Chloral hydrate, reaction

Isocyanide reaction. Since chloral hydrate is readily converted into chloroform by alkali, it will give the isocyanide reaction. To a few crystals of the solid add about 5 ml. of alcoholic NaOH solution and a few drops of aniline, and heat the disagreeable odour of phenyl isocyanide, C H(NC, is rapidly detected. 

The student is recommended to carry out the following reactions with chloral hydrate in order to familiarise himself with its general properties. 

Fit a 1500 ml. bolt-head flask with a reflux condenser and a thermometer. Place a solution of 125 g. of chloral hydrate in 225 ml. of warm water (50-60°) in the flask, add successively 77 g. of precipitated calcium carbonate, 1 ml. of amyl alcohol (to decrease the amount of frothing), and a solution of 5 g. of commercial sodium cyanide in 12 ml. of water. An exothermic reaction occurs. Heat the warm reaction mixture with a small flame so that it reaches 75° in about 10 minutes and then remove the flame. The temperature will continue to rise to 80-85° during 5-10 minutes and then falls at this point heat the mixture to boiling and reflux for 20 minutes. Cool the mixture in ice to 0-5°, acidify with 107-5 ml. of concentrated hydrochloric acid. Extract the acid with five 50 ml. portions of ether. Dry the combined ethereal extracts with 10 g. of anhydrous sodium or magnesium sulphate, remove the ether on a water bath, and distil the residue under reduced pressure using a Claiseii flask with fractionating side arm. Collect the dichloroacetic acid at 105-107°/26 mm. The yield is 85 g. 

Dichloroacetic acid is produced in the laboratory by the reaction of chloral hydrate [302-17-0] with sodium cyanide (31). It has been manufactured by the chlorination of acetic and chloroacetic acids (32), reduction of trichloroacetic acid (33), hydrolysis of pentachloroethane [76-01-7] (34), and hydrolysis of dichloroacetyl chloride. Due to similar boiling points, the separation of dichloroacetic acid from chloroacetic acid is not practical by conventional distillation. However, this separation has been accompHshed by the addition of a eotropeforming hydrocarbons such as bromoben2ene (35) or by distillation of the methyl or ethyl ester. 

A novel type of ring closure is the reaction of 6-amino-5-dichloroacetylaminopyrimidines (285) with sulfur and morpholine under the conditions of a Kindler reaction (B-64MI21605). 7-Morpholinopteridin-6-ones (287) are formed, either via thiooxamide derivatives (286) or via corresponding 7,8-dihydropteridines (284 equation 102). Chloral hydrate also reacts with 2-substituted 5,6-diaminopyrimidin-4-ones to form pteridin-6-ones (56JCS3311, 64JCS565) by a so far unknown mechanism. 

Reactions.—i. Add a few drops of a solution of chloral hydrate to a little ammonio-silver nitrate solution and waiin. Metallic silver will be deposited. 

Reaction of o-toluidine with chloral hydrate in presence of hydroxylamine hydrochloride and subsequent treatment with H2SO4 gave the isatin derivative 337. Bromination of 337 followed by reaction with sodium diethyl malonate gave 338. Catalytic reduction with Pd/C gave the oxoindole derivative 339 that upon hydrolysis with aqueous NaOH followed by... 

Accoiiding to Hanriot ionone can be detected in very minute amount by the following reaction If traces of it be dissolved in concentrated hydrochloric acid, the liquid becomes of an intense golden colour, and if the solution he warmed with chloral hydrate, a dirty violet colour results. The violet colouring matter is extracted by ether, and if the ether be evaporated a water-soluble violet-coloured residue is left. This test will detect 1 part of ionone in 2b00. 

An intimate mixture of betaine hydrate (67.5 g) and chloral hydrate (100 g) was warmed to ca. 60°C when an exothermic reaction occurred and the mixture became pasty. It was then stirred at 60°C for 30 minutes. The residue solidified on cooling and was crystallited from a small amount of water. The product separated in hard, colorless prisms of MP 122.5° to 124.5°C (corr). 

Chirality center, 292 detection of, 292-293 Eischer projections and, 975-978 R,S configuration of, 297-300 Chitin, structure of, 1002 Chloral hydrate, structure of, 707 Chloramphenicol, structure of, 304 Chlorine, reaction with alkanes, 91-92,335-338 reaction with alkenes, 215-218 reaction with alkynes, 262-263 reaction with aromatic compounds, 550 Chloro group, directing effect of, 567-568... 

