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45 Cards in this Set
- Front
- Back
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Can charge molecules be aromatic?
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Yes!
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When it comes to charge stabiliziatoin, which is more powerful: resonance stabilization or inductive stabilization?
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resonance stabilization
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Aldehyde shows up where on the H NMR?
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9.8ppm sharp
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Addition of Amine to Carbonyl Group
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Primary amine ==> Imine
Secondary amine ==> Enamine (Note: tertiary and quaternary amines do not react with the C=0 group.) |
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E2 reaction will only occur with what conformation?
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antiperiplanar conformation
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What is the most straightforward method of making a benzoic acid from benzene?
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- Place a methyl group and then oxidize the methyl group to the carboxylic acid...
- Can do this with AlBr3/CH3Br to get the methyl group on; and then oxidize with KMnO4 |
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How do you make bromobenzene from benzene?
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FeBr3/Br2
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Reacting an alcohol with PCC will give you what?
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a ketone
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A ketone that reacts with a primary amine give an _____
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imine
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What is an imine?
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a functional group or chemical compound containing a carbon-nitrogen double bond
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(T/F) Whenever there is a double bond, there exists the possibility of having geometric isomers.
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True
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What happens when you react imines with lithium aluminum hydride (LAH)
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create an amine... LiAlH4 is a reducing agent b/c there are a lot of H's attached to either B or Al.
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If you obtain two products of unequal yield, what does this suggest?
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that hte two products are diastereomers.
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Whenever you see one molecule goign to form a ring, what should you suspect?
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intramolecular reaction
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What is faster: intramolecular or intermolecular reactions?
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intramolecular reactions
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If charged intermediates are involved in your mechanism, what should you make sure of?
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that they go away before you get to the product, unless the product is chraged as well.
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Claisen condensation
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- Step1: At least one of the esters must possess an α-hydrogen atom as the first step of the reaction is deprotonation by the base to give an enolate ion
- Step2: The enolate then attacks the ester giving a β-Keto ester. - Used when have an ester. - Can use NaOMe/MeOH |
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What should you tihnk of whenever a question gives you the pKa of the substance being purified?
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ion exchange chromatography or isoelectric focusing.
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How do you determine the isoelectric points of a sample IN THE CASE OF INDIVIDUAL AMINO ACIDS?
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In the case of individual amino acids, the isoelectric points can be determiend easily by taking the avg of the two closest pKa values.
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Amino acids will be ______ charged at pH values below thier pI and ______ charged above their pI.
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positively; negatively
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How do you determine the isoelectric points of a sample IN THE CASE OF A PROTEIN when you have the individual pI of the amino acids?
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FIND ANOTHER METHOD.
*** DO NOT TAKE THE AVERAGE OF THE pI OF THE INDIVIDUAL AMINO ACIDS! |
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What should you tihnk of whenever a question gives you the pKa of the substance being purified?
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ion exchange chromatography or isoelectric focusing.
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How do you determine the isoelectric points of a sample IN THE CASE OF INDIVIDUAL AMINO ACIDS?
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In the case of individual amino acids, the isoelectric points can be determiend easily by taking the avg of the two closest pKa values.
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Amino acids will be ______ charged at pH values below thier pI and ______ charged above their pI.
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positively; negatively
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How do you determine the isoelectric points of a sample IN THE CASE OF A PROTEIN when you have the individual pI of the amino acids?
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FIND ANOTHER METHOD.
*** DO NOT TAKE THE AVERAGE OF THE pI OF THE INDIVIDUAL AMINO ACIDS! |
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ANILINE
is this an organic/inorganic/base/acid? |
organic compound and weak base
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acetophenone / methyl phenyl ketone
- properties? |
hydrophobic since none of functional groups are capable of making hydrogen bonds.
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phenol
organic/inorganic/basic/acidic |
organic and weak acid.
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Is the organic phase always on top of the aqueous layer during an extraction?
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no. It depends on the density!
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During extraction, how do you transpose a compound that is acidic or basic to the aqueous phase?
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add base or acid, respectively.
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Nitrile
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~2200 cm^-1 indicates presence of a triple bond
(alkyne or nitrile) |
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what is an anion exchanger?
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something that attracts anions and thus must have a positive charged group.
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What can column chromatography be used for?
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to separate substances based on size or charge.
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How does an eluent for a column chromatography work?
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- they must be eluted based on their affinities for the stationary phase. For this purpose, NaCl is added in an increasing concentration gradient.
- the least negatively charged proteins will emerge from the column before the proteins with the greatest negative charge. |
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All forms of chromatography have two ____
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phases: a stationary phase and a mobile phase.
- separations of compounds take advantage of the different affinities that compounds have for the two different phases. |
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What should you watch out for when dealgin with chromatography?
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Be cautious not to assume that the desired product will attach to the stationary phase. You may be presented with a sitaution in whcih purification will be better accomplished if the desired product has a higher affinity for the mobile phase.
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For NMR spectrum, the number of signals you see tells you a lot about what?
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the symmetry ==> the fewer signals there are, the higher symmetry the molecule possesses.
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If get a sibnglet, this signifies what?
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that there are no protons on adjacent carbons.
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IR stretch at 1740 cm^-1 indicates?
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presence of carbonyl.
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IR stretch at 2220 cm^-1 indcates?
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presence of a triple bond (either an alkyne or a nitrile)
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In order fora substance to have a carboxylic acid, it must have what kind of IR stretch.
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Alcohol
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If a stretch is closer to 1740 than to 1700, it is probably ____
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an ester
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If the stretch is closer to 1700 than to 1740, it is probably a _____
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ketone
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If a molecule has four or more sites of unsaturation, what should you immediately suspect?
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aromatic ring is present
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Sites of Unsaturation equation
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(2C + 2 -H)/2
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