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solo
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Dehalogenation an Aliphatic Hydrocarbon
Need a method to dehalogenate a chlorinated primary non -benzylic amino alcohol.....want to avoid the HgAl a well known OTC method.....also the
catalytic hydrogenation is out of the option, hence have thought of using Hypophosphorous Acid for the dehalogenation. I would welcome more
suggestions as I've thought of ZnCl +HCl but the yields are very low...........solo
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BromicAcid
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How about reduction with a nickel-aluminum alloy? Quote from the handbook of destructive procedures of hazardous chemicals in the lab. | Quote: | | The halogenated compounds are reductively dehalogenated with nickel-aluminum (Ni-Al) alloy in dillute base to give the corresponding compound without
the halogen. When the products are soluble in H2O the yield of product is good, but when they are not (for example, toluene from benzyl chloride)
they are lost from solution and accountances are not complete. The product from chloronitrobenzenes is analine (concomitant reduction of the nitro
group) and the product from the reduction of 3-chloropyridine is piperidine in 87% yield(concomitant reduction of the inital product pyridine).
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Organic chem isn't really my thing and you probably thought of this already but I'm just trying to
add to the discussion.
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the alchemist
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grignard
Make a grignard with Mg metal in diethyl ether and react the Grignard with plain 'ol water.
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Marvin
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Its an alcohol, so a grignard would fail. The information given is too sparse for me to suggest anything helpful. Sounds like you need to visit a
university library solo.
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solo
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C6H5-CH2-CH(NH2)-CH2-CL-->>>>>>>>C6H5-CH2-CH(NH2)-CH3
Note:
An example of a chlorinated, former non-benzylic primary amino alcohol
As noted a primary halogen on an aliphatic compound..........solo
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Sandmeyer
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| Quote: | Originally posted by Marvin
Its an alcohol, so a grignard would fail. The information given is too sparse for me to suggest anything helpful. Sounds like you need to visit a
university library solo. |
There is an amine there, but it dosen't matter in this case - as soon as Grignard is formed it will react with the amino group, giving:
C6H5-CH2-CH(NH2)-CH2-Cl + Mg --> [C6H5-CH2-CH(NH2)-CH2-MgCl] --> C6H5-CH2-CH(NHMgCl)-CH3
This could then be worked up to amphetamine, at least in theory.
[Edited on 17-10-2005 by Sandmeyer]
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Nicodem
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The problem is that the Grignard reaction don't initialize on protic substrate as far as I know. Though there might be some trick make it work.
But anyway, dear Solo, haven’t you been explained in the now unfortunately gone forum that your substrate of eternal interest does not exists as
such. It can only exist in equilibrium with 2-benzylaziridine hydrochloride.
You can only have the stable salts of the compound you wrote down, like Ph-CH2-CH(NH2)-CH2Cl×HCl for example. This makes a big difference, making
only the reductions in acidic environment feasible. If you want to use basic conditions (like Zn-Ni/ammonia for example) than you should consider the
2-benzylaziridine form and check the literature which product, either Ph-CH2-CH(NH2)-Me or Ph-CH2-CH2-CH2-NH2 would form after the reduction of this
aziridine using the selected method.
[Edited on 17-10-2005 by Nicodem]
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solo
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Yes, I stand corrected its the HCl in the example.........its a long effort to make things easier and OTC for those that have run out of matches and
have had their dreams
put out of reach, as for me catalytic hydrogenation with Pd works just fine...............solo
[Edited on 9-11-2007 by solo]
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Nicodem
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Solo, perhaps you will find the attached file interesting for your OTC optimization.
However, I hope you know that the hydrogenation of 2-benzylaziridine results in a controlled substance and is thus a reaction not allowed in most if
not all countries of the world.
You might consider a much simpler diversion: doi:10.1016/S0022-1139(00)85218-5
[Edited on 18-10-2005 by Nicodem]
Attachment: 2-Benzylaziridines_Cyclic Analogs of A.pdf (277kB)
This file has been downloaded 1082 times
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
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Sandmeyer
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Speaking of aziridines. There is a nice method for the preparation of N-tosyl aziridines: http://www.organic-chemistry.org/pdf/mol/Molecules,2002,7,90...
