medchem 13

Question 1

in the alpha carbon the h is — and can be deprotonated by —

Answer 1

• slightly acidic
  -strong base

Question 2

resonance occurs when the pi electrons are adjacent and are separated by — to another pi electron or charge .

Answer 2

• one bonds only
  ( so basically 2 electrons will be seperated by one bond and they will enter resonance ) , CHECK THE RESOANNC STRUCTURE

Question 3

neutral nucleophiles as O and N have —- hydrogen’s

Answer 3

one or two

Question 4

aldehydes are — than ketones because of — and —

Answer 4

-more reactive
- steric reasons and electronic reasons

Question 5

steric reasons is when the space is — which allows the nuclephile to attack while in ketone the bond angle is — so substituents will move — and it — the addition reaction

Answer 5

• bigger
• reduced
• closer
• disfavours

Question 6

for electronic reasons because aldehydes are —- than ketone and the electron donor subsutiuent is —

Answer 6

• more elctrophillic
• +2< +1 since ketone have another carbon and it will decrease the charge

Question 7

why is methyl more electron donating than H?

Answer 7

• bc carbon is more electronegative than hydrogen
• so the carbon can attack the 2 pairs of electrons and making then carbon -ve so 6 electrons are closer to carbon

Question 8

can acetals and ketals be formed in base-catalysed reaction

Answer 8

NO (O-h is not a leaving group) so the reaction stops at hemicetals/hemiketals even if excess alcohol is present

Question 9

reactions w/ hydroxyl amines ( H2N - OH) which are 2 —- on the same molecules
- oxygen has — but the electronegativity is —
- nitrogen has — but the elctrongativity is —
- nitrogen is a better — than oxygen

Answer 9

-neutral nucleophiles
- 2 lone pairs , high
- 1 lone pair , low
- more nucleophilic

Question 10

hemiactelas and hemiketals are – and they tend to — to their carbonyl compounds , purification is done by —-

Answer 10

• unstable
• decompose
• removing agents , decomposition to maintain equilibrium

Question 11

glucose is a —- and has — and — groups to form – and the most stable cycles are —

Answer 11

-cyclic stable heimacetals
- aldehydes and alcohols
- intramoliuclar (internal ) hemicetals
- 6-memebered rings

Question 12

cyclic hemiacetals are stable as glucose in the forward reaction is — than the reverse because the — is closer to aldehyde and ready to react

Answer 12

• faster
• alcohol

Question 13

factors affecting the reactivity and polarisation:
( RECHECK ALL SLIDES AGAIN )

Answer 13

-Factors that place more positive charge on the carbonyl (electron withdrawing groups nearby) make the carbonyl more positive and more reactive
-The polarization of carbonyl groups also effects the boiling point of aldehydes and ketones to be higher than those of hydrocarbons in the same amount. The larger the carbonyl compound the less soluble it is in water. If the compound exceeds six carbons it then becomes insoluble.

Question 14

in oxygen nucleophiles the — will be eliminated and —
nitrogen nucleophiles will —– and forms —

Answer 14

• water will be eliminated and another nucelophile will come to replace it
• water is eliminated and double bond is formed, no 2nd nucleophile but to eliminate the water we need h+ catalyst