Benzo phenone

CeHs—CO—CH3, Phenyl methyl ketone or Aceto phenone. and CeHe—CO—CeHs, Di-phenyl ketone or Benzo phenone. 

Aceto phenone is the simplest of the aromatic ketones related to secondary aromatic alcohols. It is a crystalline substance m.p. 20.5°, b.p. 202 . It possesses a soporific or hypnotic effect on account of which it is also known as hypnone. Its reactions are those already considered. The oxime produced by the action of hydroxyl amine would, seem to be possible of existence in two stereo-isomeric forms like the benzaldoximes as the two radicals joined to the carbo-oxime group are different. In fact only one oxime is known as has been explained. 

The proofs that the known form is the syn compound are that it does not break up and yield phenyl cyanide and that it yields acet anilide by the Beckmann rearrangement which has just been discussed (p. 654). 

Benzo Phenone, CeHs—CO—CeHe, Di-phenyl Ketone 

Benzo phenone is a solid which is di-morphous, i.e.j it exists in two forms which are not isomeric as they possess the same formula in every respect. One form is a solid, m.p. 26°, while the other is a solid, m.p. 46 . On reduction with zinc dust benzo phenone yields first the corresponding secondary alcohol, CeHs—CH(OH)—CeHs, and then the hydrocarbon di-phenyl methane, CeHs—CH2—CeHs. 

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Then add 3 drops of acetophenone (or about 0 3 g. of powdered benzo-phenone dissolved in 1 ml. of acetic acid) and shake the mixture. A precipitate of the phenylhydrazone is produced on scratching. 

Solids. —It may Idc a hydrocM bon (c .g., paraffin wa, naphthalene) highei alcohol eg., cetyl alcohol) aldehyde e.g., z5-hydroxybenzaldehyde) ketone and qiiinonc e.g., benzo-phenone, camphor) acid (higher fatty, e.g., palmitic acid or aromatic acid) ester (of glycerol, phenols or aromatic alcohols) phenol e.g., thymol),... 

Organic phosphites POR(OR )OR where R=Ci—C30 represents aliphatic, cycloaliphatic, or aromatic radical, are also able of inhibiting the thermal destruction of polyolefin [19]. Of light stabilizers, benzo-phenone derivatives have the ability for inhibiting thermal destruction of polyolefins, too. 

In addition, there are many surface modification processes that use triplet sensitizers to permit oxidation reactions. In a typical process, polyisocyanate is applied on a polyolefin together with a sensitizer such as benzo-phenone and then irradiated with UV light. As shown in Eq. (15) the sensitizer has an oxidizing effect to produce hydroxyl groups over the polymer surface. These hydroxyl groups finally react with isocyanate to provide a functional polymer [56,57]. 

MACB = 5-chloro-2-(methylamino)benzo-phenone 227 Macrolide antibiotics 195 Magnesium cations 144,145, 311, 312 Malachite green reagent 45 Malathion 362... 

MACB=5-chloro-2-(methylamino)benzo-phenone la 227 Macrolide antibiotics la 195 Magnesium cations lal44,145,311,312 Malachite green la 45 Malathion lb 83, 304, 305,338,340,341 Maleic acid la 44,61,171,230,249,250 Malic acid la 45,175,230,233,250,258, 259,308... 

Fig. 131.—The reciprocal melting point plotted against the volume fraction of diluent for cellulose tributyrate in benzo-phenone ( ), in hydroquinone monomethyl ether (O), and in ethyl laurate (A). (Mandelkern and Flory. )...

The inhibitory function of the sulfur compounds then would appear to be to prevent the subsequent reaction of the initially formed ketyl radicals by catalyzing hydrogen transfer reactions. With this in mind, one can write the following mechanism for the inhibition of the photoreduction of benzo-phenone by sulfur compounds ... 

Irradiation of 36a in 1,4-dichlorobenzone at 60 °C, a temperature at which thermal decomposition of the diazo compound is still negligible 24), in the presence of benzo-phenone, acetone, or cyclohexanone leads to l,3,4X5-dioxaphosphorins 56a-c (= 57a-c)33 ... 

A somewhat related process, the cobalt-mediated synthesis of symmetrical benzo-phenones from aryl iodides and dicobalt octacarbonyl, is shown in Scheme 6.49 [100]. Here, dicobalt octacarbonyl is used as a combined Ar-I bond activator and carbon monoxide source. Employing acetonitrile as solvent, a variety of aryl iodides with different steric and electronic properties underwent the carbonylative coupling in excellent yields. Remarkably, in several cases, microwave irradiation for just 6 s was sufficient to achieve full conversion An inert atmosphere, a base or other additives were all unnecessary. No conversion occurred in the absence of heating, regardless of the reaction time. However, equally high yields could be achieved by heating the reaction mixture in an oil bath for 2 min. 

