Rational design, synthesis, and biophysical characterization of a peptidic MDM2-MDM4 interaction inhibitor.

In recent years, the restoration of p53 physiological functions has become an attractive therapeutic approach to develop novel and efficacious cancer therapies. Among other mechanisms, the oncosuppressor protein p53 is functionally regulated by MDM2 through its E3 ligase function. MDM2 promotes p53 ubiquitination and degradation following homodimerization or heterodimerization with MDM4.

A straightforward synthesis of functionalized 6-benzo[]chromenes from 3-alkenyl chromenes by intermolecular Diels-Alder/aromatization sequence.

A new and metal-free approach to the synthesis of substituted 6-benzo[]chromenes has been developed. This three-step synthetic sequence starts from variously substituted salicylaldehydes and α,β-unsaturated carbonyl compounds to form the chromene core. The ring-forming key step is based on a highly regioselective intermolecular Diels-Alder cycloaddition between 3-vinyl-2-chromenes and methyl propiolate, followed by oxidative aromatization of the cyclohexadiene cycloadduct intermediate to obtain the final products in good yields (up to 94% over two steps).

Chemoselective and metal-free reduction of α,β-unsaturated ketones by produced benzeneselenol from -(-butyl) Se-phenyl selenocarbonate.

The carbon-carbon double bond of arylidene acetones and chalcones can be selectively reduced with benzeneselenol generated by reacting -(-butyl) Se-phenyl selenocarbonate with hydrochloric acid in ethanol. This mild, metal-free and experimentally simple reduction procedure displays considerable functional-group compatibility, products are obtained in good to excellent yields, and the use of toxic Se/CO mixture and NaSeH, or the smelly and air-sensitive benzeneselenol, is avoided.

2,3-Diaminopropanols Obtained from d-Serine as Intermediates in the Synthesis of Protected 2,3-l-Diaminopropanoic Acid (l-Dap) Methyl Esters.

A synthetic strategy for the preparation of two orthogonally protected methyl esters of the non-proteinogenic amino acid 2,3-l-diaminopropanoic acid (l-Dap) was developed. In these structures, the base-labile protecting group 9-fluorenylmethyloxycarbonyl (Fmoc) was paired to the -toluensulfonyl (tosyl, Ts) or acid-labile -butyloxycarbonyl (Boc) moieties. The synthetic approach to protected l-Dap methyl esters uses appropriately masked 2,3-diaminopropanols, which are obtained via reductive amination of an aldehyde prepared from the commercial amino acid -Fmoc---butyl-d-serine, used as the starting material.

Tumor Targeting by Peptide-Decorated Gold Nanoparticles.

Cancer remains one of the most important challenges in biomedical sciences. Chemotherapeutic agents are very potent molecules that exhibit a significant level of toxicity in numerous tissues of the body, particularly in those characterized by high proliferative activity, such as the bone marrow. The scenario is even more complex in the case of the central nervous system, and in particular brain tumors, where the blood brain barrier limits the efficacy of drug therapies.

General, Mild, and Metal-Free Synthesis of Phenyl Selenoesters from Anhydrides and Their Use in Peptide Synthesis.

A mild, practical, and simple procedure for phenyl selenoesters synthesis from several anhydrides and diphenyl diselenide was developed. This transition-metal-free method provides a straightforward entry to storable Fmoc-amino acid selenoesters which are effective chemoselective acylating reagents. An application to oligopeptide synthesis was illustrated.

Sequestering ability to Cu of a new bodipy-based dye and its behavior as in vitro fluorescent sensor.

A Bodipy (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) derivative has been conceived and synthesized starting from l-aspartic acid, as a selective turn-off sensor of Cu ions. Its acid-base properties were determined to study the formation of metal/sensor complex species by titration of solutions each containing a different metal ion, such as Cu, Ca, Zn, Pb and Hg and different metal/sensor ratios. The speciation models allowed us to simulate the distribution of the metal/sensor complex species at the normal concentrations of the corresponding metals present in biological fluids.

Stereoselective Synthesis of Substituted Tetrahydropyrans and Isochromans by Cyclization of Phenylseleno Alcohols.

A selenium-mediated strategy for the stereoselective synthesis of substituted tetrahydropyrans and isochromans has been developed starting from δ-phenylseleno ketones. After enantioselective reduction, the chiral nonracemic phenylseleno alcohols were oxidized to the corresponding selenones, which underwent an effcient 6-exo-tet ring-closure reaction.

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones.

A new, efficient and mild method for the direct oxidation of selenides to selenones using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) has been developed. Noteworthy this transformation proceeds at room temperature, employs a cheap and safety oxidant and has a broad functional group tolerance. Moreover, the produced selenones could be useful intermediates for the synthesis of different heterocyclic compounds.

Synthesis of D-erythro-sphinganine through serine-derived α-amino epoxides.

A total synthesis of D-erythro-sphinganine [(2S,3R)-2-aminooctadecane-1,3-diol] starting from commercial N-tert-butyloxycarbonyl-L-serine methyl ester is described. The approach is based on the completely stereoselective preparation of an α-amino epoxide obtained by treating a protected L-serinal derivative with dimethylsulfoxonium methylide. The oxirane synthon is obtained with an anti configuration fitting the (2S,3R) stereochemistry of the 2-amino-1,3-diol polar head of D-erythro-sphinganine.

Synthesis of enantiopure sugar-decorated six-armed triptycene derivatives.

