Kaja Ilmarinen - Academia.edu (original) (raw)
Papers by Kaja Ilmarinen
Synthesis, Oct 1, 2015
A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-un... more A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-unsaturated selenones in the presence of bifunctional urea and thiourea organocatalysts is described. The Michael adducts, containing an allcarbon quaternary stereocenter, are smoothly converted into synthetically useful polyfunctional compounds by taking advantage of the excellent leaving group ability of the selenone group.
Synthesis, Jul 15, 2014
A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-un... more A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-unsaturated selenones in the presence of bifunctional urea and thiourea organocatalysts is described. The Michael adducts, containing an allcarbon quaternary stereocenter, are smoothly converted into synthetically useful polyfunctional compounds by taking advantage of the excellent leaving group ability of the selenone group.
Proceedings of the Estonian Academy of Sciences. Chemistry, 2001
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
ChemInform, Feb 24, 2015
ABSTRACT Organocatalytic Michael additions of cyclopentane-1,2-dione to different nitroolefins ha... more ABSTRACT Organocatalytic Michael additions of cyclopentane-1,2-dione to different nitroolefins have been investigated. Cyclopentane-1,2-dione undergoes an organocatalytic reaction with substituted nitroolefins giving 3-substituted products in good to high yields (48-97%) and good stereoselectivity (up to 76% ee).
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
ChemInform, Dec 12, 2013
This new and highly enantioselective method for the synthesis of the title compounds with four co... more This new and highly enantioselective method for the synthesis of the title compounds with four consecutive stereocenters proceeds via a Michael-aldol cascade reaction.
Journal of Environmental Pathology, Toxicology and Oncology, 2006
This study was aimed to estimate the participation of reactive oxygen species (ROS), other than s... more This study was aimed to estimate the participation of reactive oxygen species (ROS), other than singlet oxygen (1O2), in the antitumor effect of photodynamic therapy (PDT) with hematoporphyrin derivative (HPD) as well as to determine the ability of photoexcited HPD to the formation of protein peroxides that currently are regarded as a new form of ROS. Studies were performed on Ehrlich ascites carcinoma (EAC) cells, which were loaded with HPD in phosphate-buffered saline and then irradiated with red light at 630 run in the same buffer. Experiments indicated that H2O2 and oxygen radicals could mediate the tumoricidal action of HPD-PDT; we found that photosensitization of EAC cells with HPD leads to the formation of significant amounts of H2O2, superoxide (O2-.), and hydroxyl (OH.) radicals, which along with 1O2 were involved in photoinactivation of the cells in vitro. Our data showed that in EAC cells subjected to HPD-PDT, the generation H2O2, O2-., and OH. could be largely mediated by: (i) an increase in the activity of xanthine oxidase (XOD), due most probably to the conversion of xanthine dehydrogenase (XDH) to XOD via a Ca2+-dependent proteolytic process as well as oxidation of SH groups in XDH; and (ii) photooxidation of some cellular constituents (proteins). Another interesting finding of our studies is that in tumor cells subjected to HPD-PDT the Fenton-like reactions could play an important role in the generation of OH., and that cell-bound Cu/Zn-superoxide dismutase as well as catalase can protect tumor cells against the phototoxic action of HPD. In addition, we clearly demonstrated the ability of photoexcited HPD to the generation of protein peroxides in tumor cells. Studies suggest that 1O2 is the main agent responsible for the generation of protein peroxides in EAC cells treated with HPD-PDT, although other ROS (H2O2, O2-., and OH.) were also implicated in this process. However, further work is needed to clarify the significance of these peroxides in the antitumor effect of PDT with HPD.
