Effective Synthesis of Fluorescently Labeled Morpholino Nucleoside Triphosphate Derivatives

N-Fluoroalkylated Morpholinos - a New Class of Nucleoside Analogues

The first concise and efficient synthesis of some fluorine-containing morpholino nucleosides has been developed. One synthetic strategy was based on the oxidative ring cleavage of the vicinal diol unit of uridine, cytidine adenosine and guanosine derivatives, followed by cyclisation of the dialdehyde intermediates by double reductive amination with fluorinated primary amines to obtain various N-fluoroalkylated morpholinos. Another approach involved cyclisation of the diformyl intermediates with ammonia source, followed by dithiocarbamate formation and desulfurization-fluorination with diethylaminosulfur trifluoride yielding the corresponding morpholine-based nucleoside analogues with a N-CF₃ element in their structure.

Tightly linked morpholino-nucleoside chimeras: new, compact cationic oligonucleotide analogues

The polyanionic phosphodiester backbone of nucleic acids contributes to high nuclease sensitivity and low cellular uptake and is therefore a major obstacle to the biological application of native oligonucleotides. Backbone modifications, particularly charge alterations is a proven strategy to provide artificial oligonucleotides with improved properties. Here, we describe the synthesis of a new type of oligonucleotide analogues consisting of a morpholino and a ribo- or deoxyribonucleoside in which the 5'-amino group of the nucleoside unit provides the nitrogen of the morpholine ring. The synthetic protocol is compatible with trityl and dimethoxytrityl protecting groups and azido functionality, and was extended to the synthesis of higher oligomers. The chimeras are positively charged in aqueous medium, due to the N-alkylated tertiary amine structure of the morpholino unit.

Nucleobase morpholino β amino acids as molecular chimeras for the preparation of photoluminescent materials from ribonucleosides

Bioinspired smart materials represent a tremendously growing research field and the obtainment of new building blocks is at the molecular basis of this technology progress. In this work, colloidal materials have been prepared in few steps starting from ribonucleosides. Nucleobase morpholino β-amino acids are the chimera key intermediates allowing Phe-Phe dipeptides' functionalization with adenine and thymine. The obtained compounds self-aggregate showing enhanced photoluminescent features, such as deep blue fluorescence and phosphorescence emissions.

Synthesis of N-substituted morpholine nucleoside derivatives

Herein, we report the synthesis of substituted morpholino nucleoside derivatives starting from ribonucleosides. The present protocol shows high functional group tolerance, uses mild reaction conditions, and gives moderate to good yields. This transformation is based on two sequential pathways: (i) the oxidation of the ribonucleosides to the corresponding dialdehyde using sodium periodate and (ii) the reductive amination of the in situ generated dialdehydes with the hydrochloride salts of various the alkylamines.

Design, Synthesis and Molecular Modeling Study of Conjugates of ADP and Morpholino Nucleosides as A Novel Class of Inhibitors of PARP-1, PARP-2 and PARP-3

We report on the design, synthesis and molecular modeling study of conjugates of adenosine diphosphate (ADP) and morpholino nucleosides as potential selective inhibitors of poly(ADP-ribose)polymerases-1, 2 and 3. Sixteen dinucleoside pyrophosphates containing natural heterocyclic bases as well as 5-haloganeted pyrimidines, and mimicking a main substrate of these enzymes, nicotinamide adenine dinucleotide (NAD+)-molecule, have been synthesized in a high yield. Morpholino nucleosides have been tethered to the β-phosphate of ADP via a phosphoester or phosphoramide bond. Screening of the inhibiting properties of these derivatives on the autopoly(ADP-ribosyl)ation of PARP-1 and PARP-2 has shown that the effect depends upon the type of nucleobase as well as on the linkage between ADP and morpholino nucleoside. The 5-iodination of uracil and the introduction of the P–N bond in NAD+-mimetics have shown to increase inhibition properties. Structural modeling suggested that the P–N bond can stabilize the pyrophosphate group in active conformation due to the formation of an intramolecular hydrogen bond. The most active NAD+ analog against PARP-1 contained 5-iodouracil 2ʹ-aminomethylmorpholino nucleoside with IC50 126 ± 6 μM, while in the case of PARP-2 it was adenine 2ʹ-aminomethylmorpholino nucleoside (IC50 63 ± 10 μM). In silico analysis revealed that thymine and uracil-based NAD+ analogs were recognized as the NAD+-analog that targets the nicotinamide binding site. On the contrary, the adenine 2ʹ-aminomethylmorpholino nucleoside-based NAD+ analogs were predicted to identify as PAR-analogs that target the acceptor binding site of PARP-2, representing a novel molecular mechanism for selective PARP inhibition. This discovery opens a new avenue for the rational design of PARP-1/2 specific inhibitors.

A versatile strategy for the design and synthesis of novel ADP conjugates and their evaluation as potential poly(ADP-ribose) polymerase 1 inhibitors

A versatile strategy for the synthesis of [Formula: see text] mimetics was developed, involving an efficient pyrophosphate linkage formation in key conjugates containing a functional amino group which acts as useful reactive anchor for further derivatization. These [Formula: see text] mimetics consist of ADP conjugated through a diphosphate chain to an extended aliphatic linker bearing an aromatic acid residue. A number of conjugates containing aromatic carboxylic acids were found to inhibit poly(ADP-ribose) synthesis catalyzed by poly(ADP-ribose) polymerase-1 (PARP-1). A new class of potential PARP-1 inhibitors mimicking [Formula: see text], a substrate in the PARP-1 catalyzed reaction, was proposed.