of Macrodiprion nemoralis2000Inngår i: Synthesis, ISSN 0039-7881, Vol. 2000, nr 13, s. 1863-1867Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a new approach to the preparation of enantiomerically pure (2S,3R)-3-methylalkan-2-ols, the esters of which are sex pheromones of several pine sawflies. Thus, an asymmetric 1,3-dipolar cycloaddition between a sulfur containing 1,3-dipole and a dipolarophile attached to (1R)-camphorsultam containing a vinyl ether functionality furnished a 90:10 diastereomeric mixture of trans-3,4-disubstituted tetrahydrothiophene amides. The major one was converted to an enantiomerically pure tetrahydrothienylmethyl bromide, which was coupled with a monoalkylated dithiane unit. After Raney nickel reduction (2S,3R,7R,9S)-3,7,9-trimethyltridecan-2-ol was obtained, the acetate of which is the attractant sex pheromone component of Macrodiprion nemoralis. Because this new approach is quite efficient it can be valuable for the synthesis of similar compounds.

  • 70.
    Karlsson, Staffan
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Synthesis of enantiomerically pure 4-substituted pyrrolidin-3-ols via asymmetric 1,3-dipolar cycloaddition2001Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, nr 14, s. 1977-1982Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Asymmetric 1,3-dipolar cycloadditions of chiral azomethine ylides to 3-benzyloxy-substituted alkenoylcamphorsultams are described. trans-3,4-Disubstituted pyrrolidines containing a protected hydroxyl group at C(4) of the pyrrolidine ring are obtained in high diastereomeric ratios. Such compounds can serve as chiral building blocks for the syntheses of enantiopure bioactive pyrrolidines. This is exemplified by a short synthetic route to a known glycosidase inhibitor, (3R,4R)-4-(hydroxymethyl)pyrrolidin-3-ol and its enantiomer.

  • 71.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Andersson, Jimmy
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Liu, Rong
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enantiopure building blocks for the synthesis of 3-methyl-2-alkanols: Diastereoselective methylmetal addition to a chiral 2-methylaldehyde followed by lipase catalysed esterification2004Inngår i: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 15, nr 18, s. 2907-2915Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The racemic synthetic building block (2R*,3R*)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R*,3R*)-2 was obtained in a high diastereomeric ratio [95:5, (2R*,3R*)/(2R*,3S*)-ratio] by Lewis acid catalysed dimethylzinc addition to racemic 2-methyl-3-(phenylsulfanyl)propanal (rac-1). Two consecutive acylations with vinyl acetate catalysed by Chirazyme L-2 (immobilised Candida antarctica lipase 13, CAL-B) led to preferential esterification of three of the four stereoisomers leaving (2S,3S)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2S,3S)-2 of 98:2 dr and 98% ee. The stereoisomerically impure acetate of (2R,3R)-3-methyl-4-(phenyisulfanyl)butan-2-ol (2R,3R)-2, obtained in the first CAL-B-catalysed acylation step, was hydrolysed and reesterified using CAL-A (immobilised Novozyme SP 525) as the catalyst, which left (2R,3R)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R,3R)-2 of 98:2 dr and 99% ee as the remaining substrate. The individual enantiomers of 2-methyl-3-(phenylsulfanyl)propanal 1 were prepared from readily available (S)- and (R)-3-hydroxy-2-methylpropanoic acid methyl ester and reacted with dimethylzinc to give both enantiomers of (2R*,3R*)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2R, 3R)- or (2S,3S)-2 of both high dr and ee. These products were purified by lipase catalysed acylation to give the enantiomerically and diastereomerically highly pure enantiomers (>99.5:0.5 dr, >99.9% ee). Pure (2S,3S)-3-methyl-4-(phenylsulfanyl)butan-2-ol (2S,3S)-2 was transformed into a potential pheromone precursor isolated from some pine sawflies of the genus Gilpinia, (2S,3R)-3-methylpentadecan-2-ol in 54% yield over eight steps.

