Dinitrobenzenesulfonic acid

A mixture of 10 g of the glyoxylic acid, 100 ml of acetic anhydride, and 0.5 g of 2,4-dinitrobenzenesulfonic acid is stirred at 25° for 2 hr. Sodium acetate (0.5 g) is added and the mixture concentrated in vacuum at 50°. The residue is taken up in 100 ml of benzene and washed with two portions of 2.5 N sodium hydroxide to remove the remaining acetic anhydride. The benzene solution is washed with water, dried and concentrated in vacuum to dryness. Crystallization from 40 ml of absolute ethanol gives 9.8 g (85%) of 3a,20,23-trihydroxy-16a-methyl-11 -oxo-21 -norchola-17(20),22-dienoic acid-24(20)-lactone 3,23-diacetate mp 165-175°. 

Eisen, H.N., Belman, S., and Carsten, M.E. (1953) The reaction of 2,4-dinitrobenzenesulfonic acid with free amino groups of proteins./. Am. Chem. Soc. 75, 4583. 

With 2,4-Dinitrobenzenesulf enyl Chloride. Photochemical conversion of 2,4-dinitrobenzenesulfenyl chloride (LXVII) to 2-amino-4-nitrobenzenesulfonic acid (LXVIII) occurs in the presence of water. The intermediate 2-acetoxyamino derivative (LXIX) of LXVIII was shown to hydrolyze to acetic acid and hydroxyamino (LXX) derivative of LXVII, and to give LXVIII on irradiation. The reaction involved an intramolecular transfer of oxygen from 2,4-dinitrobenzenesulfonic acid to the sulfonamide. Compound LXX is photochemically reduced to LXVIII.146... 

C6H4CiN03 5-chloro-6-hydroxynicotinic acid, tautomers 54127-63-8 25.00 1.4818 2 6595 C6H4N207S 2,4-dinitrobenzenesulfonic acid 89-02-1 25.00 1.7452 2... 

A mixture of 1 mmol trani-cinnamaldehyde, 0.3 mmol chiral l-A-methyl-3-benzyl-5-r-butyl-imidazolidinone, and 0.3 mmol 2,4-dinitrobenzenesulfonic acid (DNBA) in 0.5 mL r-BuOH and i-PrOH (v/v, 5 1) was stirred at room temperature for 10 min. Then 5 mmol 1 -(trimethylsilylox)ethylene was added, and the mixture was stirred for 4 h at room temperature. The solution was concentrated in vacuo. The resulting residue was then purified by silica gel chromatography to afford 75% (R)-5-oxo-3,5-diphenyl-pentanal, with 90% e.e. 

Kiprianov (1957) studied the relative rates of formation of quaternary salts of 2-methylbenzothiazole with methyl iodide, methyl sulfate, and methyl esters of sulfonic acids and p-nitrosulfonic acids. He found that the reaction with methyl 2-nitrobenzenesulfonate was six times faster than that with Me2S04, while the methyl esters of the 2,3- and 2,4-dinitrobenzenesulfonic acid reacted sixty times more rapidly than did Me2S04. Such esters afford a method for very mild alkylation of very weak bases (Kip>rianov Tolmachev 1957). 

Dinitrobenzenesulfonic acid 2,4-Dinitrobenzoic acid 3,4-Dinitrobenzoic acid... 

Although debenzylative cyclizations in sugar chemistry are known, they usually proceed in acidic media. Very often, strong acids (e.g., 2,4-dinitrobenzenesulfonic acid) should be used to achieve this transformation [60]. 

Scheme 17.34 2,4-Dinitrobenzenesulfonic acid catalysed Ritter reaction.

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