Aldehydes and ketones Flashcards
1
Q
What is the IUPAC naming system for an aldehyde?
A
Change suffix of parent alkane to -al.
2
Q
What is the IUPAC naming system for a ketone?
A
Change suffix of parent alkane to -one and number from the direction that gives the carbonyl carbon the smaller number.
3
Q
How do you name cyclic aldehydes where the cyclic structure is bonded directly to the carbonyl carbon?
A
the omlecule is named by adding the suffix -carbaldehyde (e.g. cyclohexanecarbaldehyde). The carbon of the ring that is attached to carbonyl carbon is carbon #1 when numbering.
4
Q
How do you indicate a carbonyl group when there are multiple functional groups?
A
Use the infix -oxo-
5
Q
What is a phenone?
A
A ketone in which one of the groups attached to the carbonyl carbon is a phenyl group.
6
Q
How do you derive the common names of aldehydes?
A
Derived from carboxylic acids; drop the word acid and change the suffix -ic or -oic to -aldehyde.
7
Q
How do you derive the common names of ketones?
A
Naming the two alkyl or aryl groups bonded to the carbonyl group as separate words, followed by the word ketone.
8
Q
What is the common name for a 1 carbon aldehyde?
A
(Form)aldehyde
9
Q
What is the common name for a 2 carbon aldehyde?
A
(Acet)aldehyde
10
Q
What is the common name for a 3 carbon aldehyde?
A
(Propion)aldehyde
11
Q
What is the common name for a 4 carbon aldehyde?
A
(Butyr)aldehyde
12
Q
What is the common name for a 6 carbon aldehyde?
A
(Capro)aldehyde
13
Q
The is the common name for a 3 carbon ketone?
A
Acetone
14
Q
What is the common name for two phenyl groups attached to a carbonyl group?
A
Benzophenone
15
Q
What is the common name for a phenyl group and a methyl group attached to a carbonyl group?
A
Acetophenone
16
Q
What is he common name for two methyl groups attached to a carbonyl group?
A
Acetone
17
Q
What is special about assigning alpha, beta, gamma (and so forth) to carbons in an aldehyde?
A
The carbonyl carbon can’t be substituted because there must be a hydrogen, so carbon adjacent to the C=O is the alpha carbon.
18
Q
Rank the boiling points (lowest to highest) for the following 6 functional groups of similar molecular weights: alcohol, aldehyde, alkane, carboxylic acid, ether, ketone
A
- Ether
- Alkane
- Aldehyde
- Ketone
- Alcohol
- Carboxylic acid
19
Q
Only which aldehyde(s) is/are miscible in water?
A
Methanal (formaldehyde) and Ethanal (acetaldehyde)
20
Q
Only which ketone(s) is/are miscible in water?
A
Acetone
21
Q
What is a carbohydrate?
A
A polyhydroxyaldehyde, a polyhydroxyketone or a substance that gives these compounds on hydrolysis.
22
Q
Carbohydrate chemistry is essentialy the chemistry of what other functional groups?
A
The chemistry of hydroxyl groups and carbonyl groups and of the acetal bonds formed between these two functional groups.
23
Q
What is a carbohydrate?
A
A carbohydrate that cannot be hydrolyzed to a simpler carbohydrate.
24
Q
What is an aldose?
A
A monosaccharide containing an aldehyde group
25
What is a ketose?
A monosaccharide containing a ketone group.
26
How do you indicate that a compound is a carbohydate?
-ose
27
How do you indicate the number of carbons in a carbohydrate?
Tri-, Tetr-, pent-, hex-, hept-, oct-
28
What are the two trioses?
1. Glyceraldehyde
| 2. Dihydroxyacetone
29
Draw glyceraldehyde (give IUPAC name)
2,3-dihydroxypropanal
30
Draw dihydroxyacetone (give IUPAC name)
1,3-dihydroxypropanone
31
What is the purpose of the D,L- configuration system?
D- and L- glyceraldehyde (enantiomers) serve as a reference points for the assignment of relative configuration to all other aldoses and ketoses.
32
What is the penultimate carbon?
The stereocenter furthest from the carbonyl group; the second to last carbon.
33
What is a D-monosaccharide?
A monosaccharide that, when written as a Fischer projection, has the -OH on its penultimate carbon to the right.
34
What is an L-monosaccharide?
A monosaccharide that, when written as a Fischer projection, has the -OH on its penultimate carbon to the left.