  • 72.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Galandrin, Elodie
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective Addition of Organozinc Reagents to 2-alkyl-3-(arylsulfanyl)propanals2004Inngår i: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 60, nr 47, s. 10659-10669Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-alkyl moiety of high diastereomeric purity is described. Such compounds can serve as potential building blocks for the preparation of several kinds of natural products. Diastereoselective synthesis of two potential pine sawfly pheromone components, one the pure racemic threo-isomer of 3-methylpentadecan-2-ol and the other the racemic erythro-isomer of 3-methyltridecan-2-ol are described. The diastereoselective addition of R2Zn (R = Me, Et and n-Bu) to several 2-alkyl-3-(arylsulfanyl)propanals in the presence of a Lewis acid and CH2Cl2 as solvent was studied. An excellent diastereomeric ratio (95/5 anti-Cram/Cram) was obtained with 2-[(phenylsulfanyl)methyl]pentanal, 2-[(phenylsulfanyl)methyl]decanal and 2-[(phenylsulfanyl)methyl]dodecanal and Me2Zn in the presence of TiCl4. (C) 2004 Elsevier Ltd. All rights reserved.

  • 73.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diastereoselective Addition of Methylmetallic Reagents to 2-Methylaldehydes2001Inngår i: Tetrahedron, ISSN 0040-4020, Vol. 57, nr 35, s. 7541-7548Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The preparation of compounds incorporating the 3-hydroxy-2-methyl-1-butyl moiety of high diastereomeric purity is described. These compounds can serve as potential building blocks for the preparation of several kinds of natural products. The diastereoselective addition of a number of methylmetal derivatives to three 3-substituted 2-methylaldehydes in various solvents was studied. An excellent diastereomeric ratio (95:5 anti-Cram/Cram) was obtained with 2-methyl-3-(phenylsulfanyl)propanal (5) and Me2Zn in the presence of TiCl4.

  • 74.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Diasteroselective Addition to Chiral Racemic Aldehydes, via Methylmetallic Reagents.: Poster och Abstrakt, ESOC 11, Göteborgs Universitet, Göteborg1999Konferansepaper (Annet vitenskapelig)
  • 75.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Totalsyntes av två attrahentkomponenter hos Microdiprion pallipes, via en anti-Cramselektiv addition av dimetylzink till en 2-metylaldehyd: Organikerdagarna 2004 i Linköping2004Konferansepaper (Annet vitenskapelig)
  • 76.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nguyen, Ba-Vu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine Sawfly Microdiprion pallipes (Hymenoptera: Diprionidae)2001Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, Vol. 2001, nr 2, s. 353-363Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    All sixteen stereoisomers of 3,7,11-trimethyl-2-tridecanol were synthesised in high stereoisomerical purities (> 95%), for use in the identification of the stereoisomers present in females of the pine sawfly Microdiprion pallipes (Fallen) (Hymenoptera: Diprionidae) as the precursor of the actual sex pheromone (which is the propionate), and also for investigation of the biological activities of the esters. The key step in the syntheses was the coupling of each of the enantiomers of cis-3,4-dimethyl-gamma -butyrolactone with each of the four pure stereoisomers of 1-lithio-2,6-dimethyloctanes. The four corresponding alcohols were obtained by lipase-catalysed (Amano PS) kinetic separation, based on selective acylation of either (2R/S,6S)- or (2R/S,GR)-2,6-dimethyl-1-octanol (obtained from the optically pure enantiomers of citronellal). Additionally, a mixture of the 16 possible stereoisomers of 3,7,11-trimethyl-2-tridecanol was also prepared.

  • 77.
    Larsson, Michael
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Ngyuen, Ba-Vu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Synthesis and Studies of the Stereoisomeric Composition in the Sex Pheromone of Microdiprion pallipes.: Poster och abstrakt. Euchem conference, Sundsvall.1998Konferansepaper (Annet vitenskapelig)
  • 78. Lin, Guoqiang
    et al.
    Hjalmarsson, Mats
    Högberg, Hans-Erik
    Jernstedt, Karen
    Norin, Torbjörn
    Asymmetric Synthesis of 2-alkylalkanoic acids via Alkylation of Chiral Amide Anions.1984Inngår i: Acta Chemica Scandinavica, ISSN 0904-213X, E-ISSN 1902-3103, Vol. B38, s. 795-801Artikkel i tidsskrift (Fagfellevurdert)
  • 79. Lin, Guoqiqng
    et al.
    Högberg, Hans-Erik
    Norin, Torbjörn
    Asymmetric Synthesis of 2-Alkylalkanoic Acids via Alkylation of Chiral Amide Anions1984Inngår i: Chinese Science Bulletin (Kexue Tongbao -English version), ISSN 1001-6538, Vol. 29, nr 5, s. 632-634Artikkel i tidsskrift (Fagfellevurdert)
  • 80.
    Lindmark Henriksson, Marica
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Isaksson, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Vanek, Tomas
    Valterova, Irena
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Transformation of terpenes using a Picea abies suspension culture2004Inngår i: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 107, nr 2, s. 173-184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When subjected to a Picea abies suspension cell culture, beta-pinene, either one of the pure enantiomers or the racemate, was transformed mainly to trans-pinocarveol along with the minor products myrtenol, alpha-terpineol, pinocarvone, myrtenal and cis-pinocarveol. The absolute configuration of the major products corresponded to that of the starting beta-pinene enantiomer. Some of the primary transformation products, i.e. (1S)-cis- and (1S)-trans-pinocarveol, (1R)-myrtenol and (4S)-alpha-terpineol, were also tested as substrates of the P. abies suspension culture. They reacted more slowly than beta-pinene but, except for (4S)-alpha-terpineol, they were all transformed. Thus, (1R)-myrtenol was converted into both (1R)-myrtenal and (1R)-myrtanol, whereas (1S)-trans-pinocarveol was converted into (1S)-pinocarvone. (4R)-Limonene was slowly transformed by the suspension culture into limonene-(1,2)-epoxide as the major product, with carveol, perillyl alcohol and 1,8-cineole as minor products. Autoxidation of terpenes in cell-free nutrient medium was investigated in detail. alpha-Pinene and beta-pinene were both autoxidized to a certain extent, while limonene remained unaffected. The rate of the autoxidation was more than one order of magnitude slower than that of the biotransformation. Moreover, different products were formed by autoxidation than by biotransformation.

