The solubilities of (+)-biotin intermediate lactone in methanol, toluene, tetrahydrofuran, dichloromethane, ethyl acetate, and N,N-dimethylformamide were determined at the investigated temperatures 287.15–323.75 K under pressure (p = 0.1 MPa) by a laser monitoring system. The solubilities of (+)-biotin intermediate lactone in pure solvents increase with increasing temperature and in the following order: methanol < toluene < ethyl acetate < tetrahydrofuran < dichloromethane < N,N-dimethylformamide. The solubilities were correlated by the equation for ideal solution model, modified Apelblat equation, λh equation, Wilson model, and NRTL equation. The calculated values are in good agreement with the measured experimental data. The modified Apelblat equation was found to provide further accurate representation of the experimental data in six organic solvents.

Magnetic nano-Fe3O4-supported organocatalysts were synthesized by anchoring valine-derived formamide onto the surface of Fe3O4 magnetic nanoparticles, which were applied in the asymmetric reduction of imines with trichlorosilane at room temperature in toluene. The high level of yield and enantioselectivity catalyzed by magnetic nano-Fe3O4-supported organocatalysts was obtained. In the immobilization process, CuI-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) “click chemistry” was used as the anchored bridge. The magnetic nanoparticles can simplify the recovery of the organocatalyst and its separation from the reaction system. By an external magnet, the catalyst can be recycled and reused five times without a remarkable activity decline.

A new, practical and cost-effective route for scalable synthesis of 2-[(4-dodecyloxyphenyl)sulfonyl] butanoic acid, a key intermediate of a new cyan dye-forming coupler containing a sulfone group, was developed by adopting phenol as the starting material. The synthesis was accomplished in five steps with etherification, chlorosulfonation, reduction, nucleophilic reaction by C-S coupling and hydrolyzation. An important objective of the new synthetic route was the synthesis of 2-[4-(dodecyloxyphenyl)sulfonyl]butanoate. Overall yield obtained at optimized conditions increased to 66 %. The synthetic strategy was proven to be a process enabling rapid delivery of the target product with high purity.

The solubilities of 1-fluoro-4-(methylsulfonyl)benzene in five pure organic solvents (ethanol, ethyl acetate, acetone, toluene, and chloroform) at temperatures ranging from (288.40 to 331.50) K under atmospheric pressure were measured experimentally by the dynamic method with a laser monitoring apparatus. It was found that the solubilities in different solvents decreased in the order chloroform > acetone > ethyl acetate > toluene > ethanol. The experimental data were well-correlated using the modified Apelblat equation, with average relative deviations of less than 2.92 % and root-mean-square deviations of no more than 0.30 %.

The solubilities of biotin in water, methanol, ethanol, acetic acid, dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) were measured at temperatures ranging from 298.15 K to 333.85 K (p = 0.1 MPa) by the synthetic method with a laser monitoring dynamic technique. The mole fraction solubilities of biotin were observed to be highest in DMSO, and be lowest in water. The experimental data were well-correlated with the modified Apelblat equation, van’t Hoff equation, and λh equation, in which the correlation coefficients (R2) were noted in the range of 0.997 to 1.000 and the root-mean-square deviations (rmsd) were less than 2.82 %. Thermodynamic studies showed that dissolution of biotin was an endothermic and spontaneous process in all selected solvents.

Piperonyl butoxide (PBO) 1 was prepared via the successive chloromethylation and etherification of dihydrosafrole 3. In this work, during the chloromethylation of 3, several by-products such as 5 (the isomer of chloromethyldihydrosafrole 4), 6-propylpiperonyl alcohol 6, bis(chloromethyl)-dihydrosafrole 7 and 8, bis(2-propyl-4,5-methylenedioxyphenyl)methane 9 and di(2-propyl-4,5-methy lene-dioxybenzyl)ether 10 were found. However, it was found that 5, 6, 7, and 8 could undergo a further reaction to the final product (PBO), rather than its derivatives, though the by-products 9 and 10 still existed. Based on these results, the plausible mechanism of the chloromethylation and etherification of 3 was proposed. Furthermore, the reliability of the plausible mechanism was verified by quantum chemical calculations using DFT. In addition, the final product (PBO) was produced with a high selectivity and yield by reducing the by-products 9 and 10.

