Organic Chem reactions / reagents Flashcards
reagent to oxidize a primary alcohol to an aldehyde?
PCC, all other oxidizing agents will go to carboxylic acid;
reagent to oxidize a secondary alcohol to a ketone?
jones reagent or chromium reagents such as Na2Cr2O7
What does NaBH4 do?
reduces ketones / aldehydes to alcohols
what does LAH (LiAlH4) do?
reduces carboxylic acids to alcohols
R-Br + Mg forms?
R-Mg-Br = Grignard reagent which is a powerful nucleophile. these attack carbonyl centres and add alkyl groups. Acid work up is required to protonate the oxygen.
NaCN reacting with a ketone yields?
addition of the CN group and protonation via an acid to get an OH group.
called a cyanohydrin
Reacting an aldehyde with R-NH2 and acid makes?
an imine which is a carbon double bonded to a nitrogen which has some R group attached to it.
Reacting an aldehyde / ketone with R-NH2 and acid makes?
an imine which is a carbon double bonded to a nitrogen which has some R group attached to it.
note: primary amine must attack
if a secondary amine attacks we get an enamine which is a C=C-NR2 group
what is decarboxylation?
add heat to a compound with a carboxylic acid and CO2 will be kicked off
Acid catalyzed esterification? (Fischer esterification)
reacting a carboxylic acid with acid and alcohol to create an ester
CO2H + H+ primes the carboxylic acid
then CO2H2 is attached by R-OH and the H deprotonates after
What occurs when you have a C triple bonded to an N and you add H3O+ (Acid)
C triple bond N converts to a carboxylic acid
What reaction is this?
NH4Cl and NaCN are added to an aldehyde
this is followed by the addition of H3O+ to form ____?
Strecker synthesis which forms amino acids. The R group attached to the initial aldehyde determines the amino acid.
What reaction is this?
NH4Cl and NaCN are added to an aldehyde
this is followed by the addition of H3O+ to form ____?
Strecker synthesis which forms amino acids. The R group attached to the initial aldehyde determines the amino acid.
what is the enolate anion?
a deprotonated carbonyl species which exhibits resonance.
What is Keto-Enol tautomerism? which is more stable
when enolates are formed, the electrons can form a carbon = carbon double bond and shift the carbonyl double bond away to form an alcohol. (Enol). The double bond C = O can reform and break the C=C bond to form a ketone (keto)
keto is more stable
what are mesylates and tosylates?
They replace the H on OH groups and make alcohols inert in reactions. They are also great leaving groups. Note addition of the TsCl or MsCl retains stereo but Sn2 after inverts it.
what occurs if a strong base deprotonates the alpha hydrogen of an imine?
the electrons shift to break the imine C=N bond and rather form an enamine.
LDA vs. NaOH in the de-protonation of the alpha hydrogen in aldol reactions?
LDA - kinetic product
NaOH - thermo product
cold temperature also promotes kinetic product.
If you see a reaction where it shows an aldol condensation product with (-H2O) what comes next?
dehydration reaction in which the OH group is removed and a C=C bond is made (this occurs with heat and acid)
T or f, in nucleophilic addition reactions a pi bond breaks and two sigma bonds are made. A elimination reaction shows 2 sigma bonds break while a new pi bond is made.
true! a nucleophilic substitution would show the addition of one sigma and the loss of another.
what is a nucleophilic addition - elimination reaction?
when a nucleophile attacks a carbonyl species and breaks the C=O pi bond. Then reformation of the pi bond kicks off the most appropriate LG. Similar to substitution but in two steps. (Sn1 is 2 steps but different mechanism)
What is made when a carboxylic acid reacts with an alcohol and acid?
an ester
R-CO2H + R-OH —> RC(=O) - OR
hydrolysis of esters: adding acid to an ester makes? What about reacting an ester with another ester in acid?
carboxylic acid forms if you expose an ester to H3O+
if you expose an ester to acid in the presence of another ester, the ester will attack the protonated ester and cause transesterification (the ester group changes it’s R group)
Saponification produces what?
base catalyzed ester hydrolysis which creates carboxylate anion. You must protonate it to form the carboxylic acid.
saponification of triglycerides yields?
glycerol and fatty acids
treating a carboxylic acid with SOCl2?
makes an acyl chloride
T or f, carboxylic acids can be made from any carboxylic acid derivative (acyl chloride, ester, amide, etc.) by heating it in acid (aq) solution
true!
what is the reactivity of carboxylic acid derivatives
acyl chlorides > anhydrides > esters > amides
you can make anything on the left using the stuff on the right but not vice versa (can’t make anhydride from amide)
Reacting Acyl chloride with NHR2 yields?
a tertiary amide
CH3-C(=O) - NR2
in B-D-glucose is the anomeric hydroxyl group up or down?
up
t or f, the anomeric carbon is the carbon with the C=O bond in the open chain form?
true
t or f, mammalian enzymes cannot hydrolyze beta-glycosidic linkages
true and false, this is true despite one exception –> lactase can metabolize lactose for many people
what is a reducing sugar?
Any carbohydrate which can act as a reducing agent due to a free aldehyde or free ketone group.
what is beneficts test?
distinguishes between reducing sugars and non-reducing sugars
will a hemi-acetal produce a positive benedict test?
yes, hemi-acetals are in equilobrium with open chain sugars. Therefore, their free aldehyde and ketone group will react with benedicts reagent to give a positive test.
Note: once the sugar is in a glycosidic linkage (acetal form) it will not!!
all aldehydes, ketones, and hemi-acetals give positve benedict test results.
true
