Natural Product Chemistry Part 2

Question 1

Gives examples of classes under terpenes and derivation

Answer 1

Derived from reaction of dimethylallyl pyrophosphate ( DMAPP) and isopentenyl pyrophosphate (IPP)
Examples :
Monoterpenes (C10)
Sesquiterpenes (C15)
Diterpenes (C20)
Triterpenes and steroids( C30)
Tetraterpenes ( carotenoids - C40)

Question 2

Monoterpenes (C10) , synthesis? Examples and uses

Answer 2

Produced by reaction between dimethyallyl pyrophosphate and isopentenyl pyrophosphate to produce product geranyl pyrophosphate
Examples thymol, limonene ( good for colors, tastes used as perfumes and flavorings in food and cosmetic industries)

Question 3

What products does geranyl pyrophosphate produce

Answer 3

1. Thymol ( aromatic Monoterpenes)
2. Beta citronellol (a cyclic Monoterpenes rose oil)
3. Limonene ( cyclic Monoterpenes lemon)

Question 4

Formation and example of sesquiterpenes ( C15)

Answer 4

Staring compound farnesyl pyrophosphate (FPP) produced by reaction of GPP with molecule of IPP
Example - antimalarial: artemisinin

Question 5

Formation of diterpenes and example

Answer 5

Formed by rxn of farnesyl pyrophosphate (FPP) with isopentenyl pyrophosphate (IPP)
Examples : paclitaxel

Question 6

Triterpenes

Answer 6

Steroids ie testosterone

Question 7

Tetraterpenes

Answer 7

Formed by two geranyl pyrophosphate
Examples orange color of carrots ie beta-carotene
Employed as coloring agents in foods, cosmetics

Question 8

Give classes of glycosides

Answer 8

Composed of sugar and aglycone (coumarin, flavonoid etc)
1.Cyanide glycoside - amygdalin used as plant chemical defense
2. Glucosinolates ie allylisothiocynates
3.cardiac glycosides ie digoxin for HF
4.anthraquinone glycoside ie laxative ( Senna)

Question 9

Give classes of alkaloids (8)

Answer 9

1. Imidazole alkaloid
2. Xanthine alkaloid
3. Tropane alkaloid
4. Quinolone
5. Indole
6. Isoquinoline
7. Phenylalkylamine
8. Pyridine, piperidine and pyrrolizidine

Question 10

Use of pyridine, piperidine , pyrrolizidine

Answer 10

Nicotine : cessation of smoking
Coniine: poison

Question 11

Phenylalkyliamine

Answer 11

Ephedrine - treat severe asthma
Colchine- treatment of gout

Question 12

Quinolone alkaloid

Answer 12

Quinine- malaria
Quinidine - treat type 1 cardiac arrhythmia

Question 13

Isoquinoline

Answer 13

Morphine - analgesic
Codeine- otc analgesic
Papaverine- antispasmodic

Question 14

Indole

Answer 14

Reserpine- treat hypertension
Physostigmine - myasthenia gravis

Question 15

Tropane and Xanthine

Answer 15

Tropane -Cocaine - control severe pain
Xanthine- theophylline(asthma) and coffee (CNS stimulant )

Question 16

Imidazole

Answer 16

Pilocarpine treat glaucoma