1

TERPENESTERPENES

2

TERPENESTERPENES

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).

He called these compounds “terpenes”.

C C

C

C C

.

isoprene

natural rubber

isoprene unit

head

tail

C C

C C

C

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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 UNITSJOINING ISOPRENE UNITS

The terms head-to-tail andtail-to-tail are often used todescribe how the isopreneunits are joined.

C C

C

C C

.

an extrabond

Head-to-Tail

Head-to-Tail

Tail-to-Tail

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diagram showing how twoisoprene units combine toform the limonene skeleton

TERPENES CAN BE SHOWN TO BE TERPENES CAN BE SHOWN TO BE FORMED FROM ISOPRENE UNITSFORMED FROM ISOPRENE UNITS

head totail

limonenefrom lemon andorange peels

12

34

5

6

7

8910

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CLASSIFICATION OF TERPENESCLASSIFICATION OF TERPENES

TYPE OF NUMBER OF ISOPRENE TERPENE CARBON ATOMS UNITS

hemiterpene

terpene

sesquiterpene

diterpene

triterpene

tetraterpene

C5

C10

C15

C20

C30

C40

one

two

three

four

six

eight

hemi = half di = twosesqui = one and a half tri = three

tetra = four

NOTE:

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SOME TERPENES (CSOME TERPENES (C1010))

CH2OH

OH

-pinenecamphor

geraniol mentholrose and other flowers peppermint

camphor tree turpentine

O

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SESQUITERPENESSESQUITERPENES

CH3

CH3

CH CH3

CH3guaiazulenegeranium oil

CH3

CH3

CH3

caryophyllene

oil of cloves

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cedrenecedar wood oil

CH3

CH3

CH3 CH3

CH3CH3

H3C

longifolenepine species

…….. more sesquiterpenes.. more sesquiterpenes

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TRITERPENESTRITERPENES

ambreinambergis

CH3

CH3

CH3

CH3

OHCH3

CH3CH3

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-carotenecarrots

TETRATERPENETETRATERPENE

tail-to-tailhead-to-tail

head-to-tail