Trienylboronic acid, a versatile coupling tool for retinoid synthesis; stereospecific synthesis of 13-aryl substituted (11 Z )-retinal

Diastereoselective Synthesis of the Borylated d-Galactose Monosaccharide 3-Boronic-3-Deoxy-d-Galactose and Biological Evaluation in Glycosidase Inhibition and in Cancer for Boron Neutron Capture Therapy (BNCT)

Drug leads with a high Fsp³ index are more likely to possess desirable properties for progression in the drug development pipeline. This paper describes the development of an efficient two-step protocol to completely diastereoselectively access a diethanolamine (DEA) boronate ester derivative of monosaccharide d-galactose from the starting material 1,2:5,6-di-O-isopropylidene-α-d-glucofuranose. This intermediate, in turn, is used to access 3-boronic-3deoxy-d-galactose for boron neutron capture therapy (BNCT) applications. The hydroboration/borane trapping protocol was robustly optimized with BH₃.THF in 1,4-dioxane, followed by in-situ conversion of the inorganic borane intermediate to the organic boron product by the addition of DEA. This second step occurs instantaneously, with the immediate formation of a white precipitate. This protocol allows expedited and greener access to a new class of BNCT agents with an Fsp³ index = 1 and a desirable toxicity profile. Furthermore, presented is the first detailed NMR analysis of the borylated free monosaccharide target compound during the processes of mutarotation and borarotation.

Discovery of novel prostaglandin analogs of PGE2 as potent and selective EP2 and EP4 receptor agonists

Analogs of PGE(2) with introduction of diene groups at the omega-side chain have been synthesized and evaluated for their binding affinity for EP(2) and EP(4) receptors. An optimized analog (compound 9b) showed high potency and selectivity for the EP(4) receptor over other known receptors.

Preparation and biological activity of 13-substituted retinoic acids

13-Demethyl or 13-substituted all-E- and 9Z-retinoic acids were synthesized using a palladium-catalyzed coupling reaction of enol triflates and tributylstannylolefins. Their biological activities were then measured. The 13-ethyl analogs exhibited approximately one-half of the antiproliferative and differentiation-inducing activity of ATRA in HL-60 cells. In contrast, in the 9Z-derivatives, all analogs, except for the 13-butyl derivatives, showed apoptosis-inducing activity.