Janovsky

MEISENHEIMER JANOVSKY Corryilexes The adduct formed from a polynAroaromaiic compourxf in alkaline solution with RO, HO (Melsenheimer) or with acetone (Janovsky)... 

Janovsky comptex (4). m-OIntrobenzene 3 (1 00 g, 6 mmol) In acetone (10 mL) was Shaken vigorously with KOH pellets for 15 mm The purple mixture was filtered, the KOH pellets washed with acetone arxl to the combined solutions was added benzene (20 mL) The black-violet precipitate was recrystalHzed Irom benzene-acetone to give 135 mg of 4 (10%), mp 250 C. 

Janovsky Test. Color reactions produced by treating aromatic nitro compds with hot" cold alcoholic NaOH or KOH and acetonic NaOH solns. A table of color reactions of some nitro compds is given in Ref 2. See Janovsky s Reagent under COLOR REACTIONS and COLOR REAGENTS in Vol 3 of Encycl, p C405-R... 

St CA 71, 9479(1969) (Colorimetry of alkylamines, guanidines, and quaternary ammonium salts by the Janovsky Reaction) (Free Gu from its salt with AgO in the presence of nitromethane and TNB colori-metrically measure the red compd formed)... 

JANOVSKY REACTION. Reaction ol aldehydes and ketones containing or-meihylcne groups with i/i-dinitrohenzcnes in the presence of a strong base, resulting in the formation of an intense purple coloration, used for the detection of carbonyl compounds. The color is due to the fnrniaiion of Meisenheimer complex. 

Some mononitrocompds, such as o- p-Nirro-aniline, p-Nitrotoluene and some of their derivs produce orange or red color in dimethylformamide upon the addn of 0.1ml of 10% aqueous soln of tetramethylammonium hydroxide. Janovsky s reagent which is 10% aq NaOH soln may also be used) 22)G.H. Wetter, "Development of Instrumentation for Determining the Total Chromaticity and Chromaticity vs Time of... 

J3. Jirsova, V., Jirsa, M., and Janovsky, M., Importance of the quantitative determination of direct and indirect bilirubin in hemolytic disease of newborn. Acta Tediat. 47, 179-186 (1958). 

The reaction of 1,3-dinitrobenzene with alkaline acetone to give a purple-coloured solution was noted as early as 1886 by Janovsky and Erb and is now known as the Janovsky reaction . Since then strong colours have been observed from a variety of active methylene compounds and the reaction is used as a test for them. Much of the literature has been summarized by Canback (1949a, 1949b), who suggested the structure 42, and more recently by Pollitt and Saunders (1965). Chemical and spectroscopic evidence is in support of formula 42 and dark purple crystals have been prepared (Gitis and Kaminskii, 1963, 1964 Kimura et al., 1965). Oxidation with hydrogen peroxide in acidic... 

An apparently similar reaction has been described by Zimmerman (1935, 1936). However, here the dinitrobenzene is used in excess and the solvent is ethanol. It has been shown that the colour in these solutions results from anions such as 43 (Neunhoeffer et al., 1961 King and Newall, 1962) which are derived from the initially formed Janovsky adduct by oxidation with the excess nitro-compound. 

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