Structure-Activity Studies of Novel Di-substituted [1,2,5]oxadiazolo [3,4-b]pyrazine Analogs Targeting the A-loop Regulatory Site of p38 MAP Kinase
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Updated: Oct 9, 2025

Quantitative Structure-Activity Relationship, Activity Prediction, and Molecular Dynamics of Non-nucleotide Reverse Transcriptase Inhibitors
Published on: May 9, 2025
Esther Carrasco1, Patricia Gomez-Gutierrez1,2, Pedro M Campos1
1Allinky Biopharma, Campus de Cantoblanco, Faraday 7, 28049 Madrid, Spain.
Introduction:
In the quest for novel allosteric inhibitors of the p38 MAP kinase, we recently described the A-loop regulatory site, identified by means of molecular modeling studies together with the disclosure of a small molecule hit with a moderate inhibitory profile. Starting from this structure, we subsequently identified two additional hits with simpler molecular structures from an in silico screening study, using a substructure search in the SciFinder database. After corroboration of their inhibitory profile, analysis of their structures permitted to conclude about the suitability of the [1,2,5]oxadiazolo[3,4-b]pyrazine (furazano[ 3,4-b]pyrazine) scaffold for the development of potent A-loop regulatory site p38 MAP kinase inhibitors. Accordingly, we report the synthesis and pharmacological evaluation of a series of di-substituted analogs with a potent inhibitory profile of p38 MAP kinase, as shown by in vitro assays of their capability to inhibit IL-1β secretion in human monocyte-derived macrophages.
Objective:
To find small molecule potent inhibitors of the p38 MAP kinase A-loop regulatory site.
Methods:
Starting from this structure, we subsequently identified two additional hits with simpler molecular structures from an in silico screening study, using a substructure search in the SciFinder database. After corroboration of their inhibitory profile, we carried out a hit-tolead optimization process guided by molecular modeling using a [1,2,5]oxadiazolo[3,4- b]pyrazine (furazano[3,4-b]pyrazine) scaffold.
Results:
We report the synthesis and pharmacological evaluation of a series of di-substituted analogs with a potent inhibitory profile of p38 MAP kinase, as shown by in vitro assays of their capability to inhibit IL-1β secretion in human monocyte-derived macrophages.
Conclusion:
We describe in the present work a series of [1,2,5]oxadiazolo[3,4-b]pyrazine (furazano[3,4-b]pyrazine), which are potent inhibitors of IL-1β secretion in human monocytederived macrophages allosteric modulators of the p38 MAP kinase A-loop regulatory site.
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