A new approach to synthesis of benzyl cinnamate: Optimization by response surface methodology

Scalable Synthesis of the Key Fexuprazan Intermediate and Investigation of a Reaction Mechanism

A three-step method for the synthesis of methyl 5-(2,4-difluorophenyl)-4-methoxy-1H-pyrrole-3-carboxylate 1, a key intermediate of fexuprazan, is reported in this paper. Using low-priced sodium p-tolylsulfinate as the starting material, compound 28 was obtained with a 96.8% yield in the first step by optimizing the experimental parameters with a Box-Behnken experimental design. Subsequently, isonitrile compound 29 was obtained by dehydration. Finally, impurities 31 and 32 in the last step of the reaction were identified and converted into target product 1 by a one-pot method, which significantly improves the utilization of atoms. Key intermediate 1 was obtained via a three-step process with a yield of 68-70% and purity that exceeded 99%. In addition, the mechanism of the cyclization reaction was proposed. This method has potential for industrial production because the raw materials are inexpensive, the procedure is simple, and a high yield is obtained.

Effects of ultrasonic assisted high-temperature cooking method on the physicochemical structure characteristics and in vitro antioxidant capacities of dietary fiber from Dendrocalamus brandisii Munro shoots

In this study, the ultrasonic assisted high-temperature cooking extraction method of soluble dietary fiber from bamboo shoots was optimized by response surface methodology, and the effects of ultrasonic assisted high-temperature cooking extraction on the structural characteristics, physicochemical properties and antioxidant activity of soluble dietary fiber (SDF) from bamboo shoots were evaluated. The yield of modified UH-SDF¹ was significantly higher than that of untreated D-SDF². FTIR and XRD confirmed that UH-SDF had more hydrophilic groups and higher crystallinity (28.73 %), resulting in better thermal stability. SEM observation showed that UH-SDF exhibited a more loose microstructure, and the particle size of UH-SDF (601.52 μm) was significantly smaller than that of D-SDF (242.59 μm), so UH-SDF had a larger specific surface area. In addition, UH-SDF has stronger water holding capacity, water swelling capacity and oil holding capacity than D-SDF. The DPPH radical and hydroxyl radical scavenging rates of UH-SDF were 8.91 % and 7.49 % higher than those of D-SDF. In addition, the reducing ability of UH-SDF was higher than that of D-SDF, which had better antioxidant activity. In summary, UH-SDF has the potential to be developed as an anti-inflammatory functional food.

Adsorptive decontamination of paper mill effluent by nano fly ash: response surface methodology, adsorption isotherm and reusability studies

In the present study, adsorption of colour and other pollutants from agro-based paper mill effluent onto fabricated coal fly ash nanoparticles (CFA-N) have been investigated. Response surface methodology was applied to evaluate the operational conditions for maximum ouster of colour from effluent by nano structured CFA-N. Maximum reduction in colour (92.45%) and other pollutants were obtained at optimum conditions: 60 min interaction time, 60 g/L adsorbent dosage and 80 rpm agitation rate. The regression coefficient values (adjusted R² = 0.7169; predicted R² = 0.7539) established harmony between predicted and the experimental data. The adsorption equilibrium results matched perfectly with both Langmuir and Freundlich isotherms with maximum adsorption capacity of 250 platinum-cobalt/g. Additionally, the efficacy of CFA-N was also assessed in a continuous column mode. Furthermore, the feasibility of treated effluent for irrigation purpose was checked by growing the plant Solanum lycopersicum. Overall, the findings demonstrated the outstanding role of inexpensive and abundantly available CFA-N in treatment of paper mill effluent to the required compliance levels.

