Potent Anthelmintic Activity of Chalcones Synthesized by an Effective Green Approach.

There is currently an urgent need for new anthelmintic agents due to increasing resistance to the limited available drugs. The chalcone scaffold is a privileged structure for developing new drugs and has been shown to exhibit potential antiparasitic properties. We synthesized a series of chalcones via Claisen-Schmidt condensation, introducing a novel recoverable catalyst derived from biochar obtained from the pyrolysis of tree pruning waste. Employing microwave irradiation and a green solvent, this approach demonstrated significantly reduced reaction times and excellent compatibility with various functional groups. The result was the generation of a library of functionalized chalcones, exhibiting exclusive (E)-selectivity and high to excellent yields. The chalcone derivatives were evaluated on the free-living nematode Caenorhabditis elegans. The chalcone scaffold, along with two derivatives incorporating a methoxy substituent in either ring, caused a concentration-dependent decrease of worm motility, revealing potent anthelmintic activity and spastic paralysis not mediated by the nematode levamisole-sensitive nicotinic receptor. The combination of both methoxy groups in the chalcone scaffold resulted in a less potent compound causing worm hypermotility at the short term, indicating a distinct molecular mechanism. Through the identification of promising drug candidates, this work addresses the demand for new anthelmintic drugs while promoting sustainable chemistry.

Valorization of Rhizoclonium sp. algae via pyrolysis and catalytic pyrolysis.

The valorization of Rhizoclonium sp. algae through pyrolysis for obtaining bio-oils is studied in this work. The reaction is carried out at 400°C, at high contact time. The bio-oil has a practical yield of 35% and is rich in phytol. Besides, it is simpler than the corresponding to lignocellulosic biomass due to the absence of phenolic compounds. This property leads to a bio-oil relatively stable to storage. In addition, heterogeneous catalysts (Al-Fe/MCM-41, SBA-15 and Cu/SBA-15), in contact with algae during pyrolysis, are analyzed. The general trend is that the catalysts decrease the concentration of fatty alcohols and other high molecular weight products, since their mild acidity sites promote degradation reactions. Thus, the amount of light products increases upon the use of the catalysts. Particularly, acetol concentration in the bio-oils obtained from the catalytic pyrolysis with SBA-15 and Cu/SBA-15 is notably high.

Preparation of USY zeolite VOx supported catalysts from V(AcAc)3 and NH4VO3. Catalytic properties for the dehydrogenation of n-butane in oxygen-free atmosphere.

The preparation of different samples of vanadia supported on ultrastable zeolite (VO(x)/USY) is discussed. The samples were prepared in order to obtain highly dispersed V-species, avoiding the formation of crystalline vanadia and the destruction of the zeolite framework. Two methods were employed for preparing VO(x)/USY samples: an organic route using V(AcAc)3 and an inorganic route using NH4VO3. The characterization of the samples was performed with XRD, TPR, NH3-TPD, and N2 isotherms. From these results it is concluded that when VO(x) is supported on the surface of USY from acidic aqueous solution of ammonium metavanadate, the destruction of the zeolite framework is accomplished. For higher pH values in the impregnating solution, undesired V2O5 is formed on the USY surface. On the other hand, VO(x)/USY prepared from the organic precursor shows no destruction of the USY structure. In addition, highly dispersed VO(x) are formed, though for relatively high V loadings (6%) an obstruction of the zeolite windows takes place. The samples are tested as catalysts for gas phase dehydrogenation of n-butane to olefins. The catalysts prepared from NH4VO3 are almost inactive for the reaction. On the other hand, both samples prepared from V(AcAc)3 present initial conversion levels in the 8-12% range. However, the selectivity depends on the V loading, the catalysts with 6% loading being the most selective (75%). The catalytic patterns of the samples (activity and selectivity) are in agreement with the physicochemical features of the VO(x)/USY surface.

Pyrolysis of sunflower seed hulls for obtaining bio-oils.

Bio-oils from pyrolysis of as received sunflower seed hulls (SSH), hulls previously washed with acid (SSHA) and hulls submitted to a mushroom enzymatic attack (BSSH) were analyzed. The concentration of lignin, hemicellulose and cellulose varied with the pre-treatment. The liquid corresponding to SSH presented a relatively high concentration of acetic acid and a high instability to storage. The bio-oil from SSHA showed a high concentration of furfural and an appreciable amount of levoglucosenone. Lignin was degraded upon enzymatic activity, for this reason BSSH led to the highest yield of bio-oil, with relative high concentration of acetic acid and stability to storage.