Oxidation of benzophenone

Diphenyldiazomethane has been prepared only by oxidation of benzophenone hydrazone.3 The procedure given above is that of Staudinger, Anthes, and Pfenninger, with minor changes. The method of preparation of benzophenone hydrazone given above is a modification of the procedure of Curtius and Rauter-berg.4... 

Curini, M. Rosati, O. Pisani, E. Preparation of diphenylmethyl esters by oxone oxidation of benzophenone hydrazone. Tetrahedron Lett. 1997, 38, 1239-1240. 

The second project was to determine whether the anodic oxidation of benzophe-none hydrazone could be manipulated to produce diphenyldiazomethane (DDM) as the end product in high yield. Literature evidence95 indicated that the anodic oxidation of benzophenone hydrazone using either a platinum or graphite anode under various conditions with a variety of electrolytes gave a number of products that were... 

Chiba and co-workers gave no indication that the anodic oxidation of benzophenone hydrazone could be stopped at the DDM stage. Professor Martin and Dr. John Hulteen, Colorado State University, were, however, able to devise conditions, based... 

FIGURE 2. Electrochemical oxidation of Benzophenone Hydrazone to Diphenyldia-zomethane. 

Amino acid 4-toluenesulfonate or 2-naphthalenesulfonate salts are esterified in high yield with diazodiphenylmethane in DMF (50 °C, 10min).P " l Diazodiphenylmethane is prepared by oxidation of benzophenone hydrazone, e.g. with yellow mercury(II) oxide in the presence of base, and can be stored in the dark.P P l In situ oxidation of the benzophenone hydrazone is performed with peracetic acid/l2 (trace) in the presence of the N-protected amino acids or peptides.P P l This method is not compatible with sulfur-containing amino acid residues. Alternatively, Dpm esters of protected amino acids and peptides are obtained using benzhydryl chloride or diphenylmethanol by standard esterification procedures. 

Preparation of the reagent by oxidation of benzophenone hydrazone (Aldrich) with yellow mercuric oxide in petroleum ether requires 6 hrs. and gives a liquid product. An improved procedure is based upon the finding that the reaction is catalyzed by base, probably as follows ... 

Apparently diphenyldiazomethane is the actual reagent, and indeed this substance can be prepared in good yield by oxidation of benzophenone hydra-zone with CH3COOOH in CH2CI2 in the presence of iodine and a base, particularly 1,1,3,3-tetramethylguanidine. The oxidation can also be effected in CH2 CI2 -H2 O in the presence of a phase-transfer catalyst such as trioctylpropyl-ammonium chloride (85% yield). 

NCS is also regularly used for the direct oxidation of alcohols to ketones. The presence of Triethylamine serves to activate the reagent for rapid quantitative oxidation of catechols and hy-droquinones to o- and p-quinones, respectively, and for the oxidation of benzophenone hydrazone to diphenyldiazomethane. N-Chlorosuccininude—Dimethyl Sulfide is also used in the mild oxidation of alcohols, as well as in the conversion of allylic alcohols to allylic chlorides. 

KINETICS OF OXIDATION OF BENZOPHENONE KETYL RADICALS ABSOLUTE REACTION RATES AND OSCILLATORY BEHAVIOUR... 

Benzophenone is produced by the oxidation of diphenylmethane (350). This free from chlorine (FCC) route is favored for perfume uses. The Friedel-Crafts reaction of benzene and benzoyl chloride in the presence of aluminum chloride is also possible this reaction may proceed in the absence of catalyst at a temperature of 370°C and pressure of 1.4 MPa (351). 

Oxidation of Pluviine (276), isolated from Narcissus pseudonarcissus. Narcissus incomparabilis, and Lycoris radiata Herb., with benzophenone and potassium rerr-butylate yielded a red phenol-betaine 277 from which one neutral covalent form can be drawn (Scheme 90). The betaine has absorption maxima Imax (loge) in a buffer at pH 10 at 240 (4.49), 325 (4.46), 360 (3.58), 380 (3.27), and 490 (3.26) nm. In dilute HCl, a salt is formed [lmax = 260 (4.57), 295 (4.39), 340 (3.76), 355 (3.84), 400 (3.62) nm] (57CB363). The oxidation of the alkaloid Caranine gives a similar betaine, the 1,3-dioxolo derivative 278 (56CIL348). 

The use of ethyl ethylthiomethyl sulphoxide in this reaction leads to the desired addition products in much better yields (95-97%). These products were then converted into ketene dithioacetal monoxide derivatives 430 by a sequence of reactions (equation 258)505. Reaction of 2-lithio-l,3-dithiane-l-oxide with benzophenone affords a mixture of the diastereoisomeric tertiary alcohols 431 in a ratio which is temperature dependent (cis trans changes from 3 1 at — 78 °C to 1 1 at room temperature)268. 

No published work exists on the kinetics of acid permanganate oxidation of hydroxy-acids although Pink and Stewart have noted that benzilic acid is oxidised by acid permanganate to benzophenone in an autocatalytic process with knjo/ Dio of unity. 

This is consistent with the observed products of oxidation, i.e. benzyl alcohol, benzaldehyde and benzoic acid and with the observed oxidation of cyclohexane. Radical-cations are, however, probably formed in oxidation of napthalene and anthracene. The increase of oxidation rate with acetonitrile concentration was intepreted in terms of a more reactive complex between Co(III) and CH3CN. The production of substituted benzophenones at high CH3CN concentration indicates the participation of a second route of oxidation. 

