Novel 2,4-disulfonylsubstituted 5-aminothiazoles were synthesized and their anticancer activity was assessed at a high dose (10 μM) against NCI 60 cancer cell lines. Compounds 24 and 25 showed the antiproliferative activity with mean growth inhibition about 66.0%. Replacing 4-hydroxypiperidine 24 with the more hydrophilic N-methyl piperazine 25 increased the number of sensitive cell lines while replacing these hydrophilic groups with lipophilic ones abolished the anticancer activity. The COMPARE analysis showed that the tested compounds had a moderate positive correlation with alkylating agents (CCNU and methyl CCNU) and with a purine nucleotide biosynthesis inhibitor analog (L-cysteine). The results indicate that the above mechanisms of antitumor action of standard compounds are not the main ones for the tested compounds due to the lack of a high correlation. The results of this study allow us to consider compounds 24 and 25 as a basis for their further functionalization to obtain more active compounds.

On the base of 3-formylpicolinic acid by two successive heterocyclizations (the formation of a pyrone fragment by the cyclization of chloroacetone with the carboxyl and formyl groups; and the construction of the thiazole cycle through the bromination of the acetyl fragment and following interaction with thioamides), 6-(2-(phenyl/thiophen-2-yl)thiazole-4-yl)-8H-pyrano[3,4-b]pyridin-8-ones were obtained; and then the pyrone fragment was converted to pyridone by the action of ammonia under high pressure. When such 6-(2-R-thiazol-4-yl)-1,7-naphthyridin-8(7H)-ones reacted with triflic anhydride, O-sulfonylation of the pyridone fragment occurred, after that triflate group was easily substituted by secondary cyclic aliphatic amines. Thus, a number of new 8-amino-6-(2-R-thiazol-4-yl)-1,7-naphthyridines – previously inaccessible heterocyclic derivatives with promising biological activity – were obtained.

Five imidazo[1,2-c]pyrimidine and pyrimido[1,6-a]pyrimidine derivatives were designed, synthesized and evaluated for their antiproliferative activity and cytotoxicity. Primary bioassays in vitro showed that two of five synthesized compounds, 6-benzyl-8-(methylsulfonyl)-2,6-dihydroimidazo[1,2-c]pyrimidin-5(3H)-one, and 9-(methylsulfonyl)-7-propyl-2,3,4,7-tetrahydro-6H-pyrimido[1,6-a]pyrimidin-6-one possessed potent antiviral activity against BKV (EC50: 0.66 μM and 0.96, respectively). The selectivity index of these compounds is similar to that of cidofovir. Although antiviral activity was evident in secondary assays, significant virus inhibition occurred at or near the cytotoxic concentration (SI90=1). Here we show that substituted pyrimidine derivatives are a promising structure class of chemical compounds for the development of antiviral drugs against BKV infections. Hence these compounds may be taken as lead compounds for further development of novel antimicrobial and anticancer agents.

O-Acyl substituted derivatives of 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride which is a structural analog of vitamin B₁ were synthesized and evaluated towards acetylcholinesterase and butyrylcholinesterase in vitro. The inhibition properties of the O-substituted compounds depend on nature of substituents at position 3 and 5 of the thiazolium ring. Some of the thiazolium salts showed high potency in the inhibition of only one of the two enzymes. The selective effects of these inhibitors are governed by substituent at position 5. Kinetic studies and molecular docking simulation were performed for elucidating mechanisms of enzyme-inhibitor complex formation.