These could serve for a conveniant preparation of phentermines, by ring opening with a ArMgX. Since aziridines are such unstable molecules (see
below), I wonder if not arylzinc would be enough to open up the ring to corresponding N-tosyl phentermine. This route woeld be interesting particulary
for DOI phentermine as the tosyl would possibly function as a protection group during some inexpensive iodination procedures.
Damn, I just saw that isobutanolamine (2-Amino-2-methyl-1-propanol) is dirt-cheap. Next week I could dig in litterature for such ring openings in case
there is interest.
Typical Synthetic Procedures
Method A: Tosyl chloride (2.2 mmol) was added portionwise at r.t. to a stirred mixture of 3 (1.0 mmol), K2CO3 (4.0 mmol) and acetonitrile (2.0 mL).
After 6 h, toluene (5 mL) was added, the solid was filtered off and the solvents evaporated.
Method B: Tosyl chloride (2.5 mmol) was added portionwise at r.t. under vigorous stirring to a mixture of KOH (2.0 g), 3 (1.0 mmol), water (2.0 mL)
and CH2Cl2 (2.0 mL). After 30 min, ice and water were added, the organic layer was separated, washed with water, dried over MgSO4 and evaporated. The
crude products were purified by crystallization, short-path distillation or column chromatography. The optical purities of all products were proven to
be identical with those of the starting materials. The pure aziridines polymerize at r.t. within a few days, but can be stored at –30º for months.
[Edited on 25-11-2005 by Sandmeyer]
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solo
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As I recall aziridines are decomposed with hydrogenation using Pd as a catalyst however I don't recal if methanol was the solvent used.......as I
recall Rhodium posted a method to make azaridines and the reduction to meth was by catalytic hydrogenation, I just can't locate the post.....solo
[Edited on 22-12-2005 by solo]
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Sandmeyer
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2-hexyl-1-(toluene-4-sulfonyl)-aziridine + phenylmagnesium bromide ----> (+/-)-N-(1-phenyloctan-2-yl)toluene-p-sulfonamide
Yield 94 percent
Solvent tetrahydrofuran
diethyl ether
Time 18 hour(s)
Other Conditions: Ambient temperature
Toshimitsu, Akio; Abe, Hideyuki; Hirosawa, Chitaru; Tamao, Kohei; J. Chem. Soc. Perkin Trans. 1; 23; 1994; 3465-3472.
--------------------------------------------------------
2-methyl-1-N-p-toluenesulfonylaziridine + phenylmagnesium bromide ----> N-(1-methyl-2-phenyl-ethyl)-toluene-4-sulfonamide
Yield 82 percent
Solvent tetrahydrofuran
Time 5 hour(s)
Other Conditions Heating
Lin, Pen-Yuan; Bentz, Gunther; Stamm, Helmut; J. Prakt. Chem./Chem.-Ztg.; 335; 1; 1993; 23-34. (in english)
------------------------------------------------
Too bad that those papers are out of my reach, could someone get them? Nice is that reaction is done at or above the room temperature, there are
other refs where this is done at - 30 C...
-------------------------------------------------
General procedure for desulfonylation
To a suspension of Mg (0.45 g, 20 mmol) in MeOH (5 mL) was added a solution of the corresponding N-tosylalkyl-2-aryl (heteroaryl)amine (2 mmol) in
MeOH (10 mL). The resulting suspension was sonicated for 1 h until consumption of the starting material was complete. The reaction mixture was then
diluted with aqueous NH4Cl and extracted with ether (3×5 mL). The organic layer was dried over MgSO4 and evaporated. To resulting oil ethanolic
solution HCl (0.5 mL, c 2 M) was added. Hydrochloride was precipitated, filtered and
washed with ether.
The method is from V. G. Nenajdenko et al. /Tetrahedron : Asymmetry 12 (2001) 2517–2527
A new convenient approach to chiral β-aryl(heteroaryl)alkylamines
Abstract
Chiral β-aryl(heteroaryl)alkylamines have been prepared from N-tosyl alkylaziridines via regiospecific nucleophilic ring opening and subsequent
desulfonylation in good to excellent yields. The corresponding aziridines are easily obtained from commercially available (S)-α-amino acids, so
this method is the first effective route to asymmetric β-aryl(heteroaryl)alkylamines.
