Crystal structure of (S)-sec-butylammonium L-tartrate monohydrate

Abstract

The title hydrated mol­ecular salt was prepared by deprotonation of enanti­opure l-tartaric acid with racemic sec-butyl­amine in water. Only one enanti­omer was observed crystallographically, resulting from the combination of (S)-sec-butyl­amine with l-tartaric acid.

Enantio-Complementary Continuous-Flow Synthesis of 2-Aminobutane Using Covalently Immobilized Transaminases

“…However, preliminary tests had shown that when lyophilizing acidic solutions of 2-aminobutane and IPA in water, up to 25% of the initially added mass were lost, presumably due to the same apparent sublimation that is also observed for ammonium chloride. Precipitation of 2-aminobutane from the reaction mixture using tartaric acid also proved to be ineffective (data not shown).…”

“…The similar size of the R-groups (ethyl vs methyl) poses a challenge in achieving high enantioselectivity. Racemic 2-aminobutane may be separated into its enantiomers by classical resolution using tartaric acid . A recently reported asymmetric synthesis employing a chiral ruthenium catalyst only achieved 22% ee, among the lowest enantioselectivities for the substrates tried by the authors .…”

“…Racemic 2-aminobutane may be separated into its enantiomers by classical resolution using tartaric acid. 10 A recently reported asymmetric synthesis employing a chiral ruthenium catalyst only achieved 22% ee, among the lowest enantioselectivities for the substrates tried by the authors. 11 Kinetic resolution of 2-aminobutane using CAL-B, the dominant process used for making chiral amine building blocks (BASF process), requires ethyl decanoate as the acyl donor to achieve high enantioselectivity but is low yielding (25% yield, 99.8% ee (S) on a 5 g scale).…”