Lemont Burwell Kier [1] (September 13, 1930 - Jan 2, 2024) was an American chemist and researcher in the field of drug design and medicinal chemistry. [2] He was the recipient of the American Association of Pharmaceutical Scientists 2008 Research Achievement Award in Drug Development and Discovery. [3] Kier obtained his PhD in Medicinal Chemistry at the University of Minnesota in 1958 and is currently a Professor Emeritus of Medicinal Chemistry and Nurse Anesthesia at the Virginia Commonwealth University in Richmond, Virginia. He participated in the founding of the Center for the Study of Biological Complexity at Virginia Commonwealth University. [4] Kier passed away on January 2, 2024. [5]
Kier built one of the first models in which molecular orbital theory was applied successfully to drug design and development. Later, he and his colleague, Lowell Hall, developed what is now called the "Kier-Hall Index" to describe molecular connectivity. [6] [7] His particular expertise in the question “How do chemical modifications affect particular physical properties of drugs?” has been used to develop the theory of the interaction of general anesthetic gases with the body, [8] and the theory of taste (and in particular, sweetness).
Professor Kier is the author or co-author of eight books: [9] Molecular Orbital Theory In Drug Research; [10] Molecular Connectivity In Chemistry and Drug Research; [11] Molecular Connectivity in Structure Activity Analysis; [12] Molecular Structure Description: The Electrotopological State; [13] Medicinal Chemistry and Physics for Nurse Anesthetists; [14] Cellular Automata Modeling of Chemical Systems; [15] and Science and Complexity for Life Science Students. [16]
Computational chemistry is a branch of chemistry that uses computer simulations to assist in solving chemical problems. It uses methods of theoretical chemistry incorporated into computer programs to calculate the structures and properties of molecules, groups of molecules, and solids. The importance of this subject stems from the fact that, with the exception of some relatively recent findings related to the hydrogen molecular ion, achieving an accurate quantum mechanical depiction of chemical systems analytically, or in a closed form, is not feasible. The complexity inherent in the many-body problem exacerbates the challenge of providing detailed descriptions of quantum mechanical systems. While computational results normally complement information obtained by chemical experiments, it can occasionally predict unobserved chemical phenomena.
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. For many molecules, the sharing of electrons allows each atom to attain the equivalent of a full valence shell, corresponding to a stable electronic configuration. In organic chemistry, covalent bonding is much more common than ionic bonding.
Theoretical chemistry is the branch of chemistry which develops theoretical generalizations that are part of the theoretical arsenal of modern chemistry: for example, the concepts of chemical bonding, chemical reaction, valence, the surface of potential energy, molecular orbitals, orbital interactions, and molecule activation.
Sir John Edward Lennard-Jones was a British mathematician and professor of theoretical physics at the University of Bristol, and then of theoretical science at the University of Cambridge. He was an important pioneer in the development of modern computational chemistry and theoretical chemistry.
A chemical structure of a molecule is a spatial arrangement of its atoms and their chemical bonds. Its determination includes a chemist's specifying the molecular geometry and, when feasible and necessary, the electronic structure of the target molecule or other solid. Molecular geometry refers to the spatial arrangement of atoms in a molecule and the chemical bonds that hold the atoms together and can be represented using structural formulae and by molecular models; complete electronic structure descriptions include specifying the occupation of a molecule's molecular orbitals. Structure determination can be applied to a range of targets from very simple molecules to very complex ones.
Cheminformatics refers to the use of physical chemistry theory with computer and information science techniques—so called "in silico" techniques—in application to a range of descriptive and prescriptive problems in the field of chemistry, including in its applications to biology and related molecular fields. Such in silico techniques are used, for example, by pharmaceutical companies and in academic settings to aid and inform the process of drug discovery, for instance in the design of well-defined combinatorial libraries of synthetic compounds, or to assist in structure-based drug design. The methods can also be used in chemical and allied industries, and such fields as environmental science and pharmacology, where chemical processes are involved or studied.
In biology and other experimental sciences, an in silico experiment is one performed on a computer or via computer simulation software. The phrase is pseudo-Latin for 'in silicon', referring to silicon in computer chips. It was coined in 1987 as an allusion to the Latin phrases in vivo, in vitro, and in situ, which are commonly used in biology. The latter phrases refer, respectively, to experiments done in living organisms, outside living organisms, and where they are found in nature.