Colorimetric procedures used In steroid assays are often subject to drug Interference. In the determination of 17-Ketosterolds by the Zimmerman reaction, drugs with the 17-Keto basic structure such as ascorbic acid, morphine and reserplne will cause Increased values. In the determination of 17,21 -dlhydroxysterolds by the Porter-Sllber reaction the dlhydroxy-acetone chain Is the reactive unit. Drugs like meprobamate, chloral hydrate, chloropromazlne and potassium Iodide will Interfere with this reaction and cause elevated values. In the colorimetric determination of vanlllylmandellc acid (VMA) by a dlazo reaction, drugs like methocarbamol and methyl dopa cause... 

Compound listed in this column added to mixture of other reactants. b Chloral ethylate used in place of free chloral in this reaction. c Chloral hydrate used in place of free chloral in this reaction. d 60 ml. of 20% fuming H2SO4 added during course of reaction. e 50 ml. of fuming H2SO4 added during course of reaction. 

Following a published procedure for converting substituted anilines to isatins by reaction with chloral hydrate and hydroxylamine [1], it was noticed that at the end of the first stage (formation of an isonitrosoacetanilide), the odour of hydrogen cyanide was present, and this was confirmed by a Prussian blue test [2], In related work, concentrations of 100-200 ppm of hydrogren cyanide were found [3]. A mechanism for its formation from chloral hydrate and hydroxylamine was proposed [2], and the need for appropriate precautions was stressed [2,3],... 

Zn(CN) - + 4H4" + 4HCHO = Zn2+ + 4HOCH2CN Chloral hydrate (Cl3CCHO) may also be used in demasking reactions. 

Dichloroacetamide has been prepared from ethyl dichloroace-tate with alcoholic ammonia1 or aqueous ammonium hydroxide,2 from ethyl dichloromalonate and alcoholic ammonia,3 by the action of ammonia on pentachloroacetone,4 chloral cyanohydrin,5 and hexachloro-i,3,5-cyclohexanetrione,6 from chloral ammonia and potassium cyanide,7 by the action of hydrogen chloride on dichloroacetonitrile,8 from the reaction of asparagine with the sodium salt of N-chloro- -toluenesulfonamide,9 and by the action of an alkali cyanide and ammonia on chloral hydrate.10... 

Dry ethyl alcohol is saturated with dry chlorine, first at room temp for 24 hours, then at a boil, under reflux, for 24 hours. Take care not to allow atmospheric moisture into the reaction. Cool to get a crystalline mass, which is filtered and distilled with concentrated sulfuric acid to give crude chloral. To make chloral hydrate you must purify the crude chloral by fractionally distilling and collecting the fraction, boiling at 97°C. 

The determination of 17-ketosteroids is most often determined in the clinical laboratory by the Zimmerman reaction, in which the ether-extracted material is allowed to react with m-nitroaniline to yield a colored product. Thus, any compound with the 17-keto basic structure such as reserpine, morphine, ascorbic acid, or their metabolites will interfere. The Porter-Silber reaction used in the determination of 17,21-dihydroxysteroids is also not specific, and the reaction requires a di-hydroxyacetone side chain. Paraldehyde, chloral hydrate, meprobromate, and potassium iodide have been found to interfere, and patients should be maintained free of these drugs for 24-48 hours before the urine collection (Bll). 

Diloxanide was first prepared by the reaction of 4-hydroxy-A-methyl aniline with sodium cyanide and chloral hydrate in the presence of a base [9]. Furoic acid was prepared by the hypochlorite oxidation of... 

II. Identification of the reaction product as chloral hydrate. Mol. Pharmacol., 1, 247-254... 

Chalkone, 709, 718 Charcoal, decolourising, 127, 128 Chloral hydrate, 1011 reactions of, 298 ... 

Heating a mixture of 6,7,8,9-tetrahydro-ll//-pyrido[2,l-b]quinazolin-ll-one (7) and acetyl and benzoyl chlorides, acetic anhydride, and vinyl acetate under reflux gave 6-condensation products (123), whereas reactions with ethyl chloroacetate, ethyl dichloroacetate, and chloral hydrate afforded 6-substituted products (124) (86MI7). 6,7,8,9-Tetrahydro-ll//-pyrido[2,l-b]quinazolin-l 1-one (7) and acetic anhydride, heated under reflux for 36 h, gave compound 123 (X = OAc, R = Me or X = Me, R = OAc, 18%) and its 6-acetyl derivative (124, R = COMe) in 31% yield (87JHC175 91JHC2071). 

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