Ketones tests

Drug/Lab fesf/nferacf/ons Valproic acid is partially eliminated in the urine as a keto-metabolite, which may lead to a false interpretation of the urine ketone test. There have been reports of altered thyroid function tests associated with valproic acid. 

Among the aldehydes and ketones tested acetone was least toxic, formaldehyde, butyraldehyde, and crotonaldehyde next, and mesityl oxide most toxic. In this group of compounds temperature was a major factor, both formaldehyde and mesityl oxide being much more toxic at 40 than at 25 C. None were outstanding as cholesterol solvents, but mesityl oxide was the best it penetrated nematodes the most easily and killed in the lowest concentrations. 

Like other sulfhydryl-containing compounds, captopril can cause false-positive ketonuria when assessed with the Legal reaction (sodium nitroprusside reacting with acetoacetic acid and possibly with acetone). It has therefore been suggested that in patients with diabetes taking such drugs ketonuria should be assessed with the Acetest (20). Alternatively, a blood ketone test with Acetest and/ or enzymatic detection of beta-hydroxybutyric acid can be performed for confirmation. 

An alternative approach is the use of a PS support bearing sulfonate pendant groups. For this, a quaternary ammonium salt of styrenesulfonic acid was copolymerized with a N-(p-styrenesulfonyl)-l,2-diphenylethylenediamine monomer. The polymeric chiral Ru complex was prepared from 177 and [RuCl2(p-cymene)]2 and applied to the asymmetric transfer hydrogenation of aromatic ketones in water (Scheme 3.55) [114]. The polymeric chiral complex was evenly suspended in water and the reaction proceeded smoothly to produce the alcohol in quantitative yield and with high enantioselectivity. For several of the aromatic ketones tested, higher... 

Mortality rates have been steadily declining over the recent years [5], but remain close to 5% for DKA and between 10% and 15% for HH [1]. The decline in mortality may be a consequence of lower incidence of DKA and HH, earlier diagnosis, improved treatment or - more plausibly - all combined. It is likely that improved education schedules and self-monitoring (e.g. blood ketone testing), organisation of specialised diabetes clinics and the use of standardised low-dose insulin regimens [1,6] have contributed to this favourable trend. 

A false positive urine ketone test can also occur with captopril when using the alkaline-nitroprusside test (Ketodiastix), which may affect the monitoring of diabetic control. ... 

Warren SE. False-positive urine ketone test with captopril. NEnglJMed( 9 G) 303,1003-4. 

The standard test for an aldehyde or ketone is that they both form orange crystalline precipitates with 2,4 dinitrophenylhydrazine solution (Figure 10.79a). The precipitate can be recrystallized and its melting point determined (Figure 10.79b). Knowing the melting point of the crystals enables us to identify the particular aldehyde or ketone tested. 

Janssen MJW, Hendrickx BHE, Habets-van Der Poel CD, et al. Accuracy of the Precision Point-of-Care Ketone Test Examined by Liquid Chromatography Tandem-Mass Spectrometry (LC-MS/MS) in the Same Fingerstick Sample. Clin. Chem. Lab. Med. 2010 48 1781. ... 

The use of the chiral aminoborane (24) for the asymmetric synthesis of alcohols from ketones shows promise optical yields are in the range 14—23% for the three ketones tested. Stereoselective reduction of acetophenone and isobutyl methyl ketone has been observed on addition of the chiral phase-transfer catalyst (25) (derived from L-ephedrine) to sodium borohydride and the ketone in aqueous dichloromethane. ... 

The sample to be analyzed can be dissolved in an organic solvent, xylene or methylisobutyl ketone. Generally, for reasons of reproducibility and because of matrix effects (the surroundings affect the droplet size and therefore the effectiveness of the nebulization process), it is preferable to mineralize the sample in H2SO4, evaporate it and conduct the test in an aqueous environment. 

These coloration changes are given by most compounds which possess the -CHj-CO— group for further examples, see Tests 4 (a) and (b) for Ketones, p. 344. 

This is a test for the >C = 0 group. Most aldehydes and ketones readily condense with this reagent giving yello v- or orange-coloured precipitates. 

Note, (a) Aqueous solutions of formaldehyde and acetaldehyde give these addition products, which are so soluble that they rarely separate this reaction is therefore an unsatisfactory test for these aldehydes. (6) These addition products are also formed by ketones (p. 345). 

Ketones containing the CH3CO— group give the iodoform reaction. (For other compounds which give this test, see p- 91.)... 

Sulphuric add test. Heat 0 5 g. of citric acid or a citrate with 1 ml. of H2SO4 CO and COg are evolved and the mixture turns yellow, but does not char. Acetone dicarboxylic acid, OC(CH2COOH)g, is also formed, and is tested for after heating the mixture for 1 minute cool, add a few ml. of water and make alkaline with NaOH solution. Add a few ml. of a freshly prepared solution of sodium nitroprusside and note the intense red coloration (see Test 4 a) for ketones, p. 346). 

Acetone-Alkali coloration. Dissob-e a few crystals in i-2 ml. of acetone and add a few drops of aqueous XaOlI solution. A deep violet coloration is produced, and is turned red by acetrc acid but destroyed by mineral acids (see Test 4(6) for Ketones, p. 346, and also Test 2(0) p. 274). 

