INTRODUCTION Nucleosides are key compounds involved in major biological processes, such as nucleic acids and proteins synthesis, cell signaling, enzyme regulation, and metabolism. Nucleoside and their derivatives have emerged as molecules with ABSTRACT In search of new leads toward potent antibacterial agents; therefore, a series of thymidine analogues were synthesized by direct acylation method and furnished the 5´-O-acyl thymidine derivatives in good yield. A number of acyl derivatives were prepared in order to obtain a series of newer components for antibacterial screening experiments. The synthesized compounds were characterized by their FTIR, 1 HNMR spectral data and elemental analysis. These thymidine derivatives were evaluated for in vitro antibacterial screening studies against a number of human pathogenic microorganisms by disc diffusion method. The study revealed that most of the tested chemicals exhibited moderate to good antibacterial activities. It was also observed that the test chemical 2-bromobenzoyl derivative 11 very significantly inhibited the growth of all Gram-positive and Gram-negative bacterial strains used. For comparative studies, antibacterial activity of standard antibiotics, Azithromycin was also carried out against these microorganisms. Hence, these thymidine derivatives can be used to discover antibacterial agents that may serve as leads in the development of new pharmaceuticals research activities.

Due to the variable environmental nature of mine water, several species of bacteria are important in the generation of acid mine drainage (AMD) and in bioremediation treatment technology. Enzymatic metal transport and transformation allow bacteria to survive in high-metal environments and to oxidize, reduce, and exude metals. For example, the enzymes Cr (VI) reductase and cytochrome-c3 hydrogenase allow Pseudomonas sp. to reduce Cr (VI) to less toxic Cr (III). Much more toxic organomercuric compounds are transformed by Pseudomonas fluorescens and Escherichia coli, using the enzymes organomercurial lyase and mercuric reductase. The role of bacteria in the AMD environment is not yet fully understood and consequently researchers should pay attention in this field.

K arbonhidratlar, doğadaki en bol ve en çeşitli biyopolimerlerdir. Karbonhidratların önemi nedeniyle, sağlık ve hastalık için mevcut küresel durumdaki karbonhidrat bazlı ilaçların sentezi için yeni bir yöntem geliştirmek gereklidir. Bu çalışmada, metil 4,6-O-benziliden--D-glucopyranosit türevlerinin doğrudan asilasyon yöntemiyle sentezi gösterilmiştir. Yeni hazırlanan bileşiklerin yapıları, element analizi, erime noktası tayini, kızılötesi ve proton NMR spektroskopisi dahil olmak üzere çeşitli fiziko-kimyasal ve spektroskopik yöntemler kullanılarak tanımlanmış ve açıklanmıştır. Antibakteriyel tarama deneyleri için bir dizi daha yeni bileşen elde etmek için birkaç asil türevi hazırlandı. Bu asillenmiş türevler, dört insan patojenik bakterisine karşı in vitro antibakteriyel tarama çalışmaları için disk difüzyon yöntemiyle değerlendirilmiştir.