Structurally simplified zaragozic acid (squalestatin): Stereoselective preparation of a 3,4-unsubstituted derivative

Synthesis and biological evaluation of novel C-aryl d-glucofuranosides as sodium-dependent glucose co-transporter 2 inhibitors

Novel C-aryl-d-glucofuranosides were synthesized and evaluated for their capacity to inhibit human sodium-dependent glucose co-transporter 2 (hSGLT2) and hSGLT1. Compound 21q demonstrated the best in vitro inhibitory activity against SGLT2 in this series (EC50=0.62μM).

Total Syntheses of Zaragozic Acids A and C by a Carbonyl Ylide Cycloaddition Strategy

A carbonyl ylide cycloaddition approach to the squalene synthase inhibitors zaragozic acids A and C is described. The carbonyl ylide precursor 8 was synthesized starting from di-tert-butyl D-tartrate (47) via an eleven-step sequence involving the regioselective reduction of the mono-MPM (MPM=4-methoxybenzyl) ether 48 with LiBH4 and the diastereoselective addition of sodium tert-butyl diazoacetate to alpha-keto ester 10. The reaction of alpha-diazo ester 8 with 3-butyn-2-one (40) in the presence of a catalytic amount of [Rh2(OAc)4] gave the desired cycloadduct 59 as a single diastereomer. The dihydroxylation of enone 59 followed by sequential transformations permitted the construction of the fully functionalized 2,8-dioxabicyclo[3.2.1]octane core 5. Alkene 79 derived from 5 serves as a common precursor to zaragozic acids A (1) and C (2), since the elongation of the C1 alkyl side chain can be attained by olefin cross-metathesis, especially under the influence of Blechert's catalyst (85).

Synthesis of novel ammonium and selenonium ions and their evaluation as inhibitors of UDP-galactopyranose mutase

The syntheses of two ammonium salts of 1,4-dideoxy-1,4-imino-d-galactitol containing erythritol sulfate side chains are described. The parent compound is a known inhibitor of the enzyme UDP-galactopyranose mutase (UDP-galactopyranose furanomutase, E.C. 5.4.99.9), which is responsible for the conversion of UDP-galactopyranose into UDP-galactofuranose and is presumably protonated in its active form. The side chain was chosen because it is present in a known sulfonium ion alpha-glucosidase inhibitor, salacinol. The syntheses of the selenonium analogues derived from 1,4-dideoxy-1,4-seleno-d-galactitol are also described. The synthetic strategy in the syntheses of all four salts involved the nucleophilic attack of a protected derivative of the alditol at the least hindered carbon of 2,4-O-benzylidene d- or l-erythritol-1,3-cyclic sulfate to give adducts that were subsequently deprotected. The importance of different protecting groups used in the various syntheses is also highlighted. Enzyme inhibition assays carried out on these compounds, and the corresponding sulfonium ions synthesized previously, show that they are poor inhibitors of UDP-galactopyranose mutase.