Polyether Synthesis through Reductive Etherification Reaction Strategy

The reductive etherification reaction (RER) of carbonyl groups (aldehydes or ketones) through silane as a reducing agent together with Bronsted or Lewis acid affords the synthesis of symmetrical and unsymmetrical ethers. This strategy is applied at the macromolecular level for the first time in 1993, and isophthalaldehyde is self-polymerized in the presence of triethylsilane (Et₃SiH)/ tritylperchlorate (TrClO₄) to yield polyethers with low to moderate molecular weights. Next, the polyethers with alternating structures are achieved by reacting isophthalaldehyde with bis(trimethylsilyl) ethers or diols as comonomers using reducing agent silane and Lewis acid. Moreover, in recent years, it is shown that polyether synthesis and post-polymerization modification (PPM) of polymers proceeds smoothly and effectively with the RER strategy in the presence of chlorodimethylsilane (CDMS), which acts as both a reducing agent and a Lewis acid.     

芹菜素醚化及溴化衍生物的合成及抗肝癌活性研究

目的:合成芹菜素甲醚化、二氟甲醚化及溴化衍生物,进行抗肝癌活性研究。方法:以芹菜素为原料,经硫酸二甲酯甲醚化、溴素溴化或一氯二氟甲烷二氟甲醚化,柱层析分离,合成芹菜素衍生物。MTT法测定氟尿嘧啶(5-FU)、芹菜素衍生物对体外培养人肝癌HepG2细胞活性的抑制作用。结果:共得到6个化合物,结构经1H-NMR等进行了确证;MTT法测定结果表明,化合物1抑制HepG2细胞活性作用的IC50值是7.86±1.35μg/mL,与化疗药5-FU(7.18±0.85μg/mL)类似;化合物2～7的IC50值分别为2.62±0.32、0.65±0.12、3.21±0.43、4.36±0.51、4.13±0.46和1.96±0.29μg/mL;其中以化合物3的效价强度最大,是先导物芹菜素的12.09倍,化疗药5-FU的11.05倍。结论:芹菜素衍生物的抗肝癌活性较芹菜素更强,其中化合物3(6-8-二溴-7,4'-二甲氧基-5-羟基黄酮)是一个具有开发潜力的抗肝癌活性新化合物。     

Radiosynthesis of 1‐iodo‐2‐[11C]methylpropane and 2‐methyl‐1‐[11C]propanol and its application for alkylation reactions and C―C bond formation

The multitude of biologically active compounds requires the availability of a broad spectrum of radiolabeled synthons for the development of positron emission tomography (PET) tracers. The aim of this study was to synthesize 1‐iodo‐2‐[¹¹C]methylpropane and 2‐methyl‐1‐[¹¹C]propanol and investigate the use of these reagents in further radiosynthesis reactions. 2‐Methyl‐1‐[¹¹C]propanol was obtained with an average radiochemical yield of 46 ± 6% d.c. and used with fluorobenzene as starting material. High conversion rates of 85 ± 4% d.c. could be observed with HPLC, but large precursor amounts (32 mg, 333 μmol) were needed. 1‐Iodo‐2‐[¹¹C]methylpropane was synthesized with a radiochemical yield of 25 ± 7% d.c. and with a radiochemical purity of 78 ± 7% d.c. The labelling agent 1‐iodo‐2‐[¹¹C]methylpropane was coupled to thiophenol, phenol and phenylmagnesium bromide. Average radiochemical conversions of 83% d.c. for thiophenol, 40% d.c. for phenol, and 60% d.c. for phenylmagnesium bromide were obtained. In addition, [¹¹C]2‐methyl‐1‐propyl phenyl sulphide was isolated with a radiochemical yield of 5 ± 1% d.c. and a molar activity of 346 ± 113 GBq/μmol at the end of synthesis. Altogether, the syntheses of 1‐iodo‐2‐[¹¹C]methylpropane and 2‐methyl‐1‐[¹¹C]propanol were achieved and applied as proof of their applicability.     

