Nutrients and Main Secondary Metabolites Characterizing Extracts and Essential Oil from Fruits of Coss. & Dur. (Western Sahara).

The ethnobotany of the Sahrawi people considers various species of plants and crude drugs as food, cooking spices and traditional health remedies. From among these, the fruits of Coss. & Dur.

Δ1-Dehydrogenation and C20 Reduction of Cortisone and Hydrocortisone Catalyzed by Strains.

Prednisone and prednisolone are steroids widely used as anti-inflammatory drugs. Development of the pharmaceutical industry is currently aimed at introducing biotechnological processes and replacing multiple-stage chemical syntheses. In this work we evaluated the ability of bacteria belonging to the genus to biotransform substrates, such as cortisone and hydrocortisone, to obtain prednisone and prednisolone, respectively.

Enzymatic synthesis of biobased aliphatic-aromatic oligoesters using 5,5'-bis(hydroxymethyl)furoin as a building block.

5,5'-Dihydroxymethyl furoin (DHMF) is a novel biobased difuranic polyol scaffold, achievable from the benzoin condensation of 5-hydroxymethylfurfural (HMF), which has recently been employed as a monomer for the preparation of cross-linked polyesters and polyurethane. Its upgrading by means of enzymatic reactions has not yet been reported. Here we demonstrated that lipase B (CALB) is a suitable biocatalyst for the selective esterification of the primary hydroxyl groups of DHMF.

Oxidative NHC-Catalysis as Organocatalytic Platform for the Synthesis of Polyester Oligomers by Step-Growth Polymerization.

The application of N-heterocyclic carbene (NHC) catalysis to the polycondensation of diols and dialdehydes under oxidative conditions is herein presented for the synthesis of polyesters using fossil-based (ethylene glycol, phthalaldehydes) and bio-based (furan derivatives, glycerol, isosorbide) monomers. The catalytic dimethyl triazolium/1,8-diazabicyclo[5.4.

Native Quercetin as a Chloride Receptor in an Organic Solvent.

The binding properties of quercetin toward chloride anions were investigated by means of ¹H-NMR, C-NMR, and electrospray ionization mass spectrometry (ESI-MS) measurements, as well as computational calculations. The results indicate that quercetin behaves primarily as a ditopic receptor with the binding site of the B ring that exhibits stronger chloride affinity compared to the A ring. However, these sites are stronger receptors than those of catechol and resorcinol because of their conjugation with the carbonyl group located on the C ring.

Synthesis of functionalized imidazolidine-2-thiones via NHC/base-promoted aza-benzoin/aza-acetalization domino reactions.

A strategy for the synthesis of biologically relevant 5-hydroxy-imidazolidine-2-thione derivatives is presented. A novel class of α-sulfonylamines have been suitably prepared (46-81% yield) as precursors of formal benzylidenethiourea acceptors; these are generated in situ and intercepted by N-heterocyclic carbene (NHC)-activated aldehydes affording open-chain aza-benzoin-type adducts, which in turn undergo an intramolecular aza-acetalization reaction in a one-pot fashion. A thiazolium salt/triethylamine couple proved to be the more effective system to trigger the domino sequence giving the target heterocycles in good yields (45-97%) and diastereoselectivities (up to 99 : 1 dr).

Fluorous-tag assisted synthesis of bile acid-bisphosphonate conjugates via orthogonal click reactions: an access to potential anti-resorption bone drugs.

The synthesis of a small collection of novel bile acid-bisphosphonate (BA-BP) conjugates as potential drug candidates is reported. The disclosed methodology relied on the installation of azide and thiol functionalities at the head and tail positions, respectively, of the BA scaffold and its subsequent decoration by orthogonal click reactions (copper-catalyzed azide-alkyne cycloaddition, thiol-ene or thiol-yne coupling) to introduce BP units and a fluorophore. Because of the troublesome isolation of the target conjugates by standard procedures, the methodology culminated with the functionalization of the BA scaffold with a light fluorous tag to rapidly and efficiently purify intermediates and final products by fluorous solid-phase extraction.

Electron-transfer-initiated benzoin- and Stetter-like reactions in packed-bed reactors for process intensification.

A convenient heterogeneous continuous-flow procedure for the polarity reversal of aromatic α-diketones is presented. Propaedeutic batch experiments have been initially performed to select the optimal supported base capable to initiate the two electron-transfer process from the carbamoyl anion of the ,-dimethylformamide (DMF) solvent to the α-diketone and generate the corresponding enediolate active species. After having identified the 2--butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine on polystyrene (PS-BEMP) as the suitable base, packed-bed microreactors (pressure-resistant stainless-steel columns) have been fabricated and operated to accomplish the chemoselective synthesis of aroylated α-hydroxy ketones and 2-benzoyl-1,4-diones (benzoin- and Stetter-like products, respectively) with a good level of efficiency and with a long-term stability of the packing material (up to five days).

Nucleophilic and electrophilic double aroylation of chalcones with benzils promoted by the dimsyl anion as a route to all carbon tetrasubstituted olefins.

Dimsyl anion promoted the polarity reversal of benzils in a Stetter-like reaction with chalcones to give 2-benzoyl-1,4-diones (double aroylation products), which, in turn, were converted into the corresponding tetrasubstituted olefins via aerobic oxidative dehydrogenation catalyzed by Cu(OAc)2.

Unexpected reactivity of diaryl α-diketones with thiazolium carbenes: discovery of a novel multicomponent reaction for the facile synthesis of 1,4-thiazin-3-ones.

