solo
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Decreasing the chain lenght by one on an aromatic
Have been trying to find a way to decrease the alkyl chain on an aromatic where the only active site is an amine on the c2 carbon and the benzyl ring.
There are methods to reduce the chain lenght as a result of reducing a COOH or some other active end, but have not found one to reduce a CH3 from a
alkyl chain......solo
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Nerro
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Chromic acid is used to eat CH3 sidegroups but when applied to alkyl chains it would jsut eat away the whole thing. Perhaps slowly oxidizing it to
COOH and the heating to release the CO2?
#261501 +(11351)- [X]
the \"bishop\" came to our church today
he was a fucken impostor
never once moved diagonally
courtesy of bash
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solo
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Perhaps if I clarify the theoretical goal ...............
https://sciencemadness.org/talk/viewthread.php?tid=4184#pid4...
the resutling acetylamine ketone type product can have the ketone reduced but the resulting chain is one too many....so perhaps there is a reaction
that will reduce a ketone by one carbon would work and so the thread.......
https://sciencemadness.org/talk/viewthread.php?tid=6549#pid7...
...but in all the seemingly easy route the the amine is more eluding as first thought.... ....solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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not_important
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| Quote: | Originally posted by Nerro
Chromic acid is used to eat CH3 sidegroups but when applied to alkyl chains it would jsut eat away the whole thing. Perhaps slowly oxidizing it to
COOH and the heating to release the CO2? |
And generally would start at the carbon attached to the aromatic ring.
This is a tough one, solo. I remember seeing something once where an imine was formed and then tautomeric shift gave a vinyl-amine, making C4 allylic.
But
1) that would have to compete with the benzyl hydrogens for whatever reaction was selected to tag that carbon
and 2) I can't remember any details, including where I saw it. 8-(
It'd be a long shot, I'm afraid.
This looks like some sort of emzymatic task, where the C4 would be pulled into place and activated by some clever large molecule. I can't remember
seeing any such enzyme or enzyme mimicking agent, but then I haven't been sarching for such.
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WizardX
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Chain Extension via the Arndt - Eistert Reaction & Decarboxylation.
http://wizardx.t35.com/archives/XFile6.zip
Albert Einstein - \"Great ideas often receive violent opposition from mediocre minds.\"
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not_important
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Useful, except that
A) the chain needs to be shortened by a carbon, not extended
B) the end of the chain is a fairly unreactive methyl group, not a carboxyl or derivative thereof.
C) lesser problem - diazomethane is expensive, explosive, uses pretty toxic materials, and is likely to react with the amino group as is the acyl
halide.
Outside of those points, you've solved the problem!
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solo
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The chain starts off as a ketone after the dakin-west reaction where the amine group gets acylated and the COOH is converted to a ketone......I
somehow thought it would be easier to remove the methyl group once the ketone was reduced but perhaps there is a reaction similar to a reduction of
COOH minus one carbon which is nice, but if applied to the starting material on this reaction it would produce benzyl cyanide*...
------------------------------------------
*Ref provided by psloxy
Syn.Lett.; EN; 4; 2003; 542 - 546 - NBS, ammonium chloride, DMF
J.Amer.Chem.Soc.; EN; 106; 20; 1984; 6075-6076 electrooxidation 80% yield <__ could be interesting OTC-wise
Indian J.Chem.Sect.A; EN; 19; 4; 1980; 325-329. CAT
J.Indian Chem.Soc.; EN; 69; 10; 1992; 642-647 dichloramine-B, perchloric acid
J.Chem.Soc.Perkin Trans.2; EN; 1983; 323-334. chloramine-T
Synthesis; EN; 5; 1996; 600-602.CuBr2 t-BuOLi, 53% yield
J.Chem.Sect.A; EN; 27; 1; 1988; 39-43. chloramine-T, perchloric acid
-------------------------------------------------------------------------------------------
...........unless there is a similar reaction that will reduce the ketone and reduce the chain by one , I would imagine having the ketone gives it a
better chance of removing a methyl, group we'll see,.....I hope this gives a better picture............solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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labi
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getting a glycol at the desired point and periodate oxidation leads to the corresponding aldehydes which further can be reduced. i understand this is
very long but this came to my mind
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not_important
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With the (protected) amino-ketone you might more readly get the terminal methyl to react, but it is going to be a few steps to get the target.
It might be easier to clamp something really electron withdrawing onto the amino group (TFA? mesylate? triflate?), and try the Kolbe electrolysis
route.
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solo
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Radical Chain Reduction of Alkyl Halides, Dialkyl Sulphides and 0-Alkyl S-Methyl Dithiocarbonates to Alkanes by Trialkylsilanes
Stephen J. Cole, J. Nicholas Kirwan, Brian P. Roberts* and Colin R. Willis Christopher lngold
J. Chem. Soc., Perkin Trans. 1, 1991, 103 - 112
Abstract
Saturated primary, secondary and tertiary alkyl halides RX (X = CI, Br or I) are reduced to the corresponding alkanes RH in essentially
quantitative yield by triethylsilane in refluxing hexane or cyclohexane in the presence of a suitable initiator and an alkanethiol catalyst.
Reduction proceeds by a radical chain mechanism and the thiol acts as a polarity reversal catalyst which mediates hydrogen-atom transfer from the
Si-H group of the silane to the alkyl radical R'. Triphenylsilanethiol and perfluorohexanesulphenyl chloride are also effective catalysts; the
latter is probably reduced in situ to the corresponding fluorinated thiol. Other silanes R,SiH (R = Pr", Pr' or Ph) also bring about
reduction. The silane-thiol couple therefore serves as a useful replacement for tributylstannane as a homolytic reducing agent for alkyl halides.
Reduction of 6-bromohex-l-ene, to give a mixture of hex-1 -ene and methylcyclopentane, is more sluggush than reduction of saturated halides and
this is attributed to removal of the thiol catalyst by addition across the C=C bond. Ethyl 4- bromobutanoate is smoothly reduced to ethyl
butanoate without interference from the ester function. Dialkyl sulphides are reduced to alkanes by triethylsilane in a radical chain reaction,
but the effect of added thiol depends on the nature of the S-alkyl groups in the sulphide. The trialkylsilane thiol couple can also successfully
replace trialkylstannane as the reducing agent in the Barton- McCombie deoxygenation of primary and secondary alcohols via their S-methyl
dithiocarbonate (xanthate) esters. Good yields of deoxy compounds are obtained from octan-1 -01, octan-2-01, octadecan- 1 -01, 5a-cholestan
-3p-01, cholesterol and 1,2 : 5,6-di - 0- isopropylidene-a- D-g lucofuranose.
Attachment: Radical Chain Reduction of Alkyl Halides, Dialkyl Sulphides and 0-Alkyl S-Methyl Dithiocarbonates to Alkanes by Trialky (1.3MB)
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It's better to die on your feet, than live on your knees....Emiliano Zapata.
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