Chapter 4-1

No plane of symmetry the isomers of c3h4cl2 revisited

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Unformatted text preview: l2, Revisited Cl CH3 Cl Cl Cl Cl Cl Cl Cl Cl Cl CH2 Cl CH3 Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Racemic Mixtures H H3C H (E)-2-butene achiral HBr CH3 addi ti on r eacti on H3C H CH3 H H Br But do we get (R) or (S)? 2-bromobutane chiral We get both! CH3 H 50% Br CH3 Br H H3C H3C (S)-2-bromobutane 50% (R)-2-bromobutane A 50:50 mixture of 2 enantiomers is called a racemic mixture or a racemate. Racemic Mixtures In Medicine CH3 HO O CH3 CH3 HO O CH3 CH3 CH3 (S)-ibuprofen (active) (R)-ibuprofen (inactive) O N O NH O H O N O NH O H O (R)-Thalidomide (analgesic) O (S)-Thalidomide (teratogenic) Prescribed worldwide from 1957-1961 for morning sickness and as a sleep aid Optical Rotation and Polarimetry randomly oriented light No light emitted monochromatic light source optical polarizer - only allows "horizontal" light to pass through optical polarizer - only allows "vertical" light to pass through Chiral molecules will rotate polarized light: randomly oriented light chiral material detector monochromatic light source optical polarizer - only allows "vertical" light to pass through optical polarizer - only allows "horizontal" light to pass through Optical Rotation and Polarimetry randomly oriented light chiral material d e te c to r monochromatic light source optical polarizer - only allows "vertical" light to pass through optical polarizer - only allows "horizontal" light to pass through The maximum signal will be optained if the second polarizer is rotat...
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This note was uploaded on 10/06/2010 for the course ES ES271 taught by Professor Machaut during the Spring '10 term at Colby.

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