In the title compound, C(20)H(15)BrN(6)O(4)S [symstematic name: 4-({[4-amino-6-(p-bromo-benz-yl)-5-oxo-4,5-dihydro-1,2,4-triazin-3-yl]sulfan-yl}acet-yl)-3-phenyl-1,2,3-oxadiazol-3-ium-5-olate], the 4,5-dihydro-1,2,4-triazine ring is essentially planar [maximum deviation = 0.020 (1) Å] and is inclined at dihedral angles of 89.06 (9), 82.21 (8) and 83.98 (8)° with respect to the oxadiazol-3-ium, ...

Transcription factor IIS (TFIIS) stimulates RNA cleavage by RNA polymerase II by allowing backtracked enzymes to resume transcription elongation. Yeast cells do not require TFIIS for viability, unless they suffer severe transcriptional stress due to NTP-depleting drugs like 6-azauracil or mycophenolic acid. In order to broaden our knowledge on the role of TFIIS under transcriptional stress, we ...

The photophysical properties of 6-azauracil were studied by means of ab initio quantum chemical methods. On the basis of our calculations we propose here the following mechanism for the lack of fluorescence and the high triplet quantum yield that was observed experimentally after irradiation of this compound with UV light [Kobayashi et al., J. Phys. Chem. A, 2008, 112, 13308]. Multiple potentia...

Cyclooxygenase-2 (COX-2) is an important biomarker in several tumors. Available imaging probes display relatively low tumor to background ratios (smaller than 2:1). We evaluated newly developed indomethacin (Ind) derivatives for in vivo molecular imaging of COX-2 expressing carcinoma. Radioiodinated Ind derivatives Ind-NH-(CH2)4-NH-3-[I-125]I-Bz ([I-125]5), Ind-NH-(CH2)4-NH-5-[I-124/125]I-Nic (...

Mantel’s theorem says that among all triangle-free graphs of a given order the balanced complete bipartite graph is the unique graph of maximum size. We prove an analogue of this result for 3-graphs. Let K− 4 = {123, 124, 134}, F6 = {123, 124, 345, 156} and F = {K− 4 , F6}: for n 6= 5 the unique F-free 3-graph of order n and maximum size is the balanced complete tripartite 3-graph S3(n) (for n ...