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Thiosemicarbazones of p-aminobenzoic acid (PABA) were synthesized and tested for their antimicrobial and anticancer activity. Hydroxamate derivatives 4a-4l were found to have better antimicrobial and anticancer activity than their acid counterpart. Compound 4d was found to have good antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Vibrio cholerae, and Bacillus subtilis with IC(50) value of about 1 µM. Compound 4f showed potent antifungal activity against Candida albicans (IC(50)  = 1.29 µM) and compound 4h showed potent anticancer activity (IC(50)  = 0.07 µM).

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A pyrazolo[4,3-e][1,2,4]triazolo[1,5-c]pyrimidin-5-amine antagonist of the A2A adenosine receptor (AR) was functionalized as amine congeners, fluorescent conjugates and a sulfonate, and the A2AAR binding modes were predicted computationally. The optimal n-butyl spacer was incorporated into the following A2AAR-selective (Ki, nM) conjugates: BODIPY630/650 derivative 11 (MRS7396, 24.6) and AlexaFluor488 derivative 12 (MRS7416, 30.3). Flow cytometry of 12 in hA2AAR-expressing HEK-293 cells displayed saturable binding (low nonspecific) and inhibition by known A2AAR antagonists. Water-soluble sulfonate 13 was a highly potent (Ki = 6.2 nM) and selective A2AAR antagonist based on binding and functional assays. Docking and molecular dynamics simulations predicted the regions of interaction of the distal portions of these chain-extended ligands with the A2AAR. The BODIPY630/650 fluorophore of 11 was buried in a hydrophobic interhelical (TM1/TM7) region, while AlexaFluor488 of 12 associated with the hydrophilic extracellular loops. In conclusion, we have identified novel high affinity antagonist probes for A2AAR drug discovery and characterization.

Curcumin, a natural diaryl heptanoid continues to be used as an alternative medicinal agent in many parts of South East Asia for treatment of many ailments. It can be usually obtained from substituted aryl aldehydes and acetylacetone and this route enables synthesis of a diverse set of curcumin analogues. Numerous analogues have been synthesized and tested by several researchers to investigate their activity against known biological targets and to improve upon the pharmacological and ADME profile by modifying substitutions on aromatic rings, β-diketone moiety and two flanking double bonds conjugated to the β-diketone moiety. Successful synthesis of such derivatives with modifications has resulted in the development of potential anticancer candidates that target various stages in cancer cell growth and development. Based on the evidences in modifications of these three functional elements, we have attempted to summarize the structure activity relationship of molecules which can be further utilized by researchers in medicinal chemistry in exploring the structure of curcumin.

Quinazoline derivatives are reported to have anti-inflammatory, analgesic, antibacterial, and anticancer activities. The incorporation of "OCH₂CONH₂" (oxymethylcarbamide) at 4th position of the quinazoline ring was found to influence the biological activities of the molecules. With this rationale, some new oxadiazolyl methyloxy quinazolines, pyrazolyl acetoxy methyl quinazolines, triazolylmethyloxy quinazolines were synthesized from anthranilic acid through quinazolyl oxyacetylhydrazide intermediates. All the compounds were characterized by IR, ¹H-NMR, EI-MS, and C, H, N analyses and evaluated for their antimicrobial activity. Docking studies on the DNA-gyrase enzyme (1KZN) show their role in the antimicrobial activity of the molecules and explain the higher potency of compounds 6a, 6b, 8a, 8b based on ReRanking scores and binding poses of the molecules.

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