Chem Basis: Steroids 2

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  1. How do you know if a group on a steroid is alpha or beta?
    • Alpha = dotted line = opposite side as angular methyls
    • Beta = Solid line = same side as angular methyls
  2. What groups determine the top (Beta) face of the steroid?
    The C13 and C10 methyls (must be straight lines)
  3. If the C5-H is alpha, the A/B ring fusion is in what conformation?
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    • Trans (coplanar)
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    What is this nucleus called, and how many carbons does it have?
    Estrane = 18 carbons
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    What is this nucleus called, and how many carbons does it have?
    Androstane = 19 carbons
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    What is this nucleus called, and how many carbons does it have?
    Pregnane = 21 carbons
  7. The position of the double bond is critical, how is it designated in the name of the steroid?
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    • If the double bond joins consecutively numbered carbon atoms:
    • Specify only the lower numbered carbon involved

    • If the double bond joins consecutively numbered carbon atoms:
    • Both carbons must be indicated
    • higher numbered carbon is contained in parentheses

    Also can use Greek capital letter Delta with superscripted position numbers
  8. How do you name a steroid?
    • 1. Identify the sterid nucleus
    • 2. Identify specific functional groups.
    • 3. Designate the alpha/beta stereochemistry of each group
    • 4. Indicate double bonds in the name (i.e pregnene or pregnadiene)
    • 5. Indicate the position of the double bond.
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    Name the bond and nucleus of this structure:
    • 4-Pregnene
    • OR
    • Delta4-Pregnene
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    Name the bond and nucleus of this structure:
    • 5(10)-Estrene
    • OR
    • Delta 5(10)-Estrene
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    Name the bond and nucleus of this structure:
    • 1,3,5(10)-Estriene
    • OR
    • 1,3,5(10)-Estriene
  12. What does the endine –ene mean (i.e. pregnene)?
    One double bond
  13. What does the endine –diene mean (i.e. pregnadiene)?
    Two double bonds
  14. What does the endine –triene mean (i.e. pregnatriene)?
    Three double bonds
  15. All corticosteroids are derivatives of what?
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    • Pregnane
    • (contain the C21 carbon sterid nucleus)
  16. Structural modifications of the steroid hormones have been made resulting in modification of their pharmacokinetic and pharmacodynamic properties. These modifications have been done to:
    • 1. Increase or modify biological activity
    • 2. Increase oral activity and duration of action
    • 3. Effect a separation of biological action
    • 4. Obtain better solubility properties
  17. Natural corticoids are all derivatives of:
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    • Delta 4-21-hydroxypregnen-3,20-dione
  18. Which face of the corticoid structure is mist critical for binding to the glucocorticoid receptor?
    Beta face
  19. Which face of the corticoid structure is mist critical for binding to the mineralcorticoid receptor?
    Alpha face
  20. What type of bonding will be most critical at the glucocorticoid receptor?
    Hydrogen bonding
  21. Is the Pregnane nucleus essential for corticosteroid activity?
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    • Yes
  22. Do derivatives of estrange or androstene have corticosteroid activity?
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    No
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    Is this group essential for corticosteroid action, what is it called?
    • Yes
    • 17 Beta –glycolyl or Ketol group
    • (Must be free)
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    Is this structure essential for mineralcorticoid or glucocorticoid activity?
    Both
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    This group is essential, what SAR changes can be made to this group without deactivating the compounds corticoid activity?
    • C21-OH replacement with F
    • Cl can also be used, but only active topically at glucocorticoid receptors
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     Is this group essential for corticoid activity, what is its name?
    • Yes
    • Delta 4- 3-one A ring
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    What would happen if you reduced the =O on this ring?
    Inactivation
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     What would happen if you reduced the double bond on this structure?
    Inactivation
  29. What is the activity of 3 alpha-hydroxysteroid dehydrogenase?
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    • Reduces the steroid 3- keto group to a 3 alpha-OH
  30. What is the activity of 5 Beta reductase?
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    • Reduces the 4-5 double bond to a 5 Beta-H
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    What steroid characteristics are required for this metabolic inactivating reaction to take place?
    Free C21-OH (cannot be an ester)
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    What is this functional group called?
    Dihydroxyacetone
  33. What reaction does this 17 alpha-OH facilitate?
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    • D ring oxidation
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    Why do most Glucocorticoids have a 17 alpha-OH group?
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    • Enhances Glucocorticoid receptor affinity and potency
  35. Generally speaking, adding Oxygen containing function groups to a corticoid will have what effect on Glucocorticoid and Mineralcorticoid activity?
    • Increase Glucocorticoid activity by enhancing H bonding
    • Decrease Mineralcorticoid activity
  36. Image UploadAdding an 11B-OH to this molecule (at the point indicated) will affect the activity in what way?
    • Best functional group for enhancing Glucocorticoid action
    • H-donor at GC receptor
    • Critical for potent GC acitivty
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    Adding an 11-keto to this molecule (at the point indicated) will affect the activity in what way?
    • H accepting, but retains activity
    • Rapidly and reversibly reduced to 11B-OH in vivo by 11B-hydroxysteroid dehydrogenase
    • 11B-OH is ideal for potent GC activity
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    What characteristics does a 17 alpha OH impart to this molecule?
    • Enhanced GC activity
    • Synergistic activity with 11B-OH
    • Decreased DOA due to increased C17 oxidation
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    A molecule with both an 11B-OH and 17a-OH will have what activity profile?
    • Better activity at GC receptors than either functional group alone (synergistic activity)
    • Greater C17 oxidation due to the 17a-OH
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    If you treat this molecule with acid, how will it affect this group?
    No effect, protected by angular methyls (at C13 and C10)
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    If you treat this molecule with acid, how will it affect this group?
    • Sluggishly esterify
    • Slow reaction due to protection by the D ring and 17B ketol group
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    If you treat this molecule with acid, how will it affect this group?
    Readily esterify as it is the least hindered OH group
Author:
kyleannkelsey
ID:
268421
Card Set:
Chem Basis: Steroids 2
Updated:
2014-03-30 16:19:41
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Chem Basis Steroids
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Chem Basis: Steroids 2
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Chem Basis: Steroids 2
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