The reaction with sodium is by no means an infallible practical test for alcohols since, strictly speaking, it is applicable only to pure anhydrous liquids. Traces of water, present as impurities, would give an initial evolution of hydrogen, but reaction would stop after a time if an alcohol is absent furthermore, certain esters and ketones also evolve hydrogen when treated with sodium (compare Section XI,7,6). It may, however, be assumed that if no hydrogen is evolved in the test, the substance is not an alcohol. 

Prepare a solution containing about 100 g, of potassium hypochlorite from commercial calcium hypochlorite ( H.T.H. ) as detailed under -Dimethylacrylic Acid, Section 111,142, Note 1, and place it in a 1500 ml. three-necked flask provided with a thermometer, a mechanical stirrer and a reflux condenser. Warm the solution to 55° and add through the condenser 85 g, of p-acetonaphthalene (methyl p-naphthyl ketone) (1). Stir the mixture vigorously and, after the exothermic reaction commences, maintain the temperature at 60-70° by frequent cooling in an ice bath until the temperature no longer tends to rise (ca. 30 minutes). Stir the mixture for a further 30 minutes, and destroy the excess of hypochlorite completely by adding a solution of 25 g. of sodium bisulphite in 100 ml. of water make sure that no hypochlorite remains by testing the solution with acidified potassium iodide solution. Cool the solution, transfer the reaction mixture to a 2-litre beaker and cautiously acidify with 100 ml. of concentrated hydrochloric acid. Filter the crude acid at the pump. 

Both aldehydes and ketones contain the carbonyl group, hence a general test for carbonyl compounds will Immediately characterise both classes of compounds. The preferred reagent is 2 4-dinilrophenylhydrazine, which gives sparingly soluble phenylhydrazones with carbonyl compounds ... 

If an unknown compound gives a positive test with the 2 4-dinitrophenylhydrazine reagent, it then becomes necessary to decide whether it is an aldehyde or a ketone. Although the dimedone reagent (Section 111,70,2) reacts only with aldehydes, it is hardly satisfactory for routine use in class reactions. It is much simpler to make use of three other reagents given below, the preparation and properties of which have already been described (Section 111,70). 

If the tests for an aldehyde are negative, the unknown compound is a ketone. When once the compound has been established as an aldehyde or ketone, it is permissible to refer to tables of physical constants information thus obtained may be of value in indicating other possible groups to be tested for, with due regard to possible comphcations caused by the presence of these groups. 

When the compound for identification fails to respond to test 4 (aldehyde or ketone), the next class reactions to apply are the hydroxatnic acid teat and saponification, i.e., hydrolysis in alkaline solution. These are the class reactions for esters and anhydrides the rarely-encountered lactones react similarly. 

This is another reason why aldehydes, ketones and esters must be tested for in the order already given, and why it is necessary to employ both the sodium and acetyl chloride testa. 

If the compound to be tested is insoluble in water, it should be brought into solution by the addition of a little dioxan. Alcohols and some methyl ketones frequently react slowly in such cases it is advisable to employ a large excess (4-5 fold) of the relatively unstable reagent (3NaOI -> NaI03 -f- 2NaI). Quinones and hydroquinones also give the iodoform reaction. 

The polyhydric alcohols of Solubility Group II are liquids of relatively high boiling point and may be detected inter alia by the reactions already described for Alcohols (see 6). Compounds containing two hydroxyl groups attached to adjacent carbon atoms (1 2-glyeols), a-hydroxy aldehydes and ketones, and 1 2-diketones may be identified by the periodic acid test, given in reaction 9. 

Either pure aqueous or aqueous/solvent solutions work. It is entirely up to the preference of the chemist as to which one they use. Just to make one feel more secure, there is a little test one can do with the bisulfite solution to see if they got it right. Just put a little of that ketone known as acetone into the saturated solution and watch the crystals grow. Isn t it nice how chemistry works ... 

So now we have this solvent containing ketone, dried with MgS04... Not being able to vac-distill today, took about 50 mis of solvent/ketone and placed in beaker on stir plate and boiled off the solvent. The resulting oil was a nice reddish-orange color. Had a very unique smell too. Took about 2 grams worth of this ail, added to a test tube containing a saturated solution of sodium bisulfite... In less than 60 seconds the oil precipitated into a whitish yellow mass (very similar to what acetone would do if added to a bisulfite solution). Never had this quick of a crystallization. Not... 

This procedure has been tested for a lot of bees and conditions are similar. Displl solvent and distill ketone with a water pump. My yield, 41 grams, about 75 %. Scaling. Of course. This procedure have been done with 150 cc of safrol, but with T75 I of methanol with simiair yields, so I ve prefered to present this version wich is better (less solvent, less time) Addition of nitrite i/vas done in 2,5 hours. When scaling, water in B can be decreased if we have problems with our volume flasks, but this means a lot of NaN02 is not dissolved, so each 15 minutes, we close sep. funnel, and shake B a bit, and when there is no foam, we can open sep. funnel again (1 drop or abit more /second). My opinion is 150 is ok, but theorically you can scale more. More time rxn is not a problem for product. 

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