A practical and improved process for the synthesis of Hagen’s gland lactones by catalytic hydro-deiodination

Catalytic hydro-deiodination has been efficiently employed in the development of a benign process for the synthesis of Hagen’s gland lactones. The process was developed with only two column chromatographic purifications and is applicable for gram scale synthesis. No protecting groups were used in the synthesis which is an added advantage.     

氧载体的氧物种直接氧化甲烷制合成气

甲烷部分氧化制合成气由于合成气中n(H2)/n(CO)接近2,可直接用于甲醇合成或烃类F-T合成等后续工业过程而在国内外受到了广泛的关注。利用氧载体的氧物种在无气相氧下直接选择氧化甲烷制合成气是天然气化工利用的新方法,本文介绍了该方法的基本原理、概念工艺和对氧载体的性能要求,对应用于该方法的铈基复合氧化物的掺杂和助剂对选择氧化甲烷性能的影响、钙钛矿氧化物氧载体的氧缺陷、氧物种迁移、结构稳定性及其氧物种氧化甲烷的性能进行了阐述和分析,提出了控制氧载体表面状态是获得高合成气选择性的关键,并对该技术今后的研究重点进行了展望。     

利巴韦林合成概述

利巴韦林为一种高效广谱抗病毒核苷类药物,文章对利巴韦林的合成方法、原理和优缺点进行了概述。利巴韦林合成方法主要包括化学法、酶促法和发酵法三种;其中化学法的研究最为广泛,酶促法的工业化前景最为广阔,而发酵法仍不成熟。     

New process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis

A new process of low-temperature methanol synthesis from CO/CO₂/H₂ based on dual-catalysis has been developed. Some alcohols, especially 2-alcohol, were found to have high catalytic promoting effect on the synthesis of methanol from CO hydrogenation. At 443 K and 5 MPa, the synthesis of methanol could process high effectively, resulting from the synergic catalysis of Cu/ZnO solid catalyst and 2-alcohol solvent catalyst. The primary results showed that when 2-butanol was used as reaction solvent, the one-pass average yield and the selectivity of methanol, in 40 h continuous reaction at temperature as low as 443 K and 5 MPa, were high up to 46.51% and 98.94% respectively. The catalytic activity was stable and the reaction temperature was 80 K or so lower than that in current industry synthesis process. This new process hopefully will become a practical method for methanol synthesis at low temperature.     

New process of low-temperature methanol synthesis from CO/CO_2/H_2 based on dual-catalysis

A new process of low-temperature methanol synthesis from CO/CO2/H2 based on dual-catalysis has been developed. Some alcohols, especially 2-alcohol, were found to have high catalytic promoting effect on the synthesis of methanol from CO hydrogenation. At 443 K and 5 MPa, the synthesis of methanol could process high effectively, resulting from the synergic catalysis of Cu/ZnO solid catalyst and 2-alcohol solvent catalyst. The primary results showed that when 2-butanol was used as reaction solvent, the one-pass average yield and the selectivity of methanol, in 40 h continuous reaction at temperature as low as 443 K and 5 MPa, were high up to 46.51% and 98.94% respectively. The catalytic activity was stable and the reaction temperature was 80 K or so lower than that in current industry synthesis process. This new process hopefully will become a practical method for methanol synthesis at low temperature.     

Serendipitous synthesis of a cyclic formamidine. Application to the synthesis of polyazamacrocycles

An unexpected synthesis of 4,5,6,7,8,9-hexahydro-1,3-diazonine, using hexamethylenediamine and dimethylformamide, is presented. The cyclization process was explained as a two-step process involving formylation and subsequent intramolecular condensation. The scope of this process was demonstrated through the synthesis of two other nitrogen-containing macroheterocycles.     

丙烯氨氧化合成丙烯腈过程中的尾气分析

在丙烯氨氧化合成丙烯腈过程中，尾气内含有因反应而生成的ＣＯ２，ＣＯ，Ｃ２Ｈ４，未反应完全的Ｃ３Ｈ６，Ｏ２和不参与反应的Ｎ２以及丙烯原料气中少量的Ｃ３Ｈ８。使用含有双阀、双检测器、双色谱柱的气相色谱系统可使上述所有气体得到分离，而且分离效果好，定量准确，操作简单，实用性强     

Continuous Synthesis of Nanominerals in Supercritical Water

The synthesis of minerals should play a crucial role in the development of new and advanced materials. Since 2016, a renewal of interest to enlarge the mineral synthesis towards industrial requirements has been observed, especially thanks to three main recent papers. The innovative process exposed combines a continuous process with the use of supercritical water. In addition to curtail synthesis times, this process offers a control on the particle characteristics (size, crystallinity, structure, etc.) and a capacity to be easily transferable at an industrial scale. This innovative concept is demonstrated with the synthesis of three minerals which are the talc (a phyllomineral), the xonotlite and the tobermorite (two inominerals). This article proposes an overview of the possibilities to synthesize nanominerals in continuous processing for the development of advanced materials with promising industrial applications.     

