Thioglycolic acid reaction

Mono- and polyl dric phenols and enols frequently form characteristically colored complexes with Fe + ions [4, 28, 29]. Here monohydric phenols usually produce reddish-violet colors, while pyrocatechol derivatives yield green chelates [4]. Detection of acetone using Legal s test is based on the formation of an iron complex [4]. The same applies to the thioglycolic acid reaction of the German Pharmacopoeia (DAB 9) [4, 30]. 

The structure of the 5,6-dihydroxyindole thioether was finally established by a study of the adrenochrome-thioglycollic acid reaction products. This reaction gave three major indolic products the reduction product 5,6-dihydroxy-A -methylindole (44) the thioether (120) or (121) and a small amount of a third unidentified product [238]. It was not possible to isolate the thioether directly but a stable crystalline acetyl derivative was obtained [242]. The structure of this product was established mainly on the basis of n.m.r. spectroscopic evidence. It was shown that, in fact, the thiol residue was attached to the 4-position (i.e. 4-5 -carboxymethylthio-5,6-dihydroxy-7V-methylindole, (123)) in the indole ring system, since the characteristic long-range coupling of ca. 0-8 Hz which occurs between the protons in the... 

Thioglycolic acid reaction, 9 Thionol, 68 Thujone, 74 Thujyl alcohol, 74 Thymol, 43... 

In 1880, R. Andreasch (52) confirmed the new formula (37) by preparing thiohydantoine through condensation of thioglycolic acid with cyanamide (the reverse reaction of the basic hydrolysis of thiohydantoin). 

Several kinds of products can be obtained by reaction of thioglycolic acid and its esters with aldehydes to form mercaptals, RCH(SCH2COOH)2, or with ketones to form thiolketals, RR C(SCH2COOH)2. Reaction with formaldehyde (qv) yields di- -butyhnethylene-bisthioglycolate [1433882-0] (MET ester) ... 

Sensitization. The skin irritation and sensitization potentials of 9.0% thioglycolic acid were evaluated usiag the open epicutaneous test. Reactions were not observed dutiag the challenge phase. ThioglycoHc acid was an irritant, but not a sensitizer (20). 

Mercaptides are unchallenged as the ligand of choice for the other entities bonded to the tin, but carboxylates can also be used. Whereas a variety of mercaptans are used, the thioglycolic acid derivatives remain the largest single mercaptan. Dibutyltin bis(isooctyl thioglycolate) [25168-24-5] and butyltin tris(isooctyl thioglycolate) [25852-70A] are two common examples. These materials are produced by the reaction of the appropriate alkyl tin chloride or oxide, and the mercaptan. 

The Fiesselmann thiophene synthesis involves the condensation reaction of thioglycolic acid derivatives with a,P-acetylenic esters, which upon treatment with base results in the formation of 3-hydroxy-2-thiophenecarboxyIic acid derivatives. 

Soon after the 1946 report by Woodward on the condensation of thioglycolic acid and a,P-unsaturated esters in the presence of base to produce structures like 2-carbomethoxy-3-ketotetrahydrothiophene 4, Fiesselmann extended this reaction to a,p-acetylenic esters for the direct preparation of 3-hydroxy-2-thiophenecarboxyIic acid derivatives. ... 

The Fiesselmann reaction has been extensively used with p-halovinyl esters, ketones,aldehydes and nitriles as reaction partners for thioglycolic acid and its derivatives. This reaction with P-halovinyl aldehydes has been extensively explored as a result of the availability of P-chloro-a,P-unsaturated aldehydes via the Vilsmeier... 

While the majority of examples of the Fiesselmann reactions found in the literature involve thioglycolic acid or the corresponding thioglycolates, the scope of this reaction has been expanded to a variety of other a-mercaptocarbonyl derivatives. Some examples include a-mercapto aldehydes, ketones,and amides. Notably, when compound 33 is treated with 2-mercaptoacetamide, compound 34 was produced in 48% yield. ... 

