Automatic Selection of Mobile Phases. V. Thin‐Layer Chromatography on Silica vs. Alumina of 3,4‐Disubstituted Isochroman‐1‐Ones Including Spiro Analogues

Abstract

Avoiding any trial and error experiments, the LSChrom software incorporating the Snyder theory was applied successfully to automatic selection of mobile phases for thin‐layer chromatography (TLC) of substituted isochromanones 1–8 and the spiro analogues 9–12. The procedure takes into account the adsorption properties of the mobile phase (parameter ϵ and tuning parameters m and P′), stationary phase and sample structure expressed by relevant groups. The calculations yielded a recommended value of ϵ and subsequently a list of mobile phases having this value of ϵ. The approach was applied to TLC on two types of silica and, for the first time, on alumina. Within about 130 measurements using 10 computer selected mobile phases, the retention of any compound fell in a favorable range (0<R _F <1). The separation, α, of the cis/trans isomers 1–6 depended on their retention, stationary phase, and values of m and P′ of the mobile phase. Silica was more effective and did not cause compound decomposition in contrast to alumina.

Keywords:

• Normal‐phase liquid chromatography
• Thin‐layer chromatography
• Silica
• Alumina
• O‐containing heterocycles
• Cis/trans isomers
• Mobile‐phase selection
• Snyder theory in LSChrom software

Acknowledgment

The authors are grateful to Prof. Lloyd Snyder for his helpful comments and encouragement during the elaboration of both versions of LSChrom.