Thorleif Anthonsen - Academia.edu (original) (raw)
Papers by Thorleif Anthonsen
Acta Chemica Scandinavica, 1994
Acta Chemica Scandinavica, 1986
ChemInform, 1994
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform, 1993
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
European Journal of Organic Chemistry
Lipase-catalyzed transesterifications and biological reductions were used to obtain the (S)-enant... more Lipase-catalyzed transesterifications and biological reductions were used to obtain the (S)-enantiomers of 3-chloro-1-(1,3-dithian-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-3-fluoro-2-propanol and their (R)-acetates. (S)-3-Chloro-1-(1,3-dithian-2-yl)-2-propanol and (R)-3-chloro-1-(1,3-dithian-2-yl)-2-propyl acetate were converted into the respective enantiomers of 2-(1,3-dithian-2-ylmethyl)oxirane. During this work we also isolated a new gem-disubstituted epoxide, 2-(chloromethyl)-2-(1,3-dithian-2-yl)oxirane. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
Acta Chemica Scandinavica, 1980
Acta Chemica Scandinavica, 1992
Acta Chemica Scandinavica, 1994
Green and Sustainable Chemistry, 2012
Acta chemica Scandinavica (Copenhagen, Denmark : 1989), 1994
The stereoselectivity of Baker's yeast reduction of prochiral alpha-oxygenated 2-propanones h... more The stereoselectivity of Baker's yeast reduction of prochiral alpha-oxygenated 2-propanones has been studied by varying the substrate structure. The 1-hydroxy-3-methoxy-3-propanone 1a was reduced to the corresponding alcohol (R)-2a with 88% enantiomeric excess. Replacing the hydroxy group in 1a with phenoxy or benzyloxy (1b and 1c) gave the alcohols (S)-2b and (S)-2c with 53 and 32% ee, respectively. Reduction of the methyl ketone 1d gave the alcohol (S)-2d with 91% ee. Attempts to improve the enantioselectivity of the reduction of 1c by lowering the substrate concentration or addition of selective reductase inhibitors had only small effect on the enantioselectivity.
![Research paper thumbnail of 2,2-Dimethyl-1,3-propanediol as protective group promotes microbial hydroxylation of cis-bicyclo[3.3.0]octane-3,7-dione](https://attachments.academia-assets.com/43189256/thumbnails/1.jpg)
](Screening of several filamentous fungi for hydroxylation of cis-bicyclo[3.3.0]octane-3,7-dione sh... more Screening of several filamentous fungi for hydroxylation of cis-bicyclo[3.3.0]octane-3,7-dione showed only reduction of the keto groups. Several ways to protect the keto groups have been tested. This resulted in hydrolysis with subsequent reduction, or rejection of the substrate. Only when 2,2-dimethyl-1,3-propanediol was used to form diketals, the substrate was relatively stable and at least one hydroxylated product could be detected.
Acta Chemica Scandinavica, 1994
Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phth... more Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phtha limido-beta-D - glucopyranoside 5 gave methyl 3,6-di-O-benzoyl-2,4-dideoxy-2-phthalimido-beta-D-glucopyranoside 6, which was converted into the corresponding methyl thioglycoside donor 9. Methylsulfenyl trifluoromethane-sulfonate-promoted glycosylation of 2-(trimethylsilyl)ethyl 2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosyl)-bet a-D- galactopyranoside 10, followed by removal of protecting groups gave the 4"-deoxy analogue 12 of the terminal trisaccharide of globotetraose. Silver trifluoromethanesulfonate-promoted glycosylation of the same disaccharide alcohol 10 with 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-alpha/beta-D-glucopyranosyl bromide 13 and 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide 16, followed by deblocking, gave the 2"-hydroxy and 4"-epi analogues 15 and 18, respectively.
