Inhalant analgesic and anesthetic composition
United States Patent [1 1 Croix Apr. 22, 1975 INHALANT ANALGESIC AND ANESTHETIC COMPOSITION [75] Inventor:  
 [73] Assignee: Airco, Inc.. New York. N.Y.  
 [22] Filed: Oct. 9, 1973 [21] Appl. No.: 404.816  
 Related U.S. Application Data [62] Division of Ser. No. 314.222. Dec. 11. 1971. Pat. No.  
 Louise S. Croix, Summit, NJ.  
 [52] U.S. Cl. 260/614 F [51] Int. Cl C07c 43/00; C07c 43/12 [58] Field of Search 260/614 F [56] References Cited UNITED STATES PATENTS 2.066.905 l/l937 Booth 260/614 F OTHER PUBLICATIONS Larsen. Fluorine Chemistry Reviews 3. (1969). 38.  
 Primary E.\aminerl-loward T. Mars Attorney Agent. or Firm-Roger M. Rathbun; Edmund W. Bopp: H. Hume Mathews [57] ABSTRACT The present invention relates to the novel compound difluoromethyl dichlorofluoromethyl ether 1 Claim, No Drawings INHALANT ANALGESIC AND ANESTHETIC COMPOSITION This is a Division of application Ser. No. 314,222, filed Dec. 11, 1972, now [1.8. Pat. No. 3,806,602.  
  This invention relates to difluoromethyl dichlorofluoromethyl ether, its preparation and its use in producing analgesia and anesthesia in anestheticsusceptible, airbreathing mammals. This ether has the unusual property of causing strong analgesia at light anesthetic levels on such mammals.  
  The compound difluoromethyl dichlorofluoromethyl ether is represented by the following formula:  
 CHF- OCFCI This ether is normally a clear, colorless liquid with no significant odor. The compound has the following physical properties: b.p. 41C. at 760 mm.; vapor pressure 470 mm. at 25C.; specific gravity 1.49; and molecular weight 169. The compound is nonflammable, soda lime stable, and an analgesic and anesthetic for inhalation anesthetic-susceptible mammals.  
  Difluoromethyl dichlorofluoromethyl ether is readily miscible with other organic liquids including fats and oils, and has useful solvent properties, for example, as a solvent for fluorinatcd olefins and other fluorinatcd materials such as fluorowaxes. The ether can be used to prepare pastes and dispersions of such fluorinecontaining materials useful for coating and the like, and as degreasing agents.  
  The compound of the present invention can be prepared through the selective chlorination of direaction product CHF OCCI F can be readily separated from the reaction mixture by fractional distillation.  
 The following example illustrates the preparation of 5 difluoromethyl dichlorofluoromethyl ether.  
 EXAMPLE Calculated for (HF-,OCl-Ch: C, 14.2; H, 0.6; F, 33.7 Found: C, 13.9; H. 0.5; F, 33.8  
  In order to determine the usefulness of difluoromethyl dichlorofluoromethyl ether as an inhalation anesthetic in respirable mixtures containing a lifesupporting amount of oxygen, a series of tests were carried out on mice. The compound tested was at least 99.5% pure as determined by vapor phase chromatography.  
  Groups of five mice were placed in a jar and exposed to a concentration of 2.5 to 8% by volume of difluoromethyl dichlorofluoromethyl ether. The results of these tests were as follows:  
 maintenance. Rcspiration slowed. Brief cyanosis at start of recovery period.  
 10+ 111. to pain.  
 &#34;&#39;Analgcsia was measured by reaction to pain caused by clipping tail.  
 fluoromethyl monofluoromethyl ether (CHF OCH- F),  
 according to the following equation:  
  CHF OCH F C1 CHF OCFCI The starting material, difluoromethyl fluoromethyl ether (CHF OCH F), is a well known,  
 mono-- readily available material. The CHF OCH F is photo- The compound difluoromethyl dichlorofluoromethyl ether exhibits light or low potency general anesthetic properties in inhalation anesthetic-susceptible mammals, and thus its use is particularly desirable where control over the patient is desired. The compound is unusual in giving strong analgesia lasting well into the recovery period, with only minimal general anesthesia and very rapid recovery of walking. At full general anesthesia levels it depresses respiration, although recovery is still rapid. The compound is nonflammable and soda lime stable, and lends itself well to effective use as an inhalant analgesic and anesthetic in respirable mixtures containing life-supporting concentrations of oxygen.  
 The effective amounts of the CHF OCFCI to be employed depends upon the level of anesthesia to which the mammal is to be brought, the rate at which the anesthesia is to be induced, and the length of time over which anesthesia is to be maintained. Minor volume percentages of the ether compound of at least several percent, for example about 3 to preferably about 4 to 8%, can be used in respirable mixtures containing life-supporting amounts of oxygen. The person controlling the anesthesia can easily regulate the amount and gradually increase the amount until the desired plane of anesthesia is reached. By then monitoring the physical reactions of the mammal, as is the usual procedure, the duration and plane of anesthesia can be readily controlled. Lesser amounts of the ether compound can be employed along with oxygen where only an analgesic effect is desired.  
 It should be understood that the foregoing disclosure CHF OCFCI