Diacetyl test

Diacetyl Test.—A few drops of the urea solution are mixed with excess (2-3 ml.) of concentrated hydrochloric acid and 2-3 drops of 3 per cent, diacetyl monoxime. On boiling, a yellow colour develops if urea be present. The colour changes to deep orange on careful addition of an oxidiser (1-3 drops of O-l per cent, hydrogen peroxide or 1 per cent, potassium persulphate). Substituted ureas, including... 

Diacetyl Test.—Apply this test to 2-3 drops of urine mixed with 2-3 ml. HCL (p. 384). 

Other specific discovery assays have been used such as differential inhibition of a vancomycin resistant S. aureus strain and its susceptible parent, and an assay based on antagonism of the antibacterial activity by N,A/-diacetyl-L-Lys-D-Ala-D-Ala [24570-39-6] a tripeptide analogue of the dalbaheptides receptor. AppHcation of this latter test to 1936 cultures (90) led to the isolation of 42 dalbaheptides, six of which, including kibdelin (Table 3), parvodicin (Table 3), and actinoidin A2 (68) were novel. A colorimetric assay based on competition between horseradish peroxidase bound teicoplanin and the... 

In 2006 and 2007, NIOSH investigated two flavor-manufacturing plants. Medical testing of 29 production workers identified 7 workers with fixed airways obsfrucfion who had worked in plated-powder and/or liquid flavoring work areas 4 of these workers had severe fixed airways obsfrucfion (CDC, 2007b,c). Mean work area diacetyl air concentrations using NIOSH method 2557) for plated-powder production and liquid production in one of these plants were 0.25 and 0.02 ppm, respectively (CDC, 2007b). 

Further, eleven 4-phenyl-3,5-diacetyl-1,4-DHPs substituted at the C-4 phenyl ring were synthesized and compared for their cytotoxic activity and MDR reversing activity in in vitro assay systems. Among them, compound G7 (68) showed the highest cytotoxic activity against human promyelocytic leukemia HL-60 and human squamous cell carcinoma HSC-2 cells. However, no compounds tested produced radicals at pH 7.4-12.5. The activity of Pgp... 

Free formaldehyde is reacted with acetylacetone in the presence of an excess of an ammonium salt to form the yellow fluorescent compound, 3,5-diacetyl-1,4-dihydrolutidine and subsequently determined spectrophotometrically in methods A-E (14). In these methods, the test sample must be colorless and free from other carbonyl compounds. Some other derivatives have been used to analyze formaldehyde. For example, formaldehyde was reacted with sodium 4,5-dihydroxy-2,7-naphthalene disulfonate in sulfuric acid solution to yield a purple color (580 nm) and then subjected to colorimetric analysis. A purple-colored pararosaniline derivative was used to analyze formaldehyde in air (15). Air sample was passed through an aqueous solution which contained 0.4% of 3-methyl-2-benzothiazolone hydrazone hydrochloride and then a dye produced was determined at 635 or 670 nm (16). Molecular sieve (1.6 mm pettet) was used to trap formaldehyde in air samples. The formaldehyde... 

The elimination of hydrogen halide from certain halogenated sugars may be used as a test for the size of the sugar s lactol ring. Up to the present time it has been observed only when the carbon atom adjacent to the halogenated carbon atom (C5 in the case of LII) is involved in lactol ring formation. Thus, compounds such as 3,5-diacetyl-l,2-iso-... 

Fearon, W. R. The Carbamid Diacetyl Reaction A Test for Citrulline. 

The model tests were carried out both iso-thermally (i.e. at constant temperature) and in temperature gradients (from warm to cold). Alcohols (e.g. ethanol, hexanol, octa-nol, decanol), aldehydes (e.g. decanal), ketones (e.g. diacetyl), acids (e.g. caproic acid), esters (e.g. ethyl acetate), terpenes (e.g. menthol, menthone, 6-pinene, limonene), amines (e.g. butyl amine), pyrazines and other classes of substances have been investigated as flavouring substances [6,9,11,13-18]. Fig. 5.6 shows the forma-... 

Precipitation reactions for the detection of morphine have been recorded [215-38 inc.]. In the Straub biological test as little as 0-01 mg. of the alkaloid injected subcutaneously on the back of a white mouse causes the animal to lay its tail over its back [239]. Other methods for the detection of morphine [240-4] and of its diacetyl ester (heroin) [228-30, 233-4, 242, 245-6] are known. 

Recently, diacetyl reductase (Acetoin reductase, E.C. 1.1.1.5) from Bacillus stearo-thermophilus (BSDR) was reported to be a powerful catalyst in the oxidative kinetic resolution of vic-diols (Fig. 16.2-22)1901. All syn-diols tested yielded the enantiopure (R,R) diols in almost maximum theoretical yields, a-hydroxy ketones were largely further oxidized to the corresponding diketones. Oxidation of vic-anti diols only gave ee values in the range of 62-76%. 

With the same intention of establishing a relationship between a quality sensorial test and the concentrations of some volatile substances in roasted coffee, Radtke-Granzer and Piringer (1981) proposed measuring and summing the absolute concentrations of 2-methylpropanal (Section 5,C.ll), 3-methyl-butanal (Section 5,C.13), diacetyl (Section 5,D.44) and 2-methylfuran (Section 5,1.2) in commercial coffees. For freshly roasted qualities this value amounts to 110 21 mg/kg, but during storage under... 

Michotte has suggested that biolt ical oxidation processes in mesenchymal tissues require a balance of C -hydroxysteroids and adrenergic substances, and this is disturbed in rheumatic diseases owing to the failure of the adrenergic component. It is alleged that pyrocatechoic acid (V) may replace this component, restore the physiological imbalance and, consequently, suppress the inflammatory reaction. Adams and Cobb found that neither pyrocatechoic acid nor its diacetyl derivative administered orally inhibits ultra-violet erythema in the guinea-pig. The former compound, administered subcutaneously, reduces vascular permeability in the mouse peritoneum, but the effect is less than that of salicylic acid . Other dihydroxybenzoic acids tested are not active in this system . 

Many organisms impose specific end reactions on the Embden Meyerhof pathway and this test is designed to detect the presence of 2,3-butandiol, acetoin (3-hydroxy-2-butanone) or diacetyl (2,3-butanedione). Aeration of all these... 

Next treat the hydrochloric solution containing the nickel with 3 ml of diacetyl dioxime solution, 1 ml of 10 m sodium hydroxide solution and 0.3 ml of ammonium peroxodisulphate solution, mixing well each time. Dilute with water to the mark at 20 C, leave to stand for about 2 hours, and measure in a 3-cm cuvette at 60 nm against distilled water. Carry out a blank test concurrently and take into account accordingly. 

A variety of representative sulfonamide derivatives, including acylated congeners and Schiff bases of sulfadiazine, sulfamethoxypyridazine, and metachloridine, has been prepared and tested for repository antimalarial activity [38]. Among them, 4 -(2-thiazolylsulfamoyl)acetanilide (XLIII), A -diacetyl-Ai-(2-pyrimidinyl)sulfanilamide (XLIV), 4,4 -bis(2-thiazolyl-sulfamoyl)thiocarbanilide (XLV), iVi-acetyl-iV -(6-methoxy-3-pyridazinyl)-sulfanilamide (XLVIa), N, A -diacetyl-iVi-(6-methoxy-3-pyridazinyl)sulfanil-... 

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