Paper: http://rapidshare.de/files/9612711/A_new_convenient_approach...
------------------------------------
Selective removal of electron-accepting p-toluene- and naphthalenesulfonyl protecting groups for amino function via photoinduced donor acceptor ion
pairs with electron-donating aromatics
Tatsuo Hamada, Atsushi Nishida, Osamu Yonemitsu;
J. Am. Chem. Soc.; 1986; 108(1); 140-145.
Abstract: When N-tosylamines (3a, 3b, 7, 17a, 17b, 21,23) in aqueous ethanol were irradiated with a high-pressure mercury lamp in the
presence of an electron-donating aromatic such as 1,2- (6) and 1,4-dimethoxybenzenes (10) and 1,5-dimethoxynaphthalene (14) and a reductant (sodium
borohydride, ascorbic acid, ammonia borane, hydrazine), a photochemical detosylation proceeded quite easily to give the corresponding amines (4a, 4b,
8, 18a, 18b, 22,24) in the high yields. On irradiation in the presence of 10 and sodium borohydride, N-(naphthalenesulfonyl)phenethylamine (19) also
gave 4a. Mechanistic studies based on fluorescence quenching, quantum yield measurement, and free energy change calculation show that this
photoreaction involves an electron transfer from an electron-donating aromatic to an electron-accepting sulfonamide. A preliminary application for the
synthesis of lysine peptides was also described.
Paper: http://rapidshare.de/files/9612979/desulfonylation.pdf.html
----------------------------
There is also a paper describing preparation of N-tosyl aziridines from cheap alpha-amino acids: Berry, M.; Craig, D. Synlett 1992, 41.
[Edited on 22-12-2005 by Sandmeyer]
[Edited on 22-12-2005 by Sandmeyer]
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solo
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Aziridine reference material.....
Regio- and Stereocontrolled Nucleophilic Ring Opening of Chiral Oxazolidines by
Diethylaluminum Cyanide. A Short and Efficient Route to Enantiomerically Enriched a-Amino Esters
Celia Andrh Alicia Maestro, Rafael Pedrosa,* Alfonso Perez-Encabo, Martina Vicente
Synlett 1992, pg.47
Abstract: i-Amino esters 7 are prepared in good chemical yield and enantiomeric excess (53-86%) by ethanolysis and subsequent
debenzylation of the &amino nitriles 5 obtained by regio- and stereocontrolled ring opening of N-benzyl-2-phenylglycinolderived oxazolidines 4
(2-alkyl-3-benzyl-4-phenyloxazolidines) with diethylaluminum cyanide.
Attachment: regio and stereocontrolled neuclophilic ring opening of chiral oxazolidines by diethylaluminum cyanide....pdf (176kB)
This file has been downloaded 1126 times
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solo
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| Quote: | Originally posted by Nicodem
Solo, perhaps you will find the attached file interesting for your OTC optimization.
However, I hope you know that the hydrogenation of 2-benzylaziridine results in a controlled substance and is thus a reaction not allowed in most if
not all countries of the world.
You might consider a much simpler diversion: doi:10.1016/S0022-1139(00)85218-5
Attachment: 2-Benzylaziridines_Cyclic Analogs of A.pdf (277.41kb)
This file has been downloaded 85 times
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In the procedure of recovering the 2-benzylaziridine , why is it necessary to have ether and NaOH pellets in the receiving vessel can on just have
ethanol or is ether necessary as the product will be dissolved in ethanol for further RX to the amine ?
Also will hydrogenation give the correct configuration for the desired amine ? any suggestions on where to look for the answer?
Enclosed the original study referenced in the article Nicodem so kindly provided and gave so much insight.........solo
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Chemistry of Ethylenimine. VIII. Stereospecificity in the Pyrolytic Rearrangement of 1-(p-Nitrobenzoyl)-Z-benzylaziridinel
D. V. KASHELIKAARN D PAULE . FANTA
J. Amer. Chem. Soc., 82, 4930, (1960)
Abstract
Refluxing a solution of l-(p-nitrobenzoyl)-2-benzylaziridiinne toluene for twenty-four hours gave a 91 yo yield of KThe observation is best explained
in terms of an intramolecular reaction mechanism. The rearrangement is therefore (Irans-cinnamy1)-p-nitrobenzamide. in which the cis-elimination of a
proton is concerted with the opening of the aziridine ring. Analogous in facility and stereospecificity to the Chugaev reaction and the Cope reaction
of tertiary amine oxides.
