Benzophenones production

Superelectrophilic intermediates have further been proposed in the reactions of some esters. For example, a recent report describes the conversions of methyl benzoate to benzophenone products (70-93% yields) in reactions with superacid (eq 45 ).52... 

The cis-trans isomerisation process in the photofading of azo dyes has been found to be a first-order process in polypropylene and independent of polymer crystallinity l. oye lightfastness on leather has however been found to depend upon the colour of the dye lS while alkyl and peroxy radicals have been observed in the photofading of Rhodamine and azo dyes in solution . More specifically basic triphenylmethane dyes have been found to give benzophenone products on photofading 20 structure of a series... 

Triflic acid-catalyzed Friedel-Crafts acylation reactions of aromatics with methyl benzoate give benzophenone products in good to excellent yields (eq 33). To explain the high level of electrophilic reactivity of this system, protosolvated species are proposed as possible intermediates (eq 32). In the triflic acid-catalyzed cyclization of some ethylene dications, protonation of the ester group is thought to be a key activation step. Reaction of a-(methoxycarbonyl)diphenylmethanol with TfOH gives the fluorene product in 94% yield (eq 34). ... 

Phenyl-substituted p-hydroxybenzoates (Structure 4) have been used as light Stabilizers in polyolefins for some time. They were shown to operate through a photo-Fries rearrangement to give a more effective 2-hydroxy-benzophenone product by the following reaction sequence (Scheme 4) to give 2-hydroxybenzophenones as products [1,2]. Obviously for such a reaction to occur, the original stabilizer must absorb appreciably in... 

Beckmann rearrangement of benzophenone oxime to benz-anilide. Dissolve 2 g. of benzophenone oxime in 20 ml. of anhydrous ether in a small conical flask and add 3 g. of powdered phosphorus pentachloride (or 3 ml. of pure tbionyl chloride). Distil off the solvent and other volatile products on a water bath CAUTION ether), add 25 ml. of water, boil for several minutes and break up any lumps which may be formed. Decant the supernatant liquid, and recrystallise, in the same vessel, from boiling alcohol. The product is benzanilide, m.p. 163° confirm this by a mixed m.p. determination with an authentic specimen. 

Secondary alcohols, such as isopropyl alcohol, j -butyl alcohol, 2-pentanol, 3-pentanol, cyclopentanol, and cyclohexanol, have been autoxidized to hydroxyaLkyl hydroperoxides (1, X = OH R = H) (10,44). These autoxidations usually are carried out at ca 20°C with uv radiation in the presence of a photosensitizer, eg, benzophenone. a-Oxygen-substituted dialkyl peroxides (2, X = Y = OH and X = Y = OOH), also are formed and sometimes they are the exclusive products (10). 

Benzoyl chloride is an important benzoylating agent. In this use the benzoyl radical is introduced into alcohols, phenols, amines, and other compounds through the Friedel-Crafts reaction and the Schotten-Baumaim reaction. Other significant uses are in the production of benzoyl peroxide [94-56-0], benzophenone [119-61-9], and in derivatives employed in the fields of dyes, resins, perfumes, pharmaceuticals, and as polymerization catalysts. 

Photodecomposition of A -l,2,3-triazolines gives aziridines. In cyclohexane the cis derivative (304) gives the cis product (305), whereas photolysis in benzene in the presence of benzophenone as sensitizer gives the same ratio of cis- and trans-aziridines from both triazolines and is accounted for in terms of a triplet excited state (70AHC(ll)i). A -Tetrazo-lines are photolyzed to diaziridines. 

Dimethyl carbonate is available from Aldrich Chemical Company, Inc. The checkers dried the tetrahydrofuran Immediately before use by distillation from the sodium ketyl of benzophenone under a nitrogen atmosphere. The submitters purchased sodium hydride (50% oil dispersion) from Alfa Products, Morton/Thiokol, Inc. The checkers used 12.24 g of a 50% dispersion of sodium hydride in mineral oil obtained from the same supplier. The dispersion was washed with three portions of pentane to remove the mineral oil and the remaining sodium hydride was allowed to dry under nitrogen. 

Diphenylmethane has been prepared with aluminum chloride as a catalyst from methylene chloride and benzene, from chloroform and benzene as a by-product in the preparation of triphenylmethane, and from benzyl chloride and benzene. It has been prepared by the reduction of benzophenone with hydriodic acid and phosphorus, or with sodium and alcohol. It has also been made by heating a solution of benzyl chloride in benzene with zinc dust, or with zinc chloride. The above method is only a slight modification of the original method of Hirst and Cohen. ... 

In 2-propanoI, the quantum yield for photolytic conversion of benzophenone to the coupled reduction product is 2.0. The reason is that the radical remaining after abstraction of a hydrogen atom from 2-propanol transfers a hydrogen atom to ground-state benzophenone in a nonphotochemical reaction. Because of this process, two molecules of benzophenone are reduced for each one that is photoexcited ... 

While discussing ethers we should mention that the presence of unreacted anisoles or methyl anisoles is highly undesirable in the manufacture of phenol-formaldehyde resoles. These materials tend to be unreactive relative to phenol under normal resole conditions. They are also volatile and have odors detectable at very low concentrations. They have been the source of worker complaints and costly claims in the wood products industry. Benzophenones and methyl phenyl ketones are also common phenol contaminants that are problematic in this regard. 