Production of benzyl cinnamate by a low-cost immobilized lipase and evaluation of its antioxidant activity and toxicity

In this work was optimized the production of benzyl cinnamate by enzymatic catalysis using the immobilized lipase NS88011 and to evaluate its biological properties. The optimized condition for this system was 1:3 (acid:alcohol) molar ratio, 59 °C, biocatalyst concentration 4.4 mg.mL-1 for 32 h, with a yield of 97.6 %. The enzyme stability study showed that the enzyme remains active and yields above 60 % until the 13th cycle (416 h), presenting a promising half-life. In the determination of the antioxidant activity of the ester, an inhibitory concentration necessary to inhibit 50 % of the free radical 2,2-diphenyl-1-picryl-hydrazyl DPPH (IC50) of 149.8 mg.mL-1 was observed. For acute toxicity against bioindicator Artemia salina, lethal doses (LD50) of 0.07 and 436.7 μg.mL-1 were obtained for the ester and cinnamic acid, showing that benzyl cinnamate had higher toxicity, indicating potential cytotoxic activity against human tumors.

Optimization, kinetic, and scaling-up of solvent-free lipase-catalyzed synthesis of ethylene glycol oleate emollient ester

The use of enzymatic catalysts is an alternative to chemical catalysts as they can help to obtain products with less environmental impact, considered sustainable within the concept of green chemistry. The optimization, kinetic, lipase reuse, and scale-up of enzymatic production of ethylene glycol oleate in the batch mode were carried out using the NS 88011 lipase in a solvent-free system. For the optimization step, a 2³ Central Composite Design was used and the optimized condition for the ethylene glycol oleate production, with conversions above 99%, was at 70 °C, 600 rpm, substrates molar ratio of 1:2, 1 wt% of NS 88011 in 32 H of reaction. Kinetic tests were also carried out with different amounts of enzyme, and it showed that by decreasing the amount of the enzyme, the conversion also decreases. The lipase reuse showed good conversions until the second cycle of use, after which it had a progressive reduction reaching 83% in the fourth cycle of use. The scale-up (ninefold increase) showed promising results, with conversion above 99%, achieving conversions similar to small-scale reactions. Therefore, this work proposed an environmentally safe route to produce an emollient ester using a low-cost biocatalyst in a solvent-free system.

Response surface methodology approach for adsorptive removal of Reactive Blue 19 onto green pea pod

In the present study, removal of Reactive Blue 19 dye by using green pea pod as a low-cost adsorbent was investigated. Box-Behnken design was used to determine the independent and interaction influences of process variables of pH, temperature and adsorbent amount. The variance analysis (ANOVA) results showed that the second order model with high coefficient of determination value (R2 = 0.9997) was statistically significant. The experimental results stated that the removal efficiency increased when the pH value decreased and the adsorbent amount increased. The maximum removal (99.42%) was obtained at pH 2, temperature of 35 °C and adsorbent amount of 1.5 g/100 mL. The equilibrium data investigation showed that the Freundlich isotherm model fitted better for removal of dye than did the Langmuir isotherm model. Furthermore, the adsorption kinetic was also evaluated and it was found that the adsorption followed the pseudo second order model for the Reactive Blue 19 removal onto green pea pod.

Optimization of microwave-assisted extraction of bioactive compounds from New Zealand and Chinese Asparagus officinalis L. roots

The extraction of total phenolics (TPC), total flavonoids content (TFC), total saponins content (TSC), and caffeic acid (AC) contents of asparagus roots extract (ARE) from New Zealand and Chinese AR cultivars was optimized following a microwave-assisted extraction combined with central composite design. The determination of AC was conducted by HPLC in samples extracted under the optimum extraction conditions. The optimal variables for ethanol extraction generated a maximum TPC, TFC and TSC of optimal results for 68.6 mg GAE/g, 11.9 mg RE/g and 0.7 mg SE/g as well as antioxidant power towards β-carotene bleaching assay (%β_sc) (57.2%), superoxide anion radical (%O_sc ^2-) scavenging capacity (20.1%) and ferric reducing antioxidant power assay (FRAP) (1.63 µmol/g). For methanol, optimum extraction conditions obtained maximum TPC (62.6 mg GAE/g) TFC (10.7 mg RE/g), TSC (0.68 mg SE/g) with %β_sc (53.9%), %O_sc ^2- (19.1%) and FRAP (0.63 µmol/g). The content of caffeic acid from ARE ranged from 0.46 to 2.89 mg/g with ethanol and from 0.41 to 2.64 mg/g with methanol.

