Fisher Progection Formula

• Fischer projection formulas

  • a method for giving molecular chirality specifications in two dimensions.
  • a two-dimensional structural notation for showing the spatial arrangement of groups about chiral centers in molecules.
• • Carbon - a chiral center, is represented as

  the intersection of vertical and horizontal

  lines.

  • Functional groups of high priority will be

  written at top
• D and L system - used to designate the handedness of glyceraldehyde enantiomers


  D - right yung OH; L - left yung OH and magiging HO s’ya sa left kasi yung hydrogen ay hindi na pwede mag bond kaya yung O ang nasa malapit sa gitna

  A) L

  B) d

  
• D and L system

  A) cho

  B) cho

  C) ho

  D) h

  E) h

  F) oh

  G) ch2oh

  H) ch2oh

  
• Tetrahedral Arrangements

  - The four groups attached to the atom at the chiral

  center assume a tetrahedral geometry and it is

  governed by the following convention:

  • Vertical lines - from the chiral center

  represent bonds to groups directed INTO the

  printed page.

  • Horizontal lines - from the chiral center

  represent bonds to groups directed OUT of the

  printed page.
• The DL system - used to designate the

  handedness of glyceraldehyde enantiomers

  can be extended to other monosaccharides

  with more than one chiral center
• • Epimers - diastereomers whose molecules

  differ only in the configuration at one chiral

  center
• The DL system - used to designate the

  handedness of glyceraldehyde enantiomers

  can be extended to other monosaccharides

  with more than one chiral center

  The carbon chain is numbered starting at the

  carbonyl group end of the molecule, and the

  highest-numbered chiral center is used to

  determine D or L configuraton

  
• Two Types:

  Dextrorotatory - Chiral compound that rotates

  light towards right (clockwise; +)

  Levorotatory - Chiral compound that rotates

  light towards left (counterclockwise; -)
• Monosaccharides - are often classified by both

  their number of carbon atoms and their functional

  group.
• Aldohexose - six-carbon monosaccharide with

  an aldehyde functional group (6 carbons)

  Ketopentose - five-carbon monosaccharide with

  a ketone functional group (5 carbons)
• • D glucose - is the most abundant in nature

  and the most important from a human

  nutritional standpoint.

  
• D Fructose - is biochemically the most important ketohexose. It is also known as levulose and fruit sugar.

  
• d fructose is also known as - levulose and fruit sugar
• D-Galactose

  1.Milk sugar

  2.Synthesize in human

  3.Used to differentiate between blood types

  4.Six membered cyclic form

  
• D-Ribose

  1. Part of RNA

  2. Part of ATP

  3. Part of DNA

  4. Five membered cyclic form

  
• 2 forms of D-glucose:

  
  

  Alpha form: -OH of C1 and CH2OH of C5

  are on opposite sides

  Beta form: -OH of C1 and CH2OH of C5 are

  on same sides

  
  

  A cyclic monosaccharide containing a six-

  atom ring is called a pyranose, and one

  containing a five-atom ring is called

  furanose because their ring structures resemble the ring structures in the cyclic ethers pyran and furan respectively.

  
• 2 forms of d-glucose

  1. alpha form
  2. beta form