1) Carbohydrates: Formula (& how they fit into Life)

2) Carbohydrates: Fischer projections Is D-glyceraldehyde a carbohydrate ?

3) Carbohydrates: Naming (Generic)

4) Carbohydrates: Configurations

The product will be a 1,5-dicarbonyl compound

5) Carbohydrates: Enantiomers + Diasteromers

Maximum Number of Possible Stereoisomers

(including meso compounds) 2 n

6) Carbohydrates: Optical Rotation

Forming Hemiacetals of Aldoses INTRAmolecular attack of OH on an aldehyde

Amino (Deoxy) Sugars contain an -NH2 group in place of an -OH group

CHO

OHOHHNH2

HH

HOH

CH2OH

CHO

OHOHHH

HH

HOH2N

CH2OH

CHO

OHOHHNHCCH3

HH

HOH

CH2OH

OCHO

OHHHNH2

HHOHOH

CH2OH

4

2

D-Mannosamine(C-2 stereoisomer of D-glucosamine

D-Glucosamine D-Galactosamine(C-4 stereoisomer of D-glucosamine)

N-Acetyl-D-glucosamine

three amino sugars are common in nature: !D-glucosamine, D-mannosamine, and D-galactosamine!

1) Cyclic Aldose Rxns: Acylation

The OH groups of monosaccharides exhibit the same chemistry as typical alcohols

Ac can be used as an abbreviation for the acetyl group, CH3-C=O

All OH groups react.

2) Cyclic Aldose Rxns: Alkylation

All OH groups react.

The OH groups of monosaccharides exhibit the same chemistry as typical alcohols

The acetal of a monosaccharide is called a glycoside.

3A) Cyclic Aldose Rxns: Formation of Glycosides

Heat

By-Product is water + H2O

Key Point: Ethanol is used in the example (above), but ANY alcohol (i.e. an OH group on another carbohydrate) can be used.

This is how well make disaccharides, oligosaccharides, and polysaccharides.

The name ends with oside.

The anomeric carbon (the carbon with an OR and OH groups) is more activated than the others.

Hemiacetal (anomeric carbon with OR and OH) becomes an Acetal (anomeric carbon with OR and OR)

3B) Cyclic Aldose Rxns: Mechanism of Glycoside Formation

4) Cyclic Aldose Rxns: Formation of an N-Glycoside

More Examples

Glycoside (Acetal) Hydrolysis Glycosides (Acetals) can be hydrolyzed with acid(aq) + heat

+ heat

Glycoside (Acetal) Hydrolysis: Mechanism Glycosides (Acetals) can be hydrolyzed with acid (aq) + heat

+ heat

1

Heterocyclic Aromatic Compounds: Heterocycles are any cyclic compound that

contains at least one heteroatom (N, O, S, P) in a ring Aromaticity is a bit more complex

Aromaticity = stability = unreactive

2

Criteria for Aromaticity

[1] A molecule must be cyclic.

3

[2] A molecule must be completely conjugated. Aromatic compounds must have a p orbital on every atom.

Criteria for Aromaticity

To be aromatic, each p orbital must overlap with

p orbitals on adjacent atoms.

4

[3] A molecule must be planar. All adjacent p orbitals must be aligned so that the electron density can be delocalized.

Since cyclooctatetraene is non-planar, it is not aromatic, and it undergoes addition reactions just like those of other alkenes.

Criteria for Aromaticity

5

[4] A molecule must satisfy Hckels rule, and contain a particular number of electrons.

Hckel's rule:

Criteria for Aromaticity

Erich Hckel

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[5] A heteroatom with an sp3 lone (non-bonding) pair of electrons will re-hybridize to a p-orbital to obtain aromaticity (to satisfy Hckel number of electrons).

[6] Carbonyl Groups have very polar bonds. So, you can consider them as:

Criteria for Aromaticity

7

N pyridine

Pyridine: -electron structure (6 -electrons) The nitrogen lone pair electrons are not part of the aromatic system.

8

+ B:H

H H H H

HH+ B:H

cyclopropenyl anion4 -electrons

1

2 3

Cyclopropenyl anion

6 electrons (a Hckel number)

aromatic

4 electrons (NOT a Hckel number)

anti-aromatic

HH

H H

HH + B:

H

H H

HH + B:H

cyclopentadienyl anion6 -electrons

1

2 3

4 5

pKa ~ 16

Cyclopentadienyl anion

Examples: heterocyclic aromatic compounds

Cytotoxin- Inhibits DNA-topoisomerase enzymes

NN

Me

N NHMe

NNC

H

H

Ovarian & lung cancer GSK - Topotecan

Pfizer - Irinotecan

Camptothecin Analogues

Treating stomach & intestinal ulcers

Examples: heterocyclic aromatic compounds