TERPENOID

TERPENE AND TERPENOIDS are the natural products or secondary metabolites.

These are produced by living organism so belongs to the category of natural products. 

Terpenes are hydrocarbon in nature. 

While terpenoids are oxygenated hydrocarbon or de - hydrogenated derivative of terpene. 

ISOPRENE RULE

GIVEN BY-ruzicka and wallach in 1887.

According to this rule thermal decomposition of almost all terpene give isoprene as one of product. 

Head-branched end of isoprene

Tail-unbranched end of isoprene

It is a carbon-5 unit. 

According to this rule maximum number of terpene are formed by linking of isoprene unit in head to tail linkage. 

[1,4 linkage] 

But it is not a fixed rule it is just the guiding principle.

Has many exceptions like carotenoid, lavandulol. 

CLASSIFICATION OF TERPENE

Similarly terpenoids can be classified 

Properties 

They are volatile in nature. 

Colourless, non polar, highly flammable in nature. 

Uses of terpenes 

1. Produced by plants to attract the insect

    For pollination, or to expel certain animals using these plants as food. 

2.natural rubber are also terpene. 

3.some used as organic solvent. 

4.used as fragrance in consumer products such as perfumes. 

5.some are also used as traditional medicines.