Carbohydrates Flashcards
where is the carbonyl bond for aldehydes?
C1
where is the carbonyl bond for ketones?
C2
how do you find out the number of OH groups in a monosaccharide?
OH = N - 1
- N = # of carbons
What is a tautomer?
two structures with the same atomic position, which differ only in the position of their H atoms and double bonds
what are constitutional isomers?
same molecular formula but different connectivity of their atoms
what is a chiral compound?
a mirror image of a structure that is non-superimposable
- carbon with 4 different constituents attached
what is a stereoisomer?
molecules that have the same molecular formula and the same connectivity of atoms but differ in the spatial arrangement (3D)
what are enantiomers?
a type of stereoisomer that are non-superimposable mirror images of each other
what are diastereomers?
Diastereomers are a type of stereoisomer that are not mirror images of each other and cannot be superimposed
where is carbon 1 labled from?
the carbon closests to the double bond
what classifies if a sugar is D or L?
if the chiral carbon furthest away from from the carbonyl group has it OH group on the right or left
right = D sugar
left = L sugar
what is the equation figure out the number of stereoisomers a compound has?
2 ^n
what is an empimer?
strucures that differ in configuration only around ONE carbon
what compounds form a hemiacetal?
alcohol + aldehyde
what is an anomeric carbon?
A carbon that goes from achiral to chiral following the transition to a cyclic structure
what kind of sugars will readily form ring structures? (how many carbons do they need)
Aldotetroses (4C) and higher
ketotetoses (4C) and higher
will a triose form a ring?
No, it must be at least 4C
what compounds form a hemiketal?
Alcohol + Ketone
how many C is furan? what type of ring does it form?
4C forming a 5-membered ring including oxygen
how many C is pyran? what type of ring does it form?
5C ring forming a 6-membered ring including oxygen
For a cyclic hemiacetal of an aldopentose pyranose ring explain:
1) what membered ring
2) where the carbonyl C would be
3) which C will attack the carbonyl
1) 5 C with a 6 membered ring
2) carbonyl on C1
3) C5 will attack
For a cyclic hemiacetal of an aldotetrose furanose ring explain:
1) what membered ring
2) where the carbonyl C would be
3) which C will attack the carbonyl
1) 4C - 5 membered ring
2) carbonyl on C1
3) C4 will attack
what is an anomer?
isomers that only differ at the anomeric carbon
when transposing fisher projections to geometric form, where is C1 / C2 located?
C1 is located on the right for aldoses
C2 is located on the right for ketoses
when transposing the fisher projection to geometric form where will the last carbon always be ?
the last carbon will always be a part of a CH2OH group
When transposing from the fisher projection to geometric form:
what direction are C numbered?
clockwise
When transposing from the fisher projection to geometric form:
where are groups on the right located when in a geometric form? and groups on the left?
below the plane of the ring
-above the plane for groups on the left
When transposing from the fisher projection to geometric form:
where is the CH2OH and OH group at C1/C2 for beta anomers?
CH2OH group at C5
OH at C1/C2 on the SAME side of the ring
When transposing from the fisher projection to geometric form:
where is the CH2OH and OH group at C1/C2 for alpha anomers?
CH2OH group at C5
OH at C1/C2 on OPPOSITE sides of the ring
when naming deoxy sugars, what does the placement of the number indicate? where is it most common to be put?
The number indicates the position where carbon is replaced
-commonly on C2,3 or 4
what is an amino sugar?
sugar molecules that have had their hydroxyl replaced by an amino groupx
how are alcohols formed from aldoses and ketoses? what sugar would form ribotol?
from the reduction of them to make sugar alcohol
ribotol is formed from the reduction of ribose
What major factors classifies a sugar as a reducing agent?
1) being an aldose (or a ketose that has gone through tautomerization to have carbonyl at C1)
2) must have a free anomeric carbon
3) having a linear form
what is an O-glycosidic bond?
a bond linking an anomeric carbon to the oxygen atom of a hydroxyl group
what are N/O glycosidic bonds?
formation of glycosidic bonds from the reaction of an anomeric carbon with:
1) Hydroxyl to form O-glycosidic
2) Nitrogen to form N-glycosidic
what type of bonds are present in glycogen?
alpha 1, 6
