Organic Chemistry Part (3 Of 3)

Front 1

Predict the product
Recongnize the reaction
Markovnikov or anti markovnikov?
What adds acroos the double bond?
H adds to which carbon?
Draw the Product

Back 1

The type of reaction must be recognized as hydration. Markovnikov or anti-Markovnikov, the reaction is Markovnikov. What adds across the double bond? Water. H adds to the least substituted carbon, which is the left side. Draw the product. Trans-3-methyl-2-pentene is hydrated to form 3-methyl-3-pentanol.

Front 2

How does alcohol form from an alcohol halides

Back 2

its a substituition reaction where the halide is displaced by a hydroxide atom

Front 3

What are the three different products from reaction with organometallics (grinard reagent) with aldehydes (formaldehyde) ketone

Back 3

A Grignard reagent or organolithium reacting with formaldehyde produces a primary alcohol. A Grignard reagent or organolithium reacting with a higher aldehyde produces a secondary alcohol. A Grignard reagent or organolithium reacting with Ketone produces a tertiary alcohol.

Front 4

What is an example of a grinard reagent

Back 4

general formula RMgX
CH3CH2Mg-Cl

Front 5

Back 5

1. assign of partial charges on C-O bond
2. The e- pair between CH2 and Mg goes to CH2
3. Now CH2 can attack the electron deficient C of the C-O bond
4. E- that was between the C-O go to O
5. Now O attacks Mg. (metal )

Front 6

Back 6

1. O- can abstract H from hydronium ion
2. e- from H-O goes to O
3. water departs
An alcohol forms

Front 7

Back 7

1. Grinard reaction
2. R of RMgCl attacks C of C-O
3. Primary we are starting with formaldehyde

Front 8

Alcohols can also be synthesized by the reduction of aldehydes and ketones name the reducing agents used for the typical reduction reaction

Back 8

Aldehydes and ketones are reduced to alcohols with hydrogen(H2) and Raney nickel, lithium aluminum hydride(LiAlH4), or sodium borohydride NaBH4 Alcohol water esters with H3O+

Front 9

When a ketone or aldehyde is reduced to form an alcohol what are the general structures

Back 9

Formaldehyde is reduced to methanol. A higher aldehyde is reduced to a primary alcohol. A ketone is reduced to a secondary alcohol.

Front 10

Back 10

Recognize the type of reaction, which is reduction. (we know it is a reduction because of the hydride reagent What is added across the double bond? Hydrogen. Classify the starting material, which is a ketone. The product is predicted to be a secondary alcohol. Draw the product. 3-Pentanone is hydrogenated to yield 3-pentanol.

Front 11

Alkoxide ion

Back 11

is the ion formed by the deprotonating an alcohol Alkoxide ions are formed from the reaction of alcohols with metals

Front 12

How can Alkyl halides be synthesized using alcohols

Back 12

1. Alcohols react with hydrogen halide to form alkyl halides with the use of hydrohalic acids 2, 3 via SN1 1 by SN2 (H-Br)
2. Alcohols react with phosphorus trihalide (PX3) to produce alkyl halides P(OH3) 3 degree doesnt work often the best reagent
3. Alcohols react with thionyl chloride SOCl2 to yield alkyl and O=S=O chlorides H-Cl

Front 13

What doesa dehydration of an alchol yield

Back 13

dehydration takes heat and acid to form an alkene and hydronium ion this is a reduction reaction and is not very common the process is take H2SO4 and hear dehydrogenation and then hydrogenate with H2 and pt or you can use tos ether than hydride reducing agent LiAlH4

Front 14

Back 14

1. O from alcohol abstracts a H from the acid
2. H-O electrons go to O
3. Sulfate group leaves

Front 15

Back 15

1. electron pair goes to water
2. water departs
3. formation of carbocation =slow step (rate determining step)

Front 16

Back 16

1. Water abstracts H from H adjacent to carbocation (which is stabalized by secondary Carbon)
2. C-H electrons go to C-C double bond towards the positive charge
3. This is a fast step of the reaction because the carbocation is highly reactive

