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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 It is a potent inhalation anesthetic, that once enjoyed wide use, but has been replaced by less combustible gases.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 ?
By providing a xanthate next to the cyclopropane ring at the C-3 position, free radical generation with [Bu.
Sun Frost recently made a demonstration model using cyclopropane as the coolant; German and Japanese manufacturers are also experimenting with alternatives to Freon.
Kopko cited such possibilities as dimethyl ether and cyclopropane compounds.
3r) -3- (2, 2 dibromovinyl) -2, 2 dimethyl cyclopropane carboxylate).
Notations 'Me', "OH' and 'cy' are, respectively, methyl, hydroxyl, cyclopropane groups, and notations T and 'a' are, respectively, iso- and anteiso-branched fatty acids.
Incidence of PONV has decreased from 60% when ether and cyclopropane were used, to approximately 30% nowadays.
Chemical Class n (%) Definition of Chemical class (c) (a) Pyrethroid 189 Synthetic insecticides (77) (typically cyclopropane carboxylates) structurally similar to pyrethrins, which are naturally occurring insecticidal compounds.
TABLE 3 Triggering agents Agent Anaesthetics (total=329) Sevoflurane 134 Isoflurane 87 Halothane 71 Desflurane 20 Enflurane 7 Trichloroethylene 2 Cyclopropane 6 Suxamethonium 2 Suxamethonium + inhalational 47 TABLE 4 Intraoperative recordings No.
umbrella tree had 11 different fatty acids that included saturated (12:0, 16:0 and 18:0), unsaturated (11 methyl 18:1 w7c and 18:1 w7c), hydroxyl (10:0 3-OH, 12:0 2OH and 12:0 3OH), cyclopropane (17: CYCLO) and two Sum in Features (3, 7) (Table VII).
Comparisons are made between the conventional strain energy of cyclopropane and cyclobutane, methylcyclobutane, and the dimethyl-substituted cyclobutanes.