Deoxyfluorinating reagents such as DAST and PyFluor can be successfully employed as tools for sel... more Deoxyfluorinating reagents such as DAST and PyFluor can be successfully employed as tools for selective modification of γ-amino-α-hydroxyphosphonates.
Herein, we described the efficient and straightforward synthesis of N-substituted α,α-difluoro-β-... more Herein, we described the efficient and straightforward synthesis of N-substituted α,α-difluoro-β-aminophosphonates with the use of electrophilic fluorination by Selectfluor®.
Abstract Structures of the most stable conformers of derivatives of 5-vinyluracil and fluorinated... more Abstract Structures of the most stable conformers of derivatives of 5-vinyluracil and fluorinated analogues have been determined using MM and semiempirical MNDO calculations. It has been found that the most stable conformers of 5-trifluorovinyl and 5- E / Z -pentafluoropropenyl groups are almost perpendicular to the plane of the uracil ring. These findings are in good agreement with X-ray data obtained for 1,3,6-trimethyl-5-trifluorovinyluracil. The calculated energy barrier for rotation of exocylic 5-substituents depends on the structure of the fluorinated fragments as well as on the nature of the substituent at the 6-position of uracil. A methyl group at the 6-position causes steric hindrance and significantly disturbs the rotation of fluorinated groups.
The synthesis of the stable surrogates of an important amino acid (R)-4-amino-3-hydroxybutyric ac... more The synthesis of the stable surrogates of an important amino acid (R)-4-amino-3-hydroxybutyric acid (GABOB) such as substituted hydroxy aminophosphonic acids bearing a quaternary stereogenic center is presented. Highly diastereoselective formations of fluorinated spiroepoxy alkylphosphonate or related tertiary carbon-containing oxiranes from β-keto phosphonates possessing methyl, phenyl, or cyclohexenyl substituents, are reported. Stereoselective acid-promoted epoxide opening by bromide or azide followed by reduction/protection afforded tertiary bromides or N-Boc derivatives of β-amino-γ-hydroxy alkylphosphonates in most cases, while the reactions of oxiranes with different amines yielded their β-hydroxy-γ-amino regioisomers. Surprisingly, during the synthesis of amino phosphonic acids, we observe that the acid-induced rearrangement proceeded in a high diastereospecific manner, leading finally to substituted β-hydroxy-γ-aminoalkylphosphonic acids.
A study on the α-(difluoromethyl)styrene (DFMST) reactivity under conventional radical (co)polyme... more A study on the α-(difluoromethyl)styrene (DFMST) reactivity under conventional radical (co)polymerization conditions is presented.
A new convenient synthetic procedure for the preparation of tri- and tetrafluoropropanamides deri... more A new convenient synthetic procedure for the preparation of tri- and tetrafluoropropanamides derived from sugars has been described.
Biochemical and Biophysical Research Communications, 1979
ABSTRACT The thymine derived quasimetacyclophane exist in two conformers and . The absorption spe... more ABSTRACT The thymine derived quasimetacyclophane exist in two conformers and . The absorption spectra of and were evaluated and the conformational equilibrium in different solvents /H2O : EtOH/ were examined. The rate constant k−1 for reaction was established as well as Ea.
The synthesis of phosphonated derivatives of trifluoromethyl aziridines by two methods and their ... more The synthesis of phosphonated derivatives of trifluoromethyl aziridines by two methods and their application in ring opening reactions have been demonstrated.
Deoxyfluorinating reagents such as DAST and PyFluor can be successfully employed as tools for sel... more Deoxyfluorinating reagents such as DAST and PyFluor can be successfully employed as tools for selective modification of γ-amino-α-hydroxyphosphonates.
Herein, we described the efficient and straightforward synthesis of N-substituted α,α-difluoro-β-... more Herein, we described the efficient and straightforward synthesis of N-substituted α,α-difluoro-β-aminophosphonates with the use of electrophilic fluorination by Selectfluor®.
Abstract Structures of the most stable conformers of derivatives of 5-vinyluracil and fluorinated... more Abstract Structures of the most stable conformers of derivatives of 5-vinyluracil and fluorinated analogues have been determined using MM and semiempirical MNDO calculations. It has been found that the most stable conformers of 5-trifluorovinyl and 5- E / Z -pentafluoropropenyl groups are almost perpendicular to the plane of the uracil ring. These findings are in good agreement with X-ray data obtained for 1,3,6-trimethyl-5-trifluorovinyluracil. The calculated energy barrier for rotation of exocylic 5-substituents depends on the structure of the fluorinated fragments as well as on the nature of the substituent at the 6-position of uracil. A methyl group at the 6-position causes steric hindrance and significantly disturbs the rotation of fluorinated groups.
The synthesis of the stable surrogates of an important amino acid (R)-4-amino-3-hydroxybutyric ac... more The synthesis of the stable surrogates of an important amino acid (R)-4-amino-3-hydroxybutyric acid (GABOB) such as substituted hydroxy aminophosphonic acids bearing a quaternary stereogenic center is presented. Highly diastereoselective formations of fluorinated spiroepoxy alkylphosphonate or related tertiary carbon-containing oxiranes from β-keto phosphonates possessing methyl, phenyl, or cyclohexenyl substituents, are reported. Stereoselective acid-promoted epoxide opening by bromide or azide followed by reduction/protection afforded tertiary bromides or N-Boc derivatives of β-amino-γ-hydroxy alkylphosphonates in most cases, while the reactions of oxiranes with different amines yielded their β-hydroxy-γ-amino regioisomers. Surprisingly, during the synthesis of amino phosphonic acids, we observe that the acid-induced rearrangement proceeded in a high diastereospecific manner, leading finally to substituted β-hydroxy-γ-aminoalkylphosphonic acids.
A study on the α-(difluoromethyl)styrene (DFMST) reactivity under conventional radical (co)polyme... more A study on the α-(difluoromethyl)styrene (DFMST) reactivity under conventional radical (co)polymerization conditions is presented.
A new convenient synthetic procedure for the preparation of tri- and tetrafluoropropanamides deri... more A new convenient synthetic procedure for the preparation of tri- and tetrafluoropropanamides derived from sugars has been described.
Biochemical and Biophysical Research Communications, 1979
ABSTRACT The thymine derived quasimetacyclophane exist in two conformers and . The absorption spe... more ABSTRACT The thymine derived quasimetacyclophane exist in two conformers and . The absorption spectra of and were evaluated and the conformational equilibrium in different solvents /H2O : EtOH/ were examined. The rate constant k−1 for reaction was established as well as Ea.
The synthesis of phosphonated derivatives of trifluoromethyl aziridines by two methods and their ... more The synthesis of phosphonated derivatives of trifluoromethyl aziridines by two methods and their application in ring opening reactions have been demonstrated.
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Papers by Henryk Koroniak