-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds.

Since Garner's aldehyde has several drawbacks, first of all is prone to racemization, alternative three-carbon chirons would be of great value in enantioselective syntheses of natural compounds and/or drugs. This review article summarizes applications of -(1-phenylethyl)aziridine-2-carboxylates, -carbaldehydes and -methanols in syntheses of approved drugs and potential medications as well as of natural products mostly alkaloids but also sphingoids and ceramides and their 1- and 3-deoxy analogues and several hydroxy amino acids and their precursors. Designed strategies provided new procedures to several drugs and alternative approaches to natural products and proved efficiency of a 2-substituted -(1-phenylethyl)aziridine framework as chiron bearing a chiral auxiliary.

Synthesis of nonracemic hydroxyglutamic acids.

Glutamic acid is involved in several cellular processes though its role as the neurotransmitter is best recognized. For detailed studies of interactions with receptors a number of structural analogues of glutamic acid are required to map their active sides. This review article summarizes syntheses of nonracemic hydroxyglutamic acid analogues equipped with functional groups capable for the formation of additional hydrogen bonds, both as donors and acceptors.

Acyclic nucleoside phosphonates containing the amide bond: hydroxy derivatives.

Abstract: To study the influence of a linker rigidity and changes in donor-acceptor properties, three series of nucleotide analogs containing a P-X-HN-C(O)- residue (X=CH(OH)CH, CH(OH)CHCH, CHCH(OH)CH) as a replacement for the P-CH-O-CHR- fragment in acyclic nucleoside phosphonates, e.g., adefovir, cidofovir, were synthesized.

Novel isoxazolidine analogues of homonucleosides and homonucleotides.

Isoxazolidine analogues of homonucleos(t)ides were synthesized from nucleobase-derived nitrones (uracil, 5-fluorouracil, 5-bromouracil, thymine, adenine) employing 1,3-dipolar cycloadditions with allyl alcohol as well as with alkenylphosphonates (allyl-, allyloxymethyl- and vinyloxymethyl- and vinylphosphonate). Besides reactions with vinylphosphonate the additions proceeded regioselectively to produce mixtures of major cis and minor trans 3,5-disubstituted isoxazolidines (d.e.

Acyclic nucleoside phosphonates containing the amide bond.

Abstract: To study the influence of a linker rigidity and donor-acceptor properties, the P-CH-- fragment in acyclic nucleoside phosphonates (e.g., acyclovir, tenofovir) was replaced by the P-CH-- residue.

1'-Homonucleosides and their structural analogues: A review.

Nucleoside analogues belong to an important class of antiviral and anticancer drugs. Insertion of a methylene fragment between the anomeric carbon and pyrimidine or purine bases transforms nucleosides into 1'-homonucleosides. When compared with nucleosides this modification lengthens the separation between HO-C5' of pentofuranoside fragments and nitrogen (N1 or N9) atoms of nucleobases, lowers the steric and electronic interactions between nucleobases and sugar rings, introduces greater flexibility around a CH2-Base bond and thus allows for more rotational freedom, and since the anomeric effect no longer operates any sugar or pseudosugar moiety exists in its unique conformation and experiences specific conformational mobility and hydrolysis of the C1'-CH2Base bond by cellular enzymes is no longer feasible.

Novel acyclic phosphonylated 1,2,3-triazolonucleosides with an acetamidomethyl linker: synthesis and biological activity.

A new series of 4-substituted [(1,2,3-triazol-1-yl)acetamido]methylphosphonates as acyclic nucleotide analogs were synthesized from diethyl (2-chloroacetamido)methylphosphonate via azidation followed by 1,3-dipolar cycloaddition with selected alkynes derived from natural nucleobases or their mimetics. All compounds were tested for their antiviral activities against DNA and RNA viruses as well as for cytostatic activity or cytotoxicity. Among all tested compounds, [(1,2,3-triazol-1-yl)acetamido]methylphosphonate 6e substituted with the N(3)-Bz-benzuracil moiety showed activity against the vesicular stomatitis virus (EC50 = 45 µM) in HeLa cell cultures.

Design, synthesis, antiviral and cytotoxic evaluation of novel acyclic phosphonate nucleotide analogues with a 5,6-dihydro-1-[1,2,3]triazolo[4,5-]pyridazine-4,7-dione system.

Abstract: A series of diethyl 2-(4,5-dimethoxycarbonyl-1-1,2,3-triazol-1-yl)alkylphosphonates was synthesised from -azidoalkylphosphonates and dimethyl acetylenedicarboxylate and was further transformed into the respective diamides, dihydrazides, and 5,6-dihydro-1-[1,2,3]triazolo[4,5-]pyridazine-4,7-diones as phosphonate analogues of acyclic nucleosides having nucleobases replaced with substituted 1,2,3-triazoles. All compounds containing P-C-C-triazole or P-C-C-CH-triazole moieties exist in single conformations in which the diethoxyphosphoryl and substituted 1,2,3-triazolyl or substituted (1,2,3-triazolyl)methyl groups are oriented . All phosphonates were evaluated in vitro for activity against a variety of DNA and RNA viruses.

The synthesis, antiviral, cytostatic and cytotoxic evaluation of a new series of acyclonucleotide analogues with a 1,2,3-triazole linker.