Front 17

What is the oxidative agent when 0 degree and 1 degree alcohols are synthesized to form aldehydes

Back 17

PCC ( pyridinuim Chlorochromate)

Front 18

When talking about oxidation of 0 degree and 1 degree alcohols to for carboxylic acid name all the possible reagents

Back 18

Na2 Cr 2 O7, H2SO4 (chromic acid reagent)
K2Cr2O7, H2SO4
KMnO4, H2O
NaOCl

Front 19

What does oxidation of a secondary alcohol yield and what reagents can be used

Back 19

ketone
PCC,
NaCr2O7, H2SO4
K2Cr2O7, H2SO4
KMnO4, H2O
NaOCl
HNO3
CrO3, H2SO4

Front 20

Why is it that tertiary alcohols can not be oxidized

Back 20

already has four substituents on the carbon

Front 21

Back 21

1. Oxidation
2. Primary
3. Strong (the only weak oxidizing agent that will give you a aldehyde is PCC
4. carboxylic acid
5. draw the product
CH3CH2CH2-C(OH)=O

Front 22

Alcohols + Carboxylic acid + Acid = ?

Back 22

alcohols react with carboxlic acids in the presence of acid to yield Esters and water

Front 23

Define: Pinacol rearrangement

Back 23

The pinacol rearrangement is a dehydration of a diol to form a rearranged ketone product.

Front 24

Back 24

Alcohols can be converted into alkyl sulfonates by reaction with a sulfonyl chloride that will give a good leaving group like mesylates with a methyl or tosylates

Front 25

Back 25

1. as you can see molecule went from one molecule into 2 molecule- Cleavage
2. one degree
3. Alcohol, alkyl halide

General R-O-R ---> RX+ROH
(HX)
R in RX is the least hindered

Front 26

Back 26

1. Acid Chloride
2. Ester
Both are derivatives of carboxylic acids and can be used ultimately to form ketones to make tertiary alcohols
basically the OH group is removed and replaced by a cl or O-R group and the react with twp equivalent grinard reagents the first atacks the cl and the ester and the alkoxide ion a good leaving group because it stabalizes the negative charge an intermediate is formed and it shift on itself to form a ketone and than the second attack causes the the formation of an alkoxide and H3O dissociated the mgX

Front 27

Back 27

1. R group attacks C
2. E- from C-O bond goes to O
3. Ethylene oxide
4. Alkoxide
5. Primary Alcohol

Front 28

What is the downfall when using Raney nickel and 2 H2 for reducing ketones and aldehydes ?

Back 28

it is very effective but carbon to carbon double bonds will also be reduced as well

Front 29

Infared Spectroscopy background

Back 29

Method of structure determination based upon the amount of infrared light absorbed by a compound. The frequencies indicate stretching and bending between atoms. Absorption of infrared photon produces the excitation of the molecule to a higher vibrational quantum state and this excitation results in absorption of infrared light.

Front 30

for stretching vibration IR intensity is dependent on what

Back 30

For stretching vibration, a photon is absorbed and the molecule is excited to a higher vibrational quantum state only if this vibration results in a change in bond dipole. The bond dipole is based upon bond length and the difference in charge of the bonded atoms. The bond length changes as the bond vibrates. The difference in charge is determined by the electronegativity of the bonded atoms. Atoms that are not identical have a difference in electronegativity and will have a charge difference. No photon is absorbed if the atoms have equal electronegativity.

Front 31

How to calculate number of unsaturation

Back 31

U = C + 1 - ½H + ½N. U = unsaturation number. C = number of carbons. H = number of hydrogens + halogens. N = number of nitrogens + phosphorus.