35
Draw the Fischer projection of D-glyceraldehyde
North: CHO
East: OH
South: CH2OH
West: H
36
Draw the Fischer projection of L-glyceraldehyde
North: CHO
East: H
South: CH2OH
East: OH
37
What do prefixes such as Rib-, arabin- and gluc- indicate?
The configuration of all other chiral enters in the monosaccharide.
38
What are the three most abundant hexoses in the biological world?
D-glucose, D-galactose, D-fructose
39
The disaccharide sucrose is composed of what two monosaccharides?
D-fructose and D-glucose
40
The disaccharide lactose is composed of what two monosaccharides?
D-galactose and D-glucose
41
The disaccharide maltose is composed of what two monosaccharides?
Two molecules of D-glucose
42
Draw the Fischer projection of D-glucose
```
CHO (Right, Right, Left, Right)
H (-) OH
HO (-) H
H (-) OH
H (-) OH
CH2OH
```
43
Draw the Fischer projection of D-galactose
```
CHO (Right, Left, Left, Right)
H (-) OH
HO (-) H
HO (-) H (Differs from glucose only at C-4)
H (-) OH
CH2OH
```
44
Draw the Fischer projection of D-Fructose
```
CH2OH (Right, Right, Left)
C=O
HO (-) H
H (-) OH
H (-) OH
CH2OH
```
45
The terms alpha and beta refer to what carbon in carbohydrates?
Alpha and beta refer to the configuration at the anomeric carbon.
46
Define an anomeric carbon
The carbon that becomes a stereocenter from cyclic hemiacetal/acetal formation of a carbohydrate.
47
Define anomers
Carbohydrates that differ in configuration only at their anomeric carbons
48
What is a furanose?
A five-membered cyclic form of a monosaccharide
49
What is a pyranose?
A six-membered cyclic form of a monosaccharide
50
How do you predict the product of hemiacetal formation?
Attach the oxygen of the alcohol group to the carbonyl carbon and reduce the C=O bond to an alcohol (using the hydrogen from the former -OH bond)
51
Groups on the right of a Fischer projection, in general, point in which direction in a Haworth projection?
Down
52
Groups on the left of a Fischer projection, in general, point in which direction in a Haworth projection?
Up
53
When hemiacetal bond is formed, what direction does a D-hydroxyl point if its not part of the ring?
Down
54
When hemiacetal bond is formed, what happens to the D-hydroxyl and terminal carbon if the hydroxyl becomes part of the ring?
The terminal carbon points up
55
When a hemiacetal bond is formed, what happens to the L-hydroxyl and terminal carbon if the hydroxyl becomes part of the ring?
The terminal carbon points down
56
How do you designate an anomer as alpha or beta?
Alpha means the new -OH is opposite the terminal carbon of the penultimate carbon. Beta means the same side. Whether the terminal carbon is up or down is determined by if its a D or L carbohydrate.
57
Is glucose an aldose or a ketose?
Aldohexose
58
Is galactose an aldose or a ketose?
Aldohexose
59
Is fructose an aldose or a ketose?
Ketohexose
60
Draw the fischer projection of D-Ribose
```
CHO (Right, Right, Right)
H (-) OH
H (-) OH
H (-) OH
CH2OH
```
61
Is ribose an aldose or a ketose?
Aldopentose
62
What type of ring do aldopentoses and ketohexoses form?
5-membered rings (furanoses)
63
What are three (5) steps when converting from a Fischer projection to a Haworth projection?
1. Identify the type of monosaccharide and the ring it will form. Aldohexoses form pyranoses and aldopentoses and ketohexoses form furanoses.
2. Draw the structure base structure. The Oxygen atom is at the point of a five membered ring or in the back right of six membered ring.
3. On the carbon to the left of the oxygen (the penultimate carbon), draw the terminal carbon (pointing up if D, down if L)
4. On the carbon to the right of the oxygen [carbon 1], draw the -OH (opposite the terminal carbon if alpha, same side if beta)
5. Following the Fischer projection, draw in the -Hs and -OHs (right of fisher projection point down, left point up)
64
Define mutarotation
The change in specific rotation that occurs when an alpha or beta hemiacetal form of a carbohydate in aqueous solution is converted to an equilibrium mixture of the two forms.
65
Define glycoside
A carbohydrate in which the -OH on its anomeric carbon is replaced by -OR
66
What is the biochemistry term for a cyclic acetal derived from a monosaccharide?
Glycoside
67
What is a glycosidic bond?
The bond from the anomeric carbon of a glycoside to an -OR group.
68
What happens when a glycoside is placed in aqueous acid?
