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Organic chemistry is a subdiscipline within chemistry involving the science study of the structure, properties, and reactions of and organic matter, i.e., matter in its various forms that contain carbon .Clayden, J.; Greeves, N. and Warren, S. (2012) Organic Chemistry. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of includes the chemical synthesis of , , and , and study of individual organic in the laboratory and via theoretical (in silico) study.
The range of chemicals studied chemistry includes (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements,Elschenbroich, C. (2006) Organometallics 3rd Ed., Wiley-VCHMorrison, Robert T.; Boyd, Robert N. and Boyd, Robert K. (1992) Organic Chemistry, 6th ed., Benjamin Cummings. . especially oxygen, nitrogen, sulfur, phosphorus (included in many biochemicals) and the . Organometallic chemistry is the study of compounds containing carbon–metal bonds.
Organic compounds form the basis of all earthly life and constitute the majority of known chemicals. The bonding patterns of carbon, with its valence of four—formal single, double, and triple bonds, plus structures with delocalized electrons—make the array of organic compounds structurally diverse, and their range of applications enormous. They form the basis of, or are constituents of, many commercial products including drug; and , and products made from them including lubricants, solvents; ; fuels and explosives. The study of organic chemistry overlaps organometallic chemistry and biochemistry, but also with medicinal chemistry, polymer chemistry, and materials science.
After Wöhler, Justus von Liebig worked on the organization of organic chemistry, being considered one of its principal founders.
In 1856, William Henry Perkin, while trying to manufacture quinine, accidentally produced the organic dye now known as Perkin's mauve. His discovery, made widely known through its financial success, greatly increased interest in organic chemistry.
A crucial breakthrough for organic chemistry was the concept of chemical structure, developed independently in 1858 by both Friedrich August Kekulé and Archibald Scott Couper. Both researchers suggested that tetravalent carbon atoms could link to each other to form a carbon lattice, and that the detailed patterns of atomic bonding could be discerned by skillful interpretations of appropriate chemical reactions. (2025). 9789385998898, Medtech (Scientific International, reprint of revised 4th edition, Macmillan, 1998). ISBN 9789385998898
The era of the pharmaceutical industry began in the last decade of the 19th century when the German company, Bayer, first manufactured acetylsalicylic acid—more commonly known as aspirin.Roberts, Laura (7 December 2010) History of Aspirin. The Telegraph By 1910 Paul Ehrlich and his laboratory group began developing arsenic-based arsphenamine (Salvarsan) as the first effective medicinal treatment of syphilis, and thereby initiated the medical practice of chemotherapy. Ehrlich popularized the concepts of "magic bullet" drugs and of systematically improving drug therapies. His laboratory made decisive contributions to developing antiserum for diphtheria and standardizing therapeutic serums.
Early examples of organic reactions and applications were often found because of a combination of luck and preparation for unexpected observations. The latter half of the 19th century however witnessed systematic studies of organic compounds. The development of synthetic indigo is illustrative. The production of indigo from plant sources dropped from 19,000 tons in 1897 to 1,000 tons by 1914 thanks to the synthetic methods developed by Adolf von Baeyer. In 2002, 17,000 tons of synthetic indigo were produced from .Steingruber, Elmar (2004) "Indigo and Indigo Colorants" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim.
In the early part of the 20th century, and were shown to be large organic molecules, and petroleum was shown to be of biological origin.
The multiple-step synthesis of complex organic compounds is called total synthesis. Total synthesis of complex natural compounds increased in complexity to glucose and terpineol. For example, cholesterol-related compounds have opened ways to synthesize complex human hormones and their modified derivatives. Since the start of the 20th century, complexity of total syntheses has been increased to include molecules of high complexity such as lysergic acid and vitamin B12. (1996). 9783527292318, Wiley. ISBN 9783527292318
The discovery of petroleum and the development of the petrochemical industry spurred the development of organic chemistry. Converting individual petroleum compounds into types of compounds by various chemical processes led to organic reactions enabling a broad range of industrial and commercial products including, among (many) others: plastics, synthetic rubber, organic adhesives, and various property-modifying petroleum additives and Catalysis.
The majority of chemical compounds occurring in biological organisms are carbon compounds, so the association between organic chemistry and biochemistry is so close that biochemistry might be regarded as in essence a branch of organic chemistry. Although the history of biochemistry might be taken to span some four centuries, fundamental understanding of the field only began to develop in the late 19th century and the actual term biochemistry was coined around the start of 20th century. Research in the field increased throughout the twentieth century, without any indication of slackening in the rate of increase, as may be verified by inspection of abstraction and indexing services such as BIOSIS Previews and Biological Abstracts, which began in the 1920s as a single annual volume, but has grown so drastically that by the end of the 20th century it was only available to the everyday user as an online electronic database.Allan, Barbara. Livesey, Brian (1994). How to Use Biological Abstracts, Chemical Abstracts and Index Chemicus. Gower.
