Efficient Preparation of Racemic gamma-Nonalactone

Science and Technology Planning Project of Xiamen City, P. R. China [3502Z20113001]; Fundamental Research Funds for the Central Universities, P. R. China [2011121019

Efficient and convenient preparation of γ-nonalactone, with use of a Dean-Stark trap to remove methanol

We describe the development of an efficient and convenient process for preparation of γ-nonalactone. The synthesis was accomplished by free-radical addition of methyl acrylate and n-hexanol. A Dean-Stark trap filled with water and n-hexanol was used to remove the methanol generated during the process. Orthogonal experiments were performed to optimize the reaction conditions, and the desired product, γ-nonalactone, was produced in better than 70 % yield. ? 2013 Springer Science+Business Media Dordrecht

Efficient and convenient preparation of 纬-Unsecalactone

Conference Name:2nd International Conference on Chemical Engineering and Advanced Materials, CEAM 2012. Conference Address: Guangzhou, China. Time:July 13, 2012 - July 15, 2012.纬-Unsecalactone was prepared efficiently via the free radical addition reaction with acrylic acid and n-octanol as raw materials. An improved process which used Dean-Stark trap with adding anhydrous Na2SO4 as desiccant was developed. Through the orthogonal experiments about the dosages of di-t-butyl peroxide(DTBP) and zinc bromide (ZnBr2), the optimal reaction conditions were as follows:n(DTBP): n(acrylic acid) = 0.160, n(ZnBr2): n(acrylic acid) = 0.050. The yield of 纬-unsecalactone based on the optimal reaction conditions reached 71%.漏 (2012) Trans Tech Publications, Switzerland

Improving the Forming Quality of Laser Dynamic Flexible Micropunching by Laser Pre-Shocking

Laser pre-shocking (LPS) was introduced into the laser dynamic flexible micropunching process to refine the grain size of a workpiece to improve the forming quality of punched parts. T2 copper foils with five different grain sizes and seven different laser power densities with and without LPS were used for the experiment. The results showed that the grains are refined and the average surface roughness Ra decreases after LPS. For copper foils annealed at 650 °C, the value of Ra decreases from 0.430 to 0.363 µm. The increase in laser energy density and grain size leads to the deterioration of the fracture surface. LPS can improve the quality of the fracture surface. Compared with punched holes without LPS, the dimensional accuracy and shape accuracy of punched holes can be improved by LPS. When grain size is close to the thickness of the copper foil, the forming quality of the punched parts becomes uncertain, owing to the difference in the orientation of the initial grains. The instability of laser dynamic flexible micropunching can be reduced by LPS. Especially, the improvement of forming quality of the punched part brought by LPS is significant for the copper foils with coarse grains

Efficient and convenient preparation of gamma-nonalactone, with use of a Dean-Stark trap to remove methanol

National Nature Science Foundation of China [21106119]; Fundamental Research Funds for the Central Universities, P.R. China [2011121019]; Science and Technology Planning Project of Xiamen City, P.R. China [3502Z20113001]We describe the development of an efficient and convenient process for preparation of gamma-nonalactone. The synthesis was accomplished by free-radical addition of methyl acrylate and n-hexanol. A Dean-Stark trap filled with water and n-hexanol was used to remove the methanol generated during the process. Orthogonal experiments were performed to optimize the reaction conditions, and the desired product, gamma-nonalactone, was produced in better than 70 % yield

Protecting-Group-Free Total Synthesis of (−)-Jiadifenolide: Development of a [4 + 1] Annulation toward Multisubstituted Tetrahydrofurans

A concise, protecting-group-free total synthesis of (−)-jiadifenolide, a synthetically challenging <i>seco</i>-prezizaane sesquiterpene with potent neurotrophic activity, is reported. The convergent route features a SmI₂/H₂O-mediated stereoselective reductive cyclization, an unprecedented formal [4 + 1] annulative tetrahydrofuran-forming reaction and programmed redox manipulations. The newly developed annulation of β-hydroxy aldehydes or ketones with lithium trimethylsilyldiazomethane provides access to a diverse array of multisubstituted tetrahydrofurans. The synthetic jiadifenolide exhibited weak cytotoxicity against five human cancer cell lines