ChemInform, 1999
Synthesis of 1,3-Dithianes and 1,3-Dithiolanes. Baker's Yeast Reduction and Lipase-Catalyzed Reso... more Synthesis of 1,3-Dithianes and 1,3-Dithiolanes. Baker's Yeast Reduction and Lipase-Catalyzed Resolution for Synthesis of Enantiopure Derivatives. -The synthesis of several dithiane and dithiolane derivatives starting from β-ketodithioacetals (I) is presented. Aldol reactions with formaldehyde (II) or benzaldehyde (XI) proceed at the enolate positions to afford enones (III) and (XII), resp., while enolate reactions take place at the carbonyl carbon or the oxygen atom. Reduction of β-ketoacetals (I) with baker's yeast proceeds with excellent enantioselectivity to afford optically pure alcohols (IX). In contrast, for enone (IIIb) with baker's yeast an enantioselective reduction of the methylene group is observed. Lipase-catalyzed transesterification of racemic alcohols (VI) and (IX), obtained from the corresponding ketones by NaBH 4 reduction, represents an efficient and highly stereoselective resolution method to yield optically pure (S)-alcohols and the corresponding (R)-acetates. -
Tetrahedron: Asymmetry, 2004
Biocatalytic asymmetrizations of diethyl 3-hydroxyglutarate furnish a route to the enantiomers of... more Biocatalytic asymmetrizations of diethyl 3-hydroxyglutarate furnish a route to the enantiomers of ethyl 4-cyano-3hydroxybutanoate. The enantiopreference of different enzymes has been established by chiral chromatography. Conclusive evidence for absolute configurations has been provided by X-ray crystallographic structure determination of co-crystals of the predominant monoester with (R)-phenylethylamine. The predominant enantiopure monoester produced by ammonolysis of diethyl 3-hydroxyglutarate catalyzed by immobilized lipase B from Candida antarctica (Novozym 435) was ethyl (3S)-4-carbamoyl-3-hydroxybutanoate. This was converted to ethyl (3S)-4-cyano-3-hydroxybutanoate in high yield and enantiomeric excess. Growing cells of Acinetobacter lwoffii gave low ee and predominance of the (S)-enantiomer when used for hydrolysis of diethyl 3-hydroxyglutarate as opposed to previous reports. When Novozym 435 was used for hydrolysis it could be re-used 10 times without loss of activity and selectivity.
Acta Chemica Scandinavica, 1999
Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-... more Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-propanone and 1-(1,3-dithian-2-yl)-2-propanone, respectively. Asymmetric reductions of these ketones using baker's yeast gave the corresponding enantiopure (S)-alcohols. Baker's yeast also reduced the double bond in 3-(1,3-dithian-2-yl)-3-buten-2-one enantioselectively to give (S)-3-(1,3-dithian-2-yl)-2-butanone. 3-(1,3-Dithian-2-yl)-3-buten-2-one was also reduced chemo-selectively and the resulting 3-(1,3-dithian-2-yl)-3-buten-2-ol was resolved by transesterification in organic solvent using lipase B from Candida antarctica to yield the (S)-alcohol and the (R)-acetate with very high enantiomeric ratio, E. Racemic 1-(1,3-dithiolan-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-2-propanol were also resolved under similar conditions to give the (S)-alcohols and the corresponding (R)-acetates.
International Journal of Chemistry, 2012
Kinetic resolution of rac-Stiripentol, catalysed by lipase A from Candida antarctica by esterific... more Kinetic resolution of rac-Stiripentol, catalysed by lipase A from Candida antarctica by esterification with vinyl butanoate was performed with an E-value of 24. This allowed isolation of (3S)-Stiripentol with an ee of 86 % and the corresponding (3R)-butanoate with an ee of 87 %. Enzymatic hydrolysis of the ester product gave (3R)-Stiripentol with 94 % ee.
Acta Chemica Scandinavica - ACTA CHEM SCAND, 1985
Tetrahedron: Asymmetry, 1996
A computer program for the determination of kinetic and thermodynamic parameters in biocatalytic ... more A computer program for the determination of kinetic and thermodynamic parameters in biocatalytic ping-pong bi-bi resolutions has been developed. The program uses enantiomeric excesses of both product (eep) and remaining substrate (ees) measured at more than one conversion (ξ), and determines both the equilibrium constant Keq, the enantiomer ratio E and the selectivity factor α. The program has been tested
Tetrahedron: Asymmetry, 1995
Lipase-catalysed hydrolysis of butanoates of 3-methoxy-1-(phenylmethoxy)-2-propanol and 3-chloro-... more Lipase-catalysed hydrolysis of butanoates of 3-methoxy-1-(phenylmethoxy)-2-propanol and 3-chloro-1-(phenylmethoxy)-2-propanol with various lipases gave low enantioselectivity, E. By additon of water miscible organic cosolvents, in particular tert-butanol and acetone, the E-value was raised from 7 to 220 for the useful chloro derivative. This finding has led to proposal of a process for production of homochiral C-3 synthons such as both enantiomers of
Acta Chemica Scandinavica, 1994
Acta Chemica Scandinavica, 1986
ChemInform, 1994
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform, 1993
ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
European Journal of Organic Chemistry
Lipase-catalyzed transesterifications and biological reductions were used to obtain the (S)-enant... more Lipase-catalyzed transesterifications and biological reductions were used to obtain the (S)-enantiomers of 3-chloro-1-(1,3-dithian-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-3-fluoro-2-propanol and their (R)-acetates. (S)-3-Chloro-1-(1,3-dithian-2-yl)-2-propanol and (R)-3-chloro-1-(1,3-dithian-2-yl)-2-propyl acetate were converted into the respective enantiomers of 2-(1,3-dithian-2-ylmethyl)oxirane. During this work we also isolated a new gem-disubstituted epoxide, 2-(chloromethyl)-2-(1,3-dithian-2-yl)oxirane. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004).
