Studies of enantiomerization of chiral 3,4-dihydro-1,2,4-benzothiadiazine 1,1-dioxide type compounds

An on-column HPLC procedure using a chiral stationary phase (CSP) was devel oped for the determination of rate constants and free energy barriers of en antiomerization of (+/-)IDRA21. Subsequently, the HPLC method was applied f or investigation of two structurally related chiral compounds. The individu al enantiomers of the studied compounds were isolated in parallel by prepar ative HPLC and rate constants and free energy barriers of enantiomerization were determined in different solvents. The on-column enantiomerization dat a revealed that CSP induces different rate constants for the two enantiomer s. The results generated off-line were used to determine the influence of s olvents on the racemization of (+) and (-) IDRA21 and to gain further insig ht into the enantiomerization mechanism of chiral 3,4-dihydro-1,2,4-benzoth iadiazine 1,1-dioxide type compounds. Chirality 13:94-101, 2001, (C) 2001 W iley-Liss. Inc.