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manimal
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Thiourea Dioxide --> better than borohydride?
Here's an article that I also posted on wetdreams about reducing stuff (ketones) with TUD. Since this compound has been used in the past to reduce
nitro groups, and is otherwise mainly unexplored, one wonders what other interesting things can be reduced.
Reduction of Organic Compounds with TUD I: Reduction of Ketones to Secondary Alcohols
Tet. Letters, Vol. 13, Issue 5, 1972, pp. 343-346
Attachment: sdarticle.pdf (166kB)
This file has been downloaded 2824 times
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Ebao-lu
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You mean the reductuve amination of ketones? Possibly, it would work. As well as with nitroalkene reduction to amines..
Very interesting reagent, indeed (never heared about it).
[Edited on 7-2-2009 by Ebao-lu]
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sparkgap
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So I thought I should be mentioning this patent and the patents that reference formamidine sulfinic acid (which is thiourea dioxide's fancy name) listed... 
sparky (~_~)
"What's UTFSE? I keep hearing about it, but I can't be arsed to search for the answer..."
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Formula409
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| Quote: | Originally posted by Ebao-lu
You mean the reductuve amination of ketones? Possibly, it would work. As well as with nitroalkene reduction to amines..
Very interesting reagent, indeed (never heared about it).
[Edited on 7-2-2009 by Ebao-lu] |
How would this be done? Would the imine be formed, isolated and then reduced with the thiourea dioxide?
Formula409.
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manimal
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Well, seeing as imines are stable in basic solutions I would stick to the conditions described in the paper.
IIRC sodium dithionite can also reduce ketones, but yields are poor unless a cosolvent of diethylformamide is used. Here, the authors simply used
aqueous ethanol and got excellent yields (100% yield of diphenylcarbinol from benzophenone).
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UnintentionalChaos
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Ah! Thiourea dioxide (Thiox, aminoiminomethanesulfinic acid, formamidine sulfinic acid) is highly OTC, as it is available for use with dyes. One of
the more popular uses is to reduce indigo dye to a soluble form before dipping the cloth in. Upon air exposure, the "leucoindigo" reoxidizes to the
insoluble blue form within the fibers of the cloth. If reduction is anything like with indigo, the reaction is sluggish.
I wonder if this reaction can be modified to promote the dimerized side products. This would essentially be a pinacol coupling, but without the need
for multiple equivalents of metallic magnesium and mercury salts or any of the other expensive or nasty things usually used for pinacol couplings.
[Edited on 2-8-09 by UnintentionalChaos]
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Siddy
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That reference stats it is effective for aromatic nitro, azo etc, but not aliphatic nitro - any reference for that? Nitromethane > Methylamine?
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Ebao-lu
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no refference- only proposal. Methylamine can be prepared from urotropine, or if it is not avaliable, from ammonia+formaldehyde
[Edited on 8-2-2009 by Ebao-lu]
[Edited on 8-2-2009 by Ebao-lu]
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Vogelzang
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More interesting patents:
US 5350425 Method of reducing vat dyes and the process of dyeing fabrics therein
column 1 lines 49+
Typically, sodium dithionite has been employed to reduce the dyes to
their leuco form, as is shown U.S. Pat. No. 3,798,172. Sodium dithionite
decomposes rapidly in the presence or absence of air; therefore, large, excess
quantities of this compound are used to reduce all of the dye and to maintain
the dye in is soluble leuco form. Regrettably, the use of sodium dithionite
raises ecological concerns.
column 1 lines 64+
Another reducing agent that has received some attention is
thiourea dioxide in an alkaline solution. However, thiourea dioxide is a
strong reducing agent, and therefore tends to over reduce the vat dye. When
reducing indigo overreduction is readily apparent by the smell of fecal
material which is present when indole (the overreduction product) is in the
reaction.
indigo -> leucoindigo using Al, NaOH & H2O column 7, several examples columns 8 and 9
US 2872482 Process of making thiourea dioxide
Column 1
Thiourea dioxide has heretofore been prepared by the oxidation of thiourea by the use of hydrogen peroxide.
