Terpenes and Terpenoids Terpenes - class of >20,000 compounds containing carbon atoms in multiples of five Terpenoids - oxygen-containing terpenes (alcohols, ketones, aldehydes) The name "terpene" is derived from the word "turpentine" (terebentin-reçineden elde edilir) Terpenes and terpenoids are the primary constituents of the essential oils of many types of plants and flowers. Essential oils : bitkilerdeki sellüloz ve nişasta dışındaki çoğu kez uçucu olan belli bir tad/kokuya sahip bileşikler) rose oil (zencefil) (kereviz) 1
The basic molecular formulae of terpenes are multiples of that, (C 5 H 8 ) n where n is the number of linked isoprene -Isoprene - 2-methyl-1,3-butadiene- units. This is called the isoprene rule or the C5 rule. Compounds containing carbon atoms in multiples of 5 suggest a C 5 building block - isoprene units linked in a head-to-tail fashion Ancak unutulmamalıdır ki moleküller büyüyüp halkalaştıkça biyosentezler başkalaşmalara yol açabilirler. Retrosentezlerle başa gidilir. 2-methyl-1,3-butadiene Head - branched end of isoprene Tail - unbranched end of isoprene 2
Finding the isoprene building block - cyclic compounds Finding the isoprene building block - sesquiterpenes (C 15 ) 3
Finding the isoprene building block - triterpenes (C 30 ) - Squalene has a natural and vital part in the synthesis of all plant and animal sterols, including cholesterol, steroid hormones, and vitamin D in the human body Finding the isoprene building block - tetraterpenes (C 40 ) Lycopene's eleven conjugated double bonds give it its deep red color and are responsible for its antioxidant activity. Lycopene is responsible for the red color in tomatoes and watermelon β-carotene is the compound that causes carrots and apricots to be orange 4
Biosynthesis of Terpenes Biological isoprene - isopentenyl pyrophosphate (3-methyl-3-butenylpyrophosphate). Enzimlerle izomerizasyona uğrar. İzomerizasyon ürünü yeni bir isopentenilpirofosfat ile reaksiyonda monoterpen içeren pirofosfat türevi oluşturur. Bu son türev doğal koşullarda ester hidrolizine uğrar ve bir terpenoid olan geraniol ü verir. Aldol cond S N 2 Enzimle hid. Tioesterden alkole 5
Isopentenyl pyrophosphate is only one of the necessary reagents for the biosynthesis of terpenes dimethylallyl pyrophosphate, a C 5 isomer, is also necessary: Add. of H + elimination of a proton RULE - isopentenyl pyrophosphate and dimethylallyl pyrophosphate are the C 5 building blocks for the biosynthesis of terpenes Elimination of a proton from a carbocation intermediate generates a double bond (E1 reaction) Geranyl pyrophosphate - C 10 building block for many biological monoterpenes Geranyl pyrophospate ester hid ile geraniol verir. 6
humulene found in the essential oils of Humulus lupulus Hemiterpenes consist of a single isoprene unit. Isoprene itself is considered the only hemiterpene, but oxygen-containing derivatives are hemiterpenoids such as prenol (found in citrus fruits, cranberry, grapes, raspberry, blackberry, tomato, white bread ) and isovaleric acid (found in in essential oils). Monoterpenes consist of two isoprene units and have the molecular formula C 10 H 16. Examples of monoterpenes are: geraniol, limonene and terpineol. Sesquiterpenes consist of three isoprene units and have the molecular formula C 15 H 24. Examples of sesquiterpenes are: humulene, farnesenes, farnesol. Prenol isovaleric acid limonene a strong smell of oranges terpineol found in pine oil 7
Diterpenes are composed of four isoprene units and have the molecular formula C 20 H 32. Examples are cafestol, kahweol, cembrene and taxadiene (precursor of taxol). Diterpenes also form the basis for biologically important compounds such as retinol, retinal, and phytol. They are known to be antimicrobial and antiinflammatory. Retinol is one of the forms of vitamin A Taxadiene from enzymes taxol used in cancer chemotherapy Pasifik porsuk ağacı kabuklarından Sesterterpenes, terpenes having 25 carbons and five isoprene units, are rare relative to the other sizes. An example of a sesterterpene is geranylfarnesol. Triterpenes consist of six isoprene units and have the molecular formula C 30 H 48. The linear triterpene squalene, the major constituent of shark liver oil. Tetraterpenes contain eight isoprene units and have the molecular formula C 40 H 64. Biologically important tetraterpenes include the acyclic lycopene, the monocyclic gamma-carotene, and the bicyclic alphaand beta-carotenes. Polyterpenes consist of long chains of many isoprene units. Natural rubber consists of polyisoprene in which the double bonds are cis. 8
Terpenler HALKA SAYISINA göre de sınıflandırılabilirler: Asiklik, monosiklik, bisiklik, trisiklik (2Z)-3,7-dimethyl-2,6-octadien-1-ol Terpenlerde isimlendirme: IUPAC kuralları yanısıra özel okumalar da söz konusudur. Asiklik terpen örnekleri: 8 7 8 7 CH 2 OH Kuyruk 4 baş 7-methyl-3-methyleneocta-1,6- diene Mirisen from parsley.. 3 1 (trans)-3,7-dimethyl-2,6-octadien-1-ol Ald turevi citral-a 4 3 (2Z)-3,7-dimethyl-2,6-octadien-1-ol Ald turevi citral-b Monosiklik Monoterpen örnekleri: menthol menthol Thymol Carvone Kimyon yağı 9
Bisiklik terpenlerin IUPAC okunması: 1 4 6 3,7,7-trimethylbicyclo[4.1.0]hepta-3-ene 1-metil-7-metiliden-4-izopropiliden bisiklo[4.4.0]dekan 2,6,6-trimethylbicyclo[3.1.1]hepta-2-ene 10