It hydrolyzes to an alcohol and a monosaccharide.
69
How are glycosides named?
Listing the alkyl or aryl group bonded to oxygen followed by the name of the carbohydrate in which the ending -e is replaced by -ide (e.g. methyl alpha-D-glucopyranoside)
70
Define aldonic acid
The product formed when the aldehyde function of an aldose is oxidized to a carboxylic acid.
71
Define aldaric acid
The product formed when the hydroxyl function of terminal carbon and aldehyde function are oxidized to a carboxylic acid.
72
Define uronic acid
The product formed when the hydroxyl function of terminal carbon is oxidized to a carboxylic acid.
73
Describe (draw) the structure of sucrose
Carbon 1 of alpha-D-glucopyranose is joined to carbon 2 of beta-D-fructofuranose by an alpha-1,2-glycosidic bond.
74
Describe (draw) the structure of lactose
Carbon 1 of beta-D-galactopyranose is joined to carbon 4 of beta-D-glucopyranose by a beta-1,4-glycosidic bond.
75
Describe (draw) the structure of maltose
Carbon 1 of alpha-D-glucopyranose is joined to carbon 4 of alpha-D-glucopyranose by an alpha-1,4-glycosidic bond.
76
Is sucrose a reducing sugar? Why or why not?
No. The anomeric carbons of both the monosaccharides are involved in the formation of the glycosidic bond.
77
Is lactose a reducing sugar? Why or why not?
Yes. The hemiacetal group on glucose exists in equilibrium with the open chain aldehyde and can be oxidized to a carboxylic acid.
78
Is maltose a reducing sugar? Why or why not?
Yes. The hemiacetal group on the glucose exists in equilibrium with the open chain aldehyde and can be oxidized to a carboxylic acid.
79
What are four (4) reactions of monosaccharides?
1. Formation of glycosides (acetals)
2. Reduction to alditols
3. Oxidation to aldonic acids
4. Oxidation to uronic acids
80
What are the reagents for the formation of glycosides from monosaccharides?
H+ (to protonate alcohol so it leaves) and Alcohol (nucleophile, H+ leaves to form stable ion)
81
How do you predict the products for the formation of glycosides from monosaccharides?
Replace the OH at the anomeric carbon with the nucleophilic alcohol, and remove H+ from alcohol.
82
What is an alditol?
The product formed when the C=O group of a monosaccharide is reduced to a CHOH group.
83
What are the reagents for the reduction of monosaccharides to an alditol?
Many reducing agents, including:
1. Sodium borohydride
2. Hydrogen in the presence of transition metal catalyst
84
How do you predict the products for the reduction of monosaccharides to an alditol?
Add an H to both atoms of the C=O and remove the pi bond.
85
What are the reagents for the oxidation of monosaccharides to aldonic acids?
1. Oxidizing agent (including O2)
| 2. Basic conditions
86
How do you predict the products for the reduction of monosaccharides to aldonic acids?
Replace the C-H of the aldehyde function to a C-OH
87
Define an epimer
Epimers differ at one chiral center, not the anomeric carbon. (Example: Glucose and Galactose differ at C-4)
88
Why do aldehydes and ketones undergo nucleophilic addition reactions but carboxylic acids and their derivatives undergo nucleophilic substitution reactions?
The only possible leaving groups in an aldehyde or ketone are alkyl groups or hydrogen which are both unstable.
89
What are four ways to prepare an aldehyde or ketone?
1. Oxidation processes
2. Reduction processes
3. Organometallic substitution (provide 'carbanion')
4. Addition on alkynes and tautomerization
90
What reagents are used to reduce a carboxylic acid derivative to an aldehyde?
Lithium Aluminum Tri Tert-butoxide Hydride (LiAlH[OC(CH3)3]3
91
What are two reagents that can be used to hydrate an alkyne?
1. Hg2+, H2SO4
| 2. Sia2BH -> H2O2 NaOH
92
What organometallic reagents can be substituted to form a ketone?
1. Organocadmium R2Cd
2. Cuprate R2CuLi
[These can be used to substitute a carboxylic acid chloride!]
93
What test tube test can differentiate aldehydes/ketones from other functional groups?
2,4-dinitrophenylhydrazine
94
What test tube test can differentiate aldehydes from ketones?
Tollen's Test, Chromic acid test
95
What are five (5) classes of reactions at the carbonyl functional group?
1. Nucleophilic addition
2. Addition of Ammonia derivatives
3. Oxidation (oxygen nucleophiles)
4. Wittig reaction
5. Aldol Condensation
96
How do you predict the product for a nucleophilic addition at an aldehyde or ketone function?
