共查询到20条相似文献,搜索用时 46 毫秒
1.
2.
3.
4.
5.
6.
(3'→5')亚甲基缩醛连接的二聚和三聚体脱氧核苷的另法合成 总被引:1,自引:0,他引:1
3'-O-(甲硫甲基)缩醛的脱氧核苷(1)与N-碘代丁二酰亚胺(MS)和二苯基次膦酸反应得到相应的3'-O-(二苯膦酰氧)甲基缩醛(2).在三甲基硅三氟甲磺酸酯(TMSOTf)的条件下,后者与3'-位保护的脱氧核苷(5)缩合,得到(3'→5')甲缩醛连接的二聚体d[(B1-m-B2)](m=次甲基)(6).同样的,2(B=T或B=C)与3'-位保护的二聚体9(T-M-T或C-m-T)缩合,可得到相应的三聚体10(T-m-T-m-T,C-m-T-T和Y-m-C-m-T). 相似文献
7.
O-甲基-α-羟基烃基膦酸酯单金属盐的合成及植物生长调节活性;α-羟基烷基膦酸酯单金属盐;合成;植物生长调节活性 相似文献
8.
3′-O-(甲硫甲基)缩醛的脱氧核苷(1)与N-碘代丁二酰亚胺(NIS)和二苯基次膦酸反应得到相应的3′-O-(二苯膦酰氧)甲基缩醛(2)。在三甲基硅三氟甲磺酸酯(TMSOTf)的条件下,后与3′-位保护的脱氧核苷(5)缩合,得到(3′→5′)亚甲基缩醛连接的二聚体d[(B1-m-B2)](m=次甲基)(6)。同样的,2(B=T或B=C)与3′-位保护的二聚体9(T-m-T或C-m-T)缩合,可得到相应的三聚体10(T-m-T-m-T,C-m-T-m-T和T-m-C-m-T)。 相似文献
9.
基于氯过氧化物酶(CPO)对有机底物的手性识别功能,以CPO催化、叔丁基过氧化氢(TBHP)氧化甲基苄基硫醚合成手性R-苄基甲基亚砜,并在反应体系中引入多羟基化合物及季铵盐提高了目标产物的产率;反应主要受体系的pH值、氧化剂类型、反应时间、氧化剂/底物摩尔比,以及CPO用量等因素控制.引入多羟基化合物(甘油,PEG400,PEG600)时,R-苄基甲基亚砜的产率及ee值可分别达到65.5%和96.3%;而引入季铵盐(TEABr,TPABr,TBABr)时,其产率提高到78.2%~68.5%,ee值为95.4%~94%.UV-vis及荧光光谱分析表明反应体系中引入少量添加剂时CPO活性中心的血红素辅基暴露程度增加,底物容易接近,同时CPO的α-螺旋结构得以加强,从而有效改善了CPO的催化性能.与目前的合成方法相比,CPO酶促氧化制备手性R-苄基甲基亚砜高效、定向,酶用量极少,具有一定的产业化应用潜能. 相似文献
10.
11.
Yanqing Fan Jing He Lin Liu Guoqin Liu Shengzhu Guo Zhe Lian Xiaonan Li Weijie Guo Xuebo Chen Ying Wang Hua Jiang 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304623
We report the synthesis and chiroptical properties of novel chiral carbon nanorings S p-/Rp-[12]PCPP containing a planar chiral [2.2]PCP unit, and demonstrate that S p-/Rp-[12]PCPP can not only host crown ether 18-Crown-6 to form ring-in-ring complexes with a binding constant 3.35×103 M−1, but also accommodate the complexes of 18-Crown-6 and S/R-protonated amines to form homochiral S @Sp -/ R @Rp - and heterochiral S @Rp -/ R @Sp - ternary complexes, displaying significantly larger binding constants of up to 3.31×105 M−1 depending on the chiral guests. Importantly, homochiral S @Sp -/ R @Rp - ternary complexes exhibit an enhanced CD signal, while the heterochiral S @Rp -/ R @Sp - ones have a constant CD signal compared with the chiral carbon nanorings, respectively, which suggests that homochiral S @Sp -/ R @Rp - ternary complexes display a highly narcissistic chiral self-recognition for S/R-protonated chiral amines, respectively. Finally, the chiral ternary complexes can be further applied to determine the ee values of chiral guests. The findings highlight a new application of carbon nanorings in supramolecular sensors, beyond the common recognition of π-conjugated molecules. 相似文献
12.
