Terpenes, Isoprenes, Steroids, and Sterols
- Both isoprenes and terpenes are alkenes, but derived compounds that include oxygen and other moeities are called isoprenoids and terpenoids.
- Mini-molecular model kit emphasizes that the entire isoprene unit is planar. Completely flat except for the -CH3 methyl groups tetrahedral terminal hydrogens.
- Isoprenes such as 2-methyl-1,3-butadiene are 5-carbon subunits that are used to build up larger molecules like terpenes and ultimately steroids which are lipids.
- Each terpene has 5n carbons per the biogenetic isoprene rule aka the C5 rule proposed in 1953.
- See also Alberts 5th Edition p. 115 and JH notes from 7/28/2020 and Khan Academy lectures 1 and 2 on terpenes and steroids.
Naming of terpene compounds
| # of carbons | # of isoprenes | # of terpenes | Name |
|---|---|---|---|
| 10 | 2 | 1 | mono-terpene |
| 15 | 3 | 1.5 | sesqui-terpene |
| 20 | 4 | 2 | di-terpene |
| 25 | 5 | 2.5 | ses-terpene |
| 30 | 6 | 3 | tri-terpene |
| 40 | 8 | 4 | tetra-terpene |
List of terpenes and steroids covered in JH notes:
- OPP = pyrophosphate of 2 linked PO43- connected to isoprenes as part of isoprene/terpene synthesis
- dimethyl allyl pyrophosphate aka DMAPP
- Isopentenyl pyrophosphate aka IPP
- Geranyl pyrophosphate aka GPP
- Farnesyl pyrophosphate aka FPP
- Squalene, a 30-carbon triterpene that is a precursor to all plant and animal sterols, including cholesterol and all human steroid hormones
- Human steroids
- Sex hormones: E1 Estrone, E2 Estradiol, E3 Estriol, progesterone (P4); and testosterone along with other androgens
- Adrenal hormones: Cortisone, Cortisol, Aldosterone
- Steroids in other species
- Plants: Stigmasterol
- Amphibians, reptiles, rodents, birds: corticosterone
Notes from terpene / terpenoid lectures
- 2018 YouTube Lecture by Nandkishor Karade
- Introduction
- Terpenes and terpenoids are natural products mainly synthesized by plants
- Contain isoprene (C5H8) monomers as repeating unit
- Terpenes are just hydrocarbons
- Terpenoids contain carbon, hydrogen, and oxygen
- More than 23,000 terpene systems are known
- Examples of terpenes and terpenoids
- Myrecene is a major component of Bay Leaves
- α-Phellandrene is a component of eucalyptus oil
- Geraniol is the primary component in citronella oil, rose oil, palmarosa oil.
- Menthol is a monoterpenoid. Made synthetically or obtained fromt eh oils of corn mint, peppermint, or other mints.
- Carvone in caraway seeds
- Zingiberene main constituent in ginger
- Citral is a pleasant sent of lemon
- α-Pinene and β-Pinene. Extracted from pine trees leads to turpentine
- β-carotene causes organge color of carrots
- Classification of terpenes
- 2 isoprene units - monoterpenes. Ex: citral, menthol
- 3 isoprene units - sesquiterpenes. Ex. Farnesol
- 4 isoprene units - diterpenes. Ex. Abietic acid, Vitamin A
- 5 isoprene units - sesterterpenes. Ex. Gascardic Acid
- 6 isoprene units - triterpenes. Ex. Squalene
- 8 isoprene units - tetraterpenes. Ex. Lycopene, β-carotene
-
100 isoprene units - polyterpenes. Ex. both natural and synthetic versions of rubber.
Progress
- 11/23/2021 First post on terpenes
- 11/24 drew notebook of various views of monoterpene myrcene
- 11/26 built model of squalene and took notes
- 11/27 realized that squalene is not 6 isoprenes all arranged head to tail. But in fact it’s 3 isoprenes H-T and then T-H, T-H, T-H for the final 3 isoprenes. This means that squalene has radial symmetry from the center of the molecule.
- 11/29 redrew paper notes version of squalene
- 11/30 posted IG story about Basking Sharks and how they were harvested for their shark liver oil which contained unsaturated squalene. Now, environmentally conscious companies produce vegan saturated squalane as an alternative.
- 12/1 prep for first warm marble post with Gonane
- 12/2 good reference at VCU for steroids, structure, naming, etc. See also ppt and PDF of VCU lecture slides in ~/Downloads
- 12/3 β-gonane
- 12/5 posted nat-cholesterol
- 12/6 posted ent-cholesterol
- 12/7 prepped next 4 days of stigmasterol and stigmastanol
- 12/8 labeled stigmasterol photos and researched content
- 12/9 posted stigmasterol day 2
- 12/10 posted stigmastanol day 1
- 12/11 thinking about terpenes for next series to post
- 12/12 more research on which terpenes next
- 12/14 beta-Pinene
- 12/15 alpha-Pinene
- 12/16 alpha-Thujone and planned out next several days of monoterpene posts
- 12/17 Thujone is a key ingredient in absinthe from Artemesia absinthium
- 12/18 break
- 12/19 returned to posting with 3-carene
- 12/20 Looked at this article on Terpinolene and a good general introductory article on terpenes in cannabis
- 12/24/2021 posted alpha-terpineol
- 1/01/2022 posted alpha-terpinene
- 1/03 ergosterol - the “cholesterol of fungi”
- 1/09 first post about diatoms (and cabbage family rapeseed) which both produce Brassicasterol. Began research on diatom produced fucoxanthin, which is a xanthophyll. There are two categories of carotenoids (tetraterpernoids): (1) xanthophylls which contain oxygen and (2) carotenes which are unsaturated hydrocarbons
- 1/10 researched and photographed fucoxanthin. note that carotenoids are all tetraterpenes. Two subcategories: (1) carotenes are pure hydrocarbons and (2) xanthophylls also contain oxygen.
- 1/13 posted fucoxanthin
- 1/14 photographed fucosterol
- 1/15 researched beta-carotene
- 1/16 researched and photographed campesterol
- 1/19 posted beta-carotene
- 1/22 researched more carotenoids
- 1/31 posted lutein
- 2/05 posted lycopene
- 2/13 posted fucosterol
- 2/18 experimented with alliin
- …
- 6/12 posted white marble version of 18-crown-6
- 6/13 posted dark wood version of 18-crown-6