  • 81.
    Lindmark-Henriksson, Marica
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Isaksson, Dan
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Vanek, Tomas
    Valterova, Irena
    Transformation of alpha-pinene using Picea abies suspension culture2003Inngår i: Journal of Natural Products, ISSN 0163-3864, Vol. 66, nr 3, s. 337-343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    alpha-Pinene, both as the pure enantiomers and as the racemate, was transformed mainly to trans-verbenol by treatment with a Picea abies suspension cell culture. These reactions were followed by a slow transformation of the verbenol to verbenone, which was not transformed further. trans-Pinocarveol, myrtenol, cis-verbenol, and alpha-terpineol were byproducts of intermediate abundance. When subjected to the action of the suspension culture, cis-verbenol was not only transformed to verbenone but also isomerized to trans-verbenol. The transformation of alpha-pinene was fast, and the products were detected within one minute. The absolute configuration of the major products corresponded to that of the starting alpha-pinene enantiomer

  • 82. Lindström, M
    et al.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Servi, S
    Pedrocchi-Fantoni, G
    Preparation of enantiomerically pure methyl (R)-a-hydroxy(2-furyl)acetate by Baker's yeast reduction in multiphase systems1999Inngår i: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 53, nr 5, s. 378-380Artikkel i tidsskrift (Fagfellevurdert)
  • 83.
    Liu, Rong
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Berglund, Per
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Preparation of the four stereoisomers of 3-bromo-2-butanol or their acetates via lipase-catalysed resolutions of the racemates derived from dl- or meso-2,3-butanediol2005Inngår i: Tetrahedron: asymmetry, ISSN 0957-4166, E-ISSN 1362-511X, Vol. 16, nr 15, s. 2607-2611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The four stereoisomeric 3-bromo-2-butanols and/or their acetates were prepared via lipase-catalysed kinetic resolution by hydrolyses of the acetates of the (+/-)-syn- and (+/-)-anti-3-bromo-2-butanols, or via esterifications of the alc hols. The diastereomeric bromoacetates were obtained by syntheses from the dl- and meso-2,3-butanediols, respectively. On a preparative scale, the four stereoisomers, either as the free alcohols or as their acetates, were obtained in > 95% ee, and in 35-40% yield (based on the starting racemates).

  • 84.
    Liu, Rong
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Chemoenzymatic preparation of (2S, 3S)- and (2R, 3R)-2,3-butanediols and their esters from mixtures of d,l- and meso-diols2001Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 12, nr 5, s. 771-778Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An efficient method of preparing the pure enantiomers of 2,3-butanediol front commercially available mixtures of the d,l- and meso-isomers was developed. It furnished (2S,3S)-2.3-butanediol with > 99% e.e. and a >9.5/0.5 diastereomeric ratio and (2R,3R)-2,3-butanediol in 95% e.e. and >9.5/<5 diastereomeric ratio.

