Chemical modifications of the aliphatic bridge of ansamycins. 2. Synthesis and activity of 23-epi-25-deacetylrifamycin S.

doi:10.7164/ANTIBIOTICS.38.259

Paper

Chemical modifications of the aliphatic bridge of ansamycins. 2. Synthesis and activity of 23-epi-25-deacetylrifamycin S.

Published Feb 1, 1985 · M. Brufani, G. Cecchini, L. Cellai

The Journal of antibiotics

Q3 SJR score

2

Citations

0

Influential Citations

Full textSemantic Scholar

Abstract

Rifamycins inhibit bacterial DNA-dependent RNA polymerase through the formation of non-covalent bonds by the oxygenated groups at C(1), C(8), C(21), and C(23). These must be unhindered and underivatized, with the antibiotic in a proper overall molecular conformation. The present study shows that contrary to previous conclusions the availability of the hydroxyl group at C(21) is not as important as that of the other three groups. In support of this is the observation that 21-epi-rifamycin S is partially active, both on the isolated DNA-dependent RNA polymerase and on some Gram-positive bacterial strains.

In Vitro Study

Study Snapshot

The availability of the hydroxyl group at C(21) is not as important as the other three groups in inhibiting bacterial DNA-dependent RNA polymerase, as demonstrated by the partial activity of 21-epi-rifamycin S on isolated DNA-dependent RNA polymerase and some Gram-positive

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

Sign up to use Study Snapshot

Consensus is limited without an account. Create an account or sign in to get more searches and use the Study Snapshot.

Create an account

Paper

Chemical modifications of the aliphatic bridge of ansamycins. 2. Synthesis and activity of 23-epi-25-deacetylrifamycin S.

Sign up to use Study Snapshot

References

Chemical modifications of the aliphatic bridge of ansamycins. Synthesis and activity of 25-deacetoxy-25-epi-hydroxyrifamycin S.

25-deacetoxy-25-epi-hydroxyrifamycin S (8) shows promising configuration and conformation, but its biological evaluation did not confirm the hypothesis of increased inhibitory activity against bacterial DNA-dependent RNA polymerase.

Early intermediates in the biosynthesis of ansamycins. III. Isolation and identification of further 8-deoxyansamycins of the rifamycin-type.

This study identified two types of minor compounds in the biosynthesis of ansamycins, indicating that they may serve as early intermediates in the biosynthesis of ansamycins.

Rifamycins: an insight into biological activity based on structural investigations.

Rifamycins show common constitutional and conformational features, but the remaining part of the ansa-bridge can vary in different compounds.

Zur Kenntnis von Rifamycin‐S.‐Reaktionen des Ansaringes. Modifikationen von Antibiotica, 8. Mitteilung [1]

Rifamycin-S shows reactivity with acids, bases, and oxidizing or reducing agents, leading to compounds and derivatives from acylation and ketalisation reactions.

Zuordnung des 13C-NMR.-Spektrums von Rifamycin-S Aufgrund der selektiven Protonen-Entkopplung

13C-NMR spectroscopy provides a more complete picture of rifamycins, particularly their naphthoquinone chromophore, than previously possible by 1H-NMR.

The rifamycins--relation of chemical structure and action on RNA polymerase.

Rifamycin derivatives inhibit RNA polymerase by altering the macrocyclic ring's shape, with slight modifications affecting binding and permeation into bacterial cells.

3 Bacterial DNA-Dependent RNA Polymerases

Bacterial DNA-dependent RNA polymerase catalyzes the transcription of genetic sequences, recognizing various genetic signals and transforming them into biochemical events.

Citations

Chemical modifications of the aliphatic bridge of ansamycins. 3. Synthesis and activity of 21-epi-rifamycin S.

21-epi-rifamycin S shows partial activity against DNA-dependent RNA polymerase and some Gram-positive bacteria, suggesting that the availability of the hydroxyl group at C(21) is less important than the other three groups.