Ketones, determination

Dehennin L, Scholler R. 1973. Dienol heptafiuorobutyrates as derivatives for gas liquid chromatography of steroidal A -3-ketones determination of the structure of the isomeric dienol esters. Tetrahedron 29 1591-1594. 

Salicylates in the urine interact with urinary ketone determinations by the ferric chloride (Gerhardt) method producing a reddish color. 

Aldehydes and organic acids Aldehydes and ketones determined directly, oxoacids converted to methyl esters with diazomethane [235]... 

Total Ketones Determine as directed for ketones in the Hydroxylamine Method under Aldehydes and Ketones, Appendix VI, using about 1 g of sample, accurately weighed, and 77.12 as the equivalence factor (e) in the calculation. 

James RC, Chase GR. Evaluation of some commonly used semiquantitative methods for urinary glucose and ketone determinations. Diabetes 1974 23 474-9. 

Is any reasonable mechanism consistent with the data The answer lies in an observation of a probable isotope effect in a coupled nonenzymic phenomenon. The double-isotope fractionation method does not enter into the analysis. The keto group of glyoxalate is actually present as a covalent hydrate to the extent of about 99% of the total glyoxalate concentration (27). However, the ketone is the form that will react in the enzymic process and the concentration of ketone determines the rate of reaction and binding to the enzyme. The equilibrium between ketone and hydrate is not catalyzed by the enzyme and as a result the isotope effect on this equilibrium will appear in the measured kinetic isotope effects. Of course, the extent of this equilibrium will not be affected by deutera-tion of the methyl group of acetyl-CoA. Therefore, the observed HVIK) is not an indication of kinetically significant carbon-carbon bond formation but of a preequilibrium hydration, a process that is independent of the enzyme. The value for HV/K) of 1.0037 is consistent with measured equilibrium isotope effects in related molecules (23). Therefore, the deuteration of acetyl-CoA has no effect on the observed kinetic because that value in fact is due to a preequilib-... 

B. Other useful laboratory studies include electrolytes, glucose, BUN, creatinine, calcium, ammonia, liver transaminases, bilirubin, prothrombin time (PT), amylase, serum osmolality and osmolar gap (see p 32 serum levels > 1500 mg/L may increase the osmolar gap by 10 mOsm/L or more), arterial blood gases or oximetry, and EGG monitoring. Valproic acid may cause a falsepositive urine ketone determination. 

Isolated yield based on starting ketone. Determined by analysis of the Eufdcm) shifted NMR spectrum. The numbers in parentheses are corrected for 92% ee a-pinene. 100% optically pure (+)-a-pinene was used. Diastereomeric ratio (R.R to R.S) determined by LC or NMR analysis of the mixture. 

Among these species, Mikhailov [2] and Brown [8] have shown that allylboranes, especially those with low-molecular-weight, nonsterically hindered allyl groups are readily hydrolyzed and produce olefins rather than expected allylic alcohols under usual alkaline hydrogen peroxide oxidation conditions. Consequently, it is appropriate to convert the allylborane to a derivative that would give an unambiguous product on oxidation. Such a derivative is prepared by the reaction of allylborane with ketone, such as acetone, prior to oxidation [9]. The other potential adducts (I, 111, and IV) are inert to acetone under these conditions. After oxidation of this derivatized mixture, the quantity ofhomoallylic alcohol determines the amount of the attack at the terminal carbon of the allenic system (allylborane), the quantity of ketone determines the extent of internal attack (vinylborane), and the quantity of unreacted allene reveals the amount of dihydroboration (0% allene = 0% dihydroboration, 50% allene = 100% dihy-drob oration). The positions of the diol reveal the point of attack in dihydroboration. 

Since the diaryl ketone is the light-absorbing species in bimolecular photoinitiator systems, the selection of the appropriate ketone determines the wavelength sensitivity of the system. Besides benzophenone and substituted benzophe-nones, 25-27, a variety of thioxanthones (9H-thioxanthen-9-ones) and substituted thioxanthones, 28-30, are also commonly used. 

Reaction conditions 20 mmol alcohol, 0.05 mmol PhenS Pd(OAc)2,1 mmol NaOAc, 100 °C, 30bar Selectivity to ketone, determined by gas chromatography with an external standard. Ether... 

Van der Weerdt, A. I.A., Cerfontain, H., van der Ploeg, J.P.M., and den Hollander, J.A., Photochemistry of acyclic P.y-unsaturated ketones. Determination of the electronically excited state responsible for a-cleavage by chemically induced dynamic nuclear polarization, /. Chem. Soc., Perkin Trans. 2, 155,1978... 

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