Front 32

Zones for infared Spec

Back 32

Zone 1 = 3700 - 3200 cm-1; alcohol OH, NH, terminal alkyne C-H.
Zone 2 = 3200 - 2700 cm-1; alkane C-H, aryl or vinyl C-H, aldehyde C-H, carboxylic acid O-H.
Zone 3 = 2300 - 2100 cm-1; alkyne and nitrile triple bonds.
Zone 4 = 1950 - 1650 cm-1; carbonyl functional groups, aromatic overtones. Zone 5 = 1680 - 1450 cm-1; alkene, benzene ring.

Front 33

Fingerprint region

Back 33

1450 - 400 cm-1: contains many absorptions and would be difficult to make exact identification. Fingerprint region of two IR spectra of the same compound will be identical.

Front 34

Name the electromagnetic Spectrum in order of increasing energy (lower freq longer wavelength)

Back 34

Radio
Microwave
infared (2.5 x 10-4cm and 25 x 10-4 cm corresponding to energies of 4.6 to 46 KJ/mol

Front 35

The frequency of the stretching vibration depends on the masses of the atoms and the stiffness of the bond what are the trends

Back 35

heavy atoms vibrate more slowly frequency decreases with increasing atomic weight

stronger bonds are generally more stiffer requiring more force to strech or compress them stronger bonds vibrate faster therefore frequency increases with bond energy

Front 36

C-H stretch

Back 36

2840 - 3000 alkane
3000 - 3100 alkene and aromic
3260 - 3340 alkyne terminal
(s)

Front 37

C-H bend

Back 37

1360 - 1470 alkane

610 - 700 and
1120 - 1370 alkyne (terminal)

Front 38

C-C bond stretch

Back 38

single 1200
double 1660
triple <2200

Front 39

Topic: IR Spectroscopy
how can the wave numbers be broken down into 5 zones

Back 39

Zone 1- 3700- 3200 cm-1
Zone 2- 3200-2700 cm -1
Zone 3- 2300-2100 cm-1
Zone 4- 1950- 1650 cm-1
Zone 5- 1680- 1450 cm-1

Front 40

What are the important functional groups in zone 1

Back 40

3700-3200 cm-1
Alcohol OH
NH (near 3500)
Terminal alkyne C-H

Front 41

What are the important functional groups in zone 2

Back 41

3200-2700 cm-1
alkane C-H (2840-3000)
aryl or vinyl CH
aldehyde C-H (2695-2830)
carboxylic acid OH (2500-3000)
Alkene C-H 3000-3100

Front 42

What are the important functional groups in Zone 3

Back 42

2300-2100
alkyne triple
nitrile triple 2220-2260

Front 43

What are the important functional groups in Zone 4

Back 43

1950-1650
Carbonyl functional groups (1750-1690)
C double 1650

Front 44

What important function groups are in Zone 5

Back 44

1680-1450
alkene
benzene
aromatic 1400-1500 and 1585-1600

Front 45

Once you identified a carbonyl group in an IR list a technique to figure out what functional groups it can be

Back 45

all will have to have a zone 4 present
acid will also have a broad zone 2
amides will have a medium 2 peak zone 1
ester will have a medium around 1300-1000 in fingerpriint
anhydride will have two zone 4
aldehyde will have two (w) zone 2
ketone will only have carbonyl

Front 46

Both carbonyl groups acids and aldehyde can be diffrentiated how looking at an IR spec

Back 46

acid will have a broad zone 2 OH
aldehyde will have two weak in zone 2 CH

Front 47

Mass Spectrometry definition

Back 47

provides the molecular weight and valuable information about the molecular formula using a very small sample the sample is struck by high energy electrons that break the molecules apart

Front 48

Topic: Mass Spec
what are the normal trends in M+1 and M+2 ion peaks and how can you tell if S, Cl, Br, I, And N are in an molecular formula

Back 48

a molecule without s,CL,Br, I and N usually have a small M+1 peak and an even smaller M+2 peak
Br- has M+2 as large as M+
Cl- M+2 a third as large as M+
I- I+ at 127; large gap
N odd M+
S M+2 larger than usual (4% of M+)

Front 49

What is the formula that relates The strength of the magnetic field to the frequency