Acta Chemica Scandinavica, 1980
Acta Chemica Scandinavica, 1992
Acta Chemica Scandinavica, 1994
Green and Sustainable Chemistry, 2012
Acta chemica Scandinavica (Copenhagen, Denmark : 1989), 1994
The stereoselectivity of Baker's yeast reduction of prochiral alpha-oxygenated 2-propanones h... more The stereoselectivity of Baker's yeast reduction of prochiral alpha-oxygenated 2-propanones has been studied by varying the substrate structure. The 1-hydroxy-3-methoxy-3-propanone 1a was reduced to the corresponding alcohol (R)-2a with 88% enantiomeric excess. Replacing the hydroxy group in 1a with phenoxy or benzyloxy (1b and 1c) gave the alcohols (S)-2b and (S)-2c with 53 and 32% ee, respectively. Reduction of the methyl ketone 1d gave the alcohol (S)-2d with 91% ee. Attempts to improve the enantioselectivity of the reduction of 1c by lowering the substrate concentration or addition of selective reductase inhibitors had only small effect on the enantioselectivity.
Screening of several filamentous fungi for hydroxylation of cis-bicyclo[3.3.0]octane-3,7-dione sh... more Screening of several filamentous fungi for hydroxylation of cis-bicyclo[3.3.0]octane-3,7-dione showed only reduction of the keto groups. Several ways to protect the keto groups have been tested. This resulted in hydrolysis with subsequent reduction, or rejection of the substrate. Only when 2,2-dimethyl-1,3-propanediol was used to form diketals, the substrate was relatively stable and at least one hydroxylated product could be detected.
Acta Chemica Scandinavica, 1994
Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phth... more Radical deoxygenation of methyl 3,6-di-O-benzoyl-2-deoxy-4-O-imidazol-1-yl-thiocarbonyloxy-2-phtha limido-beta-D - glucopyranoside 5 gave methyl 3,6-di-O-benzoyl-2,4-dideoxy-2-phthalimido-beta-D-glucopyranoside 6, which was converted into the corresponding methyl thioglycoside donor 9. Methylsulfenyl trifluoromethane-sulfonate-promoted glycosylation of 2-(trimethylsilyl)ethyl 2,3,6-tri-O-benzyl-4-O-(2,4,6-tri-O-benzyl-alpha-D-galactopyranosyl)-bet a-D- galactopyranoside 10, followed by removal of protecting groups gave the 4"-deoxy analogue 12 of the terminal trisaccharide of globotetraose. Silver trifluoromethanesulfonate-promoted glycosylation of the same disaccharide alcohol 10 with 3,4,6-tri-O-acetyl-2-deoxy-2- phthalimido-alpha/beta-D-glucopyranosyl bromide 13 and 2,3,4,6-tetra-O-acetyl-alpha-D-galactopyranosyl bromide 16, followed by deblocking, gave the 2"-hydroxy and 4"-epi analogues 15 and 18, respectively.
