Dinitrobenzoyl chloride

Place a mixture of 30 g. of 3 5-dinitrobenzoic acid (Section IV,168 and 33 g. of phosphorus pentachloride in a Claisen flask flt a reflux condenser into the short neck and cork the other neck and side arm (compare Fig. Ill, 31,1). Heat the mixture in an oil bath at 120-130° for 75 minutes. Allow to cool. Remove the phosphorus oxychloride by distillation unda reduced pressure (25°/20 mm.) raise the temperature of the bath to 110°. The residual 3 5-dinitrobenzoyl chloride solidifies on cooling to a brown mass the yield is quantitative. Recrystallise from carbon tetrachloride the yield is 25 g., m.p. 67-68° and this is satisfactory for most purposes. Further recrystallisation from a large volume of light petroleum b.p. 40-60°, gives a perfectly pure product, m.p. 69-6°. 

3 5-Dinitrobenzoyl chloride reacts readily with water and it should be kept in sealed tubes or under light petroleum. When required for qualitative organic analysis it is usually best prepared from 3 5-dinitrobenzoic acid immediately before use (see Section III,27,J). 

This reagent, to which the name niozime has been given, is employed for the determination of palladium and may also be used for nickelit is soluble in water, and possesses advantages over dimethylglyoxime. The latter is used as a solution in alcohol and may therefore contaminate the palladium or nickel precipitate when added to an aqueous solution. 

It is important that the synthesis should be carried out as quickly as possible, particularly the washing with alkali at 0°, since the latter tends to convert the product into cyctopentane-a-hydroxycarboxylic acid. 

1 2-c3w foHexanedione-dioxime. Dissolve 55 g. of the freshly distilled dione in 500 ml. of water, cool the solution to 0°, and dissolve 170 g. of pure hydroxylamine hydrochloride in it. Add a solution of 225 g. of potassium hydroxide iii 1 litre of water at 0° dropwise over a period of 15 minutes with constant mechanical stirring. Heat the mixture on a steam bath for 2 hours, cool to 0°, neutralise with dry ice, satmate with salt, filter off the precipitated dioxime, and wash with a little ice-cold water. BecrystaUise the crude dioxime from water. The yield of pure cydo-hexanedione-dioxime (white needles), m.p. 187-188° (decomp.), is 39 g. 

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This preparation illustrates the use of phosphorus pentachloride for the preparation of acyl chlorides in this case no difficulty is experienced in separating the 3,5-dinitrobenzoyl chloride from the phosphorus oxychloride formed simultaneously (c/. p. 240), because the former is readily isolated as a crystalline... 

Occasionally benzoyl chloride gives a product which does not crystallise well in such cases the difficulty may frequently be overcome by using p-nitrobenzoyl chloride, N02C,H4C0C1, or 3,5-dinitrobenzoyl chloride, (NOiljCjHjCOCl (p. 240), which usually give highly crystalline derivatives. 

The reaction between 3,5 dinitrobenzoyl chloride and compounds containing the OH, NHj, or NH groups is very rapid, and therefore is particularly suitable for identification purposes cf. pp. 335, 338, 381). It is usual to have sodium hydroxide present during the reaction with phenols and amino-acids, but this is not necessary with alcohols if they are dry. 

Place I g. of powdered 3,5-dinitrobenzoyl chloride in a small conical flask, add 2 5 ml. of dry methanol, and warm on a water-bath until the solid has dissolved. Cool and filter off the 3,5-dinitrobenzoate which has separated. Recrystallise from ethanol or petroleum (b.p. 60-80°). The ester separates in colourless crystals, m.p. 108°. Yield,... 

Give crystalline esters with 3,5 dinitrobenzoyl chloride. 

Form derivatives with benzoyl chloride and (more rapidly and conveniently) with 3,5-dinitrobenzoyl chloride. 

Dinitrobenzoyl-glycine. Dissolve 0 4 g. of glycine in 10 ml. of TV.NaOH solution in a small stoppered bottle. And i-i g. of finely powdered 3 5-dinitrobenzoyl chloride (preparation, p. 242) and shake vigorously for about 1 minute. Filter if necessary and acidify with dil. 

Heat together under very efficient water reflux 1 g. of freshly fused dry powdered ZnClg, 2 ml. of diethyl ether and 0 5 g. of 3,5 -dinitrobenzoyl chloride for 2 hours. Shake the product with 5 ml. of water and ther add 10% NaOH solution until all the ZnCl, and excess of 3,5-dinitro> benzoyl chloride and 3,5-dinitrobenzoic acid have gone into solution. Filter at the pump and recrystallise from petroleum (b.p. 40-60°) to obtain ethyl 3,5-dinitrobenzoate, m.p. 93°. (M ps. of other 3,5 dinitro-benzoates, p. 536.)... 

Method 1. Mix 1 0 g. of 3 5-dinitrobenzoic acid (Section IV,168) with 4 ml. of thionyl chloride in a dry 50 ml. conical flask fit a reflux condenser, carrying a plug of cotton wool at the upper end, into the flask and heat on a water bath for 15-30 minutes. Remove the condenser and heat the flask in a boiling water bath FUME CUPBOARD 1) until the excess of thionyl chloride has evaporated. Use the resulting 3 5-dinitrobenzoyl chloride (about 10 g.) immediately. 

