Fernando Javier Duran

Universidad de Buenos Aires | UBA · Department of Organic Chemistry (FCEN)

C4-Symmetrical dirhodium(II) tetracarboxylates are highly efficient catalysts for the asymmetric intermolecular aziridination of substituted alkenes with sulfamates. The reaction proceeds with high levels of efficiency and chemoselectivity to afford aziridines with excellent yields of up to 95% and enantiomeric excesses of up to 99%. The scope of t...

(–)-Copalic acid is a naturally occurring labdane‐type diterpene acid usually isolated from oleoresins of Copaifera trees, being considered the biomarker for the genus. This compound has shown many remarkable biological and pharmacological activities, including anti-inflammatory, antimicrobial, antiparasitic, cytotoxic, chemopreventive, antimutagen...

Series of novel amides of isoferulic acid, where the phenolic hydroxyl was replaced by a difluoromethyl group, were synthesized and their in vitro antibacterial activities assayed against fourteen bacterial strains (six Gram-positive and eight Gram-negative). A one-pot methodology was developed to obtain the 3'-(difluoromethyl)-4'-methoxycinnamoyl...

Application of Rh( ii )-catalyzed C–H amination reactions allows the selective late-stage diversification of abietane diterpenoids.

Sixteen derivatives, eight of which are new compounds, were prepared from cycloartenone (1) and cycloartanone (2), and the cytotoxic activity of 14 of these compounds, together with 1 and 2, was evaluated against a panel of four cell lines. Compound 1 was obtained from the epiphyte plant Tillandsia tenuifolia collected at Salta, Argentina. Due to c...

Non-small cell lung cancer (NSCLC) is one of the most common malignant tumors, with a high mortality rate due to the elevated risk of resistance. Natural cucurbitacins and their derivatives are recognized as promising antitumor compounds for several types of cancer, including NSCLC. In a recent study published by our research group, DACE (2-deoxy-2...

Cucurbitacins and their derivatives are triterpenoids that are found in various plant families, and are known for their pharmacological and biological activities, including anti-cancer effects. Lung cancer represents a major public health problem, with non-small-cell lung cancer (NSCLC) being the most frequent and aggressive type of lung cancer. Th...

Objectives: Many natural antioxidants have poor pharmacokinetic properties that impair their therapeutic use. For hydroxycinnamic acids (HCAs) and other phenolic antioxidants, their major drawback is their low lipophilicity and a rapid metabolism. The difluoromethyl group may be considered as a 'lipophilic hydroxyl' due to its hydrogen bond donor...

Non-small cell lung cancer (NSCLC) represents an important cause of mortality worldwide due to its aggressiveness and growing resistance to currently available therapy. Cucurbitacins have emerged as novel potential anticancer agents showing strong antiproliferative effects and can be promising candidates for combined treatments with clinically used...

Lung cancer is the most deadly type of cancer in humans, with non-small-cell lung cancer (NSCLC) being the most frequent and aggressive type of lung cancer showing high resistance to radiation and chemotherapy. Despite the outstanding progress made in anti-tumor therapy, discovering effective anti-tumor drugs is still a challenging task. Here we de...

DIHYDROCUCURBITACIN B: SEMISYNTHESIS OF NEW GLICOSIDE DERIVATIVES. In the last ten years, the interest in natural and semi-synthetic cucurbitacin derivatives has increased, primarily due their cytotoxic and anti-tumoral activities. However, the isolation of glycosylated cucurbitacins has been difficult due the presence of b-glucosidase enzyme. With...

Cucurbitacins (CUCs) are a group of tetracyclic triterpenoid compounds found mainly in species of the Cucurbitaceae family, known for their bitterness and toxicity. In the past years, many reports confirmed the cytotoxic and antitumor activities of some cucurbitacins. In the present work a cytotoxic screening with 51 cucurbitacins and their semisyn...

Cucurbitacins are secondary metabolites that mediate insect plant interactions not only as allomones against generalists, but also as kairomones for specialist herbivores. This study was undertaken to identify the potential of cucurbitacin derivatives as insect antifeedant agents. The antifeedant capacity against a Cucurbitaceae specialist [Epilach...

