Chloranil as reagent

Characterization of compounds s. subentry derivatives Chelates s. Complex salts, inner Chloranil as reagent 16, 524 Chlorides s. a. Halides, Replacement... 

Note It is reported that the use of chlorobenzene as solvent is essential when the reagent is to be used to detect aromatic amines [1]. In the case of steroids, penicillins, diuretics and alkaloids the reaction should be accelerated and intensified by spraying afterwards with dimethylsulfoxide (DMSO) or dimethylformamide (DMF), indeed this step makes it possible to detect some substances when this would not otherwise be possible [5,9-11] this latter treatment can, like heating, cause color changes [5,9]. Penicillins and diuretics only exhibit weak reactions if not treated afterwards with DMF [10, 11]. Steroids alone also yield colored derivatives with DMSO [9]. Tlreatment afterwards with diluted sulfuric acid (c = 2 mol/L) also leads to an improvement in detection sensitivity in the case of a range of alkaloids. In the case of pyrrolizidine alkaloids it is possible to use o-chloranil as an alternative detection reagent however, in this case it is recommended that the plate be treated afterwards with a solution of 2 g 4-(dimethyl-amino)-benzaldehyde and 2 ml boron trifluoride etherate in 100 ml anhydrous ethanol because otherwise the colors initially produced with o-chloranil rapidly fade [12]. 

USE Fungicide. In manuf of chloranil electrodes for pH measurements. As reagent for pamaquine (Plasmochin) in urine (blue color) Schulemann et ai, Chem. Zentr. 1928, I, 2193. Two of the chlorine atoms in para position are easily subetituted, and compds such as 2,5-dianitino-3,6-dichloro-quinone are much used in the dye industry. Caution May ba irritating to skin, mucous membranes. 

Again, as with pyridopyrimidines, the main reaction is oxidation of di- or poly-hydro derivatives to fully aromatic structures, often merely by air or oxygen. In some cases the reagent of choice is mercury(II) oxide, whilst other reagents used include sulfur, bromine, chloranil, chromium trioxide-acetic acid, hydrogen peroxide, and potassium ferricyanide, which also caused oxidative removal of a benzyl group in the transformation (306) (307)... 

Amines (primary and secondary aromatic) / -Chloranil The reaction depends on the catalytic effect of silica gel. Monochlorobenzene, as solvent for the reagent, also contributes. There is no reaction on cellulose layers. [17, 22]... 

A series of substituted triazolo[3,4- ][l,3,4]thiadiazoles 455 have been submitted to reaction with different two-carbon activated reagents such as chloranil or 2,3-dichloroquinoxaline, to give the complex linear heterocycles 456... 

The synthetically most valuable intermediate in heterofullerene chemistry so far has been the aza[60]fulleronium ion C59N (28). It can be generated in situ by the thermally induced homolytic cleavage of 2 and subsequent oxidation, for example, with O2 or chloranil [20-24]. The reaction intermediate 28 can subsequently be trapped with various nucleophiles such as electron-rich aromatics, enolizable carbonyl compounds, alkenes and alcohols to form functionalized heterofullerenes 29 (Scheme 12.8). Treatment of 2 with electron-rich aromatics as nucleophilic reagent NuH in the presence of air and excess of p-TsOH leads to arylated aza[60]fullerene derivatives 30 in yields up to 90% (Scheme 12.9). A large variety of arylated derivatives 30 have been synthesized, including those containing cor-annulene, coronene and pyrene addends [20, 22-25]. 

The readily available reagent diphenyl selenoxide has been used as a mild and selective oxidant in the synthesis of aporphines (and homoaporphines). When the benzylisoquinoline (13) was treated with one equivalent of the reagent at room temperature in methanol, and the product was O- methylated with diazomethane, the aporphine (14) was obtained in 80% yield. The alternative use of chloranil, which is a commonly used oxidant for catechols, yielded less than 10% of (14).20... 

Numerous methods for determining fluoride are based on compounds of thorium with organic reagents, such as Alizarin S [55], Xylenol Orange [48], Arsenazo I [4], and chloranilic acid [56]. An exceptionally sensitive method is based on the ternary system Th-Chrome Azurol S-CTA (e= 1.0-10 at 635 nm) [57]. 

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