10.1002/jhet.5570380512
The study focuses on the synthesis and isolation of bromo-β-carbolines, which are derivatives of β-carboline alkaloids. The researchers used N-bromosuccinimide (NBS) as the brominating agent to induce electrophilic aromatic substitution in various β-carbolines, including nor-harmane, harmane, harmine, harmol, and 7-acetylharmol. The purpose of using these chemicals was to explore the behavior of substituted β-carbolines, prepare nitro-β-carbolines and bromo-β-carbolines, and investigate their potential use as matrices (photosensitizers) in matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry (uv-maldi-tof ms). The study also aimed to understand the effects of substituents on the acid-base properties and electronic excited states of these molecules. The researchers compared the use of NBS in solution and in solid state, and employed semiempirical AM1 and PM3 calculations to predict reactivity in terms of molecular orbital energies and charge density. The results provided insights into the regioselectivity of bromination and the influence of the β-carboline/NBS molar ratio and reaction time on product selectivity.