Organic chemistry practical course (OCP1)
WS 04/05
529-0229-00
Assistant: Fabio Di Lena
Synthesis of
exo-1,7,7-trimethylbicyclo[2.2.1]hepta-2-ol
(isoborneol)
CH3
H3C
OH
H3C
H
Presented by
Moreno Wichert
Student of Interdisciplinary Natural Sciences (Biochem.-Phys.)
D-CHAB, ETH Zurich
Nuolen SZ
January 24, 2005
1. Method
Synthesis of exo-1,7,7-trimethylbicyclo[2.2.1]hepta-2-ol by a stereoselective reduction of
D-(+)-champhor to the diastereomer using sodium borohydride
2. Chemical equation
CH3
H3C
CH3
H3C
CH3
H3C
NaBH4
MeOH
H3C
OH
H3C
O
37.83 g mol-1
32.04 g mol-1
C10H16O
152.23 g mol-1
H
H3C
H
C10H18O
154.25 g mol-1
OH
C10H18O
154.25 g mol-1
3. Mechanism
H
OR'
R
C
R
O
C
R
NaOR'
OH
BH3
R
H
H
H3
B
Na+
CH3
H3C
CH3
H3C
OCH3
H3C
H3C
H
H3C
O
H3C
H
CH3
H3C
OH
H
CH3
H3C
H
H
H3C
O-
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isoborneol
H
H3C
OH
borneol
4. Experimental accomplishment
1 g of D-(+)-champhor1 was dissolved in 5 ml methanol2 in a round-bottom flask and 720 mg
of sodium tetrahydridoborate3 were carefully added with a spatula. The mixture was refluxed
for 10 minutes. After cooling down and adding ice water, the substance was filtered. finally,
the substance was dissolved with diethyl ether4 and the two phases were seperated. The
ether phase was dried over CaCl25 and the product (isoborneol6) was then analyzed.
Comment: For the first try we used only 120 mg of sodium tetrahydridoborate which didn’t
yield enough product!
Physical and safety data of the substances
1)
C10H16O ; M = 152.23 g mol-1 ; ρ = 0.99 g cm-3 ; melting point = 176 - 180 °C ;
boiling point = 204 °C ; poison class 3 ; WGK 1 ; risk phrases: R11-36-37-38 ;
safety phrases: S16-26-37-39
2)
CH4O ; M = 32.04 g mol-1 ; ρ = 0.791 g cm-3 ; melting point = -98 °C ; boiling point = 64.7 °C ;
poison class 3 ; WGK 1 ; risk phrases: R11-23-24-25-39 ; safety phrases: S7-16-36-37-45 ;
MAK: 270 mg m-3
3)
NaBH4 ; M = 37.83 g mol-1 ; ρ = 1.07 g cm-3 ; melting point = 400 °C ; boiling point = 500 °C ;
poison class 3 ; WGK 3 ; risk phrases: R15-25-34 ; safety phrases: S7-8-14.2-26-28-36-37-39-45 ;
4)
C2H5OC2H5 ; M = 74.12 g mol-1 ; ρ = 0.714 g cm-3 ; melting point = -116 °C ; boiling point = 35 °C ;
WGK 1 ; risk phrases: R12-19-22 ; safety phrases: S9-16-29-33
5)
CaCl2 ; M = 110.99 g mol-1 ; ρ = 2.15 g cm-3 ; melting point = 782 °C ; boiling point > 1600 °C ;
poison class 5 ; WGK 1 ; risk phrases: R36 ; safety phrases: S22-23-24
6)
C10H18O ; M = 154.25 g mol-1 ; melting point = 208 - 214 °C ; safety phrases: S24-25 ;
no other data available
Refluxing apparatus with Dimroth condenser
page 3
5. Analytical results and characterization
Yield after distillation:
0.8 g (27 %)
Measured melting point: 202 °C
IR bands [cm-1]:
3615 (O-H stretch)
2955 (C-H stretch)
1478-1100 (methyl groups)
6. Literature
Bülle, Jan; Hüttermann, Aloys (2000): Das Basiswissen der organischen Chemie, Stuttgart
(Georg Thieme Verlag)
Streitwieser, A.; Heathcock, C. H.; Kosower, E. M. (1994): Organische Chemie (2. Auflage),
Weinheim (VCH Verlagsgesellschaft mbH)
http://www.chemistry.mcmaster.ca/~chem2o6/labmanual/expt7/2o6exp7.html (24.01.2005)
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