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Adam Kraszewski

Publications and source records attributed to Adam Kraszewski.

13 recordsLinked to original sources
PubMed2006

Different nucleobase orientations in two cyclic 2',3'-phosphates of purine ribonucleosides: Et(3)NH(2',3'-cAMP) and Et(3)NH(2',3'-cGMP)xH(2)O.

The crystal structures of triethylammonium adenosine cyclic 2',3'-phosphate {systematic name: triethylammonium 4-(6-aminopurin-9-yl)-6-hydroxymethyl-2-oxido-2-oxoperhydrofurano[3,4-c][1,3,2]dioxaphosphole}, Et(3)NH(2',3'-cAMP) or C(6)H(16)N(+).C(10)H(11)N(5)O(6)P(-), (I), and guanosine cyclic 2',3'-phosphate monohydrate {systematic name: triethylammonium 6-hydroxymethyl-2-oxido-2-oxo-4-(6-oxo-1,6-dihydropurin-9-yl)perhydrofurano[3,4-c][1,3,2]dioxaphosphole monohydrate}, [Et(3)NH(2',3'-cGMP)].H(2)O or C(6)H(16)N(+).C(10)H(11)N(5)O(7)P(-).H(2)O, (II), reveal different nucleobase orientations, viz. anti in (I) and syn in (II). These are stabilized by different inter- and intramolecular hydrogen bonds. The structures also exhibit different ribose ring puckering [(4)E in (I) and (3)T(2) in (II)] and slightly different 1,3,2-dioxaphospholane ring conformations, viz. envelope in (I) and puckered in (II). Infinite ribbons of 2',3'-cAMP(-) and helical chains of 2',3'-cGMP(-) ions, both formed by O-H...O, N-H...X and C-H...X (X = O or N) hydrogen-bond contacts, characterize (I) and (II), respectively.

Cyclic AMP↗
PubMed2006

A proposal for a convenient notation for P-chiral nucleotide analogues. Part 2. Dinucleoside monophosphate analogues.

A configuration of ligands around a phosphorus atom in P-chiral dinucleoside monophosphate analogues can be described using DP/LP stereochemical notation, which allows immediate correlation between the notation of configuration and the actual spatial arrangement of the phosphorus ligands. The area of applications of this new stereochemical nomenclature covers dinucleoside units bridged by virtually any type of tri-and tetra-coordinated phosphorus moieties, that is, phosphorothioates, phosphoramidates, phosphoramidites, boranephosphates, methanephosphonates, H-phosphonates, and many others.

Chemistry↗
PubMed2006

A proposal for a convenient notation for P-chiral nucleotide analogues. Part 3. Compounds with one nucleoside residue and nonnucleosidic derivatives.

Recently, we have proposed a new DP/LP stereochemical notation for P-chiral dinucleoside monophosphate analogues that permits simple correlation between spatial arrangement of the substituents and the configuration at the phosphorus center. As an extension of this work, we present here applications of the DP/LP notation to derivatives containing only one nucleoside unit (e.g., alkyl nucleoside phosphodiesters, nucleoside phosphomonoesters, cyclic phosphate derivatives, nucleoside di-, and triphosphates) and to nonnucleosidic phosphorus compounds.

Biochemistry↗
PubMed2005

Aryl nucleoside H-phosphonates. Part 15: Synthesis, properties and, anti-HIV activity of aryl nucleoside 5'-alpha-hydroxyphosphonates.

Aryl nucleoside 5'-H-phosphonates 4 bearing AZT or 2',3'-dideoxyuridine moieties were subjected to reaction with various aromatic aldehydes to produce nucleoside 5'-alpha-hydroxyphosphonate derivatives 2 as potential anti-HIV agents. Stability of the title compounds in cell culture media was investigated and three distinct decomposition pathways were identified. The anti-HIV activity of hydroxyphosphonates 2 correlates well with the type and extent of their chemical or enzymatic degradation in culture medium (RPMI 1640 containing 10% FBS), suggesting that aryl nucleoside 5'-hydroxyphosphonates 2 act as depot forms of the parent antiviral nucleosides.

Anti-HIV Agents↗
PubMed2005

A proposal for a new stereochemical notation for P-chiral nucleotide analogues and related compounds.

A new stereochemical notation for P-chiral nucleotide analogues and related compounds is proposed In this notation, the names of configurations, designated as D(P) and L(P), are derived from a geometrical relationship, rather than from priority rules, of substituents at the phosphorus centre. This new stereochemical description offers clear advantages over the CIP R/S nomenclature, particularly when used for comparing the influence of absolute configuration at the phosphorus centre on physicochemical and biological properties of oligonucleotide analogues or in stereochemical correlation analysis of P-chiral nucleotide derivatives.

Biochemistry↗
PubMed2005

Stereochemistry of internucleotide bond formation by the H-phosphonate method. 1. Synthesis and 31P NMR analysis of 16 diribonulceoside (3'-5')-H-phosphonates and the corresponding phosphorothioates.

Sixteen diribonucleoside (3'-5')-H-phosphonates were synthesized via condensation of the protected ribonucleoside 3'-H-phosphonates with nucleosides, and the influence of a nucleoside sequence on the observed stereoselectivity was analyzed. 31P NMR spectroscopy was used to evaluate a relationship between chemical shift and absolute configuration at the phosphorous center of the H-phosphonate diesters as well as of the corresponding phosphorothioate diesters. Although for the most cases such correlation was found, there was however several exceptions to the rule where the relative positions of resonances arisingfrom Rp and Sp diastereomers were reversed.

Dinucleoside Phosphates↗
PubMed2003

Aryl h-phosphonates. 14. Synthesis of new nucleotide analogues with phosphonate-phosphate internucleosidic linkage.

[reaction: see text] Aryl nucleoside H-phosphonates 3 and aryl nucleoside P-acylphosphonates 4, generated in situ from the appropriate H-phosphonate 1 and acylphosphonate monoesters 2, respectively, reacted rapidly in the presence of tertiary amines to produce in high yields the extended, pyrophosphate analogues, diaryl dinucleoside phosphonate-phosphate derivatives 6. These, depending on a substituent on the alpha-carbon of the phosphonate moiety, either underwent transformation into the dinucleoside phosphonate-phosphate 7 or afforded nucleoside H-phosphonates 8 and aryl nucleoside phosphate 9.

Nucleosides↗
PubMed2002

How to get the most out of two phosphorus chemistries. Studies on H-phosphonates.

The biological importance and practical significance of phosphate esters and their analogues have been the major driving forces for research in various areas of synthetic organic phosphorus chemistry. In this Account, the authors' studies on the development of a comprehensive H-phosphonate methodology and the underlying chemistry for the preparation of biologically important phosphate esters and their analogues are briefly discussed.

Oligonucleotides↗