Porous Organic Cage-Embedded C10-Modified Silica as HPLC Stationary Phase and Its Multiple Separation Functions.

Reduced imine cage (RCC3) was covalently bonded to the surface of silica spheres, and then the secondary amine group of the molecular cage was embedded in non-polar C10 for modification to prepare a novel RCC3-C10@silica HPLC stationary phase with multiple separation functions. Through infrared spectroscopy, thermogravimetric analysis and nitrogen adsorption-desorption characterization, it was confirmed that RCC3-C10 was successfully bonded to the surface of silica spheres. The resolution of RCC3-C10@silica in reversed-phase separation mode is as high as 2.95, 3.73, 3.27 and 4.09 for p-phenethyl alcohol, 1-phenyl-2-propanol, p-methylphenethyl alcohol and 1-phenyl-1-propanol, indicating that the stationary phase has excellent chiral resolution performance. In reversed-phase and hydrophilic separation modes, RCC3-C10@silica realized the separation and analysis of a total of 70 compounds in 8 classes of Tanaka mixtures, alkylbenzene rings, polyphenyl rings, phenols, anilines, sulfonamides, nucleosides and flavonoids, and the analysis of a variety of chiral and achiral complex mixtures have been completed at the same time. Compared with the traditional C18 commercial column, RCC3-C10@silica exhibits better chromatographic separation selectivity, aromatic selectivity and polar selectivity. The multifunctional separation mechanism exhibited by the stationary phase originates from various synergistic effects such as hydrophobic interaction, π-π interaction, hydrogen bonding and steric interaction provided by RCC3 and C10 groups. This work provides flexible selectivity and application prospects for novel multi-separation functional chromatographic columns.

Optimized extraction of astaxanthin from shrimp shells treated by biological enzyme and its separation and purification using macroporous resin.

The best enzymatic protease treatment of shrimp shells was identified by comparing the enzymatic hydrolysis effects of many different types of biological enzymes using fresh Arctic sweet shrimp as raw materials. The optimal enzymolysis conditions were determined using neutral protease as the best enzymatic protease. Among multiple macroporous adsorption resins, XDA-8 macroporous adsorption resin was preferable due to its static adsorption rate and desorption rate. The yield of astaxanthin (134.20 µg/g) after treatment with neutral protease was 3.7 times higher than that of the control group (36.03 µg/g). The yield of astaxanthin was obviously improved after enzymolysis of the shrimp shells. The purity of the astaxanthin was up to 87.34%, approximately 6508 times higher than that of the raw material. The production cost of astaxanthin would be greatly reduced by use of XDA-8 resin to obtain high-purity astaxanthin. This technique offers a high value-added utilization of shrimp shells.

Optimization of Ultrasonic-Assisted Extraction and Purification of Zeaxanthin and Lutein in Corn Gluten Meal.

Zeaxanthin and lutein have a wide range of pharmacological applications. In this study, we conducted systematic experimental research to optimize antioxidant extraction based on detection, extraction, process amplification, and purification. An ultrasonic-assisted method was used to extract zeaxanthin and lutein with high efficiency from corn gluten meal. Firstly, the effects of solid-liquid ratio, extraction temperature, and ultrasonic extraction time on the extraction of zeaxanthin were investigated in single-factor experiments. The optimization extraction parameters of zeaxanthin and lutein with ethanol solvent were obtained using the response surface methodology (RSM) as follows: liquid-solid ratio of 7.9:1, extraction temperature of 56 °C, and extraction time of 45 min. The total content of zeaxanthin and lutein was 0.501%. The optimum extraction experimental parameters were verified by process amplification, and we confirmed that the parameters of the extraction process optimized using the RSM design are reliable and precise. Zeaxanthin and lutein from crude extract of corn gluten were separated and purified using silica gel column chromatography with the purity of zeaxanthin increasing from 0.28% to 31.5% (about 110 times) and lutein from 0.25% to 16.3% (about 65 times), which could be used for large-scale industrial production of carotenoids.

Extraction and purification of astaxanthin from shrimp shells and the effects of different treatments on its content

Abstract In this study, the extraction process and purification technology of astaxanthin from shrimp shells were established, and the effects of different treatments on the content of astaxanthin were studied. The determination results of astaxanthin in various shrimp/crab shells showed that the astaxanthin content in the Procambarus clarkia shell reached 239.96 µg/g. The effects of cool-ventilated, sun-dried and cooking conditions on the content of astaxanthin during the treatment of shrimp shells were investigated respectively and fresh shrimp shells as best extraction source was determined. The nine groups orthogonal test design with four factors and three levels (L9(3)4) was used to analyze the optimization of extraction process of astaxanthin from shrimp shells with ethanol as an environmentally friendly extraction solvent. The optimum experimental condition including the solid-liquid ratio (1:7), extraction time (20 min) and temperature (50 ºC) was proposed with the maximum extraction yield of astaxanthin. Next, silica gel column chromatography was used to purify the crude extraction of astaxanthin, and the purity of astaxanthin increased from 0.34% to 85.1% (about 250 times), which has great applications in the high value utilization of shrimp shells resources and the development of astaxanthin-related products.

Nickel catalyzed alkylation of N-aromatic heterocycles with Grignard reagents through direct C-H bond functionalization.

A novel protocol for nickel-catalyzed direct sp(2) C-H bond alkylation of N-aromatic heterocycles has been developed. This new reaction proceeded efficiently at room temperature using a Grignard reagent as the coupling partner. This approach provides new access to a variety of alkylated N-aromatic heterocycles which are potentially of great importance in medicinal chemistry.

6,6'-Di-tert-butyl-4,4'-dimethyl-2,2'-[1,2-phenyl-enebis(nitrilo-methanylyl-idene)]diphenol.

In the title mol-ecule, C(30)H(36)N(2)O(2), the dihedral angles between the central benzene ring and the two benzene rings of the butyl-salicylaldimine groups are 14.3 (2) and 40.6 (2)°. There are two strong intra-molecular O-H⋯N hydrogen bonds which form S(6) rings. The crystal studied was a non-merohedral twin with refined components of 0.270 (4) and 0.730 (4).

Bis-(chloro-acetato-κO)bis(trimethyl-silylmethyl)tin(IV).

In the title complex, [Sn(C(2)H(2)ClO(2))(2)(C(4)H(11)Si)(2)], the Sn(IV) ion is coordinated in a distorted tetra-hedral environment formed by two O atoms from two monodenate chloro-acetato ligands and two C atoms from two trimethyl silyl ligands. Two further weak intra-molecular Sn⋯O contacts [2.744 (2) and 2.655 (2) Å] are formed by the chloro-acetato ligands.

Nickel-catalyzed sp2 C-H bonds arylation of N-aromatic heterocycles with Grignard reagents at room temperature.

A novel protocol for nickel-catalyzed direct sp(2) C-H bond arylation of purines has been developed. This new reaction proceeded efficiently at room temperature using Grignard reagent as the coupling partner within 5 hours in good to high yields. This approach provides a new access to a variety of C8-arylpurines which are potentially of great importance in medicinal chemistry.