Cancer represents a major public health problem from all over the world and the lung carcinoma is the leading cause of cancer death. In this sense, the aim of the present study was to examine the cytotoxic effects of a novel Cucurbitacin (Cucl) isolated from Wilbrandia ebracteata on human non-small-cell lung cancer (A549). In order to achieve this...

In the present study, the in vitro cytotoxic effects of six semi-synthetic derivatives of elatol (1) and isoobtusol (2) were investigated. Chemical modifications were performed on the hydroxyl groups aiming to get derivatives of different polarity, namely the hemisuccinate, carbamate and sulfamate. The structural elucidation of the new derivatives...

Two cucurbitacins, dihydrocucurbitacin B (1) and cucurbitacin B (2), which can be obtained in large amounts from the roots of Wilbrandia ebracteata and from the fruits of Luffa operculata, respectively, were used as starting materials for the preparation of a library of 29 semi-synthetic derivatives. The structural changes that were performed inclu...

Chemical investigation of the roots of Wilbrandia ebracteata Cogn. (Cucurbitaceae) led to the isolation of two new (1- 2) and four known (3- 6) cucurbitacins. Their structures were elucidated by NMR and MS and compared with related compounds. The in vitro cytotoxicity of isolated compounds was evaluated against RD, KB, HCT-8, and A549 cell lines sh...

[reaction: see text] Olefinic sulfamates derived from primary and secondary alcohols undergo intramolecular copper-catalyzed aziridination in the presence of iodosylbenzene to afford novel bicyclic fused aziridines. The latter were opened by various nucleophiles to give the corresponding substituted cyclic sulfamates, which in turn reacted, after n...

The synthesis of new analogues of allopregnanolone with a bridged sulfamidate ring over the beta-face of ring A has been achieved from easily available precursors, using an intramolecular aziridination strategy. The methodology also allows the synthesis of 3alpha-substituted analogues such as the 3alpha-fluoro derivative. GABA(A) receptor activity...

The lipophilic nature of allopregnanolone prevents its user-friendly application in human medicine. On inspiration by previously prepared allopregnanolone with a 16alpha-bound tetraethylammonium salt, an attempt was made to produce allopregnanolone analogues with polar groups introduced into position 16alpha with the goal of increasing water solubi...

Intramolecular copper-catalyzed aziridination of sulfamates occurs in very good yields of up to 86% and in up to 84% ee in the presence of (4S,4′S)-2,2′-(propane-2,2-diyl)bis(4-tert-butyl-4,5-dihydro-1,3-oxazole). The resulting aziridines undergo smooth ring opening with different types of nucleophiles in an SN2-type process.

Seven PNA-encoded combinatorial libraries targeting proteases and phosphatases with covalent reversible and irreversible mechanism-based inhibitors were prepared. The libraries were synthesized using modified PNA monomers, which dramatically increase the water solubility of the libraries in biologically relevant buffers. The libraries were shown to...

A procedure is described for the preparation of 6-thiapregnanes in five steps from pregnenolone via a 5-oxo-7-iodo-secopregnane intermediate. The 6-thiasteroid obtained was converted into 6-thia-allopregnanolone and its sulfoxide and sulfone derivatives. The trans stereochemistry at the A/B ring junction was accomplished by stereoselective reductio...

Conformationally restrained substituted pregnane-20-one derivatives were obtained by an intramolecular nitrene addition onto a C-5/C-6 double bond involving a tethered C-19 sulfamoyl moiety. The resulting aziridine underwent regioselective nucleophilic ring opening at C-5 at room temperature with cyanide, fluoride, and acetate. In the isolated case...

[GRAPHIC] Olefinic sulfamates derived from primary and secondary alcohols undergo intramolecular copper-catalyzed aziridination in the presence of lodosylbenzene to afford novel bicyclic fused aziridines. The latter were opened by various nucleophiles to give the corresponding substituted cyclic sulfamates, which in turn reacted, after nitrogen act...