Potassium nitrosodisulfonate Fremy

Hydroxylamine trisulfonates, e.g. (K03S)0N-(S03K)2 are made by the reaction of K2SO3 with potassium nitrosodisulfonate (Fremy s salt). Acidification of the product results in rapid hydrolysis to the 0,A-disulfonate which can be isolated as the exclusive product ... 

Potassium nitrosodisulfonate (Fremy s salt), K(S03>2N0 Oxidizes phenols to yield quinones (Section 17.10). 

A solution of potassium nitrosodisulfonate (Fremy s salt) (0.56 mmol) dissolved in 5 ml water was added to a solution of the product from Step 7 (0.18 mmol) dissolved in 5 ml dioxane, the mixture stirred at ambient temperature 2 hours, and concentrated. The material was purified by reverse phase chromatography and the product isolated in 54% yield having a HPLC retention time of 1.75 minutes. 

Potassium nitrosodisulfonate (Fremy salt), 0N(S03K)2, is a free radical capable of converting phenols [487, 488, 489 and aromatic amines [490 into quinones. 

OXIDATION WITH POTASSIUM NITROSODISULFONATE (FREMY SALT)... 

Potassium nitrosodisulfonate (Fremy s Salt) [14293-70-0] M 268.3. It forms yellow needles (dimeric) which dissolve in H2O to give the violet monomeric free radical. It is purified by dissolving ( 12g) in... 

The reaction of 148 with 10% HCl-MeOH afforded selective hydrolysis of the amide to form the 3-aminopyridine 149, in which the ring was subsequently closed after treatment with palladium(O) to give the /3-carboline 150. Friedlander condensation of 150 with 2-amino-3-benzyloxy-4-bromo-benzaldehyde (151), which was synthesized in four steps (5S), gave the 2-/3-carbolinequinoline 152. Hydrogen bromide gas debenzoylation of 152 was followed by oxidation with potassium nitrosodisulfonate (Fremy s salt) to obtain Kende s intermediate 131. 

Potassium nitrosodisulfonate [Fremy s sal 4,7-Indoloquinones. A route to these azoles such as 1 to provide 2, which undcri 7-hydroxyindoles (3). These products undci gel to provide 4. This 4-formyl-7-hydroxy... 

Ellipticine (E) 1 is an indolic alkaloid with antitumor activity. Some of its phenolic derivatives as N-methyl-9-hydroxyellipticine (Celiptinium), obtained from 9-hydroxy ellipticine (9-OH E), exhibit high cytotoxicity. 38 Syntheses of 9-OH E are not satisfactory considering yields and cost, justifying the attempts at the direct conversion of E to 9-OH E via 9-oxoellipticine (9-0X0 E). Potassium nitrosodisulfonate (Fremy s salt), a valuable oxidant for the synthesis of quinone-imine from heterocyclic amines,139 was used. Under these conditions the conversion of E to 9-0X0 E was observed for the first time. Its reduction to 9-OH E is then easily achieved with ascorbic acid. The radical nature of Fremy s salt [ 0-N(S03K)2] led us to carry out the oxidation reaction under sonication in order to increase the yields via an easier electron transfer.1 1... 

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