This process — also called sensibilisation — is of importance in preparative organic photochemistry 115) whenever a rate constant of intersystem crossing fcSl Tl for a given molecule is small or if direct irradiation of this molecule is inconvenient. This principle is illustrated in Figure 8 for benzo-phenone as donor and a diene as acceptor, the diene then isomerizing from the triplet state. 

C5D5N above 80 °C, it gains the characteristic color of phosphorus ylide, and signals of phosphorus ylides and cyclosilathianes appear in the H, 13C, and 31P NMR spectra. In the presence of an equivalent amount of benzo-phenone in this solution, 1,1-dimethyl-2,2-diphenylethylene and Ph3PO are formed in 53% yield at 100 °C for 10min. This indicates that the retro-Wittig decomposition of 20a occurs in the solution (Scheme 23, equilibrium a). Probably, phosphorus ylide is also formed in the equilibrium bimolecular reaction between two betaine molecules (Scheme 23 equilibrium b). The ratio of the contributions of these two reactions is strongly determined by the solvent and temperature. 

Photolysis of acetone forms methyl radicals, isolated as dimethyl-mercury, and acetyl radicals isolated as diacetyl. Photolysis of benzo-phenone forms phenyl radicals which remove a tellurium mirror to give diphenyltellurium. 

The thermal decomposition of />-nitrotriphenylmethyl hydroperoxide in benzene gives -nitrophenol 32%, phenol 9%, >-nitro-triphenylcarbinol 23%, -nitrobenzophenone 14%, and no benzo-phenone the decomposition in ether plus sulfuric acid gives -nitro-benzophenone 94% and phenol 81%.817 The latter reaction is very probably ... 

Phenyl /-butyl ether, 46, 89 /3-Phenylcinnamic acid, from benzo-phenone and triethyl phosphono-acetate, 48, 75... 

The benzene is heated under reflux over sodium with benzo-phenone until a permanent blue coloration develops and then is distilled with exclusion of atmospheric moisture. 

J. J. Eddine, M. Cherqaoui, Chiral Quaternary Benzo-phenone Hydrazonium Salt Derivatives Efficient Chiral Catalysts for the Enantioselective Phase-Transfer Alkylation of Imines. Application to Synthesis of Chiral Primary Amines , Tetrahedron Asymmetry 1995, 6, 1225-1228. 

The photohydrolysis of pNA ( t =59.5 kcal mole is sensitized by benzo-phenone. The pseudo first order rate constant is found to be four times higher than in the unsensitized runs. The product pattern, however, was strictly the same in both the sensitized and unsensitized photohydrolysis, and this result strongly suggests that the triplet state is an intermediate also in the unsensitized reaction... 

Reagent-grade dioxane (2 1.) is heated to reflux with the sodium ketyl of benzophenone prepared from 10 g. of benzo-phenone and 1 g. of sodium until a deep blue solution results. If the color is not developed, another portion of benzophenone and sodium is added and the heating continued until the color persists. The peroxide-free dioxane is distilled from the flask and is used immediately. 

Anion solvation has been studied by observing the shift in the absorption spectrum of the benzophenone anion in various solvents and as a function of temperature. The benzo-phenone anion was formed from the reaction of the benzophenone molecule and a precursor to the solvated electron. Approximately 0.25 M benzophenone is put into the solution so that all the presolvated electrons will react with the benzophenone and virtually none will form the solvated electron. This process occurs much more quickly than the solvation processes that are observed [14,20]. 

Oxidation of Diphenylmethane in Basic Solution. Diphenylmethane reacts with an excess of oxygen in the presence of potassium ferf-butoxide in various solvents to produce nearly quantitative yields of benzophenone. In DMSO (80% )-tert-butyl alcohol (20% ) a 96% yield of the benzo-phenone-DMSO adduct [ l,l-diphenyl-2- (methylsulfinyl) ethanol] was isolated at complete reaction (17). 

An interesting extension of the forementioned generalizations has recently been reported.43 When a dilute solution of 2,3-dimethyl-l,3-butadiene 11a is irradiated in the presence of a large excess of benzo-phenone, a product 16 arising from the photocycloaddition reaction is observed. This anomalous result has been explained as involving the 77,77- triplet of the diene, formed by triplet-triplet transfer from the n,n triplet of benzophenone, which then reacts with ground-state benzophenone. The critical steps are shown in structures 14-16. 

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