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C3H6, a gaseous hydrocarbon. It is a cyclic alkane, its three carbon atoms being joined together in a ring. The angle between successive carbon-carbon bonds in the ring is only 60°, much less than that between successive carbon-carbon bonds in a normal open-chain alkane; the cyclopropane molecule is thus said to be "strained." Many reactions of cyclopropane involve breaking one of the carbon-carbon bonds in the ring, which opens the ring and relieves the strain. Cyclopropane is prepared commercially by the reaction of 1,3-dichloropropane with zinc. It is a potent inhalation anesthetic, that once enjoyed wide use, but has been replaced by less combustible gases. Cyclopropane allowed the transport of more oxygen to the tissues than did other common anesthetics and also produced greater skeletal muscle relaxation. It is not irritating to the respiratory tract. Because of the low solubility of cyclopropane in the blood, postoperative recovery was usually rapid but nausea and vomiting were common. See anesthesiaanesthesia
[Gr.,=insensibility], loss of sensation, especially that of pain, induced by drugs, especially as a means of facilitating safe surgical procedures. Early modern medical anesthesia dates to experiments with nitrous oxide (laughing gas) by Sir Humphry Davy of England
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(also trimethylene), an alicyclic hydrocarbon having the structural formula

Cyclopropane is a colorless gas with a boiling point of –32.8°C and a density of 0.720 g/cm3 at –79°C. Insoluble in water, it is soluble in alcohol and ether.

Cyclopropane is the first member of the homologous series of cycloparaffins. Its trimethylene ring, however, is characterized by reactions of the C═C double bond; for example, it forms 1,3-dibromopropane (BrCH2CH2CH2Br) in its reaction with bromine. The cyclopropane ring is easily broken because it is strained. Nevertheless, in contrast to olefins, cyclopropane does not react with potassium permanganate and ozone at 20°C. Cyclopropane and hydrocarbons containing the cyclopropane ring may be obtained by reacting zinc dust with derivatives that have two halogens attached at the 1 and 3 positions. They may also be obtained by other methods, including the joining of carbenes to olefins.

Cyclopropane and its derivatives are of great theoretical interest; for example, it has been discovered that compounds containing the cyclopropenyl cation have aromatic properties. The cyclopropane ring is found in biologically important natural compounds (seePYRETHRINS). Cyclopropane itself is used as an anesthetic.


(organic chemistry)
C3H6 A colorless gas, insoluble in water; used as an anesthetic.
References in periodicals archive ?
Finally, the calculated strain energies are compared to those of cyclopropane, cyclobutane, oxaziridine, azetidine, phosphetane, diazetidine, and diphosphetane.
Prior to the development of fluorinated agents, the only practical inhalational anaesthetics, apart from nitrous oxide, ethylene and cyclopropane, (and a few others of short-lived popularity like acetylene), were non-halogenated ethers and chlorinated hydrocarbons such as chloroform, trichloroethylene and ethyl chloride.
It's true that some were using ethylene and acetylene, ethyl chloride and cyclopropane, di-vinyl ether and trichloroethylene, but none of these was ideal.
We demonstrate the utility of this microarray by testing it against three hepatotoxins: 3-methylcholanthrene (3-MC), Aroclor 1254, and cyclopropane carboxylic acid (CPCA).
Investigation revealed that cyclopropane was present and, once isolated, it was tested, presuming it to be the toxic compound.
Initially several members of the research staff were safely anaesthetised with cyclopropane and a demonstration was arranged for the anaesthetic department.
After further animal testing there, the first surgical anaesthetic with cyclopropane was given by Dr Waters on August 19, 1930 for an appendicectomy.
Unfortunately this research coincided with the onset of the worldwide Depression and cyclopropane was expensive.
Nitrous oxide, chloroform, trichlorethylene, ethyl chloride, ether and cyclopropane were available, each with its own limitations.
It was administered together with intravenous barbiturates, nitrous oxide, ether, cyclopropane and, in a few instances, with insufficient spinal anaesthesia.
In this research project, we propose a number of uncommon and challenging reactions making use of donor-acceptor cyclopropanes.