RIPPLY: Real-TIme Parallel Progress AnaLYsis of Organic Reactions Using Near-Infrared Spectroscopy

Abstract

High-throughput experimentation (HTE) is an important tool in pharmaceutical process research and development. However, most of the current HTE workflows do not monitor reaction progress and, therefore, provide no information on kinetic regimes (induction, deactivation, etc.). Here, we describe the development of a parallel reaction monitoring technique for micromole-scale organic reactions using near-infrared spectroscopy and multivariate semi-NMF analysis (Non-negative Matrix Factorization). This workflow produces qualitative reaction progress profiles or semiquantitative concentration profiles without the need for time-consuming calibration. Advantageously, simultaneous analysis of parallel reactions improved confidence in the black box multivariate analysis and allowed a direct comparison of predicted and measured final compositions. Two test reactions were successfully monitored using our new approach. Coincidentally, our study led to the identification of a new ketone transfer hydrogenation catalyst. Finally, initial rate kinetics and VTNA (Variable Time Normalization Analysis) experiments were successfully performed using the new technique.