[Edited on 18-7-2006 by solo]
Attachment: Chemistry of Ethylenimine.pdf (245kB)
This file has been downloaded 959 times
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solo
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Although this thread started out to be about dehalogenation of aliphatic hydrocarbons , the premise was the downside of removing an OH site via
halogenation then reductive dehalogenation. However it was suggested perhaps tosylating or making an aziridine would be an easier method hence an
easier leaving group.
With this in mind I then provide this article dealing with the removal of the aziridine via ring opening to the amine.
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NEW SYNTHETIC “TRICKS”. [Et3NH][Sn(SPh)d AND Bu2SnH2, TWO USEFUL REAGENTS FOR THE REDUCTION OF AZIDES TO AMINES
Mart1 Ebrtra, Felix Urpl. and Jaume Vilarrasa
Tetrahedron Letters Volume 28, Issue 47 , 1987, Pages 594-5944
Abstract
Treatment of Sn(SPh)z with PhSH and Et3N affords a tin(II) complex, soluble in organic solvents, which is the best reducing agent for azides
reported so far. Bu2SnH2. although not so reactive, also shows several advantages with regard to the standard reducing agents for azides. such as
its solubility in most solvents or its scarce reactivity with water.
[Edited on 19-7-2006 by solo]
Attachment: NEW SYNTHETIC TRICKS FOR THE REDUCTION OF AZIDES TO AMINES.pdf (326kB)
This file has been downloaded 1160 times
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solo
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A Novel, Simple, Chemoselective and Practical Protocol for the Reduction of Azides Using In / NH4CI
G. Vidyasagar Reddy*, G. Venkat Rao and D.S. Iyengar
Tetrahedron Letters 40 (1999) 3937-3938
Abstract : A simple, mild and efficient method for the reduction of azides to
amines using In / NH4C1 is described. © 1999 Elsevier Science Ltd. All rights reserved.
Note: I wonder if the Indium powder can be reused? since it's quite expensive 5gr. $66.40....if so this would be a nice method to reduce aziridines to
amines
Note: I stand corrected as I mis-assumed that azides would cover the azaradines but as noted azaridines=/= azides......I will
nevertheless leave the post as it's a good article for reference in reduction of azides...............solo
Note: additional reference from,
---------------------------------------------------------------------------------
Chemistry of Ethylenimine. VIII. Stereospecificity in the Pyrolytic Rearrangement of 1-(p-Nitrobenzoyl)-Z-benzylaziridinel
D. V. Kashelikar and P. E. Fanta
J. Amer. Chem. Soc., 82, 4930, (1960)
http://rapidshare.de/files/26905399/Chemistry_of_Ethylenimin...
Abstract
Refluxing a solution of l-(p-nitrobenzoyl)-2-benzylaziridiinne toluene for twenty-four hours gave a 91 yo yield of KThe observation is best explained
in terms of an intramolecular reaction mechanism The rearrangement is therefore (Irans-cinnamy1)-p-nitrobenzamide. in which the cis-elimination of a
proton is concerted with the opening of the aziridine ring. analogous in facility and stereospecificity to the Chugaev reaction and the Cope reaction
of tertiary amine oxides.
Excerp
Experimental6
( *)-Phenylalaninol (IIIa) was prepared as previously
described.' Treatment of the amino alcohol with phenyl
isothiocyanate gave the N-phenylthiocarbamyl derivative,
shining, colorless plates from ethanol, m.p. 17O-1ilo.
Anal. Calcd. for C16H18XLOS: C, 67.10; H, 6.33; IC,
9.78. Found: C, 67.18; H, 6.80; S, 9.82.
(=I=)-Phenylalaninyl Hydrogen Sulfate (IIIb) .-To a cold
suspension of phenylalaninol(l2.0 9.) in 30 ml. of water was
added 10.0 g. of cold 95% sulfuric acid. The light yellow
solution was heated in a metal-bath at 120' to remove water,
first at atmospheric pressure and finally at 130-140' (15
mm.). The brown residue was recrystallized from 100 ml.
of 407; aqueous ethanol with concentration of the mother
liquors to give a total crop of 14.5 g. (79'; of shining, elongated
needles. Xn additional recr)-stallization from 956;,
ethanol gave the analytical sample, m.p., becomes brown at
250' and decomposes at 266-270' (uncor.).