In medicinal chemistry and molecular biology, a pharmacophore is an abstract description of molecular features that are necessary for molecular recognition of a ligand by a biological macromolecule. IUPAC defines a pharmacophore to be "an ensemble of steric and electronic features that is necessary to ensure the optimal supramolecular interactions with a specific biological target and to trigger its biological response". A pharmacophore model explains how structurally diverse ligands can bind to a common receptor site. Furthermore, pharmacophore models can be used to identify through de novo design or virtual screening novel ligands that will bind to the same receptor.
Mathematical chemistry is the area of research engaged in novel applications of mathematics to chemistry; it concerns itself principally with the mathematical modeling of chemical phenomena. Mathematical chemistry has also sometimes been called computer chemistry, but should not be confused with computational chemistry.
A structural analog, also known as a chemical analog or simply an analog, is a compound having a structure similar to that of another compound, but differing from it in respect to a certain component.
The Grotthuss mechanism is a model for the process by which an 'excess' proton or proton defect diffuses through the hydrogen bond network of water molecules or other hydrogen-bonded liquids through the formation and concomitant cleavage of covalent bonds involving neighboring molecules.
William L. Jorgensen is a Sterling Professor of Chemistry at Yale University. He is considered a pioneer in the field of computational chemistry. Some of his contributions include the TIP3P, TIP4P, and TIP5P water models, the OPLS force field, and his work on free-energy perturbation theory for modeling reactions in solution, protein-ligand binding, and drug design; he has over 450 publications in the field. Jorgensen was the Editor of the ACS Journal of Chemical Theory and Computation from its founding in 2005 until 2022.
Tetramethoxyamphetamine, or 2,3,4,5-tetramethoxyamphetamine, is a lesser-known psychedelic drug and a substituted amphetamine. Tetramethoxyamphetamine was first synthesized by Alexander Shulgin. In his book PiHKAL , the minimum dosage is listed as 50 mg, and the duration unknown. Tetramethoxyamphetamine produces a threshold, mydriasis, and a headache. Limited data exists about its pharmacological properties, metabolism, and toxicity.
Etoxadrol (CL-1848C) is a dissociative anaesthetic drug that has been found to be an NMDA antagonist and produce similar effects to PCP in animals. Etoxadrol, along with another related drug dexoxadrol, were developed as analgesics for use in humans, but development was discontinued in the late 1970s after patients reported side effects such as nightmares and hallucinations.
In the fields of chemical graph theory, molecular topology, and mathematical chemistry, a topological index, also known as a connectivity index, is a type of a molecular descriptor that is calculated based on the molecular graph of a chemical compound. Topological indices are numerical parameters of a graph which characterize its topology and are usually graph invariant. Topological indices are used for example in the development of quantitative structure-activity relationships (QSARs) in which the biological activity or other properties of molecules are correlated with their chemical structure.
Molecular descriptors play a fundamental role in chemistry, pharmaceutical sciences, environmental protection policy, and health researches, as well as in quality control, being the way molecules, thought of as real bodies, are transformed into numbers, allowing some mathematical treatment of the chemical information contained in the molecule. This was defined by Todeschini and Consonni as:
Chemical similarity refers to the similarity of chemical elements, molecules or chemical compounds with respect to either structural or functional qualities, i.e. the effect that the chemical compound has on reaction partners in inorganic or biological settings. Biological effects and thus also similarity of effects are usually quantified using the biological activity of a compound. In general terms, function can be related to the chemical activity of compounds.
Arylcyclohexylamines, also known as arylcyclohexamines or arylcyclohexanamines, are a chemical class of pharmaceutical, designer, and experimental drugs.
Building block is a term in chemistry which is used to describe a virtual molecular fragment or a real chemical compound the molecules of which possess reactive functional groups. Building blocks are used for bottom-up modular assembly of molecular architectures: nano-particles, metal-organic frameworks, organic molecular constructs, supra-molecular complexes. Using building blocks ensures strict control of what a final compound or a (supra)molecular construct will be.