As for the energy transfer to the subsurface layers of zinc oxide from the singlet oxygen molecules, the transfer should lead to an intn ease in the electrical conductivity of semiconductor either due to ejection of electrons into the conduction band h-om shallow traps [67], or due to the injection of electrons into zinc oxide by excited particles [68]. Effects of this kind were observed in the interaction between a ZnO surface and excited pairs of benzophenone [70], and also in adsorption of singlet oxygen on the surface of ZnO monocrystal in electrolyte [69]. 

Another photocyclization to a benzo[c]phenanthridine was reported (127). Oppenauer oxidation of ( )-ophiocarpine (92) with potassium fm-butoxide and benzophenone in dioxane effected C-6—N bond cleavage to afford the hydroxyisoquinoline 219 via berberinephenolbetaine (121) (Scheme 39). Although photolysis of 219 gave only the oxepine 221, that of its methyl ether 220 furnished directly norchelerythrine (222) through electrocyclization followed by spontaneous elimination of methanol. 

Scheme 8 displays reactions where 43 behaves as a source of a Zr(II) derivative.30 They can be formally viewed as oxidative additions to the [p-Bu -calix[4]-(0Me)2(0)2Zr] fragment. The main driving force in the case of ketones is the high oxophilicity of the metal, which induces the reductive coupling of benzophenone leading to 45, or the addition of dibenzoyl causing the formation of the dioxo-metallacycle in 46, which contain a C-C double bond. It has to be mentioned that... 

Benzophenoneoxime has been prepared in quantity by treating an aqueous alcoholic mixture of benzophenone and hydroxyl-amine hydrochloride with hydrochloric acid,2 with sodium carbonate,3 with alcoholic potassium hydroxide,4 or with aqueous sodium hydroxide. It has also been obtained by treating bis-nitrosylbenzohydryl with alcoholic potassium hydroxide,6 and by the oxidation of a-aminodiphenylmethane with magnesium persulfate solution.7... 

C. Diphenyldiazomethane. In a pressure bottle are placed 19.6 g. (0.1 mole) of benzophenone hydrazone, 22 g. (0.1 mole) of yellow oxide of mercury, and 100 ml. of petroleum ether (b.p. 30-60°). The bottle is closed, wrapped in a wet towel, and shaken mechanically at room temperature for 6 hours. The mixture is then filtered to remove mercury and any benzophenone azine (Note 5), and the filtrate is evaporated to dryness under reduced pressure at room temperature. The crystalline residue of diphenyldiazomethane melts when its temperature reaches that of the room (Note 6), but it is difficult to purify and this product is pure enough for all practical purposes. The material weighs 17.3-18.6 g. (89-96%). The product should be used immediately (Note 7). 

Triphenylcarbinol has been obtained by the reaction between phenylmagnesium bromide and benzophenone,1 methyl benzoate, or phosgene 8 by action of phenylsodium upon benzophenone, benzoyl chloride, ethyl chlorocarbonate, or ethyl benzoate 4 by hydrolysis of triphenylchloromethane 5 and by oxidation of tri-phenylmethane.6... 

Though the triplet sensitized photolysis of isoprene (159) does, as noted above, produce a complex mixture of products, one of these adducts has been used in the context of complex molecule synthesis (equation 5)71. Cyclobutane 160, which was formed in ca 20% yield by the benzophenone sensitized photolysis of 159, could be easily transformed into fragrantolol, 161, an isomer of grandisol isolated from the roots of the Artemisia fragrans, by simple hydroboration/oxidation of the less hindered double bond. 

Moro-Oka et al. (1976) have reported that the oxidation of 9,10-dihydroanthracene by K02 solubilized in DMSO by 18-crown-6 gives mainly the dehydrogenated product, anthracene. Under the same conditions, 1,4-hexadiene is dehydrogenated to benzene. The authors proposed a mechanism in which the superoxide ion acts as a hydrogen-abstracting agent only. The oxidations of anthrone (to anthraquinone), fluorene (to fluorenone), xanthene (to xanthone) and diphenylmethane (to benzophenone) are also initiated by hydrogen abstraction. 

Oxidation of the quinine C-9 hydroxy substituent to the ketone is best accomplished using the Woodward3 benzophenone/potassium t-butoxide method, now using toluene. The other oxidation methods investigated (Swern, Jones, ROCI variations) were less effective or limited because of the poor solubility of the substrate. Thermodynamic equilibration of these ketones has also been reported.3... 

Benzophenones are produced by the oxidation of diarylmethanes under basic conditions [6-9], The initial step requires a strongly basic medium to ionize the methane and the more lipophilic quaternary ammonium catalysts are preferred (Aliquat and tetra-n-octylammonium bromide are better catalysts than tetra-n-butyl-ammonium bromide). The oxidation and oxidative dehydrogenation of partially reduced arenes to oxo derivatives in a manner similar to that used for the oxidation of diarylmethanes has been reported, e.g. fluorene is converted into fluorenone (100%), and 9,10-dihydroanthracene and l,4,4a,9a-tetrahydroanthraquinone into anthraquinone (75% and 100%, respectively) [6]. 

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