Effect of adenosine modified with a boron cluster pharmacophore on reactive oxygen species production by human neutrophils.

Methods for the synthesis of adenosine/boron cluster conjugates are proposed and the potential of the obtained derivatives to modulate neutrophil activity, especially reactive oxygen species (ROS) production in vitro, is described. An efficient inhibition of ROS production in activated neutrophils by adenosine modified at the 2'-C and 6-N positions with a para-carborane cluster (C(2)B(10)H(11)) was discovered. The high affinity of the selected compounds for adenosine receptor A(2A) was established.

Antiviral activity of triazine analogues of 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]cytosine (cidofovir) and related compounds.

Treatment of 5-azacytosine sodium salt with diisopropyl [(2-chloroethoxy)methyl]phosphonate followed by removal of ester groups with BrSi(CH3)3 afforded 1-[2-(phosphonomethoxy)ethyl]-5-azacytosine (3). Reaction of 5-azacytosine with [(trityloxy)methyl]-(2S)-oxirane followed by etherification with diisopropyl (bromomethyl)phosphonate and removal of ester groups gave 1-(S)-[3-hydroxy-2-(phosphonomethoxy)propyl]-5-azacytosine (1). The synthesis of 6-azacytosine congener 2 was analogous using N4-benzoylated intermediates.

Efficacy of DNA hypomethylating capacities of 5-aza-2'-deoxycytidine and its alpha anomer.

In this paper, we have compared hypomethylating ability of classical beta-d-anomer of 5-aza-2'-deoxycytidine (5-aza-CdRf) and its alpha anomer in cell cultures. Alpha anomers of nucleosides generally exhibit low biological activity compared to their beta counterparts. It is reported that alpha anomer of 5-aza-CdRf efficiently hypomethylated genomic DNA in human T-lymphoblastoid CCRF-CEM cells.

Improved synthesis, antibacterial activity and potential carcinogenicity of 5-amino-1 ,2,4-thiadiazol-3(2H)-one.

This paper reports on the preparation of 5-amino-1,2,4-thiadiazol-3(2H)-one, a sulfur-containing analogue of cytosine with the -CH=CH- group between the positions 5 and 6 of the pyrimidine ring replaced by the divalent sulfur (-S-). Improved procedures for the preparation of thiobiuret, some of its methyl derivatives and 5-amino-1,2,4-thiadiazol-3(2H)-one are documented. Thiobiuret and its N-methyl derivatives were obtained by addition of hydrogen sulfide to the respective 1-cyanoureas.

Potential carcinogenicity of the synthetic 1,3,6-triazine (6-azapyrimidine) nucleic acid analogues determined by DC polarography. II. Nucleosides of 6-azauracil.

The polarographic reduction of six synthetic 1,3,6-triazine (6-aza) nucleosides with 6-azauracil as the nucleoside base in the strictly anhydrous solutions was studied in the absence and presence of alpha-lipoic acid. The values of the half-wave potentials E1/2 and the parameter of potential carcinogenicity tg alpha were compared for six nucleosides of 6-azauracil and two nucleosides of 4-thio-6-azauracil. The current value of the first diffuse polarographic wave or a new diffuse polarographic wave belonging to the nucleoside-alpha-lipoic acid complex increased with the increase of the alpha-lipoic acid concentration for the all compounds only marginally.