HPLC separation of some purine and pyrimidine derivatives on Chromolith Performance Si monolithic column

The chromatographic behavior of some purines and pyrimidines on a monolithic Chromolith Performance Si column under normal-phase high-performance liquid chromatography mode has been studied. Column pressure, column efficiency and selectivity of Chromolith Performance Si column were compared to those of conventional spherical 5 microm silica packed columns Econosphere Silica and Zorbax Rx-SIL. The investigation has shown that application of Chromolith Performance Si column for analysis of polar solutes can reduce the separation time without sacrificing column efficiency and selectivity. Improvement of the monolithic silica column efficiency for polar solutes is observed when ternary mobile phases (mixtures of hexane-isopropanol with ethylene glycol, water or acetonitrile) are applied.     

Two-dimensional protein separation by the HPLC system with a monolithic column

A two-dimensional high-performance liquid chromatography (2D-HPLC) system for protein separation was developed using an ion-exchange column in the first dimension and a reversed-phase monolithic column in the second dimension. The system demonstrated efficient separation of proteins in comparison with conventional systems. For proteomic analysis, proteins extracted from the cell surface of the yeast were separated by 2D-HPLC and evaluated.     

Optimization of separation of purine and pyrimidine compounds using ion-pair reversed-phase high performance chromatography (HPLC)

Utilization of ion-air reagents in a reversed-phase chromatographic system allows solving a number of problems related to the separation of purine and pyrimidine derivatives. Simultaneous analysis of nucleotides, nucleosides and their bases was carried out by acetonitrile gradient elution using tetrabutyl ammonium phosphate as a counterion in the mobile phase. Besides, optimal conditions were selected for isocratic separation of adenine nucleotides and their metabolites. Furthermore, isocratic separation of certain purines and pyrimidines was achieved by modifying the stationary C18-phase with pentane- and heptane sulphonic acids.     

Synthesis and fungitoxicity of some pyrimidine derivatives

A series of 12 pyrimidine derivatives were prepared and testedin vitro against growth, sporulation and nucleic acid content ofFusarium oxysporum f. sp.lycopersici andHelminthosporium oryzae. Introduction of a thiazole ring together with two aryl groups into 2-aminopyrimidine brought about drastic toxicity for both fungi. Pyrimidine derivatives with aryl groups alone were less toxic. Nitro groups were found to enhance the toxicity of the pyrimidine derivatives especially when substituted in the ortho-position of the aryl groups. Inhibition of nucleic acid synthesis of both fungi was attributed mainly to the presence of the thiazole ring.     

Acid-soluble purine and pyrimidine derivatives of growing, encysting and encystment-inhibited amoebae

The intracellular acid-soluble purine and pyrimidine derivatives of myxamoebae-swarm cells of Physarum flavicomum were investigated during growth, microcyst formation, and during adenine-inhibition of encystment, using high performance liquid chromatography (HPLC). We also studied the incorporation of exogenous radioactive adenine into the acid soluble purine derivatives and S-adenosyl-sulphur compounds separated by HPLC. The most abundant ribonucleoside monophosphate was AMP in the growing and 15 h encysting cells (NC), while it was UMP in the 15 h adenine-inhibited cells (AIC). ADP was the nucleoside diphosphate present in the greatest quantity in the growing and NC cells but it was CDP in the AIC. The nucleoside triphosphate in highest concentration was ATP, UTP, and GTP in growing, NC, and AIC, respectively. Guanosine was the most abundant nucleoside in all cells. The nucleobase occurring in greatest concentration was cytosine, cytosine and guanine, and adenine in the growing, NC, and AIC, respectively. The AMP content in the 15 h AIC was 2.1-fold higher than that of adenosine. The 15 h NC had the lowest adenylate energy charge, a value of 0.54 +/- 0.02, while the values for growing cells and the AIC were 0.62 +/- 0.02 and 0.76 +/- 0.01, respectively. [14C]-Adenine labelling studies (15 h) revealed the occurrence of purine nucleotide interconversion, as the label was detected not only in adenosine, AMP, ADP, ATP, but also in guanine, guanosine, GMP, GDP, GTP, as well as, in inosine monophosphate and xanthosine monophosphate. The percentage incorporation of the radiolabelled adenine into AMP was higher than into adenosine. An increased intracellular level of guanine nucleotides is associated with the inhibition of encystment. The extracellular adenine, rather than internal adenine sources, appears to be the primary precursor of nucleotide for S-adenosylmethionine synthesis during adenine-inhibition of encystment.     

