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Safety evaluation index system of dimethyl oxalate synthesis process
This paper focuses on dimethyl oxalate and, based on the results of HAZOP analysis for its synthesis process, conducts the following studies: (1) establish a safety evaluation index system for dimethyl oxalate synthesis using hierarchical analysis and calculate the weights of each indicator, determining the acceptable range of each indicator according to the 3σ criterion, (2) develop an evaluation index scoring method based on this, (3) classify the overall process safety into four levels: safe, relatively safe, unsafe, and extremely unsafe based on the evaluation index scores and corresponding weights.
Journal Article
Recent progress in the synthesis of metal-organic frameworks
Metal-organic frameworks (MOFs) have attracted considerable attention for various applications due to their tunable structure, porosity and functionality. In general, MOFs have been synthesized from isolated metal ions and organic linkers under hydrothermal or solvothermal conditions via one-spot reactions. The emerging precursor approach and kinetically tuned dimensional augmentation strategy add more diversity to this field. In addition, to speed up the crystallization process and create uniform crystals with reduced size, many alternative synthesis routes have been explored. Recent advances in microwave-assisted synthesis and electrochemical synthesis are presented in this review. In recent years, post-synthetic approaches have been shown to be powerful tools to synthesize MOFs with modified functionality, which cannot be attained via de novo synthesis. In this review, some current accomplishments of post-synthetic modification (PSM) based on covalent transformations and coordinative interactions as well as post-synthetic exchange (PSE) in robust MOFs are provided.
Journal Article
Vox ex machina : a cultural history of talking machines
\"By documenting how voice synthesis developed over the course of the 20th century, as well as the cultural imagination that emerged around new talking machines as they were introduced, this book shows how synthetic voices index the complicated and sometimes paradoxical relationships that people have with increasingly lifelike digital technologies\"-- Provided by publisher.
BOOK
Computational planning of the synthesis of complex natural products
Training algorithms to computationally plan multistep organic syntheses has been a challenge for more than 50 years
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. However, the field has progressed greatly since the development of early programs such as LHASA
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, for which reaction choices at each step were made by human operators. Multiple software platforms
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are now capable of completely autonomous planning. But these programs ‘think’ only one step at a time and have so far been limited to relatively simple targets, the syntheses of which could arguably be designed by human chemists within minutes, without the help of a computer. Furthermore, no algorithm has yet been able to design plausible routes to complex natural products, for which much more far-sighted, multistep planning is necessary
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and closely related literature precedents cannot be relied on. Here we demonstrate that such computational synthesis planning is possible, provided that the program’s knowledge of organic chemistry and data-based artificial intelligence routines are augmented with causal relationships
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, allowing it to ‘strategize’ over multiple synthetic steps. Using a Turing-like test administered to synthesis experts, we show that the routes designed by such a program are largely indistinguishable from those designed by humans. We also successfully validated three computer-designed syntheses of natural products in the laboratory. Taken together, these results indicate that expert-level automated synthetic planning is feasible, pending continued improvements to the reaction knowledge base and further code optimization.
A synthetic route-planning algorithm, augmented with causal relationships that allow it to strategize over multiple steps, can design complex natural-product syntheses that are indistinguishable from those designed by human experts.
Journal Article
Copper-catalysed selective hydroamination reactions of alkynes
The development of selective reactions that utilize easily available and abundant precursors for the efficient synthesis of amines is a long-standing goal of chemical research. Despite the centrality of amines in a number of important research areas, including medicinal chemistry, total synthesis and materials science, a general, selective and step-efficient synthesis of amines is still needed. Here, we describe a set of mild catalytic conditions utilizing a single copper-based catalyst that enables the direct preparation of three distinct and important amine classes (enamines, α-chiral branched alkylamines and linear alkylamines) from readily available alkyne starting materials with high levels of chemo-, regio- and stereoselectivity. This methodology was applied to the asymmetric synthesis of rivastigmine and the formal synthesis of several other pharmaceutical agents, including duloxetine, atomoxetine, fluoxetine and tolterodine.
Amines are essential in a number of research areas, but a general, selective and step-efficient synthesis has been elusive. Now, the use of a single copper catalyst to transform alkynes into enamines, α-chiral branched alkylamines, and linear alkylamines is described. These transformations have been applied in the preparation of a selection of current pharmaceutical agents.
Journal Article
Recent Advances in the Chemical Synthesis and Evaluation of Anticancer Nucleoside Analogues
Nucleoside analogues have proven to be highly successful chemotherapeutic agents in the treatment of a wide variety of cancers. Several such compounds, including gemcitabine and cytarabine, are the go-to option in first-line treatments. However, these materials do have limitations and the development of next generation compounds remains a topic of significant interest and necessity. Herein, we discuss recent advances in the chemical synthesis and biological evaluation of nucleoside analogues as potential anticancer agents. Focus is paid to 4′-heteroatom substitution of the furanose oxygen, 2′-, 3′-, 4′- and 5′-position ring modifications and the development of new prodrug strategies for these materials.
Journal Article