ChemInform, 1999
Synthesis of 1,3-Dithianes and 1,3-Dithiolanes. Baker's Yeast Reduction and Lipase-Catalyzed Reso... more Synthesis of 1,3-Dithianes and 1,3-Dithiolanes. Baker's Yeast Reduction and Lipase-Catalyzed Resolution for Synthesis of Enantiopure Derivatives. -The synthesis of several dithiane and dithiolane derivatives starting from β-ketodithioacetals (I) is presented. Aldol reactions with formaldehyde (II) or benzaldehyde (XI) proceed at the enolate positions to afford enones (III) and (XII), resp., while enolate reactions take place at the carbonyl carbon or the oxygen atom. Reduction of β-ketoacetals (I) with baker's yeast proceeds with excellent enantioselectivity to afford optically pure alcohols (IX). In contrast, for enone (IIIb) with baker's yeast an enantioselective reduction of the methylene group is observed. Lipase-catalyzed transesterification of racemic alcohols (VI) and (IX), obtained from the corresponding ketones by NaBH 4 reduction, represents an efficient and highly stereoselective resolution method to yield optically pure (S)-alcohols and the corresponding (R)-acetates. -
Tetrahedron: Asymmetry, 2004
Biocatalytic asymmetrizations of diethyl 3-hydroxyglutarate furnish a route to the enantiomers of... more Biocatalytic asymmetrizations of diethyl 3-hydroxyglutarate furnish a route to the enantiomers of ethyl 4-cyano-3hydroxybutanoate. The enantiopreference of different enzymes has been established by chiral chromatography. Conclusive evidence for absolute configurations has been provided by X-ray crystallographic structure determination of co-crystals of the predominant monoester with (R)-phenylethylamine. The predominant enantiopure monoester produced by ammonolysis of diethyl 3-hydroxyglutarate catalyzed by immobilized lipase B from Candida antarctica (Novozym 435) was ethyl (3S)-4-carbamoyl-3-hydroxybutanoate. This was converted to ethyl (3S)-4-cyano-3-hydroxybutanoate in high yield and enantiomeric excess. Growing cells of Acinetobacter lwoffii gave low ee and predominance of the (S)-enantiomer when used for hydrolysis of diethyl 3-hydroxyglutarate as opposed to previous reports. When Novozym 435 was used for hydrolysis it could be re-used 10 times without loss of activity and selectivity.
Acta Chemica Scandinavica, 1999
Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-... more Three 1,3-dithiolanes and four 1,3-dithianes have been synthesised from 1-(1,3-dithiolan-2-yl)-2-propanone and 1-(1,3-dithian-2-yl)-2-propanone, respectively. Asymmetric reductions of these ketones using baker's yeast gave the corresponding enantiopure (S)-alcohols. Baker's yeast also reduced the double bond in 3-(1,3-dithian-2-yl)-3-buten-2-one enantioselectively to give (S)-3-(1,3-dithian-2-yl)-2-butanone. 3-(1,3-Dithian-2-yl)-3-buten-2-one was also reduced chemo-selectively and the resulting 3-(1,3-dithian-2-yl)-3-buten-2-ol was resolved by transesterification in organic solvent using lipase B from Candida antarctica to yield the (S)-alcohol and the (R)-acetate with very high enantiomeric ratio, E. Racemic 1-(1,3-dithiolan-2-yl)-2-propanol and 1-(1,3-dithian-2-yl)-2-propanol were also resolved under similar conditions to give the (S)-alcohols and the corresponding (R)-acetates.
International Journal of Chemistry, 2012
Kinetic resolution of rac-Stiripentol, catalysed by lipase A from Candida antarctica by esterific... more Kinetic resolution of rac-Stiripentol, catalysed by lipase A from Candida antarctica by esterification with vinyl butanoate was performed with an E-value of 24. This allowed isolation of (3S)-Stiripentol with an ee of 86 % and the corresponding (3R)-butanoate with an ee of 87 %. Enzymatic hydrolysis of the ester product gave (3R)-Stiripentol with 94 % ee.
Acta Chemica Scandinavica - ACTA CHEM SCAND, 1985
Tetrahedron: Asymmetry, 1996
A computer program for the determination of kinetic and thermodynamic parameters in biocatalytic ... more A computer program for the determination of kinetic and thermodynamic parameters in biocatalytic ping-pong bi-bi resolutions has been developed. The program uses enantiomeric excesses of both product (eep) and remaining substrate (ees) measured at more than one conversion (ξ), and determines both the equilibrium constant Keq, the enantiomer ratio E and the selectivity factor α. The program has been tested
Tetrahedron: Asymmetry, 1995
Lipase-catalysed hydrolysis of butanoates of 3-methoxy-1-(phenylmethoxy)-2-propanol and 3-chloro-... more Lipase-catalysed hydrolysis of butanoates of 3-methoxy-1-(phenylmethoxy)-2-propanol and 3-chloro-1-(phenylmethoxy)-2-propanol with various lipases gave low enantioselectivity, E. By additon of water miscible organic cosolvents, in particular tert-butanol and acetone, the E-value was raised from 7 to 220 for the useful chloro derivative. This finding has led to proposal of a process for production of homochiral C-3 synthons such as both enantiomers of