US 2150921 Manufacture of imino-amino-methane-sulphinic acid
oxidation of thiourea by the use of hydrogen peroxide
US 2164930 Process for reducing vat dyestuffs
use of thiourea dioxide for reducing vat dyes
http://www.pat2pdf.org
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Nicodem
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| Quote: | Originally posted by UnintentionalChaos
I wonder if this reaction can be modified to promote the dimerized side products. This would essentially be a pinacol coupling, but without the need
for multiple equivalents of metallic magnesium and mercury salts or any of the other expensive or nasty things usually used for pinacol couplings.
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Pinacol coupling requires one electron donor reducents since it goes via a SET mechanism. Thiourea dioxide is a two electron donor.
…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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UnintentionalChaos
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| Quote: | Originally posted by Nicodem
| Quote: | Originally posted by UnintentionalChaos
I wonder if this reaction can be modified to promote the dimerized side products. This would essentially be a pinacol coupling, but without the need
for multiple equivalents of metallic magnesium and mercury salts or any of the other expensive or nasty things usually used for pinacol couplings.
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Pinacol coupling requires one electron donor reducents since it goes via a SET mechanism. Thiourea dioxide is a two electron donor.
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I was merely mentioning page 344 of the original paper, which suggests SET as a possible mechanism to explain the formation of
(9,9'-bifluorenone)-9,9'-diol when the molar ratio of thiourea dioxide to NaOH to fluorenone was 1:1:1. I suspect it works very well in this case
since the proposed intermediate radical is in the benzylic position of two phenyl rings simultaneously. Perhaps this side reaction could be promoted
and extended to other phenyl carbonyl compounds and alpha-beta unsaturated carbonyls.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Nicodem
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You are correct, they even detected the anion radical with ESR. This is thus not such a simple reduction as it appears at the first glance. I doubt
the reaction can be made selective for the pinacol coupling even for such cases where the anion radical intermediate is exceptionally stabilized
simply because it will always react faster with the reducent rather than encountering another radical anion (a problem which is obviated in the
reactions with metals where the coupling happens on the metal surface). However, a SET mechanism of reduction using thiourea dioxide opens other more
promising possibilities, especially for radical cyclisations, and I'm surprised nobody made any further research since 1972 when that study was
published.
…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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manimal
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Literature from Scifinder:
Thiourea dioxide as a reducing agent.
Gore, P. H. Acton Tech. Coll., London,
Chemistry & Industry (London, United Kingdom) (1954), 1355. CODEN: CHINAG ISSN: 0009-3068. Journal language unavailable. CAN 49:68864 AN
1955:68864 CAPLUS Abstract
A preliminary survey shows that +H2N:C(NH2)SO2- (I) is a powerful reducing agent, capable of reducing aromatic nitro, azoxy, azo, and hydrazo compds.
to amines, quinones
to hydroquinones, and a no. of dyes to their leuco derivs., in excellent yields.
Reduction is carried out by adding I in 1 portion to H2O, pyridine, or HCONMe2 (or mixts. of these) in the presence of excess NH4OH, or caustic alkali
and warming the mixt. to 70° on a H2O bath with occasional shaking.
Synthesis of 2-aminomorphine and 2-aminocodeine. Reduction of aromatic nitro groups with formamidinesulfinic acid.
Chatterjie, Nithiananda; Minar, Arlene; Clarke, Donald D.
New York State Inst. Basic Res. Mental Retard., Staten Island, NY, USA.
Synthetic Communications (1979), 9(7), 647-57. CODEN: SYNCAV ISSN: 0039-7911. Journal written in English. CAN 92:42180 AN 1980:42180
CAPLUS
Abstract
2-Aminomorphine (I, R = H, R1 = H2N) and 2-aminocodeine (I, R = Me, R1 = H2N) were prepd. in yields of 60 and 81%, resp., by redn. of I (R1 = NO2)
with formamidinesulfonic acid. 2-H2NC6H4CO2H, 3-H2NC6H4OH, and 4-H2NC6H4Me were similarly prepd. in yields of 85, 90, and 56%, resp., by redn. of the
corresponding nitro compds.
Reduction of organic compounds with thiourea dioxide. II. Reduction of aromatic nitro compounds and syntheses of hydrazo compounds.
Nakagawa, Kunio; Mineo, Satoshi; Kawamura, Satoko; Minami, Kyoji. Fac. Pharm. Sci., Tokushima Bunri Univ., Tokushima, Japan. Yakugaku Zasshi
(1977), 97(11), 1253-6.