Anal. Calcd. for CsHlaA-08: C, 46.74; H, 5.66; S,
6.06. Found: C, 46.84; H, 5.63; S, 5.66.
(&-Z-Benzylaziridine (IVa).-.k solution of 11 .0 g. of the
sulfate ester and 10.0 g. of sodium hi-droxide in 35 ml. of
water was heated in a distilling flask, and the distillate was
collected in a cooled receiver containing 50 ml. of ether over
sodium hydroxide pellets. During the distillation, water
was added intermittently to the distilling flask whenever the
residue began to crystallize. When the condensate no
longer contained oily drops, the ether layer was separated
and the aqueous layer was extracted with three 30-ml. portions
of ether. The combined ether solution was dried cver
sodium hydroxide pellets, concentrated, and distilled through
a short column, giving 4.8 g. (76'3,) of colorless imine with a
characteristic sharp odor, b.p. 73-75' (1 mm.), %*OD 1.5431,
,,,A, 3 . 1(~N -H band).
Anal. Calcd. for CSH~INC: , 81.15; H, 8.33; S, 10.52.
Found: C,81.03; H,8.75; N, 10.05.
[Edited on 25-7-2006 by solo]
Attachment: A Novel Simple Chemoselective and Practical Protocol for the Reduction of Azides Using In -NH4CI.pdf (114kB)
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solo
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Note: As a side note and observation not to deviate from the topic of the thread ......
I'm wondering if the method of making azidirines would work in benzyl type amino alcohols....following the approach used in the primary non benzylic
amino alcohol used in the synthesis of 2-benzylaziridine. If this is so then it would be a great way to convert benzyl type amino alcohols to the
respective amines .....in theory of course........solo
[Edited on 24-7-2006 by solo]
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Sandmeyer
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| Quote: | Originally posted by solo
A Novel, Simple, Chemoselective and Practical Protocol for the Reduction of Azides Using In / NH4CI
G. Vidyasagar Reddy*, G. Venkat Rao and D.S. Iyengar
Tetrahedron Letters 40 (1999) 3937-3938
Abstract : A simple, mild and efficient method for the reduction of azides to
amines using In / NH4C1 is described. © 1999 Elsevier Science Ltd. All rights reserved.
Note: I wonder if the Indium powder can be reused? since it's quite expensive 5gr. $66.40....if so this would be a nice method to reduce aziridines to
amines |
I wouldn't be surprised to see a synthesis of acetic acid from acetic anhydride using 10 eq. gold under 10000 atm pressure with no experimental
details in the comming issue of tetrahedron Letters, it's pure crap, like reading chemistry gossips. I was even stupid enough to waste some precious
starting materials by following methods (or better hints) published in that journal, they sounded wonderful but there was a catch - they simply don't
work. I'd guess that from the late 1980-ies the quality became worse and worse. Anyways, azides can be reduced with a number of different agents, but
I see no relevance, are you maybee misstaking aziridines for azides?
[Edited on 24-7-2006 by Sandmeyer]
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solo
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| Quote: | Originally posted by Sandmeyer
| Quote: | Originally posted by solo
A Novel, Simple, Chemoselective and Practical Protocol for the Reduction of Azides Using In / NH4CI
G. Vidyasagar Reddy*, G. Venkat Rao and D.S. Iyengar
Tetrahedron Letters 40 (1999) 3937-3938
Abstract : A simple, mild and efficient method for the reduction of azides to
amines using In / NH4C1 is described. © 1999 Elsevier Science Ltd. All rights reserved.
Note: I wonder if the Indium powder can be reused? since it's quite expensive 5gr. $66.40....if so this would be a nice method to reduce aziridines to
amines |
I wouldn't be surprised to see a synthesis of acetic acid from acetic anhydride using 10 eq. gold under 10000 atm pressure with no experimental
details in the comming issue of tetrahedron Letters, it's pure crap, like reading chemistry gossips. I was even stupid enough to waste some precious
starting materials by following methods (or better hints) published in that journal, they sounded wonderful but there was a catch - they simply don't
work. I'd guess that from the late 1980-ies the quality became worse and worse. Anyways, azides can be reduced with a number of different agents, but
I see no relevance, are you maybee misstaking aziridines for azides?
