RECEIVED DATE (to be automatically inserted after your manuscript is accepted if required according to the journal that you are submitting your paper to) Abbreviations: 11,11, poly(dAdT)2, duplex of two alternating adenine-thymine polynucleotides; RA, rheumatoid arthritis; 2 SAR, structure activity relationship; SDS, sodium dodecyl sulphate; VZV, varicella-zoster virus; YO, oxazole yellow; YOYO, homodimeric derivative of oxazole yellow (YO).3 AbstractHere we present the synthesis of five novel indoloquinoxaline derivatives and investigate the DNA binding properties of these monomeric as well as dimeric compounds using absorption, fluorescence and linear dichroism. Several of the mono-and di-cationic derivatives presented have previously demonstrated an excellent antiviral effect that is higher than already acknowledged agents against human cytomegalovirus (CMV), herpes simplex virus type 1 (HSV-1) and varicella-zoster virus (VZV).We find that the DNA binding constants of the monomeric and dimeric derivatives are high (10 6 ) and very high (10 9 ), respectively. Results from the spectroscopic measurements show that the planar aromatic indoloquinoxaline moieties upon interaction with DNA intercalate between the nucleobases.Furthermore, we use poly(dA-dT) 2 and calf thymus DNA in a competitive binding experiment to show that all our derivatives have an AT-region preference. The findings are important in the understanding of the antiviral effect of these derivatives and give invaluable information for the future optimization of the DNA binding properties of this kind of drugs.4

Reaction of P4S10 in hot pyridine produces a crystalline solid which can be collected and used for thionations in other solvents such as acetonitrile and sulfolane. The biologically active natural products tryptanthrine, rutaecarpine, 7,8-dehydrorutaecarpine, and some related compounds have now been converted to thionated versions simply by heating the molecules with this thionating reagent in sulfolane (typically at 135 °C for 20 min) followed by a workup in water. No chromatography was necessary.