Knowledge Bank

There has been some interest from the medical community in using a portable Fourier-transform microwave (FTMW) spectometer as a continuous, real-time monitor for the level of an anesthetic that a patient is respiring during surgical procedures. A number of the anesthetics currently in use are volatile halogenated ethers which makes them quite amenable to analysis via the FTMW technique. In order to demonstrate that FTMW spectroscopy can be used for this application, the rotational spectrum of the anesthetic desflurane (1, 2, 2, 2 tetrafluoroethyl difluoromethyl ether, $CF3CFHOCF2H$) has been observed and analyzed via FTMW spectroscopy. This chemical is similar to E-245, an alternative refrigerant, (2, 2, 2 trifluoroethyl difluoromethyl ether, $CF3CH2OCF2H$) which was reported on in a previous $meeting2$. Unlike E-245 which has a symmetry plane, desflurane is chiral and has no symmetry. Spectroscopically it is a more challenging problem since all three selection rules can occur. Furthermore the conformational structure is important since the pure enantiomers have been shown to have different $effectivenessb$ which led to the suggestion that stereospecific binding between brain proteins and the anesthetic agent might occur. A comparision of the derived structure with the structure obtained using vibrational circular dichroism will be $made.c$