Pu Mao Yajing Cai Yongmei Xiao Liangru Yang Yuan Xue Maoping Song 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2418-2425
Using commercially available natural amino acids (L-Val, L-Leu, L-Phe) as chiral precursors, a series of N-substituted imidazole derivatives containing chiral groups was synthesized from the condensation reaction of amino acids, formaldehyde, glyoxal, and ammonia. Through esterification, reduction, chlorination, and subsequent substitution by thiols, chiral thioethers containing imidazole rings were synthesized, and the synthetic conditions were optimized. All the intermediates and the final products were characterized by NMR, ESI MS, HR MS, and IR. 相似文献
13.
14.
A series of fourteen anilide derivatives of ibuprofen were resolved on six chiral stationary phases (CSPs) derived from N-arylcarbamoyl derivatives of (S)-phenylglycine. Excellent chiral resolutions were achieved on these CSPs. The ionic-type CSPs showed better chiral recognition abilities than the corresponding covalent-type CSPs, and the CSP bearing two chiral centers has better performance than the CSPs bearing only one chiral center. The highest separation factor was achieved using the ionic-type CSP bearing two chiral centers for the resolution of the 3,5-dinitroanilide derivative of ibuprofen. This result is better than those reported in literature for the resolution of ibuprofen on the CSPs derived from amino acids, According to the chromatographic behaviors, the hydrogen bonding interaction, the π-π interactions provided by the phenyl groups in CSPs bearing one chiral center, and the phenylethylcarbamoyl moiety in CSPs bearing two chiral centers dominate the chiral recognition. 相似文献
15.
手性二环[3.3.0]辛-3-烯类化合物的合成 总被引:5,自引:0,他引:5
研究了5-(1-孟氧基)-3-溴-2(5H)-呋喃酮新手性源(1)与某些碳亲核试剂发生的串联不对称Michael加成/分子内亲核取代反应,反应中生成2个新的手性中心得到一般方法难以合成的光学纳二环[3.3.0]辛-3-烯类化合物.通过[α]、IR、UV、1HNMR、13CNMR、MS、元素分析以及X射线四圆衍射等方法确定了手性二环[3.3.0]辛-3-稀类化合物化学结构和绝对构型. 相似文献
16.
Repeated reaction between chiral quaternary ammonium dimer and disodium disulfonate gave the ionic polymer, which contains chiral quaternary ammonium sulfonate structure as a repeating unit. This chiral ionic polymer showed an excellent catalytic activity in asymmetric alkylation reaction. With the chiral ionic polymer catalysts, high level of enantioselectivities up to 97% ee were attained. 相似文献
17.
18.
手性模板合成CdS纳米棒 总被引:2,自引:0,他引:2
由于纳米材料具有量子尺寸效应及大的比表面积等性质而使其在电子学[1]、光学[2]、催化[3]和陶瓷[4]等领域显示出诱人的应用前景. 近年来纳米材料的制备及纳米技术发展迅速, 特别是具有特殊光电活性的新型无机纳米材料的制备已引起人们的普遍关注. 现在合成纳米材料的方法主要包括反相胶束法[5]、 LB膜法[6]、嵌段共聚物法[7]和模板合成法[8]. 其中模板合成技术不仅可以通过设计新型的模板分子, 还可通过模板分子的不同自组装行为来调控纳米材料的尺寸和形貌. Stupp等[9]曾利用溶致液晶的六方中间相作为模板, 在其纳米孔隙中成功地合成了具有六方排列超晶格纳米结构的材料. 本文以双亲性丙氨酸衍生物为模板, 在不同的化学微环境下合成了结构不同的CdS纳米棒. 相似文献
19.
Three new chiral heterocalix [4] crowns containing aza thio atoms bearing two chiral sites provided by (R)‐cysteine ester were synthesized. All new compounds were characterized by 1H NMR, MS and elemental analysis. 相似文献
20.
A new chiral tetradentate ligand (S,S)-1,5-bis (4-benzyloxazolin-2-yl-methyl)-1,5-diazacyclo-octane I has been synthesized and the application of 1 as catalyst in the enantioselective addition of diethyl zinc to benzaldehyde is also described. 相似文献