Novozym 40086 as a novel biocatalyst to improve benzyl cinnamate synthesis

Benzyl cinnamate is one of the derivatives of cinnamic acid, which can be used as the main constituent in perfume, UV filters and medicines. In this work, several commercial immobilized lipases (Novozym 40086, Novozym 435 and Lipozyme TLIM) and free lipases (lipase A and B from Candida sp., and lipozyme from Thermomyces linuginosous) were used as catalysts for benzyl cinnamate preparation by the esterification of benzyl alcohol with cinnamic acid. The effect of various esterification parameters (reaction time, reaction temperature, lipase concentration and substrate ratio) on benzyl cinnamate yield were also optimized and evaluated using response surface methodology (RSM). Among all tested lipases, Novozym 40086, as a new commercial immobilized lipase from Rhizomucor miehei immobilized on acrylic resin beads, showed the best activity for the esterification. Esterification parameters were optimized as follows: reaction temperature 46.3 °C, substrate molar ratio 1 : 3 (cinnamic acid/benzyl alcohol), Novozym 40086 concentration 23.1 mg mL-1, reaction time 11.3 h, and maximum benzyl cinnamate yield (96.2 ± 1.4%) were achieved under the optimal conditions. Novozym 40086 can be reused 9 times without significant decrease in benzyl cinnamate yield (90.1% yield after nine times). The activation energy for the Novozym 40086-catalyzed esterification was 14.96 ± 0.25 kJ mol-1. These results showed that Novozym 40086 was a novel and efficient biocatalyst for the esterification, which can be used as a good alternative for benzyl cinnamate production.

Optimisation of enzyme cascades for chiral amino alcohol synthesis in aid of host cell integration using a statistical experimental design approach

Chiral amino alcohols are compounds of pharmaceutical interest as they are building blocks of sphingolipids, antibiotics, and antiviral glycosidase inhibitors. Due to the challenges of chemical synthesis we recently developed two TK-TAm reaction cascades using natural and low cost feedstocks as substrates: a recycling cascade comprising of 2 enzymes and a sequential 3-step enzyme cascade yielding 30% and 1% conversion, respectively. In order to improve the conversion yield and aid the future host strain engineering for whole cell biocatalysis, we used a combination of microscale experiments and statistical experimental design. For this we implemented a full factorial design to optimise pH, temperature and buffer type, followed by the application of Response Surface Methodology for the optimisation of substrates and enzymes concentrations. Using purified enzymes we achieved 60% conversion for the recycling cascade and 3-fold improvement using the sequential pathway. Based on the results, limiting steps and individual requirements for host cell metabolic integration were identified expanding the understanding of the cascades without implementing extensive optimisation modelling. Therefore, the approach described here is well suited for optimising reaction conditions as well as defining the relative enzyme expression levels required for construction of microbial cell factories.

Effects of Ultrasonic-Microwave-Assisted Technology on Hordein Extraction from Barley and Optimization of Process Parameters Using Response Surface Methodology

We investigated the process intensification of ultrasonic-microwave-assisted technology for hordein extraction from barley. Response surface methodology was utilized to optimize the extraction conditions and to analyze the interaction between four selected variables: temperature, microwave power, ultrasonic power, and extraction time. The validated extraction yield of hordein reached 8.84% at 78°C, microwave power 298 W, and ultrasonic power 690 W after 20 min as optimum conditions. Compared with traditional water-bath extraction (4.7%), the ultrasonic-microwave-assisted technology effectively increased the hordein extraction yield and shortened the extraction time. According to the obtained quadratic model (R2 = 0.9457), ultrasonic power and extraction time were the first two significant factors. However, temperature limited the effects of other factors during extraction. SDS-PAGE and scanning electron microscopy were used to identify the hordein extract and to clarify the difference between the two hordein fractions extracted with new and traditional methods, respectively. Ultrasonic-microwave-assisted technology provided a new way to improve hordein extraction yield from barley and could be a good candidate for industrial application of process intensification.