The application of N-phenyltriflamide to the synthesis of deoxyaspergillic acid

2(1H)-Pyrazinones from acyclic building blocks: methods of synthesis and further derivatizations

Pyrazinones (2(1H)-pyrazinones) are found as components of a range of natural substances and are involved in the preparation of a great number of bioactive molecules. Synthesis of such compounds, and analogues, requires knowledge of the heterocyclic properties of pyrazinones and, in particular, methods for their ring construction. This review deals with the strategies that have been developed for the synthesis of pyrazinones from acyclic precursors, especially α-amino acid-derived units, from the first examples in 1905 up to the most recent in 2021.

Screening solution-phase combinatorial libraries using pulsed ultrafiltration/electrospray mass spectrometry

A method is described whereby a family of homologues is synthesized in a one-pot reaction, without isolation or purification, and the reaction mixture is screened using a competitive binding assay based on pulsed ultrafiltration/electrospray mass spectrometry (PUF/ESMS) to tentatively identify those derivatives having the highest affinity for a target receptor. As a model system to test this approach, a synthetic scheme designed to prepare a series of analogues of the adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), as diastereomeric mixtures, was carried out. Pulsed ultrafiltration screening of the crude reaction mixture against controls without protein detected protonated molecules corresponding to EHNA-type derivatives and three of its linear, alkyl homologues but did not show protonated molecules for an isobutyl or benzylic EHNA derivative, suggesting the latter was inactive. To verify this conclusion, we prepared E/THNA, the linear homologues, and the benzylic derivative (each as a diastereomeric mixture) and bioassayed them for them adenosine deaminase inhibition index ([I]/[S]0.5). The bioassay results for the individually synthesized analogues were in good agreement with that predicted by the observed relative ion enhancement in the PUF experiments. Thus, the PUF protocol might be used as a general method to quickly provide direction to the chemist in search of drug candidates.