Andrew Rodriguez - Academia.edu (original) (raw)
Address: San Diego, California, United States
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Institute of Archaeology of Ukrainian National Academy of Sciences
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Papers by Andrew Rodriguez
Molecules, 2017
Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) liga... more Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) ligands represent an emerging approach to antisense therapy. Our current generation of GalNAc-ASO conjugates link the GalNAc to the 5′-terminus of the ASO. The conjugation reaction can be accomplished using solution-phase or solid-phase techniques. Here we show a direct comparison of a solution-phase and a solid-phase conjugation strategy. The solution-phase approach, using amine-pentafluorophenyl (PFP) ester coupling, is higher yielding and gives material of slightly higher purity, but requires several additional unit operations and longer production time. The solid-phase approach, using a protected GalNAc ligand phosphoramidite, is more expedient, but results in lower yield and purity. Both strategies efficiently deliver conjugated material in excellent purity.
Bioorganic & medicinal chemistry letters, 2014
The acetyl 'capping' reaction routinely employed during phosphorothioate oligonucleotide ... more The acetyl 'capping' reaction routinely employed during phosphorothioate oligonucleotide synthesis has been implicated in the formation of an impurity species with a mass 41 amu greater than the expected oligonucleotide molecule. The impurity has been found to arise by conversion of a protected guanine nucleobase to N(2)-acetyl-2,6-diaminopurine. A two-part mechanism is proposed consisting of transamidation of the protecting group on guanine and substitution of guanine's O(6) atom.
Tetrahedron Letters, 2009
New achiral sulfamide, phosphoric triamide, and thiophosphoric triamide compounds have been synth... more New achiral sulfamide, phosphoric triamide, and thiophosphoric triamide compounds have been synthesized. Their activity as hydrogen bond catalysts for the Friedel-Crafts and Baylis-Hillman reactions compares favorably with that of a known and active thiourea catalyst. The new compounds were also studied by X-ray crystallography and their solid state structures are described.
Organic Letters, 2009
A new class of C(2) symmetric bisoxazaborolidinone compounds is described which exhibits bidentat... more A new class of C(2) symmetric bisoxazaborolidinone compounds is described which exhibits bidentate binding to carbonyl substrates. Using the Diels-Alder reaction as a model system, the catalytic activity of these bis-Lewis acids is probed. Reaction rates and selectivities are observed that are higher than the corresponding mono-Lewis acids. This novel system offers a potentially powerful new approach to asymmetric Lewis acid catalysis.
Nano Letters, 2009
Room temperature ionic liquids (RTILs) are substances composed entirely of ions and are liquids a... more Room temperature ionic liquids (RTILs) are substances composed entirely of ions and are liquids at or below 100 degrees C. Ionic conductivity of RTIL is one of the most important physical properties of these unique substances that determine their potential applications as a new medium for capacitors, fuel and solar cells as well as in separation systems. The quality of performance of these devices relies on the understanding of ionic transport of RTIL on a nanoscale. In this letter, we use ionic current carried by RTILs in single nanopores as a probe for their nanoscale transport properties. We show that the conductivity of RTILs through nanopores is significantly less than corresponding bulk values. Our experiments allowed us to address the nature of the interaction of these confined RTILs with charged surfaces. Electrostatic interactions of RTILs with nanopores are the basis for the formation of ionic diodes rectifying transport of the constituent ions.
Molecules, 2017
Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) liga... more Antisense oligonucleotides (ASOs) conjugated to triantennary N-acetyl galactosamine (GalNAc) ligands represent an emerging approach to antisense therapy. Our current generation of GalNAc-ASO conjugates link the GalNAc to the 5′-terminus of the ASO. The conjugation reaction can be accomplished using solution-phase or solid-phase techniques. Here we show a direct comparison of a solution-phase and a solid-phase conjugation strategy. The solution-phase approach, using amine-pentafluorophenyl (PFP) ester coupling, is higher yielding and gives material of slightly higher purity, but requires several additional unit operations and longer production time. The solid-phase approach, using a protected GalNAc ligand phosphoramidite, is more expedient, but results in lower yield and purity. Both strategies efficiently deliver conjugated material in excellent purity.
Bioorganic & medicinal chemistry letters, 2014
The acetyl 'capping' reaction routinely employed during phosphorothioate oligonucleotide ... more The acetyl 'capping' reaction routinely employed during phosphorothioate oligonucleotide synthesis has been implicated in the formation of an impurity species with a mass 41 amu greater than the expected oligonucleotide molecule. The impurity has been found to arise by conversion of a protected guanine nucleobase to N(2)-acetyl-2,6-diaminopurine. A two-part mechanism is proposed consisting of transamidation of the protecting group on guanine and substitution of guanine's O(6) atom.
Tetrahedron Letters, 2009
New achiral sulfamide, phosphoric triamide, and thiophosphoric triamide compounds have been synth... more New achiral sulfamide, phosphoric triamide, and thiophosphoric triamide compounds have been synthesized. Their activity as hydrogen bond catalysts for the Friedel-Crafts and Baylis-Hillman reactions compares favorably with that of a known and active thiourea catalyst. The new compounds were also studied by X-ray crystallography and their solid state structures are described.
Organic Letters, 2009
A new class of C(2) symmetric bisoxazaborolidinone compounds is described which exhibits bidentat... more A new class of C(2) symmetric bisoxazaborolidinone compounds is described which exhibits bidentate binding to carbonyl substrates. Using the Diels-Alder reaction as a model system, the catalytic activity of these bis-Lewis acids is probed. Reaction rates and selectivities are observed that are higher than the corresponding mono-Lewis acids. This novel system offers a potentially powerful new approach to asymmetric Lewis acid catalysis.
Nano Letters, 2009
Room temperature ionic liquids (RTILs) are substances composed entirely of ions and are liquids a... more Room temperature ionic liquids (RTILs) are substances composed entirely of ions and are liquids at or below 100 degrees C. Ionic conductivity of RTIL is one of the most important physical properties of these unique substances that determine their potential applications as a new medium for capacitors, fuel and solar cells as well as in separation systems. The quality of performance of these devices relies on the understanding of ionic transport of RTIL on a nanoscale. In this letter, we use ionic current carried by RTILs in single nanopores as a probe for their nanoscale transport properties. We show that the conductivity of RTILs through nanopores is significantly less than corresponding bulk values. Our experiments allowed us to address the nature of the interaction of these confined RTILs with charged surfaces. Electrostatic interactions of RTILs with nanopores are the basis for the formation of ionic diodes rectifying transport of the constituent ions.