Provide the structure of the imine produced from the following reaction

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Provide the structure of the imine produced from
the following reaction
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Protonate, and go to town. . . Or Attack and go
to town. . .
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Addition of Alcohol
(H and R on the C)
(2 R groups on the C)
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Mechanism

• Must be acid-catalyzed.
• Adding H to carbonyl makes it more reactive with
  weak nucleophile, ROH.
• Hemiacetal forms first, then acid-catalyzed loss
  of water, then addition of second molecule of ROH
  forms acetal.
• All steps are reversible.

Protonate, and go to town. . .
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Mechanism for Hemiacetal
Hemiacetal or hemiketal
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Hemiacetal to Acetal
Hemiacetal or hemiketal
Acetal or Ketal
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Cyclic Acetals

• Addition of a diol produces a cyclic acetal.
• Sugars commonly exist as acetals or hemiacetals.

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Acetals as Protecting Groups

• Hydrolyze easily in acid, stable in base.
• Aldehydes more reactive than ketones.

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Selective Reaction of Ketone

• React with strong nucleophile (base)
• Remove protective group.

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X
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D-glucose is a monosaccharide I am sure you have
all heard about. Its Fischer projection is
shown below.   The aldehyde at position A
reacts with the hydroxyl group at position B to
give the ring structure shown here.  
Circle the hemi-acetal portion of the D-glucose
ring shown above
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Point Down
Point up
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When a small amount of acid is present, the
hemi-acetal portion of the above molecule reacts
with another alcohol to form what biochemists
call a glycoside. Quite often this alcohol is
one of the alcohol groups on another
monosaccharide to form di-, tri-, or
polysaccharides. In fact, glycosides formed by
adding several glucose rings together make either
starch or cellulose. But, lets keep your task
simple. Show the glycoside formed from the
reaction of a-D-glucose with methanol.  
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Disaccharide
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Trisaccharide
Starch