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A Brief Background
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
Organic reactions are used to synthesise drugs. Considerations of the stereochemistry are obviously vital in the design of new medicines. In cases where one of the two stereoisomers is the active drug, an asymmetric synthesis is required where special measures are taken to ensure stereospecificity. With knowledge of the characteristic reactions that different functional groups display, organic chemists can synthesise a target drug molecule from the relevant readily available starting materials. To build a target molecule, making carbon-carbon bonds is essential. Functional groups that will undergo addition reactions are useful for this purpose. To ensure strong interactions with the drugs’ biological target, a particular functional group may be needed in the molecule. Here, a substitution reaction may be relevant. Ultimately, a drug molecule is made with the correct size, shape, correctly positioned functional groups, and chemical properties that will interact with the biological system to produce a biological response. A selection of functional groups that are key to organic synthesis are shown in Figure 1.2. Whether the compound acts as a medicine or a poison depends on the dose level of the compound. This can be described by the drugs therapeutic index, which is a measure of a drugs beneficial effect at low dose versus its harmful effects at high dose. No drug is absolutely harmless and drugs may vary in the side effects they have.
Polymers as Conditioning Agents for Hair and Skin
Published in Randy Schueller, Perry Romanowski, Conditioning Agents for Hair and Skin, 2020
Condensation polymerization normally employs two difunctional monomers that are capable of undergoing typical organic reactions. For example, a diacid can be allowed to react with a diol in the presence of an acid catalyst to afford a polyester. In this case, chain growth is initiated by the reaction of one of the diacid's carboxyl groups with one of the diol's hydroxyl groups. The free carboxyl or hydroxyl group of the resulting dimer can then react with an appropriate functional group in another monomer or dimer. This process is repeated throughout the polymerization mixture until all of the monomers are converted to low-molecular-weight species, such as dimers, trimers, tetramers, etc. These molecules, which are called oligomers, can then react further with each other through their free functional groups. Polymer chains that have moderate molecular weights can be built in this manner. The high molecular weights common to chain-reaction polymerizations are usually not reached. This is due to the fact that as the molecular weight increases, the concentration of the flee functional groups decreases dramatically. In addition, the groups are attached to the ends of chains and, hence, are no longer capable of moving freely through the viscious reaction medium.
Innovative industrial technology starts with iodine
Published in Tatsuo Kaiho, Iodine Made Simple, 2017
SmI2 is a strong reducing agent that reacts rapidly with water to produce hydrogen. In an organic reaction, it can reduce halides, ketones, esters, and sulfoxides. A typical SmI2 reaction is the Barbier reaction which produces tertiary alcohol from ketone and alkyl halide. There are reports on the intramolecular reaction producing a five-membered ring or a six-membered ring. Furthermore, pinacol coupling stereoselectively proceeds with a high yield [40b].
Critical assessment of AI in drug discovery
Published in Expert Opinion on Drug Discovery, 2021
W. Patrick Walters, Regina Barzilay
More recently, multiple groups have developed methods that use AI to process large databases of organic reactions and propose new synthetic routes [110,111]. These methods divide synthesis planning into two discrete tasks, search and reaction prediction. In the search task, the program attempts to identify a set of chemical reactions that will form a retrosynthetic ‘path’ between a target molecule and a set of readily available starting materials. In the reaction prediction task [111,112], the network seeks to determine, based on precedent, whether the reactions along the path will be feasible and will provide a reasonable yield of the desired product. Since the specific proposed reaction is often unprecedented, the feasibility of the reaction must be inferred from context. The two tasks are complementary; given a choice between multiple alternative reactions at a particular step along the path, the network will choose the most feasible reaction.
Microtiter plate-based chemistry and in situ screening: SuFEx-enabled lead discovery of selective AChE inhibitors
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
Kun Tang, Huan-Huan Li, Chengyao Wu, Shi-Long Zhang, Jian-Guo Yang, Wenjian Tang, Hua-Li Qin
An approach derived from combinatorial chemistry has been attracting attention in the last two decades: microtiter plate-based synthesis coupled with in situ screening through click chemistry, which uses automation to rapidly detect biological or biochemical activity12,13. This approach leverages high yield organic reactions with high selectivity, starting with a set of building blocks to generate a focused library in a microplate, in which a compound is ideally formed in each well14. SuFEx click chemistry can achieve the high reactivity of sulphonyl fluorides with suitable amines. The formation of the intended sulphonamides would be efficient, with high purity and high yield.
Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions
Published in Expert Opinion on Drug Delivery, 2022
Arya Kadukkattil Ramanunny, Sachin Kumar Singh, Sheetu Wadhwa, Monica Gulati, Bhupinder Kapoor, Rubiya Khursheed, Gowthamarajan Kuppusamy, Kamal Dua, Harish Dureja, Dinesh Kumar Chellappan, Niraj Kumar Jha, Piyush Kumar Gupta, Sukriti Vishwas
Majority of the research works carried out for NANEs show that its application is quite significant in pharmaceuticals as well as non-pharmaceutical areas. In non-pharmaceuticals, it has been used as an agent for carrying out microencapsulation [135], organic reactions, polymer synthesis, for production of macroporous materials [143], formation of elastomeric film with disinfectant [68], and in making polymer dispersed liquid crystal devices [144].