tsathoggua1
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Cyclooctatetraene synthesis
First-is this compound commercially available?
The first step in mind is the one I'm uncertain about.
Could a lewis acid (say, anhydrous AlCl3, from refluxing aluminium chloride in SOCl2 and distilling off and recovering unreacted SOCl2 in order to
dehydrate the AlCl3, or anhydrous ferric chloride, prepared the same way)
Could a lewis acid-promoted, perhaps photocatalyzed diels-alder be performed using benzene and acetylene? or would one have to first use a
birch-benkeser reduction using Li/anhydrous ammonia in ethereal solution (an in-situ birch reduction can be done, using a cooling bath of salted ice,
CaCl2/NaCl mixed with the ice, then methylated spirit/diethylene glycol/H2O mixture poured over the top) using anhydrous ether (simply add excess
lithium metal to clean up the last water or distill the ether from lithium, calcium or sodium metal in small chips after first distilling from CaO)
The in-situ method involves adding lithium, as much as is needed for the reaction in question, to an RBF, sat in the cooling bath, and generating NH3
gas, passing through a drying tube, such as filled with CaO or at a pinch, NaOH using ammonium sulfate, phosphate or whatever ammonium salt, and
bubbling it through the ether, with good stirring and after first purging the flask with argon, adding ether, then with stirring, and the tube
supplying the ammonia deeply placed, an airstone bubbler helps diffuse the NH3.
Takes a fair while to initiate, but one can pre-form the solvated electrons, suspension of Li metal at first forms a dark green-blue solution and then
subsequently gets darker and darker until it achieves a really almost black, blue-violet coloration. A lot safer IMO than buggering around with a dry
ice and precooler setup for liquid anhydrous NH3. Just takes longer. Have used this in-situ birch benkeser reduction successfully to reduce a
substrate, I won't say what, but it worked.
In the case of benzene, this would reduce it to cyclohexadiene, would it not?
Or can the Diels-Alder be performed directly on benzene, using acetylene to form barrelene, followed by photolysis converting barrelene to
cyclooctatetraene via semibullvalene as an intermediate?
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MeshPL
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There is no such thing as photocatalysed diels-alder reaction. Benzene is a terrible diene for diels-alder. Few are worse. By birch reduction of
benzene you get cyclohexa-1,4-diene-not a conjugeted diene. But under certain conditions it may be possible to rearrange it into cyclohexa-1,3-diene,
this would be hard for an amateur though.
Lewis acid wouldn't help with this diels alder, it is good when you use enone as dienophile.
I doubt that cyclohexadiene will react with acetylene under normal pressure and yield products useful for the synthesis of cyclotetraene.
Sorry to crush your expectations, but sadly there are problems with what you proposed.
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tsathoggua1
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Anyone got any other ideas for the synthesis of barrelene? the photocatalysis was intended to be referring to the fact that barrelene rearranges to
semibullvalene under photolysis, when solvated in isopentane and using acetone as a photosensitizer in a di-pi-methane rearrangement and then
semibullvalene rearranges to cyclooctatetraene again using photolysis .
I'd sooner avoid any organometallic type reactions, the main route I'm aware of uses n-BuLi. Not the easiest or pleasantest reagent to handle.
[Edited on 18-2-2017 by tsathoggua1]
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unionised
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According to this ref from WIKi, you can grow COD
http://www.sciencedirect.com/science/article/pii/S0168945203...
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tsathoggua1
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That looks REALLY impractical. Where am I going to get a fungus indigenous to patagonia, requiring association with a tree. This species is an
endophyte. That means difficulty. Ergot is difficult enough to work with, and I've considered attempting to isolate grass endophytes, such as that of
Lolium, which produces ergot alkaloids. But generally endophytic fungi are highly specific to the host, and just won't grow in culture. Such as for
example, the Clavicipitaceous endophyte that produces the ergot alkaloids in some strains of hawaiian baby woodrose, or the morning glory endophytes.
You just can't culture them, they are too fussy and won't grow in culture media.
Even parasitic fungi often aren't particularly compliant. I've been doing a bit of work with ergot (Claviceps purpurea) and things like strain
selection for productivity and in the case of Claviceps spp. actually getting productivity, or if you do, then you need to build a bioreactor, monitor
oxygen content, optimize culture media. And its difficult enough with a really rather well known and thoroughly explored family. I've bought the book
'the genus claviceps' by Kren and Cvak, a couple of decades old by now but still, some fairly up to date how-tos on the likes of submerged culture,
strain selection, host infection equipment.
Yet, still, its an utter shitter, starting from some wild-type sclerotia I managed to obtain growing on wild ryegrasses. Come the climate getting a
bit warmer, I'm going to re-activate that project. And build a dedicated bioreactor, and get to experimenting with encapsulation in calcium
alginate/perfluorocarbon emulsion (the alginate microsphere encapsulation of the fungus, which only produces ergot alkaloids in the sclerotia, but
trapping the sphacelial growth stage, which itself is relatively easy to culture, and after mutagen exposure and cloning from the colonies most
reactive when samples are tested with Van Urk reagent or Erlich's, trying for tryptophan autotrophs and subsequent reversion to prototrophy (this
essentially severs a link in the metabolic chain that assembles the ergoline ring structure that acts as a negative feedback control on
tryptophan-DMAT production whereby tryptophan itself is the signalling agent, too much acts as an inhibitory agent on productivity at an early stage,
DMAT synthase repression I think, certainly one of the very early stages in the biosynthetic path)
The encapsulation 'tricks' sphacelial ergot culture tissue into 'thinking' that it is in fact sclerotial growth, the microcapsules of polymerized
alginate acting as a sort of 'pseudosclerotia' and the perfluorocarbon emulsion is for enhancing O2 transport, since naturally, the microspheres have
to be very small, such as produced by electrostatic spraying through fine needles under pressure of an alginate-ergot culture into CaCl2 solution,
which produces very fine, small beads that polymerize instantaneously as Ca alginate, trapping the ergot culture, but after a couple of mm, the
alginate impairs O2 transport so that the result is essentially an anoxic core, surrounded by an outer layer of growth.. The perfluorocarbon emulsion,
along with added surfectants such as tween to improve O2 permeability of the cell walls allows for deeper penetration of the fungus and improved
alkaloid production.