Synthesis of Functionalized Aliphatic Acid Esters via the Generation of Alkyl Radicals from Silylperoxyacetals

We describe a catalytic method for the synthesis of a variety of functionalized aliphatic acid esters using silylperoxyacetals, which are versatile alkyl radical precursors with a terminal ester moiety. In the presence of an appropriate transition-metal catalyst, the in situ generation of alkyl radicals and the subsequent bond-forming process proceeds smoothly to afford synthetically valuable aliphatic acid derivatives. The present method can be applied to the efficient synthesis of a pharmaceutically important 1,1-diarylalkane motif. In addition, a novel strategy for the synthesis of structurally diverse hydroxy acid derivatives via a C−O bond formation process that utilizes TEMPO has been developed.     

Characterization of the products obtained from alkaline conversion of tuff and metakaolin

Currently, there has been a growing interest of zeolite materials for industrial and scientific purpose. Synthetic zeolites are more often used than natural ones due to its higher purity and more uniform particle sizes. Numerous investigations are conducted in searching of inexpensive raw materials suitable for zeolite synthesis. Moreover, the temperature, pressure, times and SiO₂/Al₂O₃ ratio are the most important parameters which play key roles in the synthesis processes. Due to such a large number of factors that affect the process, zeolite synthesis has been undergoing constant development. Nowadays, researchers focus on the methods of synthesizing zeolites at ambient temperature and pressure. Metakaolin and tuff are natural raw materials which can be turned into a brand new class of synthetic zeolites. However, each requires different method of synthesis in order to obtain a material with best physical properties. This paper discusses the process of alkaline activation of synthetic zeolites from natural raw materials: volcanic tuff excavated in Filipowice and metakaolin obtained from Rominco company. Two methods: fusion and low-temperature synthesis, were used in the presented research. Moreover, the physical properties of raw materials and zeolites obtained were shown. Based on the XRD analysis, it was verified that materials after the synthesis process contained zeolites A, Na-X and faujasite-Na. Furthermore, the dehydration and thermal decomposition phenomena of the tuff and metakaolin before and after the synthesis process were determined by coupled TG/MS techniques.     

Asymmetric Synthesis of Heterocyclic Chloroamines and Aziridines by Enantioselective Protonation of Catalytically Generated Enamines**

We report a method for the synthesis of chiral vicinal chloroamines via asymmetric protonation of catalytically generated prochiral chloroenamines using chiral Brønsted acids. The process is highly enantioselective, with the origin of asymmetry and catalyst substituent effects elucidated by DFT calculations. We show the utility of the method as an approach to the synthesis of a broad range of heterocycle-substituted aziridines by treatment of the chloroamines with base in a one-pot process, as well as the utility of the process to allow access to vicinal diamines.     

氮气吹扫和费托合成的脉冲过程以提高α-烯烃的选择性

费托合成可以将煤炭或者生物质气化得到的合成气转化为α-烯烃等重要的化工产品。研究将费托合成和氮气吹扫操作组合成一脉冲过程,在稳定的操作状态下保证费托合成和氮气吹扫交替进行。在传统的费托合成条件下(反应气速为2 000 h^-1,温度为497 K, 压力为 2.0 MPa, 氢碳体积比为2.0)考察了Fe-Co催化剂在脉冲过程中费托合成的活性和选择性。结果表明,N₂吹扫温度和压力分别为517 K和0.2 MPa下的费托合成的C₃烯烷比是未脉冲的相同反应条件下的九倍左右。同时,反应过程中CH₄的选择性和CO的转化率有所下降。在此基础上,通过间歇反应在固定床反应器中进行该脉冲过程,实验结果表明,利用脉冲操作在费托反应中可以获得更高的烯烃选择性。     

Continuous Flow Synthesis of [Au(NHC)(Aryl)] (NHC=N-Heterocyclic Carbene) Complexes

The use of weak and inexpensive bases has recently opened promising perspectives towards the simpler and more sustainable synthesis of Au(I)-aryl complexes with valuable applications in catalysis, medicinal chemistry, and materials science. In recent years, continuous manufacturing has shown to be a reliable partner in establishing sustainable and controlled process scalability. Herein, the first continuous flow synthesis of a range of Au(I)-aryl starting from widely available boronic acids and various [Au(NHC)Cl] (NHC=N-heterocyclic carbene) complexes in unprecedentedly short reaction times and high yields is reported. Successful synthesis of previously non- or poorly accessible complexes exposed fascinating reactivity patterns. Via a gram-scale synthesis, convenient process scalability of the developed protocol was showcased.     

