&lt;strong&gt;Pyrrolidine analogs of arylceramide HPA-12&lt;/strong&gt;

Marián Zeman,Jozef Markus,Dušan Berkeš

doi:10.3390/ecsoc-22-05673

Abstract

At the beginning of the millennium, the (R,R)-HPA-12 was found to be the first antagonist of ceramide transporter CERT, which has been identified as a key factor for the ER-to-Golgi trafficking of ceramides. Ten years later, we have revised the stereochemistry of the most active HPA-12 diastereomer to (R,S) and developed synthesis of more potent alkyl substituted HPA-12 analogs. In the present study, based on the experience of our research group, the synthesis of the constrained pyrrolidine analogs of both (R,S)-HPA-12 and (R,R)-HPA-12 starting from substituted pyroglutamic acids easily accessible via our methodology will be demonstrated. The efficient synthesis of both target diastereoisomers of pyrrolidine HPA-12 analog included four key reactions. First was aza-Michael addition in tandem with CIAT - crystallisation induced asymmetric transformation, which yielded almost pure diastereomer and established an important stereogenic centre. Second reaction was stereoselective cyclisation, which also yielded almost pure diastereomer and introduced oxoproline structure in the molecule. Consequently, the target diastereomers were prepared by stereoselective reduction of oxo group and Mitsunobu inversion respectively. Configuration of stereogenic centre created by this reduction plays significant role in biological activity of pyrrolidine HPA-12 analogs and was confirmed by X-ray analysis. The samples of final derivatives were tested against inhibition of CERT protein. The results of the binding assays to the CERT protein will be discussed.

Highlights

Sphingolipids are membrane lipids that play important roles in the regulation of cell functions such as cell growth, differentiation, apoptosis, and homeostasis
As part of our ongoing research focused on this field, we were interested in the design and synthesis of constraint HPA-12 analogs starting from enantiomerically pure 3-aroyl pyroglutamic acids
This study describes conformationally restricted HPA-12 analogs with incorporated pyrrolidine scaffold as biologically active inhibitors of the CERT protein

Summary

Introduction

Sphingolipids are membrane lipids that play important roles in the regulation of cell functions such as cell growth, differentiation, apoptosis, and homeostasis Alterations in their metabolism have been associated with several pathologies. Ceramides are important signal molecules that control important cell vital functions such as division, apoptosis, or autophagy They are formed in the endoplasmic reticulum and are the basis of glycosphingolipids and phospholipids whose synthesis takes place in the Golgi apparatus. Aryl substituted ceramide analog - HPA-12 was discovered as the first specific inhibitor of intracellular transport of ceramides by CERT[2]. In this way, it is possible to regulate the ratio of sphingolipids and ceramides in the cell, which contributes to the proper functioning of the cell. As part of our ongoing research focused on this field, we were interested in the design and synthesis of constraint HPA-12 analogs starting from enantiomerically pure 3-aroyl pyroglutamic acids

Methods

Results and discussion

Conclusions