ORGANIC & BIOMOLECULAR CHEMISTRY
·
2022
·Vol. 20
·期 14
·2909-2921
·
IF 3.89
Haidi Yang,Jinyao Liu,Pan Hu,Liang Gao,Zedu Huang,Fener Chen
A new and highly stereoselective synthesis of chiral diol (S)-14, the common synthetic intermediate to (+)-(2R,4′R,8′R)-α-tocopherol (1), was accomplished in seven steps with 13.8% overall yield. This developed route featured a lipase-catalyzed desymmetric hydrolysis of prochiral diester 39a, which was prepared through a challenging Heck coupling, to chiral quaternary carbon-containing monoester (R)-37a of the correct configuration in 81% yield and 96.7% ee, to the best of our knowledge, leading to the most efficient enzymatic desymmetric synthesis of the chiral chroman skeleton of vitamin E members reported to date. Coupled with the modified preparation of the phytol-derived side chain, the chemoenzymatic total synthesis of 1 was completed in 15 longest linear steps with 3.1% overall yield.
研究领域:
有机化学
·
合成化学
·
酶学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2026
·
IF 9.2
Zhiyu Jin,Lei Chen,Jiayu Li,Xiang Chen,Pengxiang Gao,Jiuxiang Sun,Chong Zhang,Bingcheng Hu
Substituent effects play a pivotal role in modulating the properties of organic ionic compounds through the synergistic electronic and steric effects. The substituent effect is one of the core theoretical foundations for studying structure–property relationships in materials science and organic chemistry. However, in-depth examination of the substituent effects on significant cyclo-pentazolate anion (cyclo-N5−) salts has not been studied. Herein, to explore how different substituents (R) in 4-R-1,5-diaminotetrazolium cations affect the properties of their cyclo-N5− salts, four types of cyclo-N5− salts bearing distinct substituents (−CH3, –CH2COCH3, –CH2CONH2, and –CH2COOCH3) were designed and synthesized. Analysis using X-ray single-crystal diffraction indicates that the crystal structures of these salts vary significantly based on the substituents. Among them, the cyclo-N5− salt with the –CH3 substituent exhibits optimal crystal density and stability. The –CH2CONH2 group improves crystal stability via increased hydrogen-bonding capacity. In contrast, –CH2COCH3 and –CH2COOCH3 lead to reduced stability and crystal density due to larger steric bulk and lack of hydrogen-bonding interactions. Additionally, Hirshfeld surface analysis and fingerprint plots were employed to investigate the interionic interaction regions, revealing extensive van der Waals interactions and the formation of N–H⋯N hydrogen bonds. The cyclo-N5− salt with the –CH3 substituent displays the highest detonation performance (D: 8811.47 m s−1; P: 26.94 GPa), which benefits from a higher enthalpy of formation.
✓ 已验证
DOI
高影响因子
ACS Omega
·
2023
·
IF 4.1
Long Liu,Jinhu Bai,Ze Su,Yuan Yao,Zhixiang Zhou,Yangfeng Xia,Yanqiang Zhang
In this paper, a series of energetic ionic liquid plasticizers of 1-methyl-4-methoxyethyl-1,2,4-triazolium chloride (1), 1-methyl-4-methoxyethyl-1,2,4-triazolium bis(trifluoromethylsulfonyl)imide (1a), 1-methyl-4-methoxyethyl-1,2,4-triazolium nitrate (1b), 1-methyl-4-ethyl acetate-1,2,4-triazolium chloride (2), 1-methyl-4-ethyl acetate-1,2,4-triazolium bis(trifluoromethylsulfonyl)imide (2a), and 1-methyl-4-ethyl acetate-1,2,4-triazolium nitrate (2b) were synthesized and characterized. The results show that compounds 1a, 1b, 2a, and 2b have lower melting points (Tm, −72.60 to −32.67 °C) and good thermal stability (Td, 161–348 °C) and are suitable as plasticizers for hydroxyl-terminated polybutadiene (HTPB) curing systems. Among these four ionic liquids, ester-functionalized cations can help to improve the tensile strength (2a, 0.943 MPa; 2b, 1.113 MPa) of the cured system, while ether-functionalized cations are more beneficial to improve elongation at break (1a, 522.90%; 1b, 484.45%). Ester-functionalized ionic liquids are more beneficial to reduce the glass transition temperature of HTPB elastomers. The storage modulus of HTPB elastomers containing NO3– is higher, while that of HTPB elastomers containing NTf2– is lower. The crosslink densities of HTPB/TDI/2a and HTPB/TDI/2b plasticized by ester-functionalized ionic liquids are larger, which are 9369 and 9616 mol/m3, respectively. There are hydrogen bond interactions between the ionic liquid and the HTPB elastomer, and these interactions changed the distribution of the hard and soft segments in the polymer molecules.
研究领域:
含能材料
·
高分子科学
·
推进剂化学
·
材料工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）