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Site selective acylation of monosaccharides and oligosaccharides is essential for the preparation of both natural and novel synthetic carbohydrate compounds, synthetic intermediates, postglycosylation modifications, and for the preparation of therapeutic agents, including research tools for glycobiology. Hence, site-selective octanoylation of 1,2-O-isopropylidene-α-D-glucofuranose was conducted. Under low temperature in anhydrous pyridine, direct unimolar octanoylation of this glucofuranose without any catalyst exhibited selectivity at the C-6 hydroxyl group. The C-6 O-octanoylglucofuranose, thus obtained, was then used to prepare three 3,5-di-O-acyl esters in a similar direct method to get novel esters of glucofuranose. Characterization of all the glucofuranose esters by 1D and 2D spectroscopic technique is also discussed herein.

The most widely used and accessible monosaccharides have a number of stereogenic centers that have been hydroxylated and are challenging to chemically separate. As a result, the task of regioselective derivatization of such structures is particularly difficult. Considering this fact and to get novel rhamnopyranoside-based esters, DMAP-catalyzed di-O-stearoylation of methyl α-l-rhamnopyranoside (3) produced a mixture of 2,3-di-O- (4) and 3,4-di-O-stearates (5) (ratio 2:3) indicating the reactivity of the hydroxylated stereogenic centers of rhamnopyranoside as 3-OH > 4-OH > 2-OH. To get novel biologically active rhamnose esters, di-O-stearates 4 and 5 were converted into six 4-O- and 2-O-esters 6–11, which were fully characterized by FT-IR, 1H, and 13C NMR spectral techniques. In vitro antimicrobial assays revealed that fully esterified rhamnopyranosides 6–11 with maximum lipophilic character showed better antifungal susceptibility than antibacterial activity. These experimental findings are similar to the results found from PASS analysis data. Furthermore, the pentanoyl derivative of 2,3-di-O-stearate (compound 6) showed better antifungal functionality against F. equiseti and A. flavus, which were found to be better than standard antibiotics. To validate the better antifungal results, molecular docking of the rhamnose esters 4–11 was performed with lanosterol 14α-demethylase (PDB ID: 3LD6), including the standard antifungal antibiotics ketoconazole and fluconazole. In this instance, the binding affinities of 10 (−7.6 kcal/mol), 9 (−7.5 kcal/mol), and 7 (−6.9 kcal/mol) were better and comparable to fluconazole (−7.3 kcal/mol), indicating the likelihood of their use as non-azole type antifungal drugs in the future.

Fly ash (FA), a coal combustion residue of thermal power plants has been regarded as a problematic solid waste all over the world. In this study FA samples were modified with NaOH and H2SO4. The mineralogical and microstructural characterization were carried out by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and Braunauer-Emmett-Teller's multilayer adsorption theory (BET). Experimental data showed that cenospheres were dominated with quartz and mullite glasses with both amorphous and crystalline phases. The acid treatment increased Si/Al ratios by removing impurities and dealuminations but alkali treatment significantly increased total pore volume. The specific surface area of alkali and acid treated samples were found 6.9 m 2 g -1 and 2.1 m 2 g -1 respectively, while that of virgin material was 1.5 m 2 g -1 .