  • 85. Lundh, Mårten
    et al.
    Nordin, Ove
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Enzyme Catalysed Irreversible Transesterifications with Vinyl Acetate: Are they really Irreversible?1995Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 6, nr 9, s. 2237-2244Artikkel i tidsskrift (Fagfellevurdert)
  • 86. Lyytikäinen-Saarenmaa, P
    et al.
    Anderbrant, O
    Löfqvist, J
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Monitoring European pine sawfly population density with pheromone traps in young pine plantations1999Inngår i: Forest Ecology and Management, ISSN 0378-1127, Vol. 124, nr 2-3, s. 113-121Artikkel i tidsskrift (Fagfellevurdert)
  • 87. Lyytikäinen-Saarenmaa, P
    et al.
    Varama, M
    Anderbrant, O
    Kukkola, M
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Predicting Pine Sawfly Population Densities and Subsequent Defolation with Pheromone Traps2001Inngår i: Integrated management and dynamics of forest defoliating insects, 2001, s. 108-116Konferansepaper (Fagfellevurdert)
  • 88. Lyytikäinen-Saarenmaa, P.
    et al.
    Varama, M.
    Anderbrant, O.
    Kukkola, M.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Predicting pine sawfly population densities and subsequent defoliation with pheromone traps2001Inngår i: Proceedings. Integrated management and dynamics of forest defoliating insects, Victoria, Canada, 15-19 August 1999, 2001, s. 108-116Konferansepaper (Fagfellevurdert)
  • 89.
    Lyytikäinen-Saarenmaa, P
    et al.
    Department of Applied Biology, University of Helsinki, Helsinki, Finland.
    Varama, M
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Anderbrant, O
    Department of Ecology, Lund University, Ecology Building, Lund.
    Kukkola, M
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Kokkonen, A.-M.
    Finnish Forest Research Institute, Vantaa Research Centre, Vantaa, Finland.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands2006Inngår i: Agricultural and Forest Entomology, ISSN 1461-9555, Vol. 8, nr 1, s. 7-15Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. During 1989-93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation. 2. Three traps per site were baited with 100 μg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 μg) of the pheromone were tested in 1991-92. 3. The highest number of males was observed in traps baited with the highest dose. On average, there was a 10-fold increase in trap catch between lure doses. 4. Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare. 5. Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800-1000 males per trap or higher.

  • 90. Martini, A.
    et al.
    Baldassari, N.
    Baronio, P.
    Anderbrant, O.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Rocchetta, G.
    Mating disruption of the pine sawfly Neodiprion sertifer (Hymenoptera. Diprionidae) in isolated pine stands2002Inngår i: Agricultural and Forest Enthomology, ISSN 1461-9555, Vol. 4, nr 3, s. 195-201Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    1. Previous applications of the mating disruption technique to Neodiprion sertifer resulted in decreased numbers of males caught in the treated area but no effect on sex ratio or overall population density. 2. The present study assessed the efficacy of mating disruption against N. sertifer outbreaks in pine stands surrounded by agricultural areas or pasture, and therefore isolated from other infested areas. 3. Pine stands were treated by placing dispensers with an erythro-mixture of the acetate ester of 3,7-dimethyl-2-pentadecanol every 10 m in a grid. 4. The efficacy of this technique was evaluated by comparing the number of males caught in sticky traps baited with synthetic pheromone, and by comparing the sex ratio and the population density of the sawfly in the subsequent generation between treated and control pine stands. 5. The number of males caught within treated areas was significantly lower than in the control area. 6. In the treated pine stands 46% of the egg clusters resulted in male cocoons only, compared to 3% of the clusters in the control stand. 7. A significant reduction of the sawfly population was observed in the treated pine stands. The results contrast to the earlier mating disruption attempts with N. sertifer and can probably be ascribed to the isolation of the experimental stands.

