OCHEM 238 Final

In the reduction of camphor to isoborneol, sodium borohydride is used instead of lithium aluminum hydride because:

lithium aluminum hydride would react with the solvent ethanol

A KMnO4 test on the basic hydrolysis products of aspartame will detect the presence of

methyl alcohol

The first step in the Fischer esterification is:

the protonation of the carbonyl oxygen of the carboxylic acid

how many moles of a ketone can reduce one mole of sodium borohydride?

4

false about Grignard Reaction?

Alcohols are often used as solvents in the Grignard Reactions.

In order to determine whether the desired product type was produced in the Grignard Reaction, you obtained an IR spectrum. The main peak that should have been absent was at approximately:

1700-1720 cm-1

In the addition of the HBr to butadiene, which product is the product of kinetic control?

3-bromo-1-butene

What is the UVA range of light?

315-400 nm

In order to determine whether the desired type of functional group was produced in the Grignard Reaction, you obtained an IR spectrum. The characteristic peak that should have been present for the product was at approximately:

3200-3600 cm-1

if you perform the same reaction using salicylic acid in place of salicylamide, which of the following would be produced as the major product?

5-iodosalicylic acid

What is the key IR stretch for the aromatic substitution pattern of 5-iodosalicylamide?

850-800 cm-1; 1,2,4-trisubstituted

In an aldol condensation, the reactive intermediate generated by the reaction of a carbonyl compound with a strong base is an A , which acts as a B toward another carbonyl compound.

A = enolate : B = nucleophile

tollens test

A test for aldehydes in which Ag+ in Tollens' reagent is reduced to metallic silver forming a "silver mirror" on the walls of the container.

compares the reactivity of acetanilide to ethylbenzoate toward electrophilic aromatic substitution.

Acetanilide is more reactive toward electrophilic aromatic substitution owing to the electron-donating group attached to the aromatic ring.

Substituents on an aromatic ring affect electrophilic aromatic substitutions in that:

Activating groups make substitution more likely by donating electron density

The precipitate observed in a positive iodoform test is:

CHI3

Which of the following polymers is a polyester comprising of identical repeating units? Wool Cotton Nylon Dacron 54 Creslan

Dacron 54

Benzoyl chloride can react with water in your eye. What is a product of this reaction, and what risky substance is benzoyl chloride classified as?

HCl, lachrymator

What species is responsible for generating the diazonium intermediate during the synthesis of the azo-dye?

HNO2

What is true of α-helix secondary structures?

Involve hydrogen-bonding interaction between amino acid groups that are 4 residues apart on the same chain.

Which of the following amino acids are classified as basic?

Lys and His

The active site of Mandelate racemace involves the presence of a non-protein species in the active site to which you measured some bond distances. That species (called a prosthetic group) was:

Mg2+

Why do esters, which have higher molecular weights than carboxylic acids, have lower boiling points than the carboxylic acids they were made from?

Most carboxylic acids exist as dimers which are held together by two hydrogen bonds

Which of the following reagent(s) can be used to reduce camphor in ethanol?

NaBH4

Which pair of reactants is responsible of the formation of the azo salt in the diazotization of an aromatic primary amine?

NaNO2 and HCl

test is used most often to detect the presence of amino acids?

Ninhydrin test

In the coupling reaction between the diazonium salt and the phenol compound in the Azo dye experiment the phenol acts as a(n):

Nucleophile

The aldol reaction between dibenzyl ketone and benzil is synthetically useful because

One of the compounds has no alpha hydrogens

Functionally, proteins are

Polymeric peptides

Which of the following items is false about the UV analysis of sunscreens experiment?

SPF only refers to product effectiveness against the UVA rays of the sun

Which one is not a derivative of carboxylic acids?

Schiff's base

Which method is used to determine the structure of an enzyme?

Single-crystal x-ray crystallography

The hydrolysis of esters can be done by both acid or base catalysis, however esterification of carboxylic acids can only be done by acid catalysis. Why is this?

