10-Ethyl-7-oxo-7,10-dihydropyrido[2,3-f]quinoxaline derivatives, synthesized as promising biologically/photobiologically active compounds were characterized by UV/vis, FT-IR and fluorescent spectroscopy. Photoinduced processes of these derivatives were studied by EPR spectroscopy, monitoring in situ the generation of reactive intermediates upon UVA (λmax=365 nm) irradiation. The formation of re...

Considerable interest has been focused on the triazole structure, which has been known to possess a broad spectrum of biological activities such as antitumor, anti-inflammatory, antimicrobial, antiviral, and anticonvulsant activities. Before this, several heterocyclic compounds containing triazole were synthesized that had shown considerable anticonvulsant activity. As part of our continuous re...

Glutamine (Gln) prevents apoptosis in intestinal epithelial cells, but the mechanism(s) remain unknown. Gln-derived metabolites include ammonia, glutamate (Glu), glutathione (GSH), and nucleotides. We previously showed that Gln potently inhibited apoptosis in cytokine-treated human colonic HT-29 cells; this effect was specific to Gln, unaffected by Glu, and unrelated to intracellular GSH. The c...

Leishmania donovani and Leishmania braziliensis grown in culture formed millimolar concentrations of allopurinol ribonucleoside 5’-monophosphate from [6“C]allopurinol. In addition, allopurinol l-ribonucleoside, oxipurinol riboside 5’-monophosphate, and three new metabolites of allopurinol, namely, 4-aminopyrazolo(3,4-d)pyrimidine ribonucleoside V-monophosphate and the corresponding diand tripho...

The effects of weak intermolecular interactions on 10 vibrational normal modes of pyrimidine are investigated by Raman spectroscopy and electronic structure computations. Hydrogen-bonded networks of water induce a shift to higher energy in certain normal modes of pyrimidine with increasing water concentration, while other modes are relatively unaffected. Pyrimidine molecules also exhibit weak C...

In the title compound, C20H16Cl2N2O2S, the pyrimidine ring has a screw-boat conformation. The attached di-chloro-phenyl ring is twisted at an angle of 89.29 (13)° with respect to the pyrimidine ring mean plane. The benzo-thia-zole group is approximately planar (r.m.s. deviation = 0.008 Å) and inclined to the pyrimidine ring mean plane by 3.04 (10)°. The carboxyl-ate group assumes an extended co...

New fluorescent compounds, benzo[4,5]thieno[3,2-d]pyrimidine 5,5-dioxides (3a-g), 2-amino-4-methylsulfanylbenzo[4,5]thieno[3,2-d]pyrimidine (6), and 2-amino-4-methylsulfanyl-7-methoxybenzo[4,5]furo[3,2-d]pyrimidine (7), were synthesized in good yields from heterocyclic ketene dithioacetals (1a-c) and guanidine carbonate (2a) or (S)-methylisothiourea sulfate (2b) in pyridine under reflux. Among ...

Leishmania donovani and Leishmania braziliensis grown in culture formed millimolar concentrations of allopurinol ribonucleoside 5'-monophosphate from [6-14C]allopurinol. In addition, allopurinol 1-ribonucleoside, oxipurinol riboside 5'-monophosphate, and three new metabolites of allopurinol, namely, 4-aminopyrazolo(3,4-d)pyrimidine ribonucleoside 5'-monophosphate and the corresponding di- and t...

In the title compound, [Co(2)(NCSe)(4)(C(4)H(4)N(2))(3)(CH(3)OH)(2)](n), the Co(II) ion is coordinated by three N-bonded pyrimidine ligands, two N-bonded seleno-cyanate anions and one O-bonded methanol mol-ecule in an octa-hedral coordination mode. The asymmetric unit consists of one Co(II) ion, one pyrimidine ligand, two seleno-cyanate anions and one methanol mol-ecule in general positions as ...

An approach to the detection of pyrimidine dimer-DNA glycosylase activity in living cells is presented. Mutants of Escherichia coli defective in uvr functions required for incision of UV-irradiated DNA were infected with phage T4 denV+ or denV- (defective in the T4 pyrimidine dimer-DNA glycosylase activity). In the former case the denV gene product catalyzed the incision of UV-irradiated host D...