Back 49

V= (4257.8 sec-1 gauss-1) x BO

v resonance frequency
Bo strength of external magnetic field

Front 50

Define: Chemical Shift

Back 50

chemical shift is the difference in pp, between the resonance frequency of the proton being observed and that of TMS

Chemical Shift= Shift downfield from TMS (HZ) / total spectrometer frequency MHz\

Front 51

Because of chemical shifts of O-H and N-H protons depend on the concentration and the solvent it is difficult to tell whether or not a given peak corresponds to one of these types of protons. How can you tell

Back 51

You can shake a sample with an excess of deuterium oxide, D2O. when a second NMR is recoreded the interchangable hydrogens are quickly replaced by deuterium atoms which are invisible in the proton NMR spectrum

Front 52

What is the common solvent for C-13 NMR

Back 52

CDCl3

Front 53

What is the operating frequency when the external magnet is running at 70, 459 gauss and 14,092 gauss for both proton and carbon NMR

Back 53

70,459 gauss - 300 MHz H-1
75.6 MHz C-13
14,092 gauss- 60 MHz H-1
15.1 MHz C-13

Front 54

Splitting of signals (pascal triangle)

Back 54

Number of peaks – 1 = number of hydrogens on adjacent carbons.
Singlet, s (one peak) = 0 H on adjacent C.
Doublet, d (two peaks, 1:1) = 1 H on adjacent C.
Triplet, t (three peaks, 1:2:1) = 2 H on adjacent C.
Quartet, q (four peaks, 1:3:3:1) = 3 H on adjacent C. Quintet, quint (five peaks, 1:4:6:4:1) = 4 H on adjacent C. Sextet, sext (six peaks, 1:5:10:10:5:1) = 5 H on adjacent C.
Septet, sept (seven peaks, 1:6:15:20:15:6:1) = 6 H on adjacent C.
Multiplet, m (many peaks) = cannot tell number of H.

Front 55

complex splitting

Back 55

splitting by two or more different kinds of protons with different coupling constants

Front 56

deshielded

Back 56

bonded to a group that withdraws part of the electron density from around the nucleus. the absorptions of deshielded nuclei are moved downfield resulting in larger chemical shifts

Front 57

diastereotopic atoms

Back 57

nuclei that occupy diastereomeric positions the replacement test for diastereotopic atoms give diastereomers .

Front 58

downfield

Back 58

at a lower value of the applied magnetic field towards the left on the NMR spectrum the more deshielded a nucleus is the farthur downfield it absorbs

Front 59

fourier transform spectroscopy

Back 59

spectroscopy that involves collecting transients (containing all the different resonance frequencies) and converting averged transients into a spectrum using mathamatics fourier transform

Front 60

Gyromagnetic ratio

Back 60

a measure of the magnetic properties of a nuceus the resonance freq is given by the equation v=yBeff/2pi, where b eff is the effective magnetic field at the nucleus the gyromagnetic ratio of a proton 26,753 for a proton C-13 is 6728

Front 61

induced magnetic field

Back 61

the magnetic field set up by the motion of electrons in a molecule in response to the application of external magnetic field

Front 62

magnetically coupled

Back 62

nuclei that are close enough that their magnetic fields influence each other resulting in spin-spin splitting

Front 63

off resonance decoupling

Back 63

a technique used with C-13 NMR in which only the protons directly attached to a carbon can cause spin-spin splitting

Front 64

upfield

Back 64

at a higher value of the applied magnetic field towards the right on the NMR spectrum the more shielded it is the farther upfield it absorbs

Front 65

glycol

Back 65

synonymous with diol the term is used when the hydroxide groups are 1,2 or sometimes called vicinal diols

Front 66

mercaptan (thiol)

Back 66

the sulfur analogue of an alcohol R-SH

Front 67

What is a Lucas Reagent and how does it react with primary secondary and tertiary alchols

Back 67

lucas reagent is composed of
HCl and ZnCl2
2, 3 react by a Fast Sn1 reaction while primary will react by a slow SN1 reaction

Front 68

Can alcohols act as acid or bases?

