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Question about nitrosation

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Acetophenones and propiophenones can be oxidised to the corresponding 1,2-dicarbonyl compounds using SeO2(seriously nasty) or a nitrite. There is a example in Vogel using SeO2 in aqueous 1,4-dioxane to make phenylglyoxal from acetophenone. I've seen somewhere a method which used excess methyl nitrite in MeOH to make a acetophenone dimethylacetal which is was not isolated but hydrolysed to the phenylglyoxal immediately.

Couldn't Oxone be used to oxidise propiophenone to 1-phenyl-1,2-propanedione or a acetophenone to a phenylglyoxal? I can't see any reasons why a PTC oxidation of propiophenone/oxone/DCM/water or perhaps even propiophenoneOxone/MeOH/water without a PTC shouldn't work.

Comments, pretty please..

Here is another toxic method: Post 423929 (missing) (Rhodium: "P1P to P2P - no go.", Newbee Forum)

..entitled "Process of Nitrosating Aromatic Alkyl Ketones", by Walter H. Hartung and Frank S. Crossley, patented July 1, 1941:

....Phenylalphaoximinoethyl ketone (alpha oximinopropiophenone or isonitrosopropiophenone) is prepared from propiophenone as follows:
Into a suitable reaction vessel, such as as a one liter three-necked flask, equipped with a dropping funnel, a mechanical stirrer and a thermometer, and immersed in a water bath are placed 67 parts (0.5 mol) of propiophenone, 43.9 parts (0.75 mol) of sodium chloride, 2.4 parts of of conc. hydrochloric acid with 60 parts (1 mol) of isopropyl alcohol.
To this reaction mixture, maintained under vigorous agitation throughout the process, ther is added in portions and in the manner hereinafter described a total of 38 parts (0.55 mol) of sodium nitrite and 64 parts (0.65 mol) of concentrated sulfuric acid. First 9.5 parts, or one quarter of the total required amount, of sodium nitrite is added and then 16 parts, or one quarter of the total required amount, of the sulfuric acid is added through a dropping funnel during a period of  about 30 minutes while the temperature of the reaction mixture is maintained below 35°C.
After the addition of the of the first quarter of sulfuric acid, 30 minutes are allowed to elapse and a second one-quarter of the total required quantity of sodium nitrite and of the sulfuric acid is added in the same manner and with the time interval previously described. Then the third one-quarter of the total required quantity of sodium nitrite and of the sulfuric acid is added in the same manner. The last one-quarter of each of those reagents is then added except that the addition of the last one-quarter of sulfuric acid is extended over a period of sixty minutes, after which the agitation of the reaction mixture is continued for about three hours.
After standing over night at room temperature, a solid mass of crystals phenyl alphaoximinoethyl ketone forms. The product, after recrystallisation from toluene melts at 113°C to 114.5°C. Yields of at least 85-95% of the end product based on propiophenone are obtained. These results indicate that the reaction proceeds so far towards completion as to leave practically no reacted propiophenone to be separated and recovered....

Looks like they combined the in situ formation of isopropyl nitrite with the in situ formation of nitrosyl chloride to boost up their yield significantly, when compared with the yields obtained from HCl, ethyl nitrite and propiophenone, which are in the range of 65-70%, if my memory serves me right.

Post 402025 (Rhodium: "Ye olde Benzedrine", Stimulants)

Here is a nice method for the selective formation of either alpha-oximinoketones or 1,2-diketones from ketones, with no alkyl nitrites required:

A Practical and User-Friendly Method for the Selenium-Free One-Step Preparation of 1,2-Diketones and their Monoxime Analogs
Matthias A. Oberli, Matthias Nagel, Christophe Weymuth, Hans-Jürgen Hansena
Synlett 2004 [The DOI given in the paper does not work, and the pages aren't numbered]

Treatment of alpha-methylene ketones with excess sodium nitrite and aqueous HCl in THF at reduced temperatures provides an effective tool for the preparation of a variety of 1,2-diketones. The diastereoselective synthesis of the corresponding (Z)-1,2-dione monoximes could be accomplished under similar conditions, but by using only one equivalent of nitrosating reagent.

General Procedure for the Prearation of 1,2-Diketones and 1,2-Dione Monoximes
A suspension of the starting ketone (50 mmol) and NaNO2 (10.35 g, 150 mmol) in THF (100 mL) was cooled to 0 °C. To this mixture, concd HCl (65 mL) was added in such a way that the temperature did not exceed 10 °C. In order to avoid the evolution of nitrous gases the acid was added via cannula that was immerged into the reaction mixture. After the addition the cooling bath was removed and the suspension turned dark yellow. The progress of the reaction was monitored by GC. After the starting material had vanished (0.1–12 h) the reaction mixture containing the crude 1,2-diketone was poured into a separatory funnel containing crushed ice (200 g) and Et2O (100 mL). The organic layer was separated, and the aqueous phase extracted with Et2O (3× 100 mL). The combined organic layers were washed with a sat. aq solution of NaHCO3 (100 mL) and with brine (100 mL), dried over MgSO4, filtered and concentrated under reduced pressure. The residue was purified by filtration over a pad of silica gel (5:1) using hexane–EtOAc (50:1) as eluent. The corresponding 1,2-dione monoximes were prepared accordingly by using only 3.45 g (50 mmol) of NaNO2 and 25 mL of concd HCl. The crude product was purified either by filtration over a pad of silica gel (5:1) using hexane–EtOAc (50:1) as eluent or by crystallization from hexane–EtOAc.


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