Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself is mainly of theoretical interest but many of its derivatives are of commercial or biological significance.
Despite its explosive nature, cyclopropane was used as a clinical anesthetic from the 1930s through the 1980s. It is an important precursor in the biosynthesis of plant hormones, and in the chemical synthesis of insecticides.
Cyclopropane was discovered in 1881 by August Freund, who also proposed the correct structure for the substance in his first paper. Freund treated 1,3-dibromopropane with sodium, causing an intramolecular Wurtz reaction leading directly to cyclopropane. The yield of the reaction was improved by Gustavson in 1887 with the use of zinc instead of sodium. Cyclopropane had no commercial application until Henderson and Lucas discovered its anaesthetic properties in 1929; industrial production had begun by 1936. In modern anaesthetic practice, it has been superseded by other agents.
Cyclopropane was introduced into clinical use by the American anaesthetist Ralph Waters who used a closed system with carbon dioxide absorption to conserve this then-costly agent.
Cyclopropane is a relatively potent, non-irritating and sweet smelling agent with a minimum alveolar concentration of 17.5% and a blood/gas partition coefficient of 0.55. This meant induction of anaesthesia by inhalation of cyclopropane and oxygen was rapid and not unpleasant. However at the conclusion of prolonged anaesthesia patients could suffer a sudden decrease in blood pressure, potentially leading to cardiac dysrhythmia: a reaction known as "cyclopropane shock". For this reason, as well as its high cost and its explosive nature, it was latterly used only for the induction of anaesthesia, and has not been available for clinical use since the mid 1980s.
Cylinders and flow meters were coloured orange.
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In organic chemistry, ring strain is a type of instability that exists when bonds in a molecule form angles that are abnormal. Strain is most commonly discussed for small rings such as cyclopropanes and cyclobutanes, whose internal angles are substantially smaller than the idealized value of approximately 109°. Because of their high strain, the heat of combustion for these small rings is elevated. Ring strain results from a combination of angle strain, conformational strain or Pitzer strain (torsional eclipsing interactions), and transannular strain, also known as van der Waals strain or Prelog strain.
In chemistry, a molecule experiences strain when its chemical structure undergoes some stress which raises its internal energy in comparison to a strain-free reference compound. The internal energy of a molecule consists of all the energy stored within it. A strained molecule has an additional amount of internal energy which an unstrained molecule does not. This extra internal energy, or strain energy, can be likened to a compressed spring.
Cyclopropane is the cycloalkane with the molecular formula (CH2)3, consisting of three methylene groups (CH2) linked to each other to form a ring. The small size of the ring creates substantial ring strain in the structure. Cyclopropane itself is mainly of theoretical interest but many of its derivatives are of commercial or biological significance. Despite its explosive nature, cyclopropane was used as a clinical anesthetic from the 1930s through the 1980s.
This course introduces modern computational electronic structure methods and their broad applications to organic chemistry. It also discusses physical organic concepts to illustrate the stability and
Explores strain and stabilization in organic molecules, discussing steric crowding, branching interactions, and hyperconjugation.
Explores the organic compounds in strawberries, covering their structure, aroma, and sweetness, as well as diastereoisomers and molecular conformations.
Explores bond dissociation energies as a measure of radical stability and the impact of substituents on BDE values.
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This review describes the development of enantioselective methods for the ring opening of cyclopropanes. Both approaches based on the reaction of nonchiral cyclopropanes and (dynamic) kinetic resoluti
2020
Amino alcohols, cyclopropanes and nitriles are privileged structural motifs found in the scaffold of natural products and bioactive compounds. In addition, they are versatile building blocks in organi
EPFL2021
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A Cp*Rh(III)-catalyzed C-H/C-C bond activation sequence of cyclopropyl hydroxamates has been developed. The three-component process allows trapping of the intermediate rhodacycle with diazomalonates a