ChemInform, 2010
The Ti(OiPr) 4 /tartaric acid diethyl ester/t-BuOOH complex (Sharpless catalyst) was successfully... more The Ti(OiPr) 4 /tartaric acid diethyl ester/t-BuOOH complex (Sharpless catalyst) was successfully used for the direct asymmetric oxidation of ketones resulting in lactones from cyclobutanones; α,β-dihydroxy ketones from β-hydroxy ketones; alkyl lactone carboxylic acids from 3-alkylcyclopentane-1,2-diones; and spiro-γ-dilactone from 3-(2-hydroxyethyl)cyclopentane-1,2-dione in high enantioselectivity and satisfactory yield.
The Journal of Organic Chemistry, 2013
Starting from simple alkylidene oxindoles and nitroketones, a highly stereoselective methodology ... more Starting from simple alkylidene oxindoles and nitroketones, a highly stereoselective methodology was developed for the synthesis of spiro-cyclopentaneoxindoles with four consecutive stereogenic centers. Using an organocatalytic cascade of Michael and aldol reactions in the presence of a chiral thiourea catalyst products were obtained in moderate to high yields and excellent enantioselectivities. Nitro, ester, and hydroxyl groups were introduced to the spiro ring, which could be used to facilitate further functionalization of the products.
Organic & biomolecular chemistry, Jan 14, 2014
A general and efficient approach was developed for the introduction of S-functionality at the C-5... more A general and efficient approach was developed for the introduction of S-functionality at the C-5 position of cytosine and uracil nucleosides and their analogues. The key step is a palladium-catalyzed C-S coupling of the corresponding 5-bromo nucleoside derivative and alkyl thiol. The butyl 3-mercaptopropionate coupling products were further converted to the corresponding disulphides, the stable precursors of 5-mercaptopyrimidine nucleosides.
Proceedings of the Estonian Academy of Sciences. Chemistry, 2001
3-butanediol and their acetals were prepared from commercially available (+)-dimethyl-R-R-tartrat... more 3-butanediol and their acetals were prepared from commercially available (+)-dimethyl-R-R-tartrate in good yields. A preliminary screening of the compounds as chiral ligands in catalysts for Baeyer-Villiger oxidation was performed.
Synthesis, Oct 1, 2015
A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-un... more A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-unsaturated selenones in the presence of bifunctional urea and thiourea organocatalysts is described. The Michael adducts, containing an allcarbon quaternary stereocenter, are smoothly converted into synthetically useful polyfunctional compounds by taking advantage of the excellent leaving group ability of the selenone group.
Synthesis, Jul 15, 2014
A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-un... more A novel enantioselective (up to 90% ee) Michael addition of a-substituted cyanoacetates to a,b-unsaturated selenones in the presence of bifunctional urea and thiourea organocatalysts is described. The Michael adducts, containing an allcarbon quaternary stereocenter, are smoothly converted into synthetically useful polyfunctional compounds by taking advantage of the excellent leaving group ability of the selenone group.
Proceedings of the Estonian Academy of Sciences. Chemistry, 2001
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
ChemInform, Feb 24, 2015
ABSTRACT Organocatalytic Michael additions of cyclopentane-1,2-dione to different nitroolefins ha... more ABSTRACT Organocatalytic Michael additions of cyclopentane-1,2-dione to different nitroolefins have been investigated. Cyclopentane-1,2-dione undergoes an organocatalytic reaction with substituted nitroolefins giving 3-substituted products in good to high yields (48-97%) and good stereoselectivity (up to 76% ee).
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
ChemInform, Dec 12, 2013
This new and highly enantioselective method for the synthesis of the title compounds with four co... more This new and highly enantioselective method for the synthesis of the title compounds with four consecutive stereocenters proceeds via a Michael-aldol cascade reaction.
