Chiral auxiliaryIn stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions. The auxiliary can then be typically recovered for future use. Most biological molecules and pharmaceutical targets exist as one of two possible enantiomers; consequently, chemical syntheses of natural products and pharmaceutical agents are frequently designed to obtain the target in enantiomerically pure form.
Enantioselective synthesisEnantioselective synthesis, also called asymmetric synthesis, is a form of chemical synthesis. It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts." Put more simply: it is the synthesis of a compound by a method that favors the formation of a specific enantiomer or diastereomer.
Aldol reactionThe aldol reaction (aldol addition) is a reaction that combines two carbonyl compounds (aldehydes or ketones) to form a new β-hydroxy carbonyl compound. These products are known as aldols, from the aldehyde + alcohol, a structural motif seen in many of the products. The use of aldehyde in the name comes from its discovery history, where aldehydes were first used in the reaction and not ketones. Aldol structural units are found in many important molecules, whether naturally occurring or synthetic.
EnolateIn organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the synthesis of organic compounds. Enolate anions are electronically related to allyl anions. The anionic charge is delocalized over the oxygen and the two carbon sites. Thus they have the character of both an alkoxide and a carbanion. Although they are often drawn as being simple salts, in fact they adopt complicated structures often featuring aggregates.
Michael addition reactionIn organic chemistry, the Michael reaction or Michael 1,4 addition is a reaction between a Michael donor (an enolate or other nucleophile) and a Michael acceptor (usually an α,β-unsaturated carbonyl) to produce a Michael adduct by creating a carbon-carbon bond at the acceptor's β-carbon. It belongs to the larger class of conjugate additions and is widely used for the mild formation of carbon-carbon bonds.
Asymmetric inductionAsymmetric induction (also enantioinduction) describes the preferential formation in a chemical reaction of one enantiomer or diastereoisomer over the other as a result of the influence of a chiral feature present in the substrate, reagent, catalyst or environment. Asymmetric induction is a key element in asymmetric synthesis. Asymmetric induction was introduced by Hermann Emil Fischer based on his work on carbohydrates. Several types of induction exist.
Organic synthesisOrganic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one of the most important branches of organic chemistry. There are several main areas of research within the general area of organic synthesis: total synthesis, semisynthesis, and methodology.
Organic chemistryOrganic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms. Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior.
Chemical synthesisIn chemistry, chemical synthesis (chemical combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In modern laboratory uses, the process is reproducible and reliable. A chemical synthesis involves one or more compounds (known as reagents or reactants) that will experience a transformation when subjected to certain conditions. Various reaction types can be applied to formulate a desired product.
Total synthesisTotal synthesis is the complete chemical synthesis of a complex molecule, often a natural product, from simple, commercially-available precursors. It usually refers to a process not involving the aid of biological processes, which distinguishes it from semisynthesis. Syntheses may sometimes conclude at a precursor with further known synthetic pathways to a target molecule, in which case it is known as a formal synthesis. Total synthesis target molecules can be natural products, medicinally-important active ingredients, known intermediates, or molecules of theoretical interest.
Organic redox reactionOrganic reductions or organic oxidations or organic redox reactions are redox reactions that take place with organic compounds. In organic chemistry oxidations and reductions are different from ordinary redox reactions, because many reactions carry the name but do not actually involve electron transfer. Instead the relevant criterion for organic oxidation is gain of oxygen and/or loss of hydrogen, respectively. Simple functional groups can be arranged in order of increasing oxidation state.
Oxidation stateIn chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to other atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. Conceptually, the oxidation state may be positive, negative or zero. While fully ionic bonds are not found in nature, many bonds exhibit strong ionicity, making oxidation state a useful predictor of charge. The oxidation state of an atom does not represent the "real" charge on that atom, or any other actual atomic property.
RedoxRedox (ˈrɛdɒks , ˈriːdɒks , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: Electron-transfer – Only one (usually) electron flows from the atom being oxidized to the atom that is reduced. This type of redox reaction is often discussed in terms of redox couples and electrode potentials.
OmOm (or Aum) (; ॐ, ओम्) is a symbol representing a sacred sound, syllable, mantra, and an invocation in Hinduism. Its written representation is one of the most important symbols of Hinduism. It is variously said to be the essence of the supreme Absolute, consciousness, Ātman, Brahman, or the cosmic world. In Indic traditions, Om serves as a sonic representation of the divine, a standard of Vedic authority and a central aspect of soteriological doctrines and practices.
Buddhism in VietnamBuddhism in Vietnam (Đạo Phật 道佛 or Phật Giáo 佛教 in Vietnamese), as practiced by the Vietnamese, is mainly of the Mahayana tradition and is the main religion, a combination of Pure Land and Zen (Thiền). Buddhism may have first come to Vietnam as early as the 3rd or 2nd century BCE from the Indian subcontinent or from China in the 1st or 2nd century CE. Vietnamese Buddhism has had a syncretic relationship with certain elements of Taoism, Chinese spirituality, and Vietnamese folk religion.
ElectrophileIn chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively charged, have an atom that carries a partial positive charge, or have an atom that does not have an octet of electrons. Electrophiles mainly interact with nucleophiles through addition and substitution reactions.
HanoiHanoi (Hà Nội haː˨˩ noj˧˨ʔ) is the capital and second-most populous city of Vietnam. It covers an area of . It consists of 12 urban districts, one district-leveled town and 17 rural districts. It is located within the Red River Delta of Northern Vietnam. Hanoi's history goes back to the third century BCE, when a portion of the modern-day city served as the capital of the historic Vietnamese nation of Âu Lạc. Following the collapse of Âu Lạc, the city was part of Han China.
Beta oxidationIn biochemistry and metabolism, beta oxidation (also β-oxidation) is the catabolic process by which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport chain. It is named as such because the beta carbon of the fatty acid undergoes oxidation to a carbonyl group.
Om mani padme hum(ॐ मणि पद्मे हूँ, õːː mɐɳɪ pɐdmeː ɦũː) is the six-syllabled Sanskrit mantra particularly associated with the four-armed Shadakshari form of Avalokiteshvara, the bodhisattva of compassion. It first appeared in the Mahayana Kāraṇḍavyūhasūtra where it is also referred to as the sadaksara (six syllabled) and the paramahrdaya, or “innermost heart” of Avalokiteshvara. In this text the mantra is seen as the condensed form of all Buddhist teachings. The precise meaning and significance of the words remains much discussed by Buddhist scholars.
NucleophileIn chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are Lewis bases. Nucleophilic describes the affinity of a nucleophile to bond with positively charged atomic nuclei. Nucleophilicity, sometimes referred to as nucleophile strength, refers to a substance's nucleophilic character and is often used to compare the affinity of atoms.
