2. 1. Find the longest chain1. Find the longest chain containingcontaining thethe –OH–OH
function: alkanfunction: alkanee alkanalkanol.ol. Note: This may not beNote: This may not be
the longest chain in the molecule!the longest chain in the molecule!
2. Number such as to give2. Number such as to give HO-HO-CC lowestlowest ##
3. Other rules same as in alkanes3. Other rules same as in alkanes
4,4-Dimethyl-1-4,4-Dimethyl-1-nonannonanolol 5-Bromo-3-propyl-5-Bromo-3-propyl-
2-2-heptanheptanolol
OHOH
OHOH
BrBr
11
22
3344556677
8899
11
22
334455
66
NamesNames
77
4. StructureStructure
OO can be thought of ascan be thought of as spsp33
-hybridized,-hybridized,
“tetrahedral”, i.e. bent, not linear.“tetrahedral”, i.e. bent, not linear.
DDHºHº (O H) = 119 kcal mol(O H) = 119 kcal mol-1-1
HHHH33CC
OO
5. Most striking: RelativelyMost striking: Relatively high melting andhigh melting and
boiling points,boiling points, andand water solubilitywater solubility.. Why?Why?
8. RROOHH ++ HH22OO RROO--
++ HH33OO++
ppKKaa’s’s
HH22OO
CCHH33OOHH
CCHH33CCHH22OOHH
((CCHH33))22CCHHOOHH
15.715.7
15.515.5
15.915.9
17.117.1
((CCHH33))33CCOOHH
ClClCCHH22CCHH22OOHH
CCFF33CCHH22OOHH
CCFF33CCHH22CCHH22OOHH
1818
14.314.3
12.412.4
15.415.4
StericSteric
effecteffect
““Inductive”Inductive”
electronicelectronic
effect.effect.
Tapers offTapers off
with distance.with distance.
KK Sterics
and
solvation
AcidityAcidity
9. AlkoxidesAlkoxides RROO
CHCH33OH + NaOH + Na NHNH22 CHCH33O Na + NHO Na + NH33
CHCH33CHCH22OH + Na OH CHOH + Na OH CH33CHCH22O Na + HO Na + H22OO
KK ~~ 11
ppKKaa 15.515.5 3535
KK
15.915.9 15.715.7
++ -- ++--
++--++-- KK
KK = 10= 1019.519.5
Preparation:Preparation:
When CHWhen CH33CHCH22OH isOH is solventsolvent, equilibrium is displaced to, equilibrium is displaced to
thethe rightright..
10. Lone e-pairs can be protonated.Lone e-pairs can be protonated.
Molecules which are both acidsMolecules which are both acids
and bases are calledand bases are called amphotericamphoteric..
HH
HH
R-R-OO-H +-H + HH22SOSO44 R-R-OO + HSO+ HSO44
Oxonium ionOxonium ion ppKKaa ~ -3~ -3
CompareCompare RR NNHH22 ++ HH RR NHNH33
Ammonium ionAmmonium ion ppKKaa ~10~10
Alcohols are alsoAlcohols are also basicbasic::
++ --
++ ++
15. 2. Reduction of Aldehydes and2. Reduction of Aldehydes and
Ketones .Ketones .
OO
R C R’R C R’
OO R C HR C H
CC
OO
CC
OO
CC
OO
δδ
+2e reduction+2e reduction
-2e oxidation-2e oxidation CC
OO
CC
HHOO HH 22ee + 2+ 2HH equalsequals HH22. There are. There are
two practical ways to add Htwo practical ways to add H22::
a. as such, or b. asa. as such, or b. as HH--
, then, then HH++
..-2-2HH++
+2+2HH++
++
δδ++
++
RedoxRedox relationship:relationship:
16. NaNa++
H:H:--
++ BBHH33 NaNa++
BBHH44
--
Sodium borohydrideSodium borohydride
spsp22 spsp33
LiLi++
HH--
++ AlAlHH33 LiLi++
AlAlHH44
--
Lithium aluminumLithium aluminum
hydridehydride (LAH)(LAH)
Ketones RKetones Rsecsec--OOHH
Aldehydes RAldehydes Rprimprim--OOHH
redred
redred
oxox
oxox
What areWhat are
thethe
reagents?reagents?
ReductionReduction
Hydrogenation is possible, but is cumbersome: Needs HHydrogenation is possible, but is cumbersome: Needs H22
pressure and catalysts (e.g., Pd, Pt).pressure and catalysts (e.g., Pd, Pt).
Better: Use reagent that is equivalent toBetter: Use reagent that is equivalent to H:H:--
, but not as, but not as
basic, such asbasic, such as “complex” hydrides“complex” hydrides, prepared simply by:, prepared simply by:
17. NaBHNaBH44 is less reactive, more selective:is less reactive, more selective:
NaNa++
BBHH44 44HH22 + NaB(+ NaB(OHOH))44
LiLi++
AlAlHH44 44HH22 + LiAl(+ LiAl(OHOH))44
RRXX + LiAl+ LiAlHH44 RR-H-H
HH-OH-OH
HH-OH-OH --
--
These reagents are still somewhatThese reagents are still somewhat basicbasic and willand will
undergo hydrolysis. Reactivity differs greatly.undergo hydrolysis. Reactivity differs greatly.
