Glyoxal bisulfite

Sodium wire is not essential. The reaction will proceed just as well with sodium cut into pieces the size of a small pea. It is important that the sodium be cut into small pieces otherwise a protective coating forms on the surface of the metal, preventing further reaction. 

The sodium chloride is very finely divided and quickly clogs the pores of the filter paper. The mixture should be allowed to stand for a time before filtration to allow the salt to settle the clear supernatant liquor can then be filtered rapidly. 

Care should be taken in disposing of this residue it invariably contains some unreacted sodium. 

Ethyl N-tricarboxylate has been prepared from urethan by reaction with sodium and chlorocarbonic ester1 as well as from the potassium salt of ethyl imiclodicarboxylate.2 

Submitted by Anthony R. Ronzio and T. D. Waugh. Checked by C. F. H. Allen and J. Van Allan. 

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Alternatively, this may be done in a flask, which is shaken by hand frequently to prevent formation of a solid cake. The use of a stirrer results in a granular product. The mother liquor retains about 7 g. of glyoxal bisulfite per liter. 

From the reaction of aminoguanidine with 2-bromoisobutyraldehyde dimethylacetal (522) a product was isolated which was assigned structure (523) or a tautomer thereof (70BSF1606). Semicarbazide (459a) reacts with the glyoxal-bisulfite addition product (524) to give a product formulated as structure (525) (28JA2731). 

Synthesis. Benzenehexol is available only from laboratory reagent suppliers. The simplest laboratory preparation involves the aeration of the glyoxal—bisulfite addition product in sodium carbonate solution at 40—80°C, isolation of the sodium salt of tetrahydroxybenzoquinone, followed by acidification to obtain the free tetrahydroxy-p-benzoquinone in about 8% yield the latter is reduced with stannous chloride in boiling dilute hydrochloric acid solution to benzenehexol (77) in 77% yield (261). A similar procedure affords dipotassium rhodizonate (80) in good yield (262). 

The procedure employed for tetrahydroxyquinone is based on an observation by Homolka. Tetrahydroxyquinone may also be prepared by treatment of the glyoxal-bisulfite addition compound with sodium carbonate or magnesium hydroxide and potassium cyanide or by treatment of 50% glyoxal with sodium hydro-sulfite. ... 

A solution of 68.8 g. (0.26 mole) of glyoxal bisulfite [Org. Syntheses, 24, 61 (1944) ] in 300 ml. of water is heated to 70° and added with stirring to a mixture of 27.0 g. (0.25 mole) of o-phenylenediamine [Org. Syntheses Coll. Vol. 2, 501 (1943)] and 400 ml. of water also heated to 70°, The mixture is stirred for another 5 minutes and allowed to cool to around 40° 100 g. of potassium carbonate is added. The precipitated quinoxaline is removed by extraction with one 100-ml. portion and three 50-ml. portions of ether. The combined ethereal extracts are dried over anhydrous sodium sulfate and distilled to give 29.6 to 30.5 g. (90.8-93,5%) of quinoxaline boiling at 112-115°/17 mm. 

Isonaphthazarin can be synthesized by adding a solution of o-phthalaldehyde in dioxane to an aqueous solution of glyoxal bisulfite, potassium cyanide, and sodium bicarbonate and stirring the solution in the presence of air at 20°. The solution rapidly acquires an intense violet color and is acidified after 15 min. (since the product is very sensitive to alkali) to precipitate bright red isonaphthazarin. 

Preparation of glyoxal bisulfite by refluxing a mixture of paraldehyde, selenium dioxide, dioxane, and a small volume of 50% acetic acid for 6 hrs. The solution is decanted from selenium, steam distilled to remove paraldehyde and dioxane, and... 

Quinoxaline synthesis. Condensation of glyoxal bisulfite with o-phenylenediamine in aqueous solution at about 80° affords quinoxaline in high yield, and this base on permanganate oxidation affords 2,3-pyrazinedicarboxylic acid. In the absence of sodium bisulfite, aqueous glyoxal reacts with o-phenylenediamine to give quinoxaline in only about 30% yield along with resinous by-products. 

CiHsCOCHj + HzSeOa 1 m. in 600 dioxane 1 m. under reflux. The product is isolated by distillation at 25 mm. The preparation of glyoxal bisulfite is similar, except that paraldehyde is taken in large excess and the solvent is a mixture of 540 ml. of dioxane to which 40 ml. of acetic acid is added... 

This reaction was first reported by Hinsberg in 1888. It is the synthesis of N-alkyl-oxindole from IV-alkyl aniline and the glyoxal-bisulfite adduct after hydrolysis by hydrochloric acid. Similarly, the reaction of A -alkyl naphthylamine with glyoxal-bisulfite adduct leads to benzo-oxindole. In contrast, the reaction between primary aryl amines and... 

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