Quantitative determination of the catalysed asymmetric transfer hydrogenation of 1-methyl-6,7dimethoxy-3,4-dihydroisoquinoline using in situ FTIR and multivariate curve resolution

Multivariate Curve Resolution with Alternating Least Squares (MCR–ALS) has been successfully applied to in situ infrared measurements of rhodium catalysed asymmetric transfer hydrogenation (CATHy) reaction of 1-methyl-6,7-dimethoxy-3,4-dihydroisoquinoline to provide an alternative to the traditional method of HPLC analysis. The pure spectra and concentration profile of the imine, amine and carbon dioxide (an intermediate component) were resolved without previous calibration information regarding the reaction. The root mean square prediction error (RMSPE) of the imine and amine were 0.02 and 0.04, respectively. The FTIR method developed enabled the reaction to be monitored in situ, which eliminated the need for constant sampling, required of HPLC analysis, and facilitated the quantitation of components not identified in the chromatographic analysis (CO2).