--
--
LiAlHLiAlH44 (but(but not NaBHnot NaBH44) will reduce even halides:) will reduce even halides:
slowslow, OK to use in CH, OK to use in CH33OHOH
But:But:
violentviolent, needs aprotic, needs aprotic
solvents (ethers)solvents (ethers)
18. NucleophilicityNucleophilicity:: Attack atAttack at
CC
OO
OO HHHHOO
OO LiLi++
HH33AlOAlO HH HHOO HH
NaBNaBHH44, CH, CH33OOHH
LiAlLiAlHH44
etherether
HH++
, H, H22OO
work upwork up
--
ElectrophilicElectrophilic
carbonyl carboncarbonyl carbon
HydrideHydride
The resulting alkoxide is protonated byThe resulting alkoxide is protonated by
alcohol solvent or on aqueous work upalcohol solvent or on aqueous work up
The aqueous work-up step is normally not shown in eqns.The aqueous work-up step is normally not shown in eqns.
HH HH HH
20. CrCrVIVI
reagentsreagents CrCrIIIIII
Typically, use NaTypically, use Na22CrCr22OO77
or CrOor CrO33 in Hin H22O, HO, H22SOSO44
CrCr
OO
OHOH
OO
HOHO
Chromic acidChromic acid
+3e+3e
OxidationOxidation
OHOH
+ Na+ Na22CrCr22OO77
OO
HH22SOSO44
HH22OO
Good for RGood for Rsecsec-OH-OH
Example:Example:
Best for secondary alcohols giving ketones. PrimaryBest for secondary alcohols giving ketones. Primary
alcohols arealcohols are overoxidizedoveroxidized in aqueous medium.in aqueous medium.
21. PyridinePyridinePyridinium chlorochromate :Pyridinium chlorochromate : “PCC”“PCC”
OHOH OHOH
OO
HH
OO
Mechanism:Mechanism: via intermediate chromate estervia intermediate chromate ester
NNHH
++
RCHRCH22OOHH HOHO Cr OHCr OH
OO
OO
R CH O Cr OHR CH O Cr OH
HH OO
OO
RCH +RCH +
OO
CrOHCrOH
OO
OO
goes on to Crgoes on to CrIIIIII
NN
PCCPCC
HHOHOH
VIVI
IVIV
RRprimprim–OH–OH: Use CrO: Use CrO33ClCl
--
Avoids overoxidation with aqueous Cr reagents.Avoids overoxidation with aqueous Cr reagents.
E2E2
25. Not strong enough for RNot strong enough for R ––
MM++
+ R’X R-R’+ R’X R-R’
(obviously, since they are made from RX).(obviously, since they are made from RX).
But:But:
OO
RR MM O MO M
RR
δδ--
δδ--
δδ++
δδ++
++--
RM asRM as NucleophilesNucleophiles
++
Works with ketones, aldehydes,Works with ketones, aldehydes,
even formaldehyde, CHeven formaldehyde, CH22=O=O
HH22OO
OO HH
RR
34. Initial dose causes euphoria, but alcohol isInitial dose causes euphoria, but alcohol is
a general, CNS active, depressant drug.a general, CNS active, depressant drug.
35.
36. AbsorptionAbsorption: 20% stomach, 80% gastrointestinal.: 20% stomach, 80% gastrointestinal.
Food slows it, but what is in, stays in……Food slows it, but what is in, stays in……
Distribution through the body and brain is fast.Distribution through the body and brain is fast.
Intravenous can be lethal: Sudden depression ofIntravenous can be lethal: Sudden depression of
the respiratory system, brain centers.the respiratory system, brain centers.
Excretion:Excretion: Lungs Alcoholic breath; 5% inLungs Alcoholic breath; 5% in
urine.urine.
MetabolismMetabolism: Zero order in ROH! Linear with: Zero order in ROH! Linear with
time; 10 mL/h (cocktail/hour); by oxidation:time; 10 mL/h (cocktail/hour); by oxidation:
CHCH33CHCH22OHOH CHCH33CHCH COCO22
PoisonousPoisonous
Second step is prevented bySecond step is prevented by
antabuse (disulfiram):antabuse (disulfiram):
N S
S N
S
S
OO
EnzymeEnzyme EnzymeEnzyme
37. Effect misconceptions:Effect misconceptions:
1. Not a stimulant1. Not a stimulant
2. Doesn’t warm you2. Doesn’t warm you
3. Doesn’t help your sleep3. Doesn’t help your sleep
4. Not an aphrodisiac4. Not an aphrodisiac
