Palladium-Catalyzed Arylation of Carbasugars Enables the Discovery of Potent and Selective SGLT2 Inhibitors

Design and Synthesis of Bicyclo[4.3.0]nonene Nucleoside Analogues

Nucleoside analogues are effective antiviral agents, and the continuous emergence of pathogenic viruses demands the development of novel and structurally diverse analogues. Here, we present the design and synthesis of novel nucleoside analogues with a carbobicyclic core, which mimics the conformation of natural ribonucleosides. Employing a divergent synthetic route featuring an intermolecular Diels-Alder reaction, we successfully synthesized carbobicyclic nucleoside analogues with high antiviral efficacy against respiratory syncytial virus.

Selective synthesis of 3-deoxy-5-hydroxy-1-amino-carbasugars as potential α-glucosidase inhibitors

A convenient synthesis of novel 3-deoxy-5-hydroxy-1-aminocarbasugars was developed here. The benzyl-protected glucose-derived ketone 12 was selectively converted in high yield to enone 13via retro-Michael elimination of BnOH. The double bond of 13 was regio- and stereo-selectively reduced by the induction of C4-α-OBn to the multi-functionalized 15. 15 contained all the functionalities with similar configurations to carbasugars but with 3-H and 5-OH in the ring, and it would be a very interesting building block for organic synthesis or for bioactive compounds. As one application, 15 was further transformed into 1-amino-carbasugars by the reductive amination and final deprotection of benzyls. The targets were subjected to the in vitro inhibitory activity test against sucrase or maltase. The inhibitory activity of 17b, 17h or 17j against sucrase was nearly similar to that of voglibose. In comparison with voglibose, in vivo results similarly showed that 17b, 17h or 17j could lower the post-prandial blood glucose level after sucrose loading in healthy male ICR mice, while miglitol or acarbose was less effective. The molecular modeling study of some targets or voglibose with human sucrase could explain the inhibiting action.

Concise and Stereodivergent Synthesis of Carbasugars Reveals Unexpected Structure-Activity Relationship (SAR) of SGLT2 Inhibition

Carbasugar sodium-glucose cotransporter 2 (SGLT2) inhibitors are highly promising drug candidates for the treatment of Type 2 diabetes mellitus (T2DM). However, the clinical usage of carbasugar SGLT2 inhibitors has been underexplored, due to the lengthy synthetic routes and the lack of structure-activity relationship (SAR) studies of these compounds. Herein, we report a concise and stereodivergent synthetic route towards some novel carbasugar SGLT2 inhibitors, featuring an underexploited, regioselective, and stereospecific palladium-catalyzed allyl-aryl coupling reaction. This synthetic strategy, together with computational modeling, revealed the unexpected SAR of these carbasugar SGLT2 inhibitors, and enabled the discovery of a highly selective and potent SGLT2 inhibitor.

Synthesis and conformational analysis of a simplified inositol-model of the Streptococcus pneumoniae 19F capsular polysaccharide repeating unit

Carbohydrate mimics have been studied for a long time as useful sugar substitutes, both in the investigation of biological events and in the treatment of sugar-related diseases. Here we report further evaluation of the capabilities of inositols as carbohydrate substitutes. The conformational features of an inositol-model of a simplified repeating unit corresponding to the capsular polysaccharide of Streptococcus pneumoniae 19F has been evaluated by computational analysis, and compared to the native repeating unit. The inositol mimic was synthesized, and its experimental spectroscopic data allowed for verification of the theoretical results.

C-5a-substituted validamine type glycosidase inhibitors

A series of N-alkyl derivatives of the D-galactosidase inhibitor 1,4-di-epi-validamine featuring lipophilic substituents at position C-5a was prepared and screened for their glycosidase inhibitory properties. Products turned out selective for β-galactosidases as well as β-glucosidases.