The carboxylic acid will be deprotonated by the base and will leave an unreactive carboxylate anion.

TPCP, the product in the aldol experiment

The phenyl rings of TPCP are twisted with respect to the plane of the cyclopentadienone ring, and each phenyl is twisted in the same direction as the others.

Avobenzone and oxybenzone are sunscreen ingredients that both protect against ____ rays

UVA and UVB

The major product of the reaction of camphor with NaBH4 is formed when:

a borohydride ion makes an endo attack at the carbonyl to form the exo product.

unknown compound is an aldehyde?

a silver mirror in Tollens' test

How could you have used infrared spectroscopy to determine if the sodium borohydride reduction of camphor had gone to completion?

absence of a peak at 1746 cm-1 and presence of a peak at 3500 cm-1

Isopentyl acetate has a pleasant smell of bananas. What two reagents can this ester be made from?

acetic acid and isopentyl alcohol

To prepare 2-methyl-2-pentanol from a Grignard reaction, you need to use ____ and ____ as starting material.

acetone & 1-bromopropane

In the iodination of salicylamide, what reagent was acting as the nucleophile in this reaction?

acid chlorides

What should be done to neutralize a bromine or an iodine burn?

apply sodium thiosulfate solution

ceric nitrate test

alcohols

Which class of compounds is most resistant to hydrolysis (i.e. requires more time and harshest reaction conditions)?

amides

Amides can be prepared in one step by reacting an amine with

an acid chloride

What is the intermediate formed during the reaction of an aldehyde and base in the first step of an aldol condensation?

an enolate

The imidazole functional group of histidine in an enzyme active site can act:

as a base to remove a proton from a substrate as an acid to donate a proton to a substrate

Aspartame is one of the most common alternatives to sugar. It is a dipeptide of

aspartic acid and phenylalanine

In the reduction of ketones, an excess of sodium borohydride is usually used:

borohydride reacts slowly with the solvent

What is the name of ester prepared from propanoic acid and butyl alcohol?

butyl propanoate

Which of the following substituents of an aromatic ring are electron-withdrawing?

carbonyl and nitro

Which of the following is not a polyamide? Cotton Silk Aramid Wool Nylon

cotton

To obtain the UV spectrum of sunscreen ingredients, we dissolved the samples in:

isopropyl alcohol

Why do we need to convert indigo to leucoindigo to dye a fiber?

indigo is not water soluble

A Grignard reaction of n-butylmagnesium bromide with acetone would produce:

methyl salicylate

stains was used in the peptide and amino acid lab on the TLC plate?

ninhydrin

Esters, acid chlorides, ethers and amides are all derivatives of carboxylic acids

not correct

What is the classification of an enzyme?

proteins

A catalytic amount of mineral acid in Fischer esterification of a carboxylic acid:

protonates the carbonyl oxygen of the carboxylic acid, generating a reactive, resonance stabilized electrophilic species.

The equilibrium of a Fischer esterification can be shifted to yield more ester by:

removal of water

The reaction of a Grignard reagent with most aldehydes produces a __________ alcohol and the reaction of a Grignard reagent with a ketone produces a __________ alcohol

secondary, tertiary

What type of derivatives are prepared from ketones and aldehydes?

semicarbazones and 2,4-dinitrophenylhydrazones

In the Aldol Condensation experiment a computer was used to analyze the TPCP molecule. One of the questions asked was why the molecule is not completely planar. What prevents this molecule from being planar?

steric interactions between the phenyl groups

iodoform test?

test for methyl ketones (Yellow precipitate forms CHI3)

Electrophilic substitution of methyl benzoate occurs meta to the substituent because:

the ester group is electron donating and thus activates the ring in the meta position

could be used to distinguish between benzaldehyde and phenylacetone?

tollens and iodoform

The Tollens' test is positive for both hexanal and benzaldehyde.

true

A possible cause for a Grignard reaction failing to initiate is the:

use of magnesium with heavy oxide layer

may give you a false positive result in 2,4-DNP test?

washing the glassware with acetone without letting it evaporate