1 TERPENES

2 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). He called these compounds “terpenes”. C C C C. isoprene natural rubber  isoprene unit head tail CC CC C

3 TERPENES 1.The number of C atoms is a multiple of 5 C 5 C 10 C 15 C 20 C 25 C 30 C 35 C 40 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.

4 JOINING ISOPRENE UNITS The terms head-to-tail and tail-to-tail are often used to describe how the isoprene units are joined. C C C C. an extra bond Head-to-Tail Tail-to-Tail

5 diagram showing how two isoprene units combine to form the limonene skeleton TERPENES CAN BE SHOWN TO BE FORMED FROM ISOPRENE UNITS head to tail limonene from lemon and orange peels

6 CLASSIFICATION OF TERPENES TYPE OF NUMBER OFISOPRENE TERPENE CARBON ATOMS UNITS hemiterpene terpene sesquiterpene diterpene triterpene tetraterpene C 5 C 10 C 15 C 20 C 30 C 40 one two three four six eight hemi = half di = two sesqui = one and a halftri = three tetra = four NOTE:

7 SOME TERPENES (C 10 )  -pinene camphor geraniol menthol rose and other flowerspeppermint camphor treeturpentine

8 SESQUITERPENES guaiazulene geranium oil caryophyllene oil of cloves

9 cedrene cedar wood oil longifolene pine species ….. more sesquiterpenes

10 TRITERPENES ambrein ambergis CH 3 CH 3 CH 3 CH 3 OH CH 3 CH 3 CH 3

11  -carotene carrots TETRATERPENE tail-to-tail head-to-tail