A simple method for N-alkylation of 1,2-diaminoethane with different alcohols in a fixed-bed reactor using cheap CuO-NiO/γ-Al2O3 as the catalyst has been developed. The present catalytic system was applicable in the N-alkylation of 1,2-diaminoethane with both primary and secondary alcohols. Mono-N-alkylation of 1,2-diaminoethane with low-carbon alcohols resulted in high yields; the yields of tetra-N-alkylation of 1,2-diaminoethane with low-carbon alcohols declined markedly with the increase of the molecular volume of alcohols.

A new synthesis of l-norvaline is described. Using valeric acid as the raw material, α-brominevaleryl chloride was achieved by acyl chlorination and α-position bromination in one-pot with the yield of 84.7%. The yields of the following ammoniation of α-brominevaleryl chloride and resolution of dl-norvaline were 88.7% and 26.7%, respectively. d-Norvaline was also obtained in a similar method from the waste resolution solution. Other optical active amino acids, valine, α-aminobutyric acid and alanine were also synthesized in similar ways.

A new green synthesis of phenyl vinyl sulfoxide was described. The use of ethylene oxide, strong acid resin, and solid supported phosphotungstic acid made the process green and feasible to industrialize. The optimal condition was selected in the experiments. The total yield was 80.5% and it was eco-friendly. The catalysts were easy to recycle. According to the experiments, the oxidation mechanism was assumed to follow the complex–oxidation–decomplex fashion.

The solubilities of β,β-carotene-4,4′-dione (canthaxanthin) in methanol, ethanol, acetone, ethyl acetate, toluene, cyclohexane, 1,2-dichloroethane, and trichloromethane were measured by a synthetic method over the temperature range from (293.15 to 343.15) K at atmospheric pressure. A laser monitoring observation technique was employed to determine the dissolution of the solid phase in a solid−liquid system. The experimental solubilities were fitted by the modified Apelblat equation with the deviation less than 2.7 %.

•A new highly stereoselective construction of the side chain of the C-24 and C-25 oxysterols has been achieved.•Aerobic oxidation of 24-hydroxycholesterol was explored and the mechanism was proposed.A new highly stereoselective construction of the side chain of the C-24 and C-25 oxysterols has been achieved by using desmosterol acetate as the starting material and an improved Sharpless catalytic asymmetric dihydroxylation with 100% d.e. (diastereomeric excess) as the key step. The result is much better than the usual asymmetric dihydroxylation procedure. t-Butyl nitrite/2,2,6,6-tetramethylpiperidine N-oxyl radical/FeCl3 catalyst system was developed to activate molecular oxygen for the aerobic oxidation of 24-hydroxycholesterol and the 24-ketocholesterol was obtained in 86.2% yield. The oxidation system has never been reported before. The mechanism for the catalytic aerobic oxidation was also proposed.Download full-size image

•This way shows a new approach for the allylic oxidation of Δ5-steroids.•This way shows the reaction of t-butyl hydroperoxide with Δ5-steroids in the presence of N-hydroxyphthalimide.•This way show excellent regioselectivity and chemoselectivity.•The reaction mechanism and the scope of the reaction were investigated.A new and optimized procedure for the allylic oxidation of Δ5-steroids with t-butyl hydroperoxide in the presence of catalytic amounts of N-hydroxyphthalimide (NHPI) under mild conditions was developed, showing excellent regioselectivity and chemoselectivity (functional group compatibility). It was found that Co(OAc)2 could enhance the catalytic ability of NHPI resulting in better yields and shorter reaction times. The reaction mechanism and the scope of the reaction with a variety of Δ5-steroidal substrates were also investigated.Download full-size image