Replace the =O with an -OH and add the nucleophile.
97
How do you predict the product of a wittig reaction?
1. Change the O in the C=O to a C
| 2. Add the R-groups attached to the carbon of the Ylide to the Carbon of the C=C
98
How do you prepare an ylide for a wittig reaction?
1. A primary or secondary alkyl halide reacts with triphenylphosphine
2. Butyl lithium (strong base) pulls hydrogen off of carbon
99
What is the simplified mechanism for the addition of an ammonia derivative?
1. NH2B adds to carbonyl.
2. H from NH2B+ adds to -O(-) and forms -OH.
2. H from NHB adds to -OH to form H2O and leaves.
4. Double bond forms between C=N
100
How do you predict the product for the addition of an ammonia derivative (NH2B)?
Remove the two Hs from NH2B and the O from C=O. Link the NB and C to form C=NB
101
What is an imine?
An imine is a functional group containing a carbon–nitrogen double bond, with the nitrogen atom attached to a hydrogen atom or an organic group.
102
What is an oxime?
An oxime is a functional group containing a carbon-nitrogen double bond, with the nitrogen atom attached to a hydroxyl group.
103
What is an osazone?
Phenylhydrazine (C6H5NHNH2) reacts with carbons #1 and #2 of
| reducing sugars to form derivatives called osazones.
104
What is a hydrazone?
Hydrazine (NH2NH2) reacts carbonyl carbons to form hydrazones.
105
When is the addition of HCN to an aldehyde or ketone useful?
When an additional C atom must be added
106
After the addition of HCN to an aldehyde or ketone, what are three follow up reactions?
1. LiAlH4
2. H2SO4
3. HCl/H2O
107
What will adding LiAlH4 after the addition of HCN to an aldehyde or ketone do?
Reduce C triple bond N to CH2-NH2
108
What will adding H2SO4 after the addition of HCN to an aldehyde or ketone do?
Oxidize the new carbon to a carboxylic acid and dehydrate the alcohol forming a conjugated double bond with the new carboxylic acid.
109
What will adding HCl/H2O after the addition of HCN to an aldehyde or ketone do?
Oxidize the new carbon to a carboxylic acid. Will not dehydrate the alcohol.
110
What is the Tollen's reagent?
Ag(NH3)2+
111
What is special about the Tollen's reagent?
It will only oxidize aldehydes.
112
What are four oxidation reagents?
1. K2Cr2O7/H+
2. KMnO4
3. Ag(NH3)2+
4. Cu2+ Benedict's reagent
113
What are two special oxidation reactions that can oxidize ketones?
1. Baeyer-Villiger Oxidation
| 2. Haloform reaction
114
What are the reagents for the Baeyer-Villiger oxidation?
O=C-O-O-H (peroxyacid) and Ch2Cl2 (dichloromethane solvent)
115
How do you predict the products for the Baeyer-Villiger oxidation?
Add an -O between one of the alkyl groups (tertiary > secondary > primary)
116
What are the reagents for the haloform reaction?
X2/OH-
117
How do you predict the products for the haloform reaction?
Replace a methyl group attached to ketone with -OH and form CHX3.
118
What is an enolate ion?
An enolate ion is the anion formed when an alpha hydrogen in the molecule of an aldehyde or a ketone is removed as a hydrogen ion.
119
What base can we use to remove an alpha hydrogen in an aldehyde or ketone?
lithium diisopropylamide (LDA)
120
What is the purpose of aldol condensation?
To couple two aldehydes or ketones
121
How do you predict the products of aldohol condensation (two types of products)
(Alcohol/Carbonyl product)
1. Form the enolate ion by removing an alpha hydrogen.
2. Lone electron pair attacks carbonyl carbon of another molecule. C=O of attacked molecule becomes C-OH
(Alkene/Carbonyl product)
1. Water is eliminated by an alpha-hydrogen and a beta-hydroxyl group. Forms conjugated diene.
122
Grignard reagents can work on what two functional groups?
Carbonyl and Nitriles.
123
How do you predict the product of a grignard reagent on a nitrile?
Replace the triple bond N with a double bonded O, and also add the alkyl group of the grignard reagent to the carbon.
124
What are the reagents of the wolf-kischner reduction reaction, starting with the aldehyde or ketone?
1. Aldehyde or Ketone + Hydrazine = Hydrazone
| 2. Hydrazone + KOH = Alkane