Back 68

because hydrogen is attached directly to an EN atom it becomes acidic (protic acid, or protic donors) a strong base can remove the proton from the oxygen

Front 69

How do you measure the aciditiy of an molecule

Back 69

there is the Ka value which the larger that is the stronger the acid then you have the Pka value which is simple the negative log of Ka the the smaller that value is the stronger the acid

Front 70

what is the effects of adding substituents on alcohols

Back 70

acidity will increase this is due to the electron withdrawing effect where Cl is pulling electrons away makinh the O-H bond more polar and it will dissociate better conjugate base ability to stabalize charge increases acidity

Front 71

Define the term oxidation and the term reduction

Back 71

addition of O or O2; addition of X2 (halogens), loss of H2
Reductuion: addition of H2 loss of O or O2, loss of halogens

Front 72

Chromic Acid reagent

Back 72

is it a mixture of dissolved Na2Cr2O7 in a mixture of sulfuric acid and water that oxidizes 2 alcohol to ketones

Front 73

PCC reagent

Back 73

is a mixture of CrO3' Pyridine and HCl works in non polar solvents like CH2Cl2 (dichloromethane)

Front 74

Dehydrogenation

Back 74

removing of H2 with high temperature in a CuO catalyst

Front 75

Swern oxidation

Back 75

uses DMSO- Di methyl sulfoxide + (COCl)2 Oxalyl chloride low temp also need
(CH3CH2)3N, CH2Cl2

Front 76

When talking about the oxidation of Alcohols there is Chromic acid, PCC, Dehydrogenation, Swern what is another technique that can be used

Back 76

KMnO4, H2O or HNO3 (10-20 Celcius)

Front 77

Explain exactly what bonds has to break for an alcohol to act as a nucleophile or an electrophile

Back 77

acts as a weak nucleophile when O-H bond is broken
acts as an electrophile when C-O bonds break

Front 78

What is the advantage of making tosylates from alcohols

Back 78

well alcohols can be used as electrophile if protonated but a strong base will abstract the proton so you convert it to a tosylate ether making an excellent leaving group

Front 79

Although Reduction of alcohols are rare what are the two ways you can go about doing that

Back 79

1. Via dehydrogenation with (H2SO4)/Heat then hydrogenation via H2/ pt
2. Tos ether intermediate then reducing with hydride agent LiAlH4

Front 80

Lucas reagent

Back 80

is a mixture of ZnCl2 and HCl occurs via SN1 reaction with 2 and 3 degree to form alkyl halides 1 degree are to unstable goes via SN2 this reagent is usually only used with Cl because it is smaller and less polarizable than Br and this reaction tends to be slower tertiary is the fastest

Front 81

There are two good mechanism in making alkyl-chlorides what are the two and which is better

Back 81

lucas reagnet and the use of thionyl chloride (SOCl2) which resembles that of a SN1 reaction it is a better way excpet with tertiary the best was will be H-Cl with acid catalyst

Front 82

How can you make an alcohol into an ether

Back 82

by bimolecular dehydration via SN2

Front 83

recall acid catalyzed dehydration can occur via elimination or substitution what will be the product when the reactant is an alcohol

Back 83

e1 elimination of an alcohol will yield an alkene (concef H2SO4)
Sn2 will yield an ether

Front 84

Cold dilute KMnO4 and OH- is what kind of reagent for what type of reaction ?

Back 84

This is a strong oxidizing agent and in cold dilute alkaline conditions it will oxidize an alkene to a diol in hot acidic conditions it will furthur cleave the carbon to carbon double bonds

Front 85

which reagent is better at oxidizing 2 and 3 degree alcohols to chloride halide Lucas reagent or Thionyl chloride

Back 85

thionyl chloride

Front 86

what reagent is better at oxidizing alkyl bromides

Back 86

phosphate tri bromide P/I2 for iodide