[Edited on 24-7-2006 by Sandmeyer] |
I think you're right Sandmeyer I have made a false assumption in equating aziridines with azides , thinking azides as a general term for the
former......I guess closer reading is in order...thanks for the point of reference I will need to read some more......................solo
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Nicodem
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???
AZIDES =/= AZIRIDINES
Edit:
Solo, sorry for repeating what Sandmeyer already told you. I only noticed today. Do you have access to chemistry databases (Beilstein, SciFinder)? If
so, do a search on the transformation R-CH2-CH(NH)CH2 => R-CH2-CH(NH2)-CH2 and I’m sure you will find a regioselective enough reagent for
your reduction. Remember to use a terminal aziridine as an example. This is most important, especially with reductions based on the hydride addition
mechanism. Also, N-tosyl- or N-acyl- aziridines may behave differently so find examples on N-unsubstituted or N-alkyl
aziridines first.
[Edited on 25-7-2006 by Nicodem]
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The indium gets oxidized in that reaction, similar to using Al, it would have to be recovered from the aq portion. Electrolytic recovery would likely
work.
Getting it back to a powder might be tricky, it's pretty soft. Perhaps melting it under mineral oil or kerosene, stirring like crazy, and letting it
cool; finally filter it off and wash with pet ether. I don't remember if there are any reductions that would let you take the hydroxide or chloride
to the metal below the melting point.
A related reduction using In/NH4Cl, for aromatic nitro compounds
http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=v81...
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solo
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Sorry to say Nicodem I live in a remote area , I'm lucky to have acquired access to some data bases from friends but no access to the
research data bases you mentioned. I must admit aziridines are interesting quite unlike azides,which they have their own story to tell, , as it was
brough to my attention ......thanks,............
while on the subject of ring closed amph......would anybody know if any of this compounds listed are restricted......
Closed Ring Amph Analogs
2-benzylaziridine
2-benzylazetidine
2-benzylpiperidine
3,4-dichloro-methylphenidate
ethylphenidate
N3-methyl-4-methylaminorex
3-methyl-(1-phenylcyclobutyl)butanamine
N-ethylcathinone
Had been looking for this article on the catalytic hydrogenation reduction of aziridines ......and found it over at Rhodiums archives............solo
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[Edited on 27-7-2006 by solo]
Attachment: (S)-fenfluramine.pdf (634kB)
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Nicodem
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Solo, attached is another paper on the reduction of terminal aziridines to secondary amines:
Hwang, Chung, and Lee. Efficient Synthesis of Ephedra Alkaloid Analogues Using an Enantiomerically Pure
N-[(R)-(+)-r-Methylbenzyl]aziridine-2-carboxaldehyde. J. Org. Chem., 1996, 61, 6183-6188.
Several 2-benzylaziridines having an OH group on the benzylic position were reduced to the appropriate 1-aryl-1-hydroxy-2-aminopropanes with H2 and
Pd(OH)2 at ambient temperature and pressure. The amount of catalyst used is a bit exaggerated, but it should be possible to lower it by increasing H2
pressure.
PS: Get yourself also the following reference in case you still don’t have it. It isn't about reduction of aziridines, instead it is about using
2-methylaziridine in Friedel-Crafts reactions:
Milstein, N. Friedel-Crafts reactions of three-member heterocycles. II. Alkylation of aromatic compounds with aziridines.
Journal of Heterocyclic Chemistry, 1968, 5(3), 339-341.
Attachment: J_Org_ Chem_61_ 6183-6188.pdf (211kB)
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…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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solo
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Reference Information
Friedel crafts Reaction of three -Member Heterocycles II -Alkylation of Aromatic compounds with Aziridines
Norman Milstein
Journal of Heterocyclic Chemistry, pg.339, June 1968
Abstract
The Friedel Craft reaction of propylenimine with symmetrical arenes in the presence of aluminum chloride was investigated . Electron donating
substituents increase the alpha-methyl-beta-phenethylamine/beta-methyl-beta-phenethylaimine ratio, while increasing the temparature has the opposite
effect. In the reaction of chlorobenzene or toluene with aziridine , the nature of the substituent has little effect on the ortho/para ratio.
