Cyclopropane-oxygen mixture

A cyclopropane-oxygen mixture can be used as an anesthetic. If the partial pressures of cyclopropane and oxygen are 140. torr and 560. torr, respectively what is the ratio of the number of moles of cyclopropane to the number of moles of oxygen in this mixmre What is the corresponding ratio of molecules ... 

An anesthetic gas, cyclopropane has a rapid onset of action and may be used for induction and maintenance of anesthesia Skeletal muscle relaxation is produced with full anesthetic doses. Cyclopropane is supplied in orange cylinders. Disadvantages of cyclopropane are difficulty in detecting the planes of anesthesia, occasional laryngospasm, cardiac arrhythmias, and postanesthesia nausea, vomiting, and headache Cyclopropane and oxygen mixtures are explosive, which limits the use of this gas anesthetic. 

In qualitative terms, the rearrangement reaction is considerably more efficient for the oxime acetate 107b than for the oxime ether 107a. As a result, the photochemical reactivity of the oxime acetates 109 and 110 was probed. Irradiation of 109 for 3 hr, under the same conditions used for 107, affords the cyclopropane 111 (25%) as a 1 2 mixture of Z.E isomers. Likewise, DCA-sensitized irradiation of 110 for 1 hr yields the cyclopropane derivative 112 (16%) and the dihydroisoxazole 113 (18%). It is unclear at this point how 113 arises in the SET-sensitized reaction of 110. However, this cyclization process is similar to that observed in our studies of the DCA-sensitized reaction of the 7,8-unsaturated oximes 114, which affords the 5,6-dihydro-4//-l,2-oxazines 115 [68]. A possible mechanism to justify the formation of 113 could involve intramolecular electrophilic addition to the alkene unit in 116 of the oxygen from the oxime localized radical-cation, followed by transfer of an acyl cation to any of the radical-anions present in the reaction medium. 

Cyclopropane doivatives of various structure types are involved in electron transfer-induced oxygenation reactions. For example, the photoreaction of 9,10-di-cyanoanthracene with 1,2-diarylcyclopropanes generates a mixture of cis- and... 

Numerous studies of the photoreactions of dihydrofurans have been described. On irradiation 2,3-dihydrofurans are known to undergo conversion to acylcyclopropanes by a pathway involving initial carbon-oxygen bond homolysis. The /i-enamino ester (162), for example, affords the cyclopropane (163) on triplet-sensitized irradiation.138 Similar transformations have been observed in 2,2,4-triacyl-2,3-dihydrofurans,139 and a synthesis of a cis-trans mixture of chrysanthemum carboxylic acid has been accomplished in this way.140 The conversion of the 2-thiazolines(164) to the iV-alkenylthio-amides (165) presumably involves an analogous carbon-sulfur bond homolysis, followed by a 1,2-hydrogen shift in the resulting biradical (166).141... 

What is the mole fraction oxygen in an anesthesia mixture that contains 2 moles of oxygen for every 0.5 moles of cyclopropane ... 

With regard to the preparation of the Zn/Cu couple, several methods have been developed Dibromomethane may be used instead of diiodomethane when a specifically prepared Zn/Cu couple is applied . The use of Zn/Ag couple often gives better results . Ultrasound irradiation of the reaction mixture has been shown to facilitate the reaction . The cyclopropanation of alkenes with diiodomethane and diethylzinc can be carried out in hydrocarbon solvents and is particularly suitable with easily polymerizable olefins such as vinyl ethers . It has been reported that molecular oxygen remarkably promotes the reaction of diiodomethane with diethylzinc and substantially increases the yield of the adducts . A convenient modification which avoids the handling of pyrophoric diethylzinc has been reported . In reaction of olefins which are sensitive to the unavoidably produced zinc iodide (the Lewis acid), the addition of one equivalent of dimethoxyethane (DME) to the solvent has been recommended . Zinc iodide is then precipitated as the 1 1 DME complex as it is formed. Zinc salts, which often complicate the workup of the reaction mixture, can also be removed as precipitates by the addition of pyridine prior to the workup . ... 

The free radical chain mechanism of the addition reaction of bromodicyanomethane to alkenes has been corroborated by inhibition experiments with oxygen and t-butylcatechol. The mechanism of equation 66 has been postulated. The ring-closure of the 2-bromoalkylmalononitriles gives rise to mixtures of cis- and trans-cyclopropanes. 

The fact that cinnamyl methyl ether underwent cyclopropanation under similar conditions to afford the corresponding cyclopropane as an almost racemic mixture indicates that the free hydroxy group is necessary for producing an effective chiral environment. This can presumably take place through complexation as a zinc alkoxide. The authors propose that a trinuclear zinc complex 89, in which both the oxygen atom of a zinc alkoxide and iodine atom of iodo-methylzinc contribute to the Lewis character, must be close to the transition structure of the reaction. This might account also for the distinct enantioselectivity between the allylic alcohol and its methyl ether. 

Silver(I) ions generally catalyze the rearrangement of strained polycyclic systems which contain cyclopropane groups. It was shown, however, that silver(I) cleaved one or two of the strained cyclopropane bonds in quadricyclane (13) in an oxidation reaction. A complex mixture was obtained on treatment of quadricyclane (13) with silver(I) trifluoroacetate. The main addition products contained two oxygen functions and one intact cyclopropane ring." °... 

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