  • 91.
    Nguyen, Ba-Vu
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nordin, Ove
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Vörde, Carin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Structure vs. Enantioselectivity in Pseudomonas cepacia Lipase Catalysed Transesterifications: Enantioselective Acylation of Primary 2-Methylalcohols1997Inngår i: Tetrahedron: Asymmetry, ISSN 0957-4166, Vol. 8, nr 7, s. 983-986Artikkel i tidsskrift (Fagfellevurdert)
  • 92.
    Nordin, Ove
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Stereochemistry of 1,6-Germacradien-5-ol, a Constituent of the Needles of Scots Pine Pinus silvestris) and the Defence Secretation from Larvae of the Pine Sawfly Neodiprion sertifer1999Inngår i: Acta Chemica Scandinavica, ISSN 0904-213X, Vol. 53, nr 2, s. 124-132Artikkel i tidsskrift (Fagfellevurdert)
  • 93.
    Nordin, Ove
    et al.
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Nguyen, Ba-Vu
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Vörde, Carin
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Kinetic Resolution of Primary 2-methylalcohols via Pseudomonas cepacia Lipase Catalysed Enantioselective Acylation2000Inngår i: Journal of The Chemical Society. Perkin Transactions 1, ISSN 1472-7781, s. 367-376Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The enantioselectivities of lipases from Pseudomonas cepacia (PFL, Amano PS, etc.) towards a series of primary 2-methyl-substituted alcohols using vinyl acetate as the acyl donor in transesterifications in organic solvents were studied. In terms of enantioselectivity, the best results were found for 3-aryl-2-methylpropan-1-ols with enantiomeric ratios (E-values) over 100 in most cases, whereas other 3-substituted primary 2-methylpropan-1-ols generally displayed lower enantioselectivities: 3-cycloalkyl-2-methylpropan-1-ols (E ≈ 20) and 2-methylalkan-1-ols (E ≈ 10). Moving the aryl group closer or further away from the chiral centre resulted in low enantioselectivities: 2-arylpropan-1-ols (E < 10), 2-methyl-4-(2-thienyl)butan-l-ol (E = 12), 2-methyl-5-(2-thienyl)pentan-l-ol (E=3.2) and 2-methyl-6-(2-thienyl)hexan-l-ol (E=3.8).

  • 94. Pedrocchi-Fantoni, G
    et al.
    Redaelli, S
    Servi, S
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Chiral Amino-alcohols from Baker's Yeast Reduction of Alpha-Keto-acid Derivatives1992Inngår i: Gazzetta Chimica Italiana, ISSN 0016-5603, Vol. 122, nr 12, s. 499-502Artikkel i tidsskrift (Fagfellevurdert)
  • 95. Rieske, L K
    et al.
    Townsend, L
    Anderbrant, O
    Hedenström, Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Captures of Male European Pine Sawflies, Neodiprion sertifer (Hymenoptera: Diprionidae), in Pheromone-baited Traps in Kentucky2001Inngår i: Journal of entomological science, ISSN 0749-8004, Vol. 36, nr 1, s. 67-73Artikkel i tidsskrift (Fagfellevurdert)
  • 96. Schlyter, F
    et al.
    Smitt, Olof
    Sjödin, Kristina
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Löfqvist, J
    Carvone and less volatile analogues as repellent and deterrent antifeedants against the pine weevil, Hylobius abietis2004Inngår i: Journal of applied entomology, ISSN 0931-2048, E-ISSN 1439-0418, Vol. 128, nr 9-10, s. 610-619Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The monoterpenoid carvone (1) has been shown to have strong antifeedant effects on Hylobius spp. However, because of the high volatility of carvone, long-time protection of conifer seedlings in the field using this compound has not been possible. We demonstrate, in several bioassay steps, that less-volatile, heavier analogues retain their pre-ingestive feeding inhibition activity in the large pine weevil, Hylobius abietis (L.) for a longer time. The first step in the evaluation of the biological activity of 12 carvone analogues was a micro-assay, a choice test lasting 4 h. Compounds active at 100 nmol/cm(2) were further dose-response tested to give the effective dose needed to inhibit feeding by 50% (ED50). Of the 14 compounds tested, including both carvone enantiomers, seven heavier analogues were active at low doses (had low ED50 values). As expected from their lower vapour pressure compared with carvone, the heavier analogues proved more resistant to evaporation before testing. Thus, whereas the effect of 8-hydroxy-p-menth-en-6-one 4 declined after 2 days, some of the compounds with high molar masses, such as the alkylhydroxymenthenones 6 and 8, retained a stable activity for 4 days. The retained activity at 4 days was strongly correlated to molecular mass and boiling point. When tested on natural material (host Pinus sylvestris L. twig sections for 48 h), the heavier analogues showed a rather low activity. Probably, the activity of the more volatile compound carvone (1) is due to a repellent effect (olfactory mode) rather than the deterrent effects (gustatory mode) of the heavier compounds. In agreement with the relatively low activity on twigs in the laboratory, the hydroxymenthenone 4 was not active in the field when tested for 2 months as a 1 : 9 mixture with a polar wax.

  • 97. Smitt, Olof
    et al.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Chemoselective additions of thiophenol to carvone and perillaldehyde2002Inngår i: Journal of Chemical Research. Synopses, ISSN 0308-2342, Vol. 2002, nr 11, s. 527-528Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Depending on the reaction conditions addition of thiophenol can be directed to either of the two C=C-double bonds of the monoterpenes carvone and perillaldehyde.

