Clarifying solvent effect during photocatalytic glycerol conversion on TiO2/GQD as selective photocatalyst.

Nowadays, dealing with the growing chemical and energy demands is important without compromising the environment. So, this work studies photocatalytic glycerol conversion (as biomass derivativ feedstock) into value-added products using an eco-friendly synthesized catalyst. Graphene quantum dots (GQDs) were prepared from available/cheap precursors like glucose via the hydrothermal method and used as a support for TiO2. TiO2/GQDs were characterized via different analytical techniques, revealing very small particle sizes of ~ 3-6 nm with a large surface area of ~ 253 m2/g and a band gap of ~ 2.6 eV. The prepared photocatalyst shows good efficiency during photocatalytic glycerol conversion to dihydroxyacetone (DHA). Different reaction conditions were tested: reaction time, catalyst amount, presence of oxidant (H2O2), and biphasic media (aqueous/organic phases). Comparing a monophasic (H2O) photoreactor with a biphasic reactor containing 90% organic phase (ethyl acetate) and 10% aqueous phase (H2O and/or H2O2) indicates that the presence of H2O2 increases glycerol conversion and liquid selectivity to reach 57% and 91%, respectively after 120 min. However, it still suffers a low DHA/GA ratio (2.7). On the other hand, using a biphasic reactor in the presence of an H2O2 oxidant increases the DHA/GA ratio to ~ 6.6, which was not reached in previous research. The formation of H2O/H2O2 as micro-reactors dispersed in the ethyl acetate phase increased the average light intensity effect of the glycerol/photocatalyst system in the micro-reactors. Unlike previous work, this work presents a facile way to prepare eco-friendly/cheap (noble metal free) photocatalysts for glycerol conversion to ultrapure DHA using a biphasic photoreactor.

Synthesis and characterization of some substituted 3, 4-dihydronaphthalene derivatives through different enaminones as potent cytotoxic agents.

A new series of novel substituted 3,4-dihydronaphthalene incorporated to benzo[h]quinoline, benzo[g]indazole, thiazolidin-4-one, pyrazolo[3,4-d]thiazol and thiazolo[4,5-b]pyridine ring systems were synthesized and evaluated for their cytotoxicity against selected human cancer cell lines. Some of the tested compounds exhibited promising carcinoma growth inhibition. The detailed synthesis, spectroscopic data and biological activities of the tested compounds were reported.

Pyrimidine-5-carbonitriles II: synthesis and antimicrobial activity of novel 6-alkyl-2,4-disubstituted pyrimidine-5-carbonitriles.

New series of 6-alkyl-2,4-disubstituted pyrimidine-5-carbonitriles namely, 6-alkyl-2-thiouracil-5-carbonitriles 4c,d, 6-alkyl-2-arylmethylsulfanyl-3,4-dihydro-4-oxopyrimidine-5-carbonitriles 5a-p, 6-alkyl-2-(2-methoxyethylsulfanyl)-3,4-dihydro-4-oxopyrimidine-5-carbonitriles 6a-d, 6-alkyl-2-benzyloxymethylsulfanyl-3,4-dihydro-4-oxopyrimidine-5-carbonitriles 7a-c, 6-alkyl-2-(5-nitrofuran-2-ylmethylsulfanyl)-3,4-dihydro-4-oxopyrimidine-5-carbonitriles 8a-d, 6-alkyl-4-arylthio-2-(benzylsulfanyl)pyrimidine-5-carbonitriles 10a, b and 2-benzylsulfanyl-4-[4-(2-methoxyphenyl)-1-piperazinyl]-6-pentylpyrimidine-5-carbonitrile 11, were synthesized and tested for in vitro activities against a panel of Gram-positive and Gram-negative bacteria and the yeast-like pathogenic fungus Candida albicans. Compounds 4d, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5 l, 5p, 7a, 7b, 7c, 8a, 8b, 8c, 8d and 11 -displayed marked antibacterial activity particularly against the tested Gram-positive bacteria. Meanwhile, none of these compounds were proved to be active against Candida albicans.