Chromatographic resolution of 1,2-amino alcohols on a chiral stationary phase containing N,N'-(3,5-dinitrobenzoyl)-trans-1,2-diaminocyclohexane. Theoretical and practical aspects

Optical resolution of several 1,2-diamino alcohols including some β-adrenergic blocking agents (β-blockers) was obtained by high-performance liquid chromatography on a chiral stationary phase containing 3,5-dinitrobenzoyl derivatives of trans-1,2-diaminocyclohexane (DACH-DNB) as chiral selectors. After formation of oxazolidin-2-one derivatives, racemic amino alcohols were completely resolved (α values ranging from 1.14 to 1.55 and R(s) from 1.2 to 3.3) on a 250 x 4.0 mm I.D. stainless-steel column. Further, some separations on chiral and achiral, coupled columns are reported: they show diastereo- and enantioselectivity for amino alcohols with more than one chiral centre. The method allows the utilization of both spectrophotometric and spectrofluorimetric detectors; moreover the availability of the (R,R),(S,S) selectors makes it possible to evaluate enantiomeric excesses higher than 99.9%. Some separations were also carried out with microbore columns (2.0 mm I.D.), which afforded the same performance.