Effects of purine and pyrimidine derivatives on uptake of tritium-labelled uridine by Closterium acerosum

Uracil, adenosine, cytidine, guanidine, and thymidine were potentinhibitors of uptake of tritium-labelled uridine by Closteriumacerosum. Ribonudeoside monophosphates, ribonudeoside triphosphates,and deoxyribonucleoside triphosphates weakly inhibited uptake,but adenosine triphosphate and cyclic adenosine monophosphatedid not. Ribose-5-phosphate had a slight inhibitory effect onthe uptake of uridine. (Received January 19, 1976; )     

Synthesis of racemic and enantiomeric 3-pyrrolidinyl derivatives of purine and pyrimidine nucleobases

The present work relates to the synthesis of pyrrolidine nucleoside analogs. Starting from malic acid, we have elaborated a high-yield synthesis of racemic and enantiomeric N-protected 3-pyrrolidinols and their O-mesyl derivatives as key compounds for alkylations of purine and pyrimidine nucleobases. On varying base and solvent, we have found conditions providing both satisfactory N-/O-regioisomeric ratio and acceptable yield for pyrimidine compounds.     

Synthesis and antimicrobial evaluation of some new substituted purine derivatives

A series of 8,9-disubstituted adenines (4, 5, 8), 6-substituted aminopurines (10–13) and 9-(p-fluorobenzyl/cyclopentyl)-6-substituted aminopurines (16, 17, 19–30) have been prepared and the antimicrobial activities of these compounds against Staphylococcus aureus, methicillin-resistant S. aureus (MRSA, standard and clinical isolate), Bacillus subtilis, Escherichia coli and Candida albicans were evaluated. 6-[(N-phenylaminoethyl)amino]-9H-purine (12) which has no substitution at N-9 position and 9-cyclopentyl-6-[(4-fluorobenzyl)amino]-9H-purine (24) exhibited excellent activity against C. albicans with MIC 3.12 μg/mL. These compounds displayed better antifungal activity than that of standard oxiconazole. Furthermore, compound 22 carrying 4-chlorobenzylamino group at the 6-position of the purine moiety exhibited comparable antibacterial activity with that of the standard ciprofloxacin against both of the drug-resistant bacteria (MRSA, standard and clinical isolate).     

High-pressure liquid chromatography: I. Quantitative separation of purine and pyrimidine nucleosides and bases

A high-pressure liquid column chromatographic method has been developed for the separation and identification of ribonucleosides, deoxyribonucleosides, and bases. This method is capable of detecting these components at 1.0 to 5.0 ng applied; is reproducible under conditions of constant pressure, temperature, and pH; and is rapid, requiring about 30 min for a complete chromatographic separation of ribonucleosides from deoxyribonucleosides and from bases. These separations were carried out under different pH values and buffers, namely, phosphate buffer containing 2.5% methanol at pH 6.9 and 3.0 or 50 mm sodium borate buffer, pH 9.0. These different conditions were utilized to obtain more definitive identification and quantitation of normal metabolites and their counterparts, the antimetabolites. The advantage of this method is that the 20 naturally occurring components are separated from each other by an isocratic elution method, alleviating the need for a gradient elution system, which produces a drift in the baseline with increasing concentration of the eluting buffer, especially when the instrument is operating at maximum sensitivity, thus hindering the quantitation of the separated components. The potential application of this method for the quantitation of plasma metabolites and antimetabolites such as Ara-C², Ara-U, and F-pyrimidine is describe.