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Sugar Chemistry

Discussion in 'MCAT Study Question Q&A' started by BlackSails, May 11, 2008.

  1. BlackSails

    BlackSails 2+ Year Member

    Apr 4, 2007
    Is there any good way to remember kilani-fischer synthesis and wohl degradation?
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  3. Big Lance

    Big Lance Junior Member 10+ Year Member

    Jan 27, 2004
    (sorry, no answer to your question)
    but....graduating med school soon(T minus 20 days) and I have no idea what the crap this post is referring too...what is the world coming too????????????????
  4. physics junkie

    physics junkie 5+ Year Member

    Nov 20, 2006
    99% chance this won't show up. The o chem section on the MCAT was cut down to 1 passage with 7 questions on the jan 25th test. Not sure how it was for april.
  5. BerkReviewTeach

    BerkReviewTeach Company Rep & Bad Singer Exhibitor 10+ Year Member

    May 25, 2007
    SDN Exhibitor
    I'll take that bet for Fisher-Kiliani synthesis at 99:1 odds. :)

    Sure, organic chemistry has been reduced on the MCAT this year (so the SDN feedback makes it seem), but that particular process has bio-applicability and has been tested before. Given that AAMC recycles passages (assuming they choose passages that have well established curves as their comments would indicate), there is a slightly better than 1% chance it will show. Let me have a standing 99:1 bet on every MCAT for the next three years and I'll win at least once in sixty-something MCATs.
  6. unsung

    unsung 10+ Year Member

    Mar 12, 2007
    Heh, I just studied this for my final... not that it showed up on the test! I remember Kiliani-Fischer synthesis in 3 steps:

    1. nitrile attacks
    2. hydrogenate to make imine (w/ poisoned catalyst!)
    3. acid hydrolysis of imine gives acid

    It's easy to remember that it starts with a nitrile, 'cuz really how many ways of adding a C to an aldehyde do we know? The hard part for me is remembering that a nitrile can be converted to an imine through hydrogenation. And to prevent it going too far, we have to use BaSO4 to poison the H2/Pd combo. Then, imines easily convert to carbonyl groups.

    So, that's not really a mnemonic or anything. I don't know what Wohl degradation is... we only learned Ruff degradation.
  7. BlackSails

    BlackSails 2+ Year Member

    Apr 4, 2007
    It actually did show up on mine. We had to make both D-tetroses from D-glyceraldehyde, and then figure out which stuctue was which sugar.

    Grignard, Wittig, Carbon monoxide can probably add to the carbonyl.

    They do the same thing. For Wohl, you make an oxime, and then basically do Kiliani Fischer in reverse.

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