thiourea dioxide

[Vitus_Verdegast]

Does anyone has some information on the reducing capabilities of thiourea dioxide? TFSE didn't show up anything.

Thiourea dioxide (TDO) is a strong reductant which re-arranges under alkaline conditions to form formamidine sulphinic acid. This product is used in leather processing industry, paper, pulp and board industry, photographic industry, textile processing industry, bleaching and reducing agents. This product is also a component of decolorisation agents. TDO has been very effective on a wide variety of pulp sources as a reductive bleaching aid in the pulp and paper industry. The application of TDO is crucial to achieve optimal brightness gain in the deinking process.

It is easily made from thiourea and H₂O₂, but it is readily obtained cheap and OTC.

A Chinese source stated that it is 6x more powerful than dithionite for reducing indigo.

This could maybe be a great alternative to NaBH₄ for C=C reduction?

[acid_egg]

"Has been used to reduce ketones to secondary alcohols:Tetrahedron Lett.,343(1972)"

Not much to go on there at all I'm afraid. Useful subst. for NaBH₄ in the propiophenone route to PPA perhaps?

[Vitus_Verdegast]

Precipitation of nickel with thiourea dioxide from aqueous and aqueous alcohol solutions.
Ermolina, S. V.; Makarov, S. V.; Terskaya, I. N.; Budanov, V. V. Ivanov. Gos. Khim.-Teknol. Akad\.,  Russia.    Zhurnal Neorganicheskoi Khimii  (1995),  40(9),  1466-9.  CODEN: ZNOKAQ  ISSN: 0044-457X.  Journal  written in Russian.   CAN 124:16274    AN 1995:873926   
CAPLUS  Abstract

The effect of temp. , pH of the medium, the compn. of the alc.-water solvent, and the complex forming additive on
the prepn. of high-purity nickel powders by redn. with thiourea dioxide was studied. 
The effectiveness of thiourea dioxide as a reducing agent was compared to other sulfur-contg. reducing agents. 

Indexing -- Section 67-3  (Catalysis, Reaction Kinetics,
and Inorganic Reaction Mechanisms) 
Section cross-reference(s): 56   



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. 




Thiourea dioxide - a reducing agent for textiles.
Henderson, George F. Glo-Tex Chem., Inc.,  Roebuck,  SC,  USA.    Book of Papers - National Technical Conference,
 AATCC  (1978), 102-6.  CODEN: BPNADG  ISSN: 0192-4699.  Journal  written in English. CAN 90:24633    AN 1979:24633    CAPLUS  Abstract

The advantages and disadvantages of thiourea dioxide (I)  [4189-44-0] as an environmentally safe alternative to Na2S2O4 for reducing in vat dyeing, cleaning, clearing, and stripping in textile processing were discussed.  I was effective in most formulations at .apprx.10-12% of the concn. needed for Na2S2O4.



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  



And last but not least (any Chinese speaking bees around?):


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. 


Preparation:

Continuous synthesis of aminoiminomethanesulfinic acid.
Berkowitz, Sidney; Meadow, Morton; Bunin, Donald S.  (FMC Corp.).    U.S.  (1967),     4 pp.  CODEN: USXXAM 
US  3355486  19671128  Patent  written in English.    Application: US  19650108. 
CAN 68:49061    AN 1968:49061    CAPLUS 

Patent Family Information

Patent US3355486

Abstract

The title compd. (I) (thiourea dioxide), a reducing agent for vat dyes, ketones, conjugated unsatd. acids, and an antioxidant for Cl2C:CCl2, was produced continuously in high yields of good purity.  Thus, 338 ml. 50% H2O2 and
2420 ml. 10% aq. thiourea were pumped continuously into resp. legs (internal diam. 0.35 in.) of an Al cross reactor; the reaction temp. was 8-10°, the reaction time, about 30 sec.  The reaction mixt. was withdrawn through a third leg of the reactor at 45.7 ml./min. and passed through a 20° water bath into a heat exchanger in which ice-water produced a slurry from which was filtered 318 g. I, approx. theoretical yield (based on H2O2).  A detailed
 explanation of the process diagram is given. 

Patent Classifications
U.S.:  260513700. 



Looks like it has some potential, n'est-ce pas?  

[Vitus_Verdegast]

page 1355:

Thiourea dioxide as an organic reducing agent

By P.H. Gorz
Departement of Chemistry, Acton Technical College, London, W.3


Thiourea dioxide (formamidine sulphinic acid),^1,2 which has been known for some time to be a powerful reducing agent for metallic ions, e.g. capable of reducing tin or copper salts to the metallic state in ammoniacal solution, has found application recently in photography.
It has now been found that thiourea dioxide is also a very powerful agent for the reduction of organic compounds, and this is perhaps a unique behaviour for an organic substance. A preliminary survey shows that aromatic nitro, azoxy, azo and hydrazo compounds are reduced to the amines, quinones to hydroquinones, and a number of dyes to their leuco-derivatives. Yields are generally excellent. Ketones and alpha-diketones are not reduced. The reduction equivalent of thiourea dioxide is 54 g, corresponding to oxidation to the formamidine sulphonic acid stage.

⁺H₂N:C(NH₂)SO₂^-  +  H₂O  ^__>  ⁺H₂N:C(NH₂)SO₃^-  +  2H


Reductions may be carried out using water, pyridine or dimethylformamide (or mixtures of these), in the presence of excess ammonia or caustic alkali. In practice, the reducing agent is best added in one portion, the mixture finally warmed to about 70°C on a water bath and occasionally shaken.

Further aspects of the reducing action of thiourea dioxide are under investigation,and will be published in due course, together with details of the present study.

Grateful acknowledgement is made to Harden & Holden Ltd. for a generous gift of thiourea dioxide.

References
¹ Böeseken, Proc. K. Ned. Acad. Wet. (1936), 39, 717
² Böeseken, Rec. Trav. Chim. Pays-Bas (1936) 55, 1040

[Vitus_Verdegast]

Russ. Chem. Rev. (2001), 70 (10), p. 885-895

Recent trends in the chemistry of sulfur-containing reducing agents

Sergei V. Makarov

Abstract: Data on the structure, synthesis, stability and reactivity of sulfur-containing reducing agents with C–S or S–S bonds — sodium dithionite, sodium hydroxymethanesulfinate and thiourea oxides — are surveyed. Reactions of anaerobic and aerobic decomposition of sulfur-containing reducing agents are discussed. The applications of these compounds in the studies of non-linear phenomena in chemical kinetics and in guanidine syntheses are considered. The bibliography includes 165 references.

DOI:

10.1070/RC2001v070n10ABEH000659