CODEN: YKKZAJ ISSN: 0031-6903. Journal written in Japanese. CAN 88:190270 AN 1978:190270 CAPLUS
Abstract
Thiourea dioxide, readily obtained by treating thiourea with H2O2, reduced nitro compds. to the corresponding arom. amines. Redn. of PhNO2 to PhNH2
in an alk. soln. showed that PhNHNHPh was formed from nitroso-, azo- and azoxybenzene in good yield. Substituted hydrazobenzenes were formed from the
corresponding azobenzenes.
Indexing -- Section 25-6 (Noncondensed Aromatic Compounds) Section cross-reference(s): 23
Reduction of organic compounds with thiourea dioxide.
Gu, Shang-Xiang; Yao, Ka-Ling; Hou, Zi-Jie; Wu, Ji-Gui. Dep. Chem., Lanzhou Univ., Lanzhou, Peop. Rep. China.
Youji Huaxue (1998), 18(2), 157-161.
CODEN: YCHHDX ISSN: 0253-2786. Journal written
in Chinese. CAN 128:321229 AN 1998:290865 CAPLUS
Abstract
Org. compds. contg. nitro, carbonyl, or double bond can be reduced with thiourea dioxide in good yield using an aq. ethanolic soln.
in the presence of sodium hydroxide.
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Nicodem
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Thanks for your search. To bad the reference that looks most interesting is published in Chinese. There are many other references for reductions with
thiourea dioxide, but most of them are about azo to hydrazo, N-oxides to amines, heterocyclic N-oxides to heterocycles, nitrile N-oxides to nitriles,
nitroaromatics to anilines, nitrosoamines to hydrazines, disulfides to thiols (also diselenides and ditellurides), etc.
There is almost nothing about ketones to alcohols (one example is in Bioorganic & Medicinal Chemistry, 14 (2006) 7051-7061).
An interesting reaction where thiourea dioxide is not used as a reducent is its reaction with amino acids to yield guanidino acids (Synthesis
(2000) 1656-1658).
The weirdest use is to deoxygenate 2,3-epoxyketones to the coresponding enones (Tetrahedron Letters, 38 (1997) 745-748). I did not even knew
this was possible with any reagent.
About its properties:
| Quote: |
Application of aminoiminomethanesulfinic acid as an antioxidant.
Knopp, Christian.
Scientia Pharmaceutica, 51 (1983), 51, 283-90.
Abstract: Aminoiminomethanesulfinic acid (I) [1758-73-2] has no antioxidant properties at pH <7. I reduces iodine to iodide at room temp. in alk.
soln. and on heating at acidic pH values. KMnO4 reacts with I to form MnO2 and cyanamide [420-04-2]; the latter is also formed in the reaction of I
with acidic H2O2. I is not oxidized or hydrolyzed at pH 1-6 in O-satd. H2O; at alk. pH values, cyanamide is formed together with an unidentified
compd. I is hydrolyzed by heating at pH 3.65 1% soln. without O to form formamidine [463-52-5], sulfide, and sulfite. At room temp., I forms
guanidine [113-00-8] in the presence of NH3. With benzylamine [100-46-9] at pH 8, I forms benzylguanidine [2211-57-6], and with piperidine
[110-89-4], it forms piperidinecarboxamidine [4705-39-9]. The mechanisms of the reaction are discussed. The use of I as an antioxidant in
pharmaceuticals appears problematical. |
It has quite nice and useful uses for being such an easily available reagent from photochemicals suppliers.
…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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Formula409
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Nicodem, you didn't happen to see any refs for reductions of imines did you?
Formula409.
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Nicodem
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There were a couple of references where N-oxides of imines were reduced to a mixture of secondary amine and imine, but nothing about the reduction of
imines or enamines themselves. Maybe there is more on Beilstein, but I don't have the time at the moment.
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Baphomet
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This is a good find, since reducing agents are one of the harder reagents for garage chemists to acquire (in this chemist's experience anyway  )
Perhaps it would be possible to produce it through the action of sodium percarbonate on thiourea?
If anyone has the full text for "Reduction of organic compounds with thiourea dioxide" I can translate it for you.
\"Who ARE you? You\'re like the drummer from REO Speedwagon - nobody knows who you are\" from \'Employee of the Month\'
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Formula409
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| Quote: | Originally posted by Baphomet
This is a good find, since reducing agents are one of the harder reagents for garage chemists to acquire (in this chemist's experience anyway )
Perhaps it would be possible to produce it through the action of sodium percarbonate on thiourea?