Diaryl α-diketones do not undergo polarity reversal in the presence of (benzo)thiazolium carbenes but are engaged in a novel multicomponent reaction with water to efficiently give medicinally relevant 1,4-thiazin-3-one heterocycles. Three different sets of conditions have been optimized to furnish the title compounds in fair to excellent yields depending on the electronic properties of α-diketone aromatic substituents and thiazolium or benzothiazolium substrate. A plausible reaction mechanism is also proposed based on the isolation and characterization of the postulated key intermediate and isotopic labeling experiments.

Thiazolium-catalyzed intermolecular Stetter reaction of linear and cyclic alkyl α-diketones.

An efficient method for the N-heterocyclic carbene (NHC)-catalyzed conjugate addition of acetyl anions to various α,β-unsaturated acceptors (Stetter reaction) has been optimized by using 2,3-butandione (biacetyl) as an alternative surrogate of acetaldehyde. The disclosed procedure proved to be compatible with microwave dielectric heating for reaction time reduction and with the use of different linear α-diketones as acyl anion donors (e.g.

Enzymatic diastereo- and enantioselective synthesis of α-alkyl-α,β-dihydroxyketones.

An enzymatic strategy for the preparation of optically pure α-alkyl-α,β-dihydroxyketones is reported. Homo- and cross-coupling reactions of α-diketones catalyzed by acetylacetoin synthase (AAS) produce a set of α-alkyl-α-hydroxy-β-diketones (30-60%, ee 67-90%), which in turn are reduced regio-, diastereo-, and enantioselectively to the corresponding chiral α-alkyl-α,β-dihydroxyketones (60-70%, ee >95%) using acetylacetoin reductase (AAR) as catalyst. Both enzymes are obtained from Bacillus licheniformis and used in a crude form.

Relative acidity scale of glycine- and taurine-conjugated bile acids through ESI-MS measurements.

The most important bile acids, in the form of glycine and taurine conjugates, have been ordered in terms of relative acidity scale. The measurements have been carried out using mass spectrometric techniques. The group of taurine conjugates confirm the superior acidity over the glycine derivatives.

Relative acidity scale of bile acids through ESI-MS measurements.

The anion proton affinity of the most important human bile acids and those of the corresponding keto bile acids have been examined in order to establish a true (intrinsic) relative acidity scale. The measurements have been carried out in the gas-phase using the Cooks' kinetic method. The remarkably high acidity of cholic acid with respect to the other bile acids was confirmed.

Selective removal of monoterpenes from bergamot oil by inclusion in deoxycholic acid.

A new approach for removing monoterpenes (MTs) from bergamot oil by selective inclusion in deoxycholic acid (DCA) is proposed. The inclusion process is very efficient, the included fraction being composed mainly of limonene (71.7%) and gamma-terpinene (19.

Bile acids in asymmetric synthesis and chiral discrimination.

An overview on the use of bile acid-based compounds able to catalyze transformations, control the stereochemical course of a given reaction, recognize and bind other molecules, is presented. The recent developments in inclusion discrimination of chiral and achiral guests and enantioselective recognition achieved by bile acid are described with suitable examples.

7alpha- and 12alpha-Hydroxysteroid dehydrogenases from Acinetobacter calcoaceticus lwoffii: a new integrated chemo-enzymatic route to ursodeoxycholic acid.

We report the very efficient biotransformation of cholic acid to 7-keto- and 7,12-diketocholic acids with Acinetobacter calcoaceticus lwoffii. The enzymes responsible of the biotransformation (i.e.

Preparation and characterization of some keto-bile acid azines.

New acyclic dimers of ketocholanic acids with hydrazine were obtained. Crystal structure was determined for the 3,7-dihydroxy-12-ketocholanic acid azine. Some distinctive (1)H NMR signals are assigned for the entire set of azines.

Enantioselective Baeyer-Villiger oxidation of bicyclo[3.2.0]hept-2-en-6-One with fungi: optimization of biotransformation and use of TiO2 as support of cell growth.

Fungi from Amazonian forest soil (Ecuador) and an Italian factory were screened for Baeyer-Villiger (BV) oxidation of bicyclo [3.2.0]hept-2-en-6-one to 2-oxabicyclo[3.

Xanthomonas maltophilia CBS 897.97 as a source of new 7beta- and 7alpha-hydroxysteroid dehydrogenases and cholylglycine hydrolase: improved biotransformations of bile acids.

The paper reports the partial purification and characterization of the 7beta- and 7alpha-hydroxysteroid dehydrogenases (HSDH) and cholylglycine hydrolase (CGH), isolated from Xanthomonas maltophilia CBS 897.97. The activity of 7beta-HSDH and 7alpha-HSDH in the reduction of the 7-keto bile acids is determined.

Bile acid derivatives as enantiodifferentiating host molecules in inclusion processes.

A review on the use of bile acids as hosts for molecular recognition and enantioresolution is presented. The optical resolution of different classes of organic derivatives, i.e.

Improved enantioselectivity in the epoxidation of cinnamic acid derivatives with dioxiranes from keto bile acids.

The asymmetric epoxidation of substituted cinnamic acids has been obtained in the presence of different keto bile acid derivatives as optically active carbonyl inducers and Oxone as oxygen source. Predominant or almost exclusive formation of both enantiomeric epoxides is obtained (ee up to 95%) depending on the specific substitution at carbons C(7) and C(12) of the bile acid.

7alpha-OH epimerisation of bile acids via oxido-reduction with Xanthomonas maltophilia.

The microbial 7alpha-OH epimerisation of cholic, chenodeoxycholic, and 12-ketochenodeoxycholic acids (7alpha-OH bile acids) with Xanthomonas maltophilia CBS 827.97 to corresponding 7beta-OH derivatives with scarcity of oxygen is described. With normal pressure of oxygen the 7-OH oxidation products are obtained.