Medicinal and Pharmaceutical Chemistry - Carbohydrates

Flashcards covering key concepts, definitions, and details from the Medicinal and Pharmaceutical Chemistry lecture on Carbohydrates.

What is a carbohydrate?

A broad class of polyhydroxylated aldehydes and ketones commonly called sugars.

What is the molecular formula of glucose?

C6H12O6.

What is a monosaccharide?

A simple sugar that cannot be converted into simpler sugars by hydrolysis.

What is a disaccharide?

A carbohydrate made of two simple sugars linked by glycosidic bonds.

Provide an example of a disaccharide.

Sucrose, which is composed of one glucose and one fructose.

What is a polysaccharide?

A carbohydrate that consists of several thousand linked simple sugars.

What projections are used to represent carbohydrate stereochemistry?

Fischer projections.

What is the Fischer D-notation?

Configuration where the hydroxyl group on the chiral carbon farthest from the carbonyl group is on the right.

Define the Haworth projection.

A cyclic representation of monosaccharides that illustrates their structure.

What do D and L sugars indicate?

The stereochemical configuration at the chiral center farthest from the carbonyl group.

What is an anomer?

Diastereomers that differ in configuration at the anomeric carbon (C1 in cyclic sugars).

What is the simplest aldose?

Glyceraldehyde.

How many chiral centers are present in D-glucose?

Four chiral centers.

What is the difference between D and L sugars regarding their orientation in Fischer projections?

D sugars have -OH group on the right; L sugars have -OH group on the left.

What are enantiomers?

Molecules that are mirror images of each other, such as D- and L-glyceraldehyde.

How are carbohydrates classified?

As simple (monosaccharides) or complex (disaccharides and polysaccharides).

What is the significance of the suffix -ose?

It designates a carbohydrate, indicating its classification.

Describe how Fischer projections are created for carbohydrates with multiple chiral centers.

They are shown by stacking the chiral centers on top of one another.

What role do hydroxyl groups play in the formation of cyclic sugars?

They react with carbonyl groups to form cyclic hemiacetals.

What is a pyranose?

A six-membered ring form of sugars, such as glucose.

What are diastereomers?

Stereoisomers that are not mirror images of each other, differing at one or more chiral centers.

What configuration does D-mannose have compared to D-glucose?

D-mannose is a C2 epimer of D-glucose.

What is the significance of the prefix aldo- in carbohydrates?

It identifies a sugar with an aldehyde carbonyl group.

What is a ketose sugar?

A sugar that contains a ketone group, such as fructose.

How can Fischer projections be converted to Haworth structures?

By changing the aldehyde to a hemiacetal and adjusting the position of -OH groups.

What is a hemiacetal?

A result of the nucleophilic addition of an alcohol to an aldehyde.

In what form does glucose primarily exist in an aqueous solution?

In a six-membered pyranose ring form.

What is the chair conformation?

The most stable representation for cyclic structures of sugars.

Identify the key features of D-glucose in its Fischer representation.

Bottom hydroxy group on the right (C5), C4 hydroxy group on the right, C3 on the left.

What happens during the cyclization of D-glucose?

The hydroxyl group at C5 attacks the carbonyl carbon to form a ring.

What are the two anomers formed from D-glucose?

Alpha (⍺) and beta (𝛽) D-glucose.

What distinguishes D-galactose from D-glucose?

D-galactose is a C4 epimer of D-glucose.

What type of reaction do monosaccharides undergo to form cyclic structures?

Intramolecular nucleophilic addition reactions.

How are the Haworth projections for D-mannose and D-galactose derived?

They are derived from D-glucose through epimerization at C2 and C4 respectively.

What structural representations are used to show cyclic sugar variants?

Haworth and chair structures.

What does a Fischer projection show about stereochemistry?

It displays the 3D arrangement of substituents at chiral centers on a 2D plane.

Identify one example of a five-membered cyclic structure in sugars.

Furanose form of fructose.

Describe the characteristics of epimers.

They are sugars that differ in configuration at a specific chiral center.

What is the common physical state of glucose at room temperature?

It is a crystalline solid.

What is meant by the suffix -ose in monosaccharides?

It indicates that the molecule is a sugar.

What are the chemical reactions that involve monosaccharides?

They undergo nucleophilic addition reactions with alcohols.

What is the relationship between D-glucose and L-glucose?

They are enantiomers of each other.

Define stereoisomers in the context of carbohydrates.

Isomers that differ in the spatial arrangement of atoms, despite having the same molecular formula.

What type of bond connects monosaccharides in a polysaccharide?

Glycosidic bonds.

What is the chemical nature of the functional groups present in carbohydrates?

They are primarily hydroxyl (-OH) and either aldehyde or ketone groups.

What reaction leads to the formation of anomers in cyclic sugars?

The reaction between the carbonyl group and hydroxyl group during cyclization.