The methoxy group of methoxythiophenes shows a reactivity which, in many respects, differs appreciably from the reactivity of the corresponding anisoles. Thus, in an attempted Hoesch synthesis with 5-methoxy-2-thenylcyanide (167) and phloroglucinol, the methoxy group reacted instead and 5-(2, 4, 6 -trihydroxyphenyl)-2-thenyl cyanide (168) was obtained. 2-Thenyl cyanide reacts normally in the Hoesch synthesis, Likewise, upon acid hydrolysis of the reaction product of 5-methoxy-2-thienyllithium with benzophenone, (169) was obtained instead of the expected substituted methoxythiophene. No defined products could be isolated from the attempted Claisen rear-... 

Using different mono- and diketones in acetic acid (at room temperature) afforded the following products from benzophenone, 2,2-diphenyl-2//-imid-azo[4,5-/]quinoline from dibenzylketone, the 2-benzyl-imidazo[4,5-/]quino-line and from 2,4-pentanedione, 2-methyl-imidazo[4,5-/]quinoline. Cyclohexanone under reflux gave 2-n-pentyl-, whereas at room temperature it afforded the. s pira[cyclohexane-l,2 ]-(2//)-imidazo[4,5-/]quinoline 108 (R R =(CFl2)5) (86UC527). 

Chloro-5-nitrobenzaldehyde, -acetophenone, or -benzophenone derivatives treated with 2-aminothiophenol under alkaline conditions provided good yields of the corresponding dibenzo[(3,/][l,4]thiepins. Similar treatment of 2-chloro-3,5-dinitrobenzophenone (318) provided 58% of dibenzo[(3,/][l,4]thiepin 321 and 20% of phenothiazine 323. Its formation can be easily explain by the Smiles rearrangement of the initially formed intermediate 320 into diphenylamine derivative 322, followed by denitrocyclization reaction leading to the corresponding product of denitrocyclization 323 (Scheme 49). When the reaction was done in pyridine, only this product was isolated in 50% yield (57JCS3818). 

When buta-1,3-diene 3 is irradiated in the presence of a photosensitizer (e.g. benzophenone), the isomeric divinylcyclobutanes 6 and 7 are formed via the intermediate diradical species 4 and 5 respectively in addition the [4 + 2] cycloaddition product 4-vinylcyclohexene (see Diels-Alder reaction) is obtained as a side product ... 

The intermolecular McMurry reaction is first of all a suitable method for the synthesis of symmetrical alkenes. With a mixture of carbonyl compounds as starting material, the yield is often poor. An exception to this being the coupling of diaryl ketones with other carbonyl compounds, where the mixed coupling product can be obtained in good yield. For example benzophenone and acetone (stoichiometric ratio 1 4) are coupled in 94% yield. ... 

Chlorthalidone (49) is another thiazide-like diuretic agent that formally contains an isoindole ring. Transformation of the amine in benzophenone, 47, to a sulfonamide group by essentially the same process as was outlined for chlorexolone (46) affords Intermediate 43. This product cyclizes to the desired pseudoacid 1-ketoisoindole (49) on successive treatments with thionyl... 

Sodium methoxide (1.2 g) in dimethylformamide (150 ml) was stirred with 3,5-dim ethoxy-4 reaction mixture was then treated with /3-morpholinoethyl chloride (3.4 g) and heated for 1 hour at 140°C, then evaporated to dryness, and treated with water to give a solid material. The mixture was filtered, washed and crystallized from cyclohexane to give 3,5-di-methoxv-4 -chloro-4-( morpholinoethoxy)-benzophenone (6.5 g), MP 91°C to 92°C. The product was then reacted at about 0°C with gaseous hydrogen chloride in ether to give, after crystallization from isopropanol, the corresponding hydrochloride which hada MPof 187.9°C. 

A further variant of Method B is the acylation of a 2-aminobenzophenone with a protected a-amino acid chloride, followed by conversion of the product 11 into the 2-(aminoacet-amido)benzophenone 12 by reaction with hydrobromic acid in acetic acid.196... 

A mixture of 5-chloro-2-[chloroacetyl(mcthyl)amino]benzophenone (1.136 g, 3.1 mmol), hexamethylenetetramine (1.0 g, 7 mmol) and EtOH (15 mL) was heated under reflux for 10 h. The solvent was distilled off under reduced pressure, H20 (10 mL) was added to the residue and the mixture was extracted with benzene (3 x 10 mL). The combined extracts were washed with H20, dried (Na2S04) and evaporated in vacuo. Crystallization the residue (Et2Q) gave the product yield 0.79g (80%) mp 128-130 C. 

A further variant of Method B is the conversion of the readily available aryl(2-methyl-aminoaryl)methanols 16 into the chloroacelyl derivatives 17, followed by oxidation to Ihe benzophenones 18 with chromium(VI) oxide. The products are transformed into benzodi-azepinones by treatment with sodium iodide and ammonium carbonate (Method D). Selected... 

---