Automated modular preparative HPLC-MS purification laboratory with enhanced efficiency

Automated parallel synthesis as tool to increase productivity in chemical synthesis is well-established. However, even more time-consuming than the synthesis process is the following purification of the resulting crude products. To enhance efficiency of the lead optimization process at Bayer CropScience, a high-throughput HPLC/MS-laboratory for the purification of up to 48 crude products per day in the range of 200-400 mg each in one injection per sample has been set up. The use of Covaris technology for HPLC sample preparation, automated aliquotation during fractionation, and a novel evaporation process by combination with freeze-drying are new key technologies applied successfully for the first time in this purification unit facilitating to achieve the targeted efficiency. The whole process is supported by a specially designed IT-landscape covering each step of the workflow. Both the technical instruments used within the laboratory and the workflow and IT platform are described in this article.     

A new and convenient approach to heterotetracyclic benzoxazocines through addition of 1,3-dicarbonyl compounds to quinolinium salts

The synthesis of a series of benzoxazocines has been achieved in good yields by tandem C-alkylation and intramolecular O-alkylation of 1,3-dicarbonyl compounds with quinolinium salts. This is a novel example of the synthesis of eight-membered rings via a tandem process, which provides a method for the synthesis of medium-ring heterocycles.     

Determination of epichlorohydrin and 1,3-dichloro-2-propanol in synthesis of cationic etherifying reagent by headspace gas chromatography

This study demonstrates a headspace gas chromatographic(HS-GC) technique for the determination of residual epichlorohydrin (ECH) and generated 1,3-dichloro-2-propanol (DCP) in synthesis process of 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHTAC). By a weight-based sampling method, coupled with significant dilution in 15.8% sodium sulfate and 0.1% silver nitrate mixed solution rapidly, the sample for HS-GC analysis is prepared. Based on the reaction stoichiometry, the conversion (R) of CHTAC during the synthesis process can be calculated from sampling weight and GC peak area. The results showed that the method has a good measurement precision (RSD<2.5%) and accuracy (recovery=101-104%) for the quantification of both ECH and DCP in the process samples. The present method is simple and accurate, which can be used for the efficient determination of the CHTAC conversion in the synthesis research.     

A transition metal-free tandem process to pyrrolopyrazino[2,3-d]pyridazine-diones

A transition metal-free tandem process for the synthesis of pyrrolopyrazino[2,3-d]pyridazine-diones is described. The process is an efficient construction of this tricyclic system by a one-pot coupling/Smiles rearrangement/cyclization approach. This methodology has potential applications in the synthesis of biologically and medicinally relevant compounds.     

A short and efficient synthesis of crocetin-dimethylester and crocetindial

In this paper we describe an efficient six-step synthesis of crocetin-dimethylester that could be further reduced to a "four-step" synthesis through the use of in situ procedures. The simplicity of the whole process, the ready availability of starting materials, and the high overall yield render this strategy a very attractive synthesis of this very important compound, which is the key intermediate for the synthesis of several carotenoids and other polyene natural products.     

Diversity-oriented synthesis of biaryl-containing medium rings using a one bead/one stock solution platform

Diversity-oriented synthesis of structurally complex and diverse small molecules can be used as the first step in a process to explore cellular and organismal pathways. The success of this process is likely going to be dependent on advances in the synthesis of small molecules having natural product-like structures in an efficient and stereoselective manner. The development, scope, and mechanism of the oxidation of organocuprates was investigated and exploited in the atropdiastereoselective synthesis of biaryl-containing medium rings (9-, 10-, and 11-membered rings). The methodology was performed on high-capacity, large polystyrene beads by metalating aryl bromides with i-PrBu(2)MgLi, followed by transmetalating with CuCN x 2LiBr and then oxidizing with 1,3-dinitrobenzene, and was used in a diversity-oriented synthesis of biaryl-containing medium rings (library total theoretical maximum 1412 members). The high capacity beads were arrayed into 384-well plates and, using a process optimized during the development of a one bead/one stock solution technology platform, converted into arrays of stock solutions, with each stock solution containing largely one compound. These stock solutions were used in numerous phenotypic and protein-binding assays. The process described outlines a pathway that we feel will contribute to a comprehensive and systematic chemical approach to exploring biology (chemical genetics).     

Total synthesis of polyene natural product dihydroxerulin by mild organocatalyzed dehydrogenation of alcohols

Polyene synthesis: An efficient approach to the total synthesis of polyene natural product dihydroxrulin (1) is described. A novel, mild, direct organocatalytic IBX-mediated dehydrogenation process of simple alcohols to enals has been developed, which serves as a key step in the synthesis (see scheme).