3.5- dinitrobenzoyl chloride, preparation

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. 

Another way of characterising alcohols is through TLC after having treated them with 3,5-dinitrobenzoyl chloride (preparation, see Chapter TS, 3a). Dhont and Derooy [49] were the first to show that the dinitrobenzoate esters could be separated by using benzene-petrol ether (50 + 50) on silica gel G layers. Butter yellow (p-dimethylamino-azobenzene) was chosen as reference substance to determine the positions in the chromatogram. The following values,... 

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... 

Dinitrobenzoylation. To 0 5 g. of powdered 3,5-dinitro benzoyl chloride (preparation, p. 240) in a dry test-tube, add 2 ml. of dry methanol and warm the mixture until a clear solution is obtained. Cool and filter off the solid ester which separates. Recrystallise from petroleum (b.p. 60-80 ), and take the m.p. (M.ps., pp. 536, 537.)... 

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. 

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. 

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 111,27,2). 

Suitable reagents for derivatizing specific functional groups are summarized in Table 8.21. Many of the reactions and reagents are the familiar ones used in qualitative analysis for the characterization of organic compounds by physical means. Alcohols are converted to esters by reaction with an acid chloride in the presence of a base catalyst (e.g., pyridine, tertiary amine, etc). If the alcohol is to be recovered after the separation, then a derivative which is fairly easy to hydrolyze, such as p-nltrophenylcarbonate, is convenient. If the sample contains labile groups, phenylurethane derivatives can be prepared under very mild reaction conditions. Alcohols in aqueous solution can be derivatized with 3,5-dinitrobenzoyl chloride. 

Diaminotoluene has been prepared from 2,4-dinitro-toluene by reduction with iron and acetic acid,2 and by electrolytic reduction 3 from 4-nitro-o-toluidine by reduction with tin and hydrochloric acid 4 and from 2,4-dinitrobenzoyl chloride with tin and hydrochloric acid. ... 

General methods for the preparation of acid halides from aliphatic carboxylic acids are described in Section 5.12.1, p. 692. Phosphorus pentachloride is the preferred chlorinating agent for aromatic acids which contain electron-withdrawing substituents, and which do not react readily with thionyl chloride. The preparation of both p-nitrobenzoyl chloride and 3,5-dinitrobenzoyl chloride is described in Expt 6.161. These particular acid chlorides are valuable reagents for the characterisation of aliphatic alcohols and simple phenols, with which they form crystalline esters (see Section 9.6.4, p. 1241 and Section 9.6.6, p. 1248). 

Cognate preparations. 3,5-Dinitrobenzoyl chloride. Place a mixture of 30 g (0.141 mol) of 3,5-dinitrobenzoic acid (Expt 6.160) and 33 g (0.158 mol) of phosphorus pentachloride in a round-bottomed flask fit a reflux condenser, and heat the mixture in an oil bath at 120-130°C for 75 minutes. Allow to cool. Remove the phosphorus oxychloride by distillation under reduced pressure (25 °C/20mmHg) raise the temperature of the bath to 110 °C. 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 (77%), m.p. 67-68 °C, and this is satisfactory for most purposes. Further recrystallisation from a large volume of light petroleum, b.p. 40-60 °C, gives a perfectly pure product, m.p. 69.5 °C. 

The acid chloride is available commercially, but it is preferable to prepare it from the acid as and when required since 3,5-dinitrobenzoyl chloride tends to undergo hydrolysis if kept for long periods, particularly if the stock bottle is frequently opened. The substance may, however, be stored under dry light petroleum. 

Acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine (m.p. 73-74°C) was synthesized by hydrogenation of a compound prepared from 2,3-difluoro-6-nitrophenol, l-acetoxy-3-chloro-2-propane and potassium iodide. The hydrogenation was carried out on Raney nickel. The resulting compound was dissolved in THF, and 3,5-dinitrobenzoyl chloride and pyridine were added thereto, followed by heating at 60°C for 3 hours. The mixture was concentrated, and the concentrate was dissolved in ethyl acetate, washed successively with diluted hydrochloric acid, an aqueous solution of sodium bicarbonate and water, dried over anhydrous sodium sulfate and concentrated. Addition of n-hexane to the concentrate caused precipitation of yellow crystals of a racemate. The yield of 3,5-dinitrobenzoyl derivative of the ()-3-acetoxymethyl-7,8-difluoro-2,3-dihydro-4H-[l,4]benzoxazine 3.93 g. 

This study has been carried out to analyze the nature of the complex formation between 9H-carbazole-9-ethanol and dinitrobenzoate groups attached at each chain-ends of a short PDMS backbone. The polymer was prepared in very good yields (>98%) by esterification of 3,5-dinitrobenzoyl chloride and a,to-(3-hydroxypropyl) PDMS. H NMR (Fig. 1) confirmed that the reaction was quantitative. The protons of the methylene group located near the hydroxyl group totally disappeared after functionalization. On the contrary, the signal of the protons of the methylene situated in a position of the ester appeared at 4.3 ppm. The signals of the aromatic protons also showed up on the final product at 8.8-9ppm. 

DinitrobenzoyI chloride. Place in an eight-inch tube 2 g of 3,5-dinitrobenzoic acid and 4 g of phosphorus pentachloride. Heat in the hood with a small smoky flame for five minutes. In the beginning the tube is heated to start the reaction and thereupon the flame is removed until the reaction has subsided. Then the flame is adjusted so that the vapors condense at about the middle of the tube. Allow to cool for one minute and pour carefully into a small evaporating dish. Cool and transfer the sohd to a paper drying disc or to several filter-paper circles. Press with the spatula so as to force the phosphorus oxychloride into the absorbent medium. After ten minutes transfer the crude 3,5-dinitrobenzoyl chloride into a small bottle or tube. The crude material is satisfactory for the preparation of derivatives of the lower hydroxy compounds. 

S-Dinitrobenzoyl chloride. Mol. wt. 230.57, m.p. 68°. Suppliers H. H, E, The corresponding acid is prepared by nitration of benzoic acid suppliers Eastman, Light. A process of piiriHcaliun of the acid for use in the deicrminuiion of creatinine is reported.". ... 

Cyclopropanethiols have been characterized as the corresponding thioesters, which were prepared by treating the thiols with acetyl chloride or 3,5-dinitrobenzoyl chloride. ... 

Sample preparation Dissolve a small amount in 200 pL dry pyridine, add 15 mg 3,5-dinitrobenzoyl chloride, shake for 2 h, evaporate to dryness under nitrogen under reduced pressure. Reconstitute with 1.5 mL ethyl acetate, wash 4 times with 1 mL portions of 5% sodium bicarbonate containing 2.5 mg/mL 4-dimethylaminopyridine, wash 4 times with 1 mL portions of 1% HCl, wash 4 times with 1 mL portions of water, evaporate to dryness under a stream of nitrogen, reconstitute with mobile phase, inject an aliquot (J.Chromatogr.Sci. 1983, 21, 495). 

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