I don't think COD growth is going to be practical. I don't exactly have an easy way of going out to patagonia, wandering around with my microscope,
sampling potential trees for endophytes under the oil immersion lens, carrying around a reagent kit full of stains and a spade, digging up a tree or
two and flying them back home.
Endophytes are just bitchy.
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CuReUS
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yes
| Quote: | | Or can the Diels-Alder be performed directly on benzene, using acetylene to form barrelene, followed by photolysis converting barrelene to
cyclooctatetraene via semibullvalene as an intermediate? |
you can make cyclooctatetraene directly from acetylene - http://pubs.acs.org/doi/abs/10.1021/ja00278a017
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unionised
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Quote: Originally posted by tsathoggua1  | That looks REALLY impractical. Where am I going to get a fungus indigenous to patagonia, requiring association with a tree. This species is an
endophyte. That means difficulty. Ergot is difficult enough to work with, and I've considered attempting to isolate grass endophytes, such as that of
Lolium, which produces ergot alkaloids. But generally endophytic fungi are highly specific to the host, and just won't grow in culture. Such as for
example, the Clavicipitaceous endophyte that produces the ergot alkaloids in some strains of hawaiian baby woodrose, or the morning glory endophytes.
You just can't culture them, they are too fussy and won't grow in culture media.
Even parasitic fungi often aren't particularly compliant. I've been doing a bit of work with ergot (Claviceps purpurea) and things like strain
selection for productivity and in the case of Claviceps spp. actually getting productivity, or if you do, then you need to build a bioreactor, monitor
oxygen content, optimize culture media. And its difficult enough with a really rather well known and thoroughly explored family. I've bought the book
'the genus claviceps' by Kren and Cvak, a couple of decades old by now but still, some fairly up to date how-tos on the likes of submerged culture,
strain selection, host infection equipment.
Yet, still, its an utter shitter, starting from some wild-type sclerotia I managed to obtain growing on wild ryegrasses. Come the climate getting a
bit warmer, I'm going to re-activate that project. And build a dedicated bioreactor, and get to experimenting with encapsulation in calcium
alginate/perfluorocarbon emulsion (the alginate microsphere encapsulation of the fungus, which only produces ergot alkaloids in the sclerotia, but
trapping the sphacelial growth stage, which itself is relatively easy to culture, and after mutagen exposure and cloning from the colonies most
reactive when samples are tested with Van Urk reagent or Erlich's, trying for tryptophan autotrophs and subsequent reversion to prototrophy (this
essentially severs a link in the metabolic chain that assembles the ergoline ring structure that acts as a negative feedback control on
tryptophan-DMAT production whereby tryptophan itself is the signalling agent, too much acts as an inhibitory agent on productivity at an early stage,
DMAT synthase repression I think, certainly one of the very early stages in the biosynthetic path)
The encapsulation 'tricks' sphacelial ergot culture tissue into 'thinking' that it is in fact sclerotial growth, the microcapsules of polymerized
alginate acting as a sort of 'pseudosclerotia' and the perfluorocarbon emulsion is for enhancing O2 transport, since naturally, the microspheres have
to be very small, such as produced by electrostatic spraying through fine needles under pressure of an alginate-ergot culture into CaCl2 solution,
which produces very fine, small beads that polymerize instantaneously as Ca alginate, trapping the ergot culture, but after a couple of mm, the
alginate impairs O2 transport so that the result is essentially an anoxic core, surrounded by an outer layer of growth.. The perfluorocarbon emulsion,
along with added surfectants such as tween to improve O2 permeability of the cell walls allows for deeper penetration of the fungus and improved
alkaloid production.
I don't think COD growth is going to be practical. I don't exactly have an easy way of going out to patagonia, wandering around with my microscope,
sampling potential trees for endophytes under the oil immersion lens, carrying around a reagent kit full of stains and a spade, digging up a tree or
two and flying them back home.
Endophytes are just bitchy. |
If you want practical- buy it from Aldrich.
As for "Where am I going to get a fungus indigenous to patagonia, requiring association with a tree."
Well, this might provide a partial answer.
"It also grows well in Scotland and has been planted in the North Pacific Coast of the United States."
from
https://en.wikipedia.org/wiki/Eucryphia_cordifolia
I doubt they bothered to remove any fungi before transporting the tree.
OTOH this might offer a better route:
"A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass
spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis
cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic
acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene
and 3-methyl-1-butanol, were the most abundant. "
from
https://www.ncbi.nlm.nih.gov/pubmed/21323467
The witches' brew of nickel cyanide, acetylene etc looks a lot easier.
[Edited on 19-2-17 by unionised]
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