The mercaptals obtained by the acid catalyzed reaction of J3-ketoesters, e.g., ethyl acetoacetate, with methyl thioglycolate (73) undergo the Dieckmann cyclization with alcoholic potassium hydroxide at lower temperatures to give ethyl 3-hydroxy-5-methyl-2-thiophenecarboxylate (74) in 75% yield. ° Besides ethyl acetoacetate, ethyl a-ethylacetoacetate, ethyl benzoyl acetate, and ethyl cyclopentanonecarboxylate were also used in this reaction/ It is claimed that /8-diketones, hydroxy- or alkoxy-methyleneketones, or /8-ketoaldehyde acetals also can be used in this reaction. From acetylacetone and thioglycolic acid, 3,5-dimethyl-2-thiophenecarboxyl-ic acid is obtained. ... 

The cyclized analog of meralluride is prepared by a similar synthesis. Thus, condensation of camphoric acid (42) (obtained by oxidation of camphor) with ammonia gives the bicyclic succinimide (44). Reaction with allyl isocyanate followed by ring opening and then reaction with mercuric acetate affords the mercury derivative (45) as the acetate rather than the hydroxide as above. Reaction with sodium chloride converts that acetate to the halide (46). Displacement on mercury with the disodium salt of thioglycollic acid affords the diuretic mercaptomerine (47). ... 

Trichloromethyl substituted thiazolidines have been prepared from chloral. Reaction of chloral with anilines afforded the corresponding imines which were then treated in situ with thioglycolic acid to give a series of 2-trichloromethyl substituted thiazolidinones <96HC227>. 

However, more recent work has shown that the reaction of thioglycollic acid (HSCH2COOH) with methylcobalamin to give the methyl thioether requires oxygen and shows an induction period [which can be reduced by increasing the pH, the thiol concentration, or the partial pressure of O2, and eliminated by the addition of the Co(II) complex], followed by a steady-state reaction [ whose rate increases with pH, the concentration of the CH3C0 and Co(II) complexes and the partial pressure of O2, but is independent of thiol concentration]. Neither the induction period nor the steady-state... 

In order to study heterocyclic steroid analogues, such as the 7,11-dithiaazasteroid analogues, Fravolini developed the synthesis of new heterocyclic ring systems tri- and tetracyclic 2,1-benzothiazines <82JHC1045>. Intermediate 137 was prepared from 1-methyl-4-oxo-lH-2, -bcnzothiazinc-4(3f/)-onc 2,2-dioxide 37 and thioglycolic acid and could be converted into 6-methyl-4-oxo-3,4-dihydro-2//,6//-thiopyrano[3,2-c][2,l]benzothiazine 5,5-dioxide 138 by cyclization with polyphosphoric acid. The reaction of 138 with dimethyl... 

It will be noted that the non-planar propeller form lacks a plane of symmetry and that the production of optically active products by way of an intermediate radical might therefore be possible. Attempts to make precursory optically active phenylxenyl-a-naphthylmethyl halides failed, but the corresponding active thioglycolic acid has been prepared. It is racemized by the reaction with triphenylmethyl free radicals.19 Various other reactions believed to involve radical intermediates also give inactive products ... 

The reaction of 3-methyl-6-(4-chlorophenyl)[l,2,4]triazolo[3,4-7]-l,3,4-thiadiazole 319 with thioglycolic acid gives thiazolo[2,3-3]-.r-triazolo[3,4-7][l,2,3]thiadiazol-6(7//)-one 320 (Equation 56) <2002IJH167>. 

The reaction of 2,3-diaminoquinazolin-4-one 404 with aryl aldehydes and thioglycolic acid gives 2-substituted 1,3-dihydro-thiazolo[3, 4 2,3][l,2,4]triazolo[5,l-A]quinazolin-5-ones 405 (Equation 79) <2004MI10>. 

Theory The limit test for Iron is based on the reaction between iron and thioglycollic acid in a medium buffered with ammonium citrate to give a purple colour, which is subsequently compared with the standard colour obtained with a known amount of iron (0.04 mg of Fe). Ferrous thioglycollate is a co-ordination compound that attributes the purple colour besides thioglycollic acid converts the entire Fe3+ into Fe2+. The reactions involved may be expressed as follows ... 

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