1 / 76

Terpenes: The Isoprene Rule

Terpenes: The Isoprene Rule. CH 3. H 2 C. CH. CH 2. C. Terpenes. Terpenes are natural products that are structurally related to isoprene. or. Isoprene (2-methyl-1,3-butadiene). CH 3. CH 2. CH 2. CHCH 2 CH 2 CCH. CH 3 C. Terpenes.

naasir
Download Presentation

Terpenes: The Isoprene Rule

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Terpenes: The Isoprene Rule

  2. CH3 H2C CH CH2 C Terpenes • Terpenes are natural products that are structurally related to isoprene. or Isoprene(2-methyl-1,3-butadiene)

  3. CH3 CH2 CH2 CHCH2CH2CCH CH3C Terpenes • Myrcene (isolated from oil of bayberry) is a typical terpene. or

  4. The Isoprene Unit • An isoprene unit is the carbon skeleton of isoprene (ignoring the double bonds) Myrcene contains two isoprene units.

  5. The Isoprene Unit • The isoprene units of myrcene are joined "head-to-tail." head tail tail head

  6. Common Carbon Backbone

  7. Terpenes Classification of Terpenes • Class Number of carbon atoms • Monoterpene 10 • Sesquiterpene 15 • Diterpene 20 • Sesterpene 25 • Triterpene 30 • Tetraterpene 40

  8. OH O H Terpenes Representative Monoterpenes a-Phellandrene(eucalyptus) Menthol(peppermint) Citral(lemon grass)

  9. OH O H Terpenes Representative Monoterpenes a-Phellandrene(eucalyptus) Menthol(peppermint) Citral(lemon grass)

  10. Terpenes Representative Monoterpenes a-Phellandrene(eucalyptus) Menthol(peppermint) Citral(lemon grass)

  11. Terpenes Representative Sesquiterpenes H a-Selinene(celery)

  12. Terpenes Representative Sesquiterpenes H a-Selinene(celery)

  13. Terpenes Representative Sesquiterpenes a-Selinene(celery)

  14. OH Terpenes Representative Diterpenes Vitamin A

  15. OH Terpenes Representative Diterpenes Vitamin A

  16. Terpenes Representative Diterpenes Vitamin A

  17. Common Terpenes

  18. Limonene

  19. Limonene

  20. Rearrangement

  21. Terpenes

  22. Terpenes

  23. Isoprene / Biosynthesis

  24. Terpene Biosynthesis Formation of geranyl pyrophosphate

  25. Farnesyl Pyrophosphate

  26. Formation of Squalene, the Precursor of Cholesterol

  27. Terpenes Representative Triterpene tail-to-tail linkage of isoprene units Squalene(shark liver oil)

  28. Isoprene LinksHeads or Tails?

  29. Squalene, a triterpene, is a precursor of steroids

  30. Steroids • Many hormones are steroids

  31. The B, C, and D rings are trans fused Methyl groups at C-10 and C-13 are called angular methyl groups

  32. The A and B rings are also trans fused in most naturally occurring steroids Substituents on the same side of the steroid ring system as the angular methyl groups are b-substituents Thoseon the opposite side of the plane of the ring system are a-substituents

  33. Biosynthesis of Cholesterol

  34. Synthetic Steroids

  35. TERPENE BIOSYNTHESESin detailIsopentenyl Pyrophosphate:The Biological Isoprene Unit

  36. The Biological Isoprene Unit • The isoprene units in terpenes do not come from isoprene. • They come from isopentenyl pyrophosphate. • Isopentenyl pyrophosphate (5 carbons) comes from acetate (2 carbons) via mevalonate (6 carbons).

  37. O CH3 O CH3COH HOCCH2CCH2CH2OH OH CH3 O O H2C CCH2CH2OPOPOH The Biological Isoprene Unit 3 Mevalonic acid Isopentenyl pyrophosphate

  38. CH3 O O H2C CCH2CH2OPOPOH OPP Isopentenyl Pyrophosphate or Isopentenyl pyrophosphate

  39. OPP OPP Isopentenyl and Dimethylallyl Pyrophosphate Isopentenyl pyrophosphate is interconvertible with2-methylallyl pyrophosphate. • Dimethylallyl pyrophosphate has a leaving group (pyrophosphate) at an allylic carbon; it is reactive toward nucleophilic substitution at this position. Isopentenyl pyrophosphate Dimethylallyl pyrophosphate

  40. Carbon-Carbon Bond Formation in Terpene Biosynthesis

More Related