Transcript No Slide Title

TERPENES
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TERPENES
The Czech chemist Leopold Ruzicka ( born 1887) showed that
many compounds found in nature were formed from multiples
of five carbons arranged in the same pattern as an isoprene
molecule (obtained by pyrolysis of natural rubber).
natural
rubber
D
head
tail
C
.
C
C C
C
isoprene
C
C
C
isoprene
unit
C
C
He called these compounds “terpenes”.
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TERPENES
1. The number of C atoms is a multiple of 5 C5
C10 C15 C20 C25 C30 C35 C40
2. Each group of 5 C is an isoprene subunit
3. They can be saturated or unsaturated
4. Many contain O atoms as well.
5. What they all have in common is 1 & 2 above.
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JOINING ISOPRENE UNITS
.
C
The terms head-to-tail and
tail-to-tail are often used to
describe how the isoprene
units are joined.
C
C
C
Head-to-Tail
C
an extra
bond
Tail-to-Tail
Head-to-Tail
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TERPENES CAN BE SHOWN TO BE
FORMED FROM ISOPRENE UNITS
7
1
2
6
5
10
4
9
3
head to
tail
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limonene
from lemon and
orange peels
diagram showing how two
isoprene units combine to
form the limonene skeleton
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CLASSIFICATION OF TERPENES
TYPE OF
TERPENE
NUMBER OF
CARBON ATOMS
ISOPRENE
UNITS
hemiterpene
C5
one
terpene
sesquiterpene
diterpene
C10
C15
C20
two
triterpene
C30
six
tetraterpene
C40
eight
NOTE:
hemi = half
sesqui = one and a half
three
four
di
= two
tri
= three
tetra = four
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SOME TERPENES (C10)
CH2OH
OH
geraniol
rose and other flowers
menthol
peppermint
O
camphor
a-pinene
camphor tree
turpentine
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SESQUITERPENES
CH3
CH3
CH CH3
guaiazulene
CH3
geranium oil
CH3
CH3
CH3
caryophyllene
oil of cloves
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….. more sesquiterpenes
CH3
CH3
CH3
CH3
cedrene
cedar wood oil
CH3
CH3
H3C
longifolene
pine species
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TRITERPENES
CH3
CH3
CH3
OH
CH3
CH3
CH3
CH3
ambrein
ambergis
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TETRATERPENE
b-carotene
carrots
head-to-tail
tail-to-tail
head-to-tail
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