Journal of Environmental Pathology, Toxicology and Oncology, 2006
This study was aimed to estimate the participation of reactive oxygen species (ROS), other than s... more This study was aimed to estimate the participation of reactive oxygen species (ROS), other than singlet oxygen (1O2), in the antitumor effect of photodynamic therapy (PDT) with hematoporphyrin derivative (HPD) as well as to determine the ability of photoexcited HPD to the formation of protein peroxides that currently are regarded as a new form of ROS. Studies were performed on Ehrlich ascites carcinoma (EAC) cells, which were loaded with HPD in phosphate-buffered saline and then irradiated with red light at 630 run in the same buffer. Experiments indicated that H2O2 and oxygen radicals could mediate the tumoricidal action of HPD-PDT; we found that photosensitization of EAC cells with HPD leads to the formation of significant amounts of H2O2, superoxide (O2-.), and hydroxyl (OH.) radicals, which along with 1O2 were involved in photoinactivation of the cells in vitro. Our data showed that in EAC cells subjected to HPD-PDT, the generation H2O2, O2-., and OH. could be largely mediated by: (i) an increase in the activity of xanthine oxidase (XOD), due most probably to the conversion of xanthine dehydrogenase (XDH) to XOD via a Ca2+-dependent proteolytic process as well as oxidation of SH groups in XDH; and (ii) photooxidation of some cellular constituents (proteins). Another interesting finding of our studies is that in tumor cells subjected to HPD-PDT the Fenton-like reactions could play an important role in the generation of OH., and that cell-bound Cu/Zn-superoxide dismutase as well as catalase can protect tumor cells against the phototoxic action of HPD. In addition, we clearly demonstrated the ability of photoexcited HPD to the generation of protein peroxides in tumor cells. Studies suggest that 1O2 is the main agent responsible for the generation of protein peroxides in EAC cells treated with HPD-PDT, although other ROS (H2O2, O2-., and OH.) were also implicated in this process. However, further work is needed to clarify the significance of these peroxides in the antitumor effect of PDT with HPD.
ChemInform, 2010
The Ti(OiPr) 4 /tartaric acid diethyl ester/t-BuOOH complex (Sharpless catalyst) was successfully... more The Ti(OiPr) 4 /tartaric acid diethyl ester/t-BuOOH complex (Sharpless catalyst) was successfully used for the direct asymmetric oxidation of ketones resulting in lactones from cyclobutanones; α,β-dihydroxy ketones from β-hydroxy ketones; alkyl lactone carboxylic acids from 3-alkylcyclopentane-1,2-diones; and spiro-γ-dilactone from 3-(2-hydroxyethyl)cyclopentane-1,2-dione in high enantioselectivity and satisfactory yield.
The Journal of Organic Chemistry, 2013
Starting from simple alkylidene oxindoles and nitroketones, a highly stereoselective methodology ... more Starting from simple alkylidene oxindoles and nitroketones, a highly stereoselective methodology was developed for the synthesis of spiro-cyclopentaneoxindoles with four consecutive stereogenic centers. Using an organocatalytic cascade of Michael and aldol reactions in the presence of a chiral thiourea catalyst products were obtained in moderate to high yields and excellent enantioselectivities. Nitro, ester, and hydroxyl groups were introduced to the spiro ring, which could be used to facilitate further functionalization of the products.
Organic & biomolecular chemistry, Jan 14, 2014
A general and efficient approach was developed for the introduction of S-functionality at the C-5... more A general and efficient approach was developed for the introduction of S-functionality at the C-5 position of cytosine and uracil nucleosides and their analogues. The key step is a palladium-catalyzed C-S coupling of the corresponding 5-bromo nucleoside derivative and alkyl thiol. The butyl 3-mercaptopropionate coupling products were further converted to the corresponding disulphides, the stable precursors of 5-mercaptopyrimidine nucleosides.
Proceedings of the Estonian Academy of Sciences. Chemistry, 2001
3-butanediol and their acetals were prepared from commercially available (+)-dimethyl-R-R-tartrat... more 3-butanediol and their acetals were prepared from commercially available (+)-dimethyl-R-R-tartrate in good yields. A preliminary screening of the compounds as chiral ligands in catalysts for Baeyer-Villiger oxidation was performed.