The efficient synthesis of a new series of acyclonucleotide analogues with a 1,2,3-triazole linker is described starting from diethyl azidomethyl-, 2-azidoethyl-, 3-azidopropyl-, 4-azidobutyl-, 2-azido-1-hydroxyethyl-, 3-azido-2-hydroxypropyl- and 3-azido-1-hydroxypropylphosphonates and selected alkynes under microwave irradiation. Several O,O-diethylphosphonate acyclonucleotides were transformed into the respective phosphonic acids. All compounds were evaluated in vitro for activity against a broad variety of DNA and RNA viruses and cytostatic activity against murine leukaemia L1210, human T-lymphocyte CEM and human cervix carcinoma HeLa cells.

Synthesis of a new series of phosphonylated 1,2,3-triazoles as acyclic analogs of ribavirin.

A novel series of phosphonylated 1,2,3-triazoles as structural acyclic analogs of ribavirin, in which the 1,2,3-triazole ring was substituted at C4' with COOMe, CONH2, CONHOH, and CH2 NHBoc groups, were synthesized from diethyl azidomethyl-, 2-azidoethyl-, 3-azidopropyl-, 4-azidobutyl-, 2-azido-1-hydroxyethyl-, 3-azido-2-hydroxypropyl-, 2-azidoethoxymethyl- and 2-azidoethoxyethylphosphonate. The efficient synthesis of diethyl azidomethylphosphonate from diethyl 4-nitrobenzenesulfonylmethylphosphonate employing the in situ formed azides is described. All synthesized compounds were evaluated in vitro for their inhibitory activity against a broad variety of RNA and DNA viruses.

Synthesis and biological evaluation of novel 1,2,3-triazolonucleotides.

A general procedure for the preparation of 1,2,3-triazole analogs of nucleosides from diethyl 2-azidoethoxymethyl- and 2-azidoethoxyethylphosphonates was elaborated. The application of microwave irradiation shortened the reaction time to 10 min in comparison to ca. 48 h when 1,3-dipolar cycloadditions were performed under standard conditions.

Design, synthesis, antiviral, and cytotoxic evaluation of novel phosphonylated 1,2,3-triazoles as acyclic nucleotide analogues.

The 1,3-dipolar cycloaddition of diethyl 2-azidoethyl-, 3-azidopropyl-, 2-azido-1-hydroxyethyl-, 3-azido-2-hydroxypropylphosphonates with selected N-propargyl nucleobases gave a series of the phosphonylated 1,2,3-triazole acyclonucleosides in which the phosphonate residue and nucleobases were linked by three- and four-carbon chains. Under standard conditions (TMSBr, ethanol), all synthesized O,O-diethylphosphonates were transformed into the respective phosphonic acids. All compounds were evaluated in vitro for activity against a broad variety of DNA and RNA viruses.

Design, synthesis and cytotoxicity of a new series of isoxazolidines derived from substituted chalcones.

A new series of isomeric isoxazolidin-3-yl-3-phosphonates were synthesised from N-methyl-C-diethoxyphosphorylnitrone and substituted chalcones. The respective isoxazolidin-3-yl-3-phosphonic acids were obtained from phosphonates via dealkylation procedure using trimethylsilyl bromide. Selected phosphonates and their respective phosphonic acids were screened for their cytotoxic activity to HeLa and K562 cells with IC(50) in the 0.

Design, synthesis and cytotoxicity of a new series of isoxazolidine based nucleoside analogues.

5-Arylisoxazolidin-3-yl-3-diethoxyphosphonates have been synthesized from N-methyl-C-diethoxyphosphorylnitrone and vinyl aryls in good yields and their transformation into the respective phosphonic acids has been accomplished via dealkylation procedure using trimethylsilyl bromide. Phosphonates having 1- and 2-naphthyl substituents at C5 in the isoxazolidine ring as well as the respective phosphonic acids have been found cytotoxic to HeLa and K562 cells with IC(50) in the 0.1-0.

Synthesis of (1R,2R)- and (1S,2R)-1,2-epoxy-3-hydroxypropylphosphonates as analogues of fosfomycin.

Cyclohexylammonium (1R,2R)-1,2-epoxy-3-hydroxypropylphosphonate was conveniently synthesized from dibenzyl (1S,2R)-2,3-O-cyclohexylidene-1,2,3-trihydroxypropylphosphonate by a reaction sequence including mesylation, hydrolysis of acetal, intramolecular Williamson reaction, and hydrogenation in the presence of cyclohexylamine. For dibenzyl (1S,2R)-2,3-O-cyclohexylidene-1,2,3-trihydroxypropylphosphonates the same approach was not successful, since prior the epoxide-ring closure tritylation of HO-C3 in dibenzyl (1R,2R)-2,3-dihydroxy-1-mesyloxypropylphosphonate was necessary and the hydrogenolysis of dibenzyl (1S,2R)-1,2-epoxy-3-trityloxypropylphosphonate yielded a complex reaction mixture.

P(CH(3)NCH(2)CH(2))(3)N as a dehydrobromination reagent: synthesis of vitamin A derivatives revisited.

Although P(CH(3)NCH(2)CH(2))(3)N (1) was found to be less effective than 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.