Self-disproportionation of enantiomers of prazoles via achiral, gravity-driven silica gel column chromatography

Self‐disproportionation of Enantiomers (SDE) of Chiral Nonracemic Amides via Achiral Chromatography

“…The number and variety of the reported examples evidently suggests that a relatively strong SDE magnitude will be observed in virtually any case where a chiral amide is subjected to achiral chromatography. These overwhelming data clearly identify an amide functionality as an SDE‐phoric group, along with chiral sulfoxides and fluorine‐containing compounds ,,. Thus, it would be reasonable to expect that the editorial policy of chemistry journals should include the request to perform a proper SDE test for papers dealing with catalytic chemical or enzymatic asymmetric synthesis of amide, fluorine, and sulfoxide group‐containing compounds .…”

Self-disproportionation of enantiomers (SDE) of chiral sulfur-containing compounds via achiral chromatography

“…The pure enantiomer of each prazole was isolated from non-racemic starting materials by this chromatography (entries 1, 4, 8, and 11). 89 Therefore, we suggest that further research on the SDE of these compounds could make their enantiomeric purification by achiral chromatography affordable and competitive to crystallization. © ARKAT USA, Inc Measured by HPLC on Chiralcel AD-H (Daicel).…”

“…This opinion is nicely supported by the SDE behaviour of a non-racemic mixture of esomeprazole 5, lansoprazole 12, pantoprazole 13, and rabeprazole 14 on regular gravity-driven silica gel column chromatography using different eluents. 89 It should be added here that a growing interest in the chemistry of these prazole-containig sulfoxides results from the fact that they are commonly used as drugs for peptic ulcers. 88,[94][95] Racemic omeprazole 5 (losec, prilosec) launched in 1988, was the first gastric proton-pump inhibitor (PPI) used for treatment of this type of gastric problems and quickly became the world's best selling drug in the late 1990s.…”

“…89 This proposal stems from both the X-ray crystallographic structure analysis of omeprazole 5, which showed the existence of a cyclic dimer of two enantiomers, [96][97] and a great extent of dimerization observed for a chloroform solution. 98 …”

Possible Case of Halogen Bond‐Driven Self‐Disproportionation of Enantiomers (SDE) via Achiral Chromatography

“…The corresponding monomers and the homo‐ or heterochiral molecular associations have different chromatographic behavior leading to the elution of enantiomerically enriched/depleted fractions. Although intermolecular interactions are an intrinsic occurrence for all chemical compounds, the high magnitude of the SDE via achiral chromatography is usually observed for molecules capable of hydrogen bonding, dipole–dipole, and aromatic interactions . However, despite the rapidly growing body of data, some progress in theoretical modeling, and exciting technological potential, the field of SDE phenomenon is still at an early development stage, awaiting new discoveries and applications.…”