Ref Information:
PROPYLENIMINE
(synonym): 2-methylethylenimine; nist75-55-8; methylaziridine; methylethylenimine; 1,2-propyleneimine; 2-methylazacyclopropane; 2-methylaziridine;
propyleneimine; 1,2-propylenimine
Chemical and Use Information
Chemical Abstract Symbol (CAS)
75-55-8
Additional CAS Numbers
None
Use Information
Propyleneimine is used as a chemical intermediate in the modification of latex surface coating resins, polymers in textile and paper industries, dyes,
photography, gelatins, oil additives and organic synthesis. It is a comonomer for polymers with methacrylic acid and esters.
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[Edited on 24-8-2006 by solo]
Attachment: Friedel Crafts Reactions of Three-Member Heterocycles II. Alkylation of Aromatic Compounds with Aziridines.pdf (149kB)
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solo
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In March's text 5th edition on page 1328 the following..................
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When proton acids catalyze alcohol dehydration, the mechanism is El.(160 )The
principal process involves conversion of ROH to ROH^ and cleavage of the latter to
R+ and H2O, though with some acids a secondary process probably involves
conversion of the alcohol to an inorganic ester and ionization of this (illustrated for
H2SO4):
..........................H2SO4
ROH ••>>>>>>>>>>>>> ROSO2OH •--------->.• R+ + HSO4
Note that these mechanisms are the reverse of those involved in the acid-catalyzed
hydration of double bonds (15-3), in accord with the principle of microscopic
reversibility. With anhydrides (e.g., P2O5, phthalic anhydride) as well as with some
other reagents such as HMPA,(161) it is likely that an ester is formed, and the leaving
group is the conjugate base of the corresponding acid. In these cases, the mechanism
can be El or E2. The mechanism with A12O3 and other solid catalysts has been
studied extensively but is poorly understood.(162)
Magnesium alkoxides (formed by ROH + Me2Mg —>ROMgMe) have been
decomposed thermally, by heating at 195-340°C to give the alkene, CH4, and
MgO.(163) Syn elimination is found and an Ei mechanism is likely. Similar
decomposition of aluminum and zinc alkoxides has also been accomplished.(164)
REF:
(160) For reviews of dehydration mechanisms, see Vinnik, M.I.; Obraztsov, PA. Russ. Chem.
Rev., 1990,59,63; Saunders Jr., W.H.; Cockerill, A.F. Ref. 3, pp. 221, 317; Knozinger, H. in
Patai The Chemistry of the Hydwxyl Group, pt. 2; Wiley: NY, 1971, p. 641.
(161) See, for example, Kawanisi, M; Arimatsu, S.; Yamaguchi, R.; Kimoto, K. Chem. Lett.,
1972, 881.
(162) For reviews, see Beranek, L.; Kraus, M. in Bamford; Tipper, Ref. 3, vol. 20, 1978, p. 274;
Pines, H. Intra-Sci. Chem. Rep., 1972, 6(2), 1; see pp. 17-21; Noller, H.; Andreu, P.;
Hunger, M. Angew. Chem. Int. Ed Engl, 1971,10, 172; Knozinger, H. Angew. Chem. Int.
Ed. Engl., 1968, 7,791. See also Berteau, P.; Ruwet, M.; Delmon, B. Bull. Soc. Chim. Belg.,
1985, 94, 859.
(1 6 3)Ashby, E.C.; Willard, G.F.; Goel, A.B. J. Org. Chem., 1979, 44, 1221.
(1 6 4)Reference 163; Brieger, G.; Watson, S.W.; Barar, D.G.; Shene, A.L. J. Org. Chem., 1979,
44, 1340.
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..............so the alcohol converts to the ester, then the ester is reduced to the hydrocarbon and HSO4:Noting that when applied to a primary non
benzylic amino alcohol the amine won't be affected by the acidic environment, ...........through thermal decomposition( pyrolysis) ........but is it
too high to destroy a phenylalaninol?
................I guess I better check the references next................solo
It's better to die on your feet, than live on your knees....Emiliano Zapata.
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