Method 2. Mix 1 0 g. of 3 5-dinitrobenzoic acid with 1 5 g. of phosphorus pentachloride in a small, dry test-tube. Warm the mixture gently over a small smoky fiame to start the reaction when the reaction has subsided (but not before), boil for 1-2 minutes or until the solid matter has dissolved. Pour the mixture while still liquid on a dry watch glass (CAUTION the fumes are irritating to the eyes). When the product has solidified, remove the liquid by-product (phosphorus oxychloride) by transferring the pasty mixture to a pad of several thicknesses of filter paper or to a small piece of porous tile. Spread the material until the liquid has been absorbed and the residual solid is dry. Transfer the 3 5 dinitrobenzoyl chloride to a test-tube, add 0-5-1 ml. of the alcohol, and continue as in Method 1. 

The melting points of these esters are usually much lower than those of the corresponding 3 5 dinitrobenzoates their preparation, therefore, offers no advantages over the latter except for alcohols of high molecular weight and for polyhydroxy compounds. The reagent is, however, cheaper than 3 5 dinitrobenzoyl chloride it hydrolyses in the air so that it should either be stored under light petroleum or be prepared from the acid, when required, by the thionyl chloride or phosphorus pentachloride method. 

Reaction with 3 5-dinitrobenzoyl chloride. Ethers undergo cleavage with 3 5 dinitrobenzoyl chloride in the presence of zinc chloride ... 

Add 1 ml. of the alcohol-free ether to 0-1-0-15 g. of finely-powdered anhydrous zinc chloride and 0 5 g. of pure 3 5-dinitrobenzoyl chloride (Section 111,27,1) contained in a test-tube attach a small water condenser and reflux gently for 1 hour. Treat the reaction product with 10 ml. of 1-5N sodium carbonate solution, heat and stir the mixture for 1 minute upon a boiling water bath, allow to cool, and filter at the pump. Wash the precipitate with 5 ml. of 1 5N sodium carbonate solution and twice with 6 ml. of ether. Dry on a porous tile or upon a pad of filter paper. Transfer the crude ester to a test-tube and boil it with 10 ml. of chloroform or carbon tetrachloride filter the hot solution, if necessary. If the ester does not separate on cooling, evaporate to dryness on a water bath, and recrystallise the residue from 2-3 ml. of either of the above solvents. Determine the melting point of the resulting 3 5 dinitro benzoate (Section 111,27). 

Derivatives of higher melting point may be obtained withp-nitrobenzoyl chloride the experimental details are similar to those given above for benzoyl chloride. 3 5-Dinitrobenzoyl chloride (Section 111,27,7) may also be used glycerol gives unsatisfactory results with this reagent. 

Mix 0-2 g. of 3 5-dinitrobenzoyl chloride, 6 drops of the mercaptan and 1-3 drops of pyridine in a test-tube, and heat the mixture in a beaker of boiling water until fumes of hydrogen chloride cease to appear (15-30 minutes). Add a few drops of water, followed by a drop or two of pyridine to eliminate the excess of the reagent. The product sohdifies upon stirring with a glass rod. Add water, filter, and recrystalUse from dilute alcohol or dilute acetic acid. 

Dissolve 0 -5 g. of the phenol in 4-5 ml. of dry p ridine, add 1 - 3 g. of 3 5-dinitrobenzoyl chloride and reflux for 25-30 minutes. Pour the cold reaction mixture into 40 ml. of ca. 2N hydrochloric acid. Decant the supernatant aqueous hquid from the precipitated sohd or oil and stir it vigorously with about 10 ml. of N sodium carbonate solution. Filter off the sohd derivative and wash it with water. RecrystaUise from alcohol, dilute alcohol, benzene - acetone or benzene - light petroleum (b.p. 60-80 ),... 

The esters formed with p-nitrobenzoyl chloride and 3 5-dinitrobenzoyl chloride (see Section 111,27,1 and 2 and Section IV,205) must be Includ under this heading. 

The preparation of 3 5-dinitrobenzoyl chloride by both the PCI, and SOCl, methods is described in Section 111,27,1 see also Section VII,22. 

Phosgene reacts exothermically with thiirane in two steps (Scheme 36) (77MI50602). 3,5-Dinitrobenzoyl chloride and benzoyl fluoride initiate polymerization of thiirane. A novel reaction of benzoyl isocyanate or trichloroacetyl isocyanate, which yields ethylenethiol derivatives from epithiochlorohydrin (2-chloromethylthiirane), 2-methylthiirane or cyclohexene episulfide, has been reported (Scheme 37) (71BAU2432). 

Dinitrobenzoyl chloride [99-33-2] M 230.6, m 69.5 . Crystd from CCI4 or pet ether (b 40-60°). It reacts readily with water, and should be kept in sealed tubes or under dry pet ether. 

Apply 10% 3,5-dinitrobenzoyl chloride solution [72] in p-xylene — tetrahydrofuran (15-1-2), followed by sample solution allow to react destroy excess reagent with 10% sodium hydroxide solution. 

Nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride were each reacted with dl-1-phenylethylamine and 4-amino-l-benzylpiperidine using a phase-transfer reaction [23]. The amines were in the aqueous phase and the acid chlorides in the organic phase. By this means, a 2 x 2 library was created in one experimental run. 

P 9] DL-l-Phenylethylamine and 4-amino-l-benzylpiperidine were dissolved in 0.1 M NaOH aqueous solution [23]. 3-Nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride were used as ethyl acetate solutions. The concentration of all reactants was set to 0.01 M. Syringe pumps served for liquid feed. The flow rate was 50 plmin and room-temperature processing was applied. No further temperature control was exerted as the reaction is only mildly exothermic. After having passed the micro reactor, the phases were settled in test-tubes and the organic phase was withdrawn for analysis. 

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