Conformational Evolution of Bicalutamide in Chloroform: A Comprehensive NMR Study

This study presents new findings on the conformational mobility of the nonsteroidal antiandrogen blocker, bicalutamide, in deuterated chloroform. Based on NOE NMR spectral analysis, quantitative information was obtained regarding the distribution of «open» and «closed» conformer groups in four systems: one with a solid phase (16.7%/83.3%), one without the solid phase (19.7%/80.3%), and two diluted solutions at different concentrations (16.1%/83.9% and 85.3%/14.7%). It was shown that the preparation of molecules for nucleation and the transition to the «closed» conformation occurs at low concentrations and is maintained as the concentration increases until the solid phase is formed. This behavior of conformational evolution contrasts previous understandings of the solid phase's influence on molecular conformation in solution. The results obtained will offer deeper insights into the conformational evolution of small molecules during nucleation, using bicalutamide as a model.