Fluoride ion promoted deprotection and transesterification in nucleotide triesters.

Tetrabutylammonium fluoride will remove phenyl, trichloroethyl and cyanoethyl groups from nucleotides. In addition to the desired nucleotide products other results including chain cleavage, phosphofluoridates and cyanoethylated thymidine units may be obtained depending on the conditions used. Fluoride ion has been used to successfully exchange phenyl and trichloroethyl groups for methyl, ethyl and butyl groups in nucleotide triesters. This represents a rapid high yield route to a variety of phosphate esters. The synthesis of a novel nucleotide analogue in which two chains are bridged through their phosphates is described.     

Fluoride ion catalyzed alkylation of purines, pyrimidines, nucleosides and nucleotides using alky halides.

Alkyl halides react rapidly with purines and pyrimidines in the presence of fluoride ion. Alkylation of thymidine leads to novel dimeric nucleoside derivatives bridged through N3. Alkylation of thymidine mono and dinucleotides leads to alkylation at the base (N3) as well as diester and triester formation at the phosphate.     

Stringent control of ribonucleic acid synthesis in Bacillus subtilis treated with granaticin.

The antibiotic granaticin interferes in Bacillus subtilis with the charging process of tRNALeu causing both the arrest of protein synthesis and bacteriostasis [A. Ogilvie, K. Wiebauer & W. Kersten (1975) Biochem. J. 152, 511-515]. A concomitant inhibition of RNA synthesis is observed. This inhibition was studied with mutant strains of B. subtilis. 2. Granaticin inhibits protein and RNA synthesis in stringently controlled B. subtilis (rel+) to about the same extent. In a relaxed mutant strain (rel-) of B. subtilis, protein synthesis is also inhibited, but the accumulation of RNA continues after the addition of the drug. 3. Chloramphenicol, which is known to abolish the stringent control mechanism, added simultaneously with granaticin, allows the synthesis of RNA to proceed in the stringent strain. 4. Guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) accumulate in granaticin-treated stringently controlled B. subtilis but not in the rel- mutant. 5. It is concluded that the inhibition of RNA synthesis granaticin can adequately be explained as a stringent response caused by the interference by the drug with leucyl-tRNA synthetase.     

Inhibition of leucyl-transfer ribonucleic acid synthetasymol.

The bacteriostatic effect of low concentrations of the antibiotic granaticin on Bacillus subtilis is relieved by the addition leucine to the growth medium. In cells treated with granaticin, aminoacylation of leucine tRNA is specifically decreased, but the content of free leucine is not. It is concluded that granaticin interferes with the charging process of leucine tRNA in B. subtilis leading to leucine auxotrophy.     

Synthesis of Novel Isocytosine Pseudonucleotide Analogues

Abstract

Ethyl dialkylphosphonoacetates were prepared from the corresponding dimethylalkylphosphites via the Arbuzov reaction with ethyl bromoacetate. The phosphonoacetates so produced were converted into enaminoacetates by reaction with DMF dimethylacetal and these were used as bidentate electrophiles for the synthesis of phosphonopyrimidones. Several of these compounds were tested for biological activity but none were found to possess antiviral activity.     

N-Substituted Acyclopurinenucleosides with Antiviral Activity

Abstract

N-Substituted Glyceropurines have been prepared. The N-dimethylaminomethyleneated and N-acetylated glyceroguanine derivatives have significant activity against Herpesviruses.     

Preparation,Characterization and Reactivity of Diastereomeric Sulfoxides of 8,2′-S-Anhydroadenosine

Abstract

The oxidation of 8,2′-S-anhydroadenosine (1a) has been investigated. The major product from the oxidation of 1a using 1-chlorobenzotriazole was the R-sulfoxide. The oxidation of 3′,5′-di-O-acetyl-8,2′-S-anhydroadenosine (1b) gave predominately the S-sulfoxide. These sulfoxides were found to be very succeptible to nucleophilic attack at C-8.     

Synthesis of Purine and Pyrimidine Trihydroxyacyclonucleosides

Abstract

The [[3-hydroxy-2-bis(hydroxymethyl)-l-propoxy]methyl] derivatives of adenine, guanine, cytosine and thymine have been synthesized and tested against herpesviruses.