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Role of AI in the Advancement of Drug Discovery and Development
Published in Utpal Chakraborty, Amit Banerjee, Jayanta Kumar Saha, Niloy Sarkar, Chinmay Chakraborty, Artificial Intelligence and the Fourth Industrial Revolution, 2022
Shantanu K. Yadav, Poonam Jindal, Rakesh K. Sindhu
Historically, experiments were recorded in paper lab notebooks and then archived for patent purposes. In the preceding 10 years, paper lab notebooks have been substituted by electronic lab notebooks to enhance privacy and for basic information registration, entry, and recovery. Many procedures have been altered in the pharma field for safety purposes, some previous (e.g., Birch reduction—an organic reaction where the aromatic rings are reduced by 1,4 to provide unconjugated cyclohexadiene in the presence of sodium or lithium metal in liquid ammonia and in the presence of alcohol) and some current (e.g., Stille is a chemical reaction commonly used in organic synthesis. The reaction involves the combination of two organic groups, one of which is held as an organotin compound). The collection of portfolios has been introduced into palladium-catalyzed and boron composition (Buchwald-Hartwig and Suzuki responses, among others) and is now commonly used. Transition metal catalysis includes C-H activation responses, which are particularly helpful for rapidly diversifying molecules in the late stage.
An Overview of Catalytic Bio-oil Upgrading, Part 1:
Published in Ozcan Konur, Biodiesel Fuels, 2021
Jianghao Zhang, Junming Sun, Yong Wang
As mentioned above, the ketone species can be further upgraded via aldol condensation. Aldol condensation, generally performed at mild temperatures (0–200°C), is another widely utilized reaction to upgrade carbonyl-containing compounds to larger products (Wu et al., 2016). In the upgrading of biomass-derived compounds using heterogeneous catalysts, it has been recognized that the catalyst with a combination of moderate strength acidic and basic sites is ideal to conduct aldol condensation with high performance (Cueto et al., 2017; Shen et al., 2012; Wang et al., 2016). It is also concluded that, in vapor phase aldol condensation, if the catalyst only preserves either strong acidic or basic sites, the severe deactivation seems usually to happen by the occupation of carbonaceous by-products of these sites (Shen et al., 2012). The investigated catalysts are various and can be categorized into (mixed) metal oxides (Liang et al., 2016; Shen et al., 2012), zeolites (Sharma et al., 2007), hydroxyapatite (Young et al., 2016), hydrotalcite (Sharma et al., 2007), resins (Bui et al., 2017), etc. Though the proposed mechanisms differ depending on the utilized catalysts, several reaction steps have been agreed to complete the reaction, including α-C–H activation/cleavage, C–C coupling, and dehydration.
Direct Natural Gas Conversion to Oxygenates
Published in Jianli Hu, Dushyant Shekhawat, Direct Natural Gas Conversion to Value-Added Chemicals, 2020
The approach that reaches highest yields are based on CH activation chemistry (Conley et al. 2006). CH activation consists of a two-step process in which (1) the CH bond coordinates to an open site at a transition metal center followed by (2) cleavage of the CH bond to form a metal-carbon bond. The advantage of the CH activation reaction is that can cleave the CH bond of alkanes using moderately energetic conditions. The high selectivity and mild reaction conditions of CH activation reaction is motivated by the atom transfer within the coordination sphere of carbon and the reactant.
DFT investigates the mechanisms of cross-dehydrogenative coupling between heterocycles and acetonitrile
Published in Molecular Physics, 2022
Cheng-Yu He, Hong-Xia Hou, Ming-Qiong Tong, Da-Gang Zhou, Rong Li
Cross-dehydrogenative coupling (CDC) is always used to construct new C–C bonds in synthetic organic chemistry, which is efficient, atom economic, and environment-friendly [1–4]. And its core reaction is C–H activation. Generally, C–H activation represents a universal means to fabricate desirable products without prefunctionalising reactants because C–H bonds are ubiquitous in organics. However, C−H activation is fairly challenging due to the inertia of C−H bonds and the poor selectivity. To overcome this, diverse strategies have been adopted, including harsh experimental conditions, transition metal catalysis, and metal surfaces. The free radical chemistry with a high activity of a single electron could provide new thinking to activate the inert C–H bond in organic chemistry, and many radical initiators, such as tert-butyl-hydroperoxide (TBHP) [5], di-tert-butyl peroxide (DTBP) [6], benzoyl peroxide (BPO) [7], bis(4-tert-butyl cyclohexyl)peroxy dicarbonate (TBCP) [8], tert-butylperoxybenzoate (TBPB) [9] and dicumyl peroxide (DCP) [10], can be used to generate radicals to activate the C–H bond. For example, Pan and his coworkers employed DCP to activate Csp3-H to synthesise quinazolinones and their derivatives in Scheme 1(a) [10]; and Yan and his cooperators took TBPB as the radical initiator to achieve the Csp3-H activation in Scheme 1(b) [11].