A new class of molecules with a triptycene rigid core surrounded by six monosaccharide residues was synthesized. Hexakis(bromomethyl) substituted triptycene was converted into a six-armed triptycene azide (2,3,6,7,14,15-hexakis(azidomethyl)-9,10-dihydro-9,10-[1',2']benzenoanthracene). The key step of the synthesis was the cycloaddition of the azide to 2-propyn-1-yl β-D-gluco- or galactopyranosides.

Intramolecular displacement of phenylselenone by a hydroxy group: stereoselective synthesis of 2-substituted tetrahydrofurans.

An efficient and stereocontrolled synthesis of 2-substituted tetrahydrofurans has been achieved. The approach employs the asymmetric reduction of γ-phenylseleno ketones obtained by three different procedures that are peculiarly applied to the synthesis of such compounds. Finally, the intramolecular substitution of the phenylselenone residue by the oxygen atom of a hydroxy group gives the tetrahydrofuran ring.

Antioxidant Properties of Seeds from Lines of Artichoke, Cultivated Cardoon and Wild Cardoon.

The artichoke (Cynara cardunculus L. subsp. scolymus L.

High-pressure-promoted Diels-Alder approach to biaryls: application to the synthesis of the cannabinols family.

Diels-Alder reactions of a range of 1-(alkoxy/alkyl/halogen-substituted phenyl)buta-1,3-dienes with methyl propiolate carried out in a green ethanolic medium under 9 kbar pressure were investigated. The use of high pressure as activating method of the Diels-Alder reactions allows efficient and regioselective generation of a series of cyclohexadienyl-benzene cycloadducts that are oxidized to the corresponding biaryls. The alkoxy/alkyl/halogen-substituted biaryls produced are useful precursors for accessing substituted 6H-benzo[c]chromen-6-ones and the cannabinols family.

Stereospecific synthesis of beta3-amino acid derivatives from propargylic alcohols: efficient solution-phase synthesis of oligopeptides without coupling agents.

A stereospecific synthesis of beta(3)-amino acids has been accomplished starting from readily available and enantioenriched propargylic alcohols. This conversion can be effected in only three steps by selenium-mediated organic transformations of the carbon-carbon triple bond. This method is especially attractive because the reactive Se-phenyl selenocarboxylate intermediates can be trapped with the amine functionality of an amino acid derivative.

Stereocontrolled synthesis of substituted N-arenesulfonyl azetidines from gamma-(phenylseleno)alkyl arylsulfonamides.

Different synthetic methodologies for the stereocontrolled synthesis of substituted azetidines are reported. The approach utilizes an optimized oxidation reaction of gamma-(phenylseleno)alkyl arylsulfonamides, followed by the intramolecular substitution of the resulting phenylselenonyl group by the nitrogen atom.

A chiral electrophilic selenium reagent to promote the kinetic resolution of racemic allylic alcohols.

[reaction: see text] The first example of a kinetic resolution process promoted by electrophilic selenium reagents is reported. Racemic allylic alcohols react with half equivalents of a selenenylating agent in methanol leading to the regiospecific formation of the corresponding addition products with a very high level of facial selectivity (from 95:5 to 98:2 dr). The unreacted alcohols can be recovered in an optically enriched form (from 90 to 94% ee).

Ring-closure reactions through intramolecular displacement of the phenylselenonyl group by nitrogen nucleophiles: a new stereospecific synthesis of N-tosyl and N-benzoyl-1,3-oxazolidin-2-ones from beta-hydroxyalkyl phenyl selenides.

A new and convenient method for the stereospecific synthesis of variously substituted 1,3-oxazolidin-2-ones from the easily available beta-hydroxyalkyl phenyl selenides is presented. After transformation into the N-tosyl or N-benzoyl carbamates, the selenides were oxidized to the corresponding selenones. The key step of the process is the ring-closure reaction, which occurs by stereospecific intramolecular nucleophilic substitution of the selenone group by the nitrogen atom of the carbamate.

Preparation of a new chiral non-racemic sulfur-containing diselenide and applications in asymmetric synthesis.

The synthesis of the new chiral non-racemic sulfur-containing diselenide, di-2-methoxy-6-[(1S)-1-(methylthio)ethyl]phenyl diselenide, is described. When treated with ammonium persulfate this diselenide is transformed into the corresponding selenenyl sulfate, which acts as a strong electrophilic reagent and adds to alkenes, in the presence of methanol or water, to afford the products of selenomethoxylation or selenohydroxylation, respectively, with excellent diastereoselectivities. Starting from alkenes containing internal nucleophiles, asymmetric cyclofunctionalization reactions also resulted in good chemical yields, complete regioselectivities, and high diastereoselectivities.

Intramolecular Nucleophilic Deselenenylation Reactions Promoted by Benzeneselenenyl Triflate. Stereospecific Synthesis of Vicinal Amino Alcohol Precursors.

After activation with electrophilic selenenylating agents, the phenylseleno group of vicinal azido selenides, containing internal oxygen or nitrogen nucleophilic substituents, readily undergoes intramolecular nucleophilic displacement to afford azido-substituted heterocyclic compounds. This intramolecular substitution occurs with inversion of configuration at the carbon atom bearing the selenium atom. Starting from acetamido selenides and carbamato selenides, a stereocontrolled synthesis of the vicinal amino alcohol precursor oxazolines and oxazolidin-2-ones has been developed.