Novel Regioselective Synthesis of Urolithin Glucuronides─Human Gut Microbiota Cometabolites of Ellagitannins and Ellagic Acid.

Urolithins (dibenzo-pyran-[,]-6 one derivatives) are human gut microbiota metabolites produced from the natural food antioxidant ellagic acid. Urolithins are better absorbed than ellagic acid and demonstrate biological activities that suggest that they are responsible for the health effects observed after consuming ellagitannin- and ellagic acid-containing foods. Urolithins occur in the systemic circulation as glucuronide conjugates following phase II metabolism.

Regioselective Monoborylation of Spirocyclobutenes.

We present a strategy for the synthesis of spirocyclic cyclobutanes with modulable exit vectors based on the regioselective monoborylation of spirocyclobutenes. Using an inexpensive copper salt and a commercially available bidentate phosphine, a broad variety of borylated spirocycles have been prepared with complete regiocontrol. The boryl moiety provides a synthetic handled for further functionalization, allowing access to a wide array of spirocyclic building blocks from a common intermediate.

Stereoselective Diboration of Spirocyclobutenes: A Platform for the Synthesis of Spirocycles with Orthogonal Exit Vectors.

The diastereo- and enantioselective diboration of spirocyclobutenes provides a platform for the rapid preparation of a wide variety of chiral spirocyclic building blocks. The chemoselective functionalization of the carbon-boron bond in the products, including a stereospecific sp -sp Suzuki-Miyaura cross-coupling reaction, provides a powerful tool to control the directionality and the nature of the exit vectors in the spirocyclic framework.

Copper, Boron and Vinyl Epoxides: from 1,4-Diols to Cyclopropylboronates.

Herein we describe the reactivity found between vinyl epoxides and catalytically generated copper-boryl complexes. By tuning the substituents of the alkene and/or the reaction conditions, 1,4-diols, allylic alcohols or cyclopropylboronates can be prepared. The stereochemical information of the vinyl epoxide is transferred to the products with high levels of stereocontrol.

The Effects of Trifluoromethylated Derivatives on Prostaglandin E2 and Thromboxane A2 Production in Human Leukemic U937 Macrophages.

Background: A convenient approach to modulation of the inflammation has an influence on the production of inflammatory mediators - icosanoids, generated in arachidonic acid (AA) metabolism. The common therapeutic activity of non-steroidal anti-inflammatory drugs (NSAID), such as aspirin, includes inhibition of two crucial enzymes of AA metabolism - cyclooxygenase- 1 and -2 (COX-1/2), with certain risk for gastrointestinal and renal intolerance. Ever since the enrolment of COX-2, particularly overabundance of its main products prostaglandin E2 (PGE2) and thromboxane A2 (TXA2) in numerous pathological processes was recognized, it became a significant therapeutic target.

Stereospecific Synthesis of α-Hydroxy-Cyclopropylboronates from Allylic Epoxides.

Herein, we report a catalytic and stereospecific method for the preparation of enantioenriched α-hydroxy cyclopropylboronates with control in four contiguous stereocenters. The reaction involves the borylation of readily available allylic epoxides using an inexpensive Cu(I) salt and a commercially available phosphine ligand. High diastereocontrol is achieved and different diastereomers can be selectively prepared.

Discovery of a PCAF Bromodomain Chemical Probe.

The p300/CBP-associated factor (PCAF) and related GCN5 bromodomain-containing lysine acetyl transferases are members of subfamily I of the bromodomain phylogenetic tree. Iterative cycles of rational inhibitor design and biophysical characterization led to the discovery of the triazolopthalazine-based L-45 (dubbed L-Moses) as the first potent, selective, and cell-active PCAF bromodomain (Brd) inhibitor. Synthesis from readily available (1R,2S)-(-)-norephedrine furnished L-45 in enantiopure form.

Stereoselective ZrCl4-Catalyzed Mannich-type Reaction of β-Keto Esters with Chiral Trifluoromethyl Aldimines.

A method for the synthesis of fluorinated β'-amino β-dicarbonyl compounds using a Zr-catalyzed Mannich-type reaction has been developed, starting from N-protected trifluoromethyl aldimines and cyclic or acyclic β-keto esters bearing different ester residues. The in situ generated metallic complex reacted with optically pure trifluoromethyl aldimine derived from (R)-α-methylbenzylamine, giving a highly diastereoselective asymmetric Mannich-type addition with formation of a chiral quaternary center. The absolute configuration at the new chiral centers was assigned through two-dimensional nuclear Overhauser effect spectroscopic analysis coupled with computational studies.

New Synthesis of Trifluoromethyl Aldimines Containing L-α-Amino Ester Moieties and Their Use in Mannich-Type Reactions.

L-α-amino esters were considered valuable chiral starting materials in the condensation reaction with trifluoroacetaldehyde (fluoral) ethyl hemiacetal to obtain new functionalized trifluoromethyl aldimines. Starting from these latter compounds, isovaleraldehyde was used in proline-catalyzed Mannich-type addition reactions to give trifluoromethyl syn- or anti-γ-amino alcohols bearing the L-α-amino ester function, simply by changing the reaction temperature.