# Improved synthesis and physicochemical characterization of the selective serotonin 2A receptor agonist 25CN-NBOH

## TL;DR

This paper improves the synthesis and understanding of a compound used in research to study brain receptors.

## Contribution

The study provides detailed physicochemical properties and stability of 25CN-NBOH in various states.

## Key findings

- 25CN-NBOH hydrochloride salt is stable and crystalline in solid and aqueous solution states.
- An intramolecular hydrogen bond in solution contributes to high membrane permeability.
- The compound's solubility, partition coefficient, and permeability are characterized for research use.

## Abstract

25CN-NBOH is a selective serotonin 2A receptor agonist used extensively as a tool compound in preclinical research. Herein, we perform an in-depth characterization of 25CN-NBOH and report key physicochemical properties in the solid state as well as in the solution state, namely stability, ionization, solubility, partition coefficient, and membrane permeability. We show that the hydrochloride salt is a stable and well-defined crystalline compound that is also stable in aqueous solutions at room temperature. Furthermore, we show that an intramolecular hydrogen bond is present in solution, which presumably is a key contributor to the high membrane permeability. Collectively, this physical-chemical profiling of 25CN-NBOH provides guidance to researchers with respect to the physiochemical properties and handling of the compound in various research scenarios.