One‐step reductive etherification of 4‐[18F]fluoro‐benzaldehyde with decaborane

Reductive coupling reactions between 4‐[¹⁸F]fluoro‐benzaldehyde ([¹⁸F] 1 ) and different alcohols by use of decaborane (B₁₀H₁₄) as reducing agent have the potential to synthesize 4‐[¹⁸F]fluoro‐benzylethers in one step. [¹⁸F] 1 was synthesized from 4‐trimethylammonium benzaldehyde (triflate salt) via a standard fluorination procedure (K[¹⁸F]F/Kryptofix^® 222) in dimethylformamide at 90°C for 25 min and purified by solid‐phase extraction. Subsequently, reductive etherifications of [¹⁸F] 1 were performed as one‐step reactions with primary and secondary alcohols, mediated by B₁₀H₁₄ in acetonitrile at 60°C. Various 4‐[¹⁸F]fluorobenzyl ethers (6 examples are shown) were obtained within 1–2 h reaction time in decay‐corrected radiochemical yields of 12–45%. Copyright © 2006 John Wiley & Sons, Ltd.     

二甘醇与乙醇在杂多酸盐催化剂存在下合成二甘醇乙醚

研究了以杂多酸盐为催化剂，由乙醇和二甘醇合成二甘醇乙醚的反应过程。研究表明，磷钨酸银及硅乌酸银具有较高的活性和选择性，其转化率分别为８９．０％和８７．３％，单双醚总选择性分别为７３．４％和８０．６％；磷钼酸银的活性较低。ＩＲ、ＸＲＤ、ＴＧ分析和正丁胺滴定法表面酸度测定表明，杂多酸银盐的催化性能与其所具有的酸性中心有关。     

Synthesis of lipophilic genistein derivatives and their regulation of IL-12 and TNF-α in activated J774A.1 cells

Genistein modulates inflammatory responses in part by reducing the production of the pro-inflammatory cytokines IL-12, TNF-α, and nitric oxide, by activated macrophages in response to lipopolysaccharide stimulus. Previous studies have shown that synthetic lipophilic genistein glycosides were significantly more active than hydrophilic glycosides. The aims of this study were to synthesize and to evaluate the effect of novel lipophilic genistein derivatives on IL-12, TNF-α, and nitric oxide production by J774A.1 cells. The results show that the modification of genistein enables the generation of non-cytotoxic compounds with increased IL-12 inhibition. However, these derivatives failed to inhibit TNF-α. The nitric oxide production was notably inhibited by the monoester (2, 3) and monoether (6, 7) compounds in a dose-dependent manner.     

雌甾3—甲醚的相转移催化合成

在 C_6H_5CH_2N(C_2H_5)_3Cl 等相转移催化剂存在下,雌酮(或雌二醇、炔雌醇)与碘甲烷在氢氧化钠水溶液和二氯甲烷中回流反应,生成对应的雌甾3-甲醚。此法操作简便,反应迅速,且产率高。     

一种克拉霉素关键中间体的合成工艺优化

目的研究克拉霉素关键中间体——（2＇4,″-O-双三甲基硅基）-红霉素A-9-[O-（1-乙氧基-1-甲乙基）]肟的＂一锅法＂合成工艺。方法以9-（E）-红霉素肟为原料,在内酰胺盐酸盐的催化下,与2-乙氧基丙烯进行醚化反应,再进行硅烷化,即经＂一锅法＂得到克拉霉素关键中间体。结果与结论目标物的结构经质谱、核磁共振谱确证。该合成路线收率良好（两步总收率为88%）、环境友好,为工业化生产克拉霉素提供了一种新的方法。     

双烷基聚氧烷烯醚的合成

本文介绍了双烷基聚氧烷烯醚的合成方法。研究了十二醇聚氧乙烯醚的钠化和十二醇聚氧乙烯醚钠化物的醚化反应。讨论了钠化和醚化反应中的温度、时间、原料摩尔比和催化剂等影响因素。     

克拉霉素合成中的肟醚异构化现象研究

目的改进克拉霉素合成工艺.方法通过研究红霉素A肟的醚化反应来改进工艺,提高收率.结果红霉素A肟存在E-和Z-两种异构体的热力学平衡,该平衡可由酸、碱控制;在肟羟基的酸催化醚化反应中,其热力学平衡体系被醚化反应的动力学所竞争,使原先Z-肟异构化成E-肟的方向发生了逆转.研究发现不同比例的E-、Z-红霉素肟的混合物(>7.3∶1,E/Z)会生成具有相同E/Z比例的醚化产物,该比例仅由醚化反应条件所决定,主要是溶剂和温度.结论红霉素肟的E-异构体衍生物比相应的Z-异构体有较高的6-OH区域选择性,可通过改变醚化反应条件减少Z-异构体的含量来提高克拉霉素的产率.