If anyone has the full text for "Reduction of organic compounds with thiourea dioxide" I can translate it for you. |
I've made a request in the references section for all the above articles. I will U2U you when it becomes available.
On that note, here is Synthesis of 2-aminomorphine and 2-aminocodeine. Reduction of aromatic nitro groups with formamidinesulfinic
acid., thanks tapira1!
http://www.sciencemadness.org/talk/viewthread.php?action=att...
Formula409.
[Edited on 16-2-2009 by Formula409]
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Baphomet
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Thanks Formula.
Here is an outline for preparation of the compound using H2O2:
Preparation of formamidinesulfinic acid
116 g of 30 % hydrogen peroxide weight out in a beaker on
accurate technical balance. Pour the hydrogen peroxide into a
1000 ml beaker and dilute it with 600 ml of distilled water. Place
the beaker into a large vessel (e.g. enameled pot) and encase it
with a mixture of gently grinded ice and sodium chloride. Place the
glass stirrer powered with electric motor into the liquid and under
continuing mixing allow the solution to cool down to 5 °C. Then,
during two hours, under the continuing intensive mixing, add with
spoon small doses of 38 g gently pulverized thiourea. The
temperature during this process should be between 5 and 20 °C.
Refresh the coolant if necessary. When all amount of thiourea is
added continue with cooling of the mixture with ice and sodium
chloride for next 1 hour. Then cool down all mixture close to
freezing point. Filter the separated formamidinesulfinic acid
preferably with small glass frit. Wash obtained product with small
quantity of icy water and then with small portion of methanol.
Washed acid is dried up in vacuum desiccator upon anhydrous
calcium chloride.
from
http://www.orglist.net/archive/2001/att-0115/00-part
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Nicodem
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| Quote: | Originally posted by Baphomet
Perhaps it would be possible to produce it through the action of sodium percarbonate on thiourea? |
Thiourea dioxide is available as photo developing reagent. It does not need to be bought from chemical suppliers. You can simply order it from an
online shop.
| Quote: | | If anyone has the full text for "Reduction of organic compounds with thiourea dioxide" I can translate it for you. |
The access to Yakugaku Zasshi is free for everyone. Pay attention not to use the Reference section for requesting freely available papers as
it only causes confusion.
Reduction of Organic Compounds with Thiourea Dioxide. II. Reduction of Aromatic Nitro Compounds and Syntheses of Hydrazo Compounds
…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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manimal
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| Quote: | Originally posted by UnintentionalChaos
I wonder if this reaction can be modified to promote the dimerized side products. This would essentially be a pinacol coupling, but without the need
for multiple equivalents of metallic magnesium and mercury salts or any of the other expensive or nasty things usually used for pinacol couplings.
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Have you seen European Journal of Organic Chemistry - Volume 2002, Issue 19 , Pages 3326 - 3335, from this thread?.
TiCl3+NaOH reduces aromaticketones to the dimers in good yields.
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Baphomet
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| Quote: | Originally posted by Nicodem
Thiourea dioxide is available as photo developing reagent. It does not need to be bought from chemical suppliers. You can simply order it from an
online shop.
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Thanks but online there only appears to be wholesalers selling 50kg drums. I will keep looking.
| Quote: |
The access to Yakugaku Zasshi is free for everyone. Pay attention not to use the Reference section for requesting freely available papers as
it only causes confusion.
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Thanks for the link. However it is the wrong article, I cannot read Japanese..
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Baphomet
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Ah ok, I see that it goes under the trade name of 'Thiox'
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UnintentionalChaos
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| Quote: | | TiCl3+NaOH reduces aromaticketones to the dimers in good yields. |
I take it that this is a spin off of the McMurry Reaction. The problem is 1: the TiCl3 is used in quite some excess, and TiCl3 is not happy to sit on
your shelf. It's typically made in-situ with TiCl4 and magnesium, just like samarium iodide.
You should look for thiox at places that sell supplies for the home dyer. Places that sell indigo powder usually carry it, and it is also sometimes
labelled as color remover (although this may be mixed with sodium carbonate. check before you buy it).
[Edited on 2-17-09 by UnintentionalChaos]
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'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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So am I right in thinking that this stuff can reduce both a double bond and a nitro group? Like maybe a nitrostyrene to phenethylamine in one step?
That would be lovely.
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