Carbohydrates Flashcards
Aldonic Acids
Carbon 1 CHO group oxidized into COOH
Aldaric Acids
Carbon 1 CHO group + Terminal Carbon CH2OH both oxidized into COOH
Uronic Acids
Terminal CH2OH group oxidized into COOH
Alditol
Carbon 1 CHO group reduced into CH2OH
What is used to make aldonic acids?
- Bromine water - Goes from red to colourless
- Tollen’s Reagent - Forms silver mirror
- Benedict’s/Fehling’s Reagent - Forms red solid (Cu2O)
What is used to make aldaric acids?
Nitric acid
* Oxidizes aldehyde
* Oxidizes primary alcohols
* Cannot oxidize secondary alcohols
What is used to make uronic acids?
Enzymes
What is used to make alditols?
Reducing agents
1. Catalytic hydrogenation (H2/metal)
2. NaBH4
3. LiAlH4
Reducing Sugar
- Aldehyde (Aldoses only)
- Hemiacetals
Epimer vs. Diastereomer
Epimers
* Are diastereomers
* Differ in configuration only at 1 stereocenter
What type of reaction is an aldol reaction?
Nucleophilic addition reaction
What conditions does epimerization occur?
Basic
What conditions does isomerization occur?
Basic
What reactions are present in epimerizations/isomerizations?
Tautomerizations
What does keto-enol stand for?
Ketone
Alkene
Alcohol
Acylation vs. Acetylation vs. Esterification
Acylation
* Adding acyl groups
Acetylation
* Adding acetyl groups (COCH3)
Esterification
* Forming esters
Thus a reaction can be all 3 if you use acetic anhydride (acetyl group is an acyl group)
Acylation of OH groups occurs under what conditions?
Acidic conditions
What is alkylation of OH groups done with?
Alkyl halides in an SN2 reaction
* Polar aprotic solvents (DMSO)
* Base (NaH)
Alkylation of OH groups is done under what conditions?
Basic conditions
What is the difference betweeen Killiani-Fischer and Modern Synthesis?
- Fewer steps in modern
- Fewer toxic reagents in modern
Modern reduces nitrile to imine
Killiani-Fischer requires forming lactones, salts, converting back to lactone before reducing to aldehyde