Organic compounds were traditionally characterized by a variety of chemical tests, called "wet methods", but such tests have been largely displaced by spectroscopic or other computer-intensive methods of analysis.Shriner, R.L.; Hermann, C.K.F.; Morrill, T.C.; Curtin, D.Y. and Fuson, R.C. (1997) The Systematic Identification of Organic Compounds. John Wiley & Sons, Listed in approximate order of utility, the chief analytical methods are:
Traditional spectroscopic methods such as infrared spectroscopy, optical rotation, and UV/VIS spectroscopy provide relatively nonspecific structural information but remain in use for specific applications. Refractive index and density can also be important for substance identification.
Nonsystematic nomenclature is simpler and unambiguous, at least to organic chemists. Nonsystematic names do not indicate the structure of the compound. They are common for complex molecules, which include most natural products. Thus, the informally named lysergic acid diethylamide is systematically named (6a R,9 R)- N, N-diethyl-7-methyl-4,6,6a,7,8,9-hexahydroindolo-4,3- fg quinoline-9-carboxamide.
With the increased use of computing, other naming methods have evolved that are intended to be interpreted by machines. Two popular formats are SMILES and InChI.
As the p Ka (aka basicity) of the molecular addition/functional group increases, there is a corresponding dipole, when measured, increases in strength. A dipole directed towards the functional group (higher p Ka therefore basic nature of group) points towards it and decreases in strength with increasing distance. Dipole distance (measured in ) and Steric effects towards the functional group have an intermolecular and intramolecular effect on the surrounding environment and pH level.
Different functional groups have different p Ka values and bond strengths (single, double, triple) leading to increased electrophilicity with lower p Ka and increased nucleophile strength with higher p Ka. More basic/nucleophilic functional groups desire to attack an electrophilic functional group with a lower p Ka on another molecule (intermolecular) or within the same molecule (intramolecular). Any group with a net acidic p Ka that gets within range, such as an acyl or carbonyl group is fair game. Since the likelihood of being attacked decreases with an increase in p Ka, acyl chloride components with the lowest measured PKa values are most likely to be attacked, followed by carboxylic acids (p Ka = 4), thiols (13), malonates (13), alcohols (17), aldehydes (20), nitriles (25), esters (25), then amines (35). Amines are very basic, and are great nucleophiles/attackers.
Both saturated (alicyclic) compounds and unsaturated compounds exist as cyclic derivatives. The most stable rings contain five or six carbon atoms, but large rings (macrocycles) and smaller rings are common. The smallest cycloalkane family is the three-membered cyclopropane ((CH2)3). Saturated cyclic compounds contain single bonds only, whereas aromatic rings have an alternating (or conjugated) double bond. do not contain multiple bonds, whereas the and the do.
Heterocycles are commonly found in a wide range of products including aniline dyes and medicines. Additionally, they are prevalent in a wide range of biochemical compounds such as alkaloids, vitamins, steroids, and nucleic acids (e.g. DNA, RNA).
Rings can fuse with other rings on an edge to give polycyclic compounds. The purine nucleoside bases are notable polycyclic aromatic heterocycles. Rings can also fuse on a "corner" such that one atom (almost always carbon) has two bonds going to one ring and two to another. Such compounds are termed spiro compound and are important in several .
Two main groups of polymers exist: synthetic polymers and . Synthetic polymers are artificially manufactured, and are commonly referred to as plastic."industrial polymers, chemistry of." Encyclopædia Britannica. 2006 Biopolymers occur within a respectfully natural environment, or without human intervention.
The basic reaction types are: addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions and Redox. An example of a common reaction is a substitution reaction written as:
where X is some functional group and Nu is a nucleophile.
The number of possible organic reactions is infinite. However, certain general patterns are observed that can be used to describe many common or useful reactions. Each reaction has a stepwise reaction mechanism that explains how it happens in sequence—although the detailed description of steps is not always clear from a list of reactants alone.
The stepwise course of any given reaction mechanism can be represented using arrow pushing techniques in which curved arrows are used to track the movement of electrons as starting materials transition through intermediates to final products.
Strategies to design a synthesis include retrosynthesis, popularized by E.J. Corey, which starts with the target molecule and splices it to pieces according to known reactions. The pieces, or the proposed precursors, receive the same treatment, until available and ideally inexpensive starting materials are reached. Then, the retrosynthesis is written in the opposite direction to give the synthesis. A "synthetic tree" can be constructed because each compound and also each precursor has multiple syntheses.
Organic synthesis
Synthetic organic chemistry is an applied science as it borders engineering, the "design, analysis, and/or construction of works for practical purposes".9780128007204 . ISBN 9780128007204 Organic synthesis of a novel compound is a problem-solving task, where a synthesis is designed for a target molecule by selecting optimal reactions from optimal starting materials. Complex compounds can have tens of reaction steps that sequentially build the desired molecule. The synthesis proceeds by utilizing the reactivity of the functional groups in the molecule. For example, a carbonyl compound can be used as a nucleophile by converting it into an enolate, or as an electrophile; the combination of the two is called the aldol reaction. Designing practically useful syntheses always requires conducting the actual synthesis in the laboratory. The scientific practice of creating novel synthetic routes for complex molecules is called total synthesis.
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