  • 98. Smitt, Olof
    et al.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    First Total Synthesis of (-)-1(10),5-Germacradien-4-ol2002Inngår i: Synlett, ISSN 0936-5214, Vol. 2002, nr 8, s. 1273-1276Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a total synthesis of (-)-1(10),5-germacradien-4-ol, a constituent of the needles of Scots pine and of the defence secretion from the larvae of the pine sawfly. The synthesis uses a strategy based on an intramolecular alkylation to form an unsaturated monocyclic 10-membered ring.

  • 99. Smitt, Olof
    et al.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Syntheses of a prenylbisabolane diterpene, a natural insecticide from Croton linearis, and of the bisabolane sesquiterpenes (-)-delobanone and (-)-epi-delobanone2002Inngår i: Tetrahedron, ISSN 0040-4020, Vol. 58, nr 38, s. 7691-7700Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An enantioselective first total synthesis of a constituent of Croton linearis, the (-)-7-hydroxy-3,10-prenylbisaboladien-2-one 1, is described as well as the syntheses of the 7-hydroxy-3,10-bisaboladien-2-ones (-)-epi-delobanone (14a) and (-)-delobanone (14b). The model compounds, 7-hydroxy-11-nor-methyl-3-bisabolen-2-one (8a), and 11,15-nor-dimethyl-7-hydroxy-3-bisabolen-2-one (8b), were successfully prepared by opening of the protected carvone epoxide derivative 6 with the appropriate organocuprates. An alternative approach was used for compounds 1 and 14. Thus, these were obtained from homogeranyllithium or homoprenyl Grignard reagent, which reacted successfully with a masked nor-carvone, ketone 11, prepared in four steps from (R)-carvone.

  • 100. Svedberg, U. R. A.
    et al.
    Högberg, Hans-Erik
    Mittuniversitetet, Fakulteten för naturvetenskap, teknik och medier, Institutionen för naturvetenskap.
    Högberg, Johan
    Galle, Bo
    Emission of hexanal and carbon monoxide from storage of wood pellets, a potential occupational and domestic health hazard2004Inngår i: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 48, nr 4, s. 339-349Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

     Objectives: The objective of the present study was to investigate and describe the emissions of volatile compounds, particularly hexanal and carbon monoxide, from large- and small-scale storage of wood pellets.Methods: Air sampling was performed with Fourier transform infrared spectroscopy and adsorbent sampling in pellet warehouses, domestic storage rooms, lumber kiln dryers and experimental set-ups. Literature studies were included to describe the formation of hexanal and carbon monoxide and the toxicology of hexanal.Results: A geometric mean aldehyde level of 111 +/- 32 mg/m(3) was found in one warehouse, with a peak reading of 156 mg/m(3). A maximum aldehyde reading of 457 mg/m(3) was recorded at the surface of a pellet pile. Hexanal (70-80% w/w) and pentanal (10-15% w/w) dominated, but acetone (821 +/- 24 mg/m(3)), methanol (18 7 mg/m(3)) and carbon monoxide (56 +/- 4 mg/m(3)) were also found. The emissions in a domestic storage room varied with the ambient temperature and peaked after 2 months storage in the midst of the warm season. Aldehyde levels of 98 +/- 4 mg/m(3) and carbon monoxide levels of 123 +/- 10 mg/m(3) were recorded inside such storage rooms. Elevated levels of hexanal (0.084 mg/m(3)) were recorded inside domestic housing and 6 mg/m(3) in a room adjacent to a poorly sealed storage area. Experimental laboratory studies confirmed the findings of the field studies. A field study of the emissions from industrial lumber drying also showed the formation of aldehydes and carbon monoxide.Conclusions: High levels of hexanal and carbon monoxide were strongly associated with storage of wood pellets and may constitute an occupational and domestic health hazard. The results from lumber drying show that the emissions of hexanal and carbon monoxide are not limited to wood pellets but are caused by general degradation processes of wood, facilitated by drying at elevated temperature. Emission of carbon monoxide from wood materials at low temperatures (<100degreesC) has not previously been reported in the literature. We postulate that carbon monoxide is formed due to autoxidative degradation of fats and fatty acids. A toxicological literature survey showed that the available scientific information on hexanal is insufficient to determine the potential risks to health. However, the data presented in this paper seem sufficient to undertake preventive measures to reduce exposure to hexanal.

123 51 - 100 of 106
RefereraExporteraLink til resultatlisten
Permanent link
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf