Benzophenone, preparation

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. 

In the following preparation to illustrate the Meen.vein-Pormdorf-Verley reduc tion, a solution of benzophenone in isopropanol is rapidly reduced in the presence of aluminium isopropoxide to benzhydrol (CaHs)2CO (C Hj)jCH OH. It is clear that the aluminium isopropoxide must take some essential part in this reaction, for benzophenone when dissolved even in cold isopropanol with a trace of acetic acid is reduced to tetraphenylethyleneglycol (p. 150). 

TTie true ketones, in which the >CO group is in the side chain, the most common examples being acetophenone or methyl phenyl ketone, C HjCOCH, and benzophenone or diphenyl ketone, C HjCOC(Hj. These ketones are usually prepared by a modification of the Friedel-Crafts reaction, an aromatic hydrocarbon being treated with an acyl chloride (either aliphatic or aromatic) in the presence of aluminium chloride. Thus benzene reacts with acetyl chloride... 

Iodoform reaction. To 0 5 ml. of acetone add 3 ml. of 10% KI solution and 10 ml. of freshly prepared sodium hypochlorite solution and mix well. A pale yellow precipitate of iodofonn is rapidly formed without heating. Acetophenone similarly gives iodoform, but the mixture must be shaken vigorously on account of the limited solubility of acetophenone in water. Benzophenone does not give iodoform. 

Benzophenone is more conveniently prepared from benzene and excess of carbon tetrachloride ... 

In an alternative method of preparation, benzophenone is used. Prepare the Grignard reagent from 13 -5 g. of magnesium turnings as above, cool in cold water, and add a solution of 91 g. of benzophenone (Section IV,139) in 200 ml. of dry benzene at such a rate that the mixture refluxes gently. Reflux the mixture for 60 minutes, and isolate the triphenylcarbinol in the manner described above. The yield is of the same order. 

Keta.Is, Trimethylpentanediol reportedly forms a cycHc ketal by heating it with benzophenone ia the presence of sulfonic acid catalysts at reflux temperatures ia toluene (64). These are said to be useful as aprotic solvents for ink-jet printing and as inflammation inhibitors for cosmetic preparations... 

Poly(phenylquinoxaline—arnide—imides) are thermally stable up to 430°C and are soluble in polar organic solvents (17). Transparent films of these materials exhibit electrical insulating properties. Quinoxaline—imide copolymer films prepared by polycondensation of 6,6 -meth5lene bis(2-methyl-3,l-benzoxazine-4-one) and 3,3, 4,4 -benzophenone tetracarboxyUc dianhydride and 4,4 -oxydianiline exhibit good chemical etching properties (18). The polymers are soluble, but stable only up to 200—300°C. 

In the ketone method, the central carbon atom is derived from phosgene (qv). A diarylketone is prepared from phosgene and a tertiary arylamine and then condenses with another mole of a tertiary arylamine (same or different) in the presence of phosphoms oxychloride or zinc chloride. The dye is produced directly without an oxidation step. Thus, ethyl violet [2390-59-2] Cl Basic Violet 4 (15), is prepared from 4,4 -bis(diethylamino)benzophenone with diethylaruline in the presence of phosphoms oxychloride. This reaction is very useful for the preparation of unsymmetrical dyes. Condensation of 4,4 -bis(dimethylamino)benzophenone [90-94-8] (Michler s ketone) with AJ-phenjl-l-naphthylamine gives the Victoria Blue B [2580-56-5] Cl Basic Blue 26, which is used for coloring paper and producing ballpoint pen pastes and inks. 

Also due to the high barrier of inversion, optically active oxaziridines are stable and were prepared repeatedly. To avoid additional centres of asymmetry in the molecule, symmetrical ketones were used as starting materials and converted to oxaziridines by optically active peroxyacids via their ketimines (69CC1086, 69JCS(C)2648). In optically active oxaziridines, made from benzophenone, cyclohexanone and adamantanone, the order of magnitude of the inversion barriers was determined by racemization experiments and was found to be identical with former results of NMR study. Inversion barriers of 128-132 kJ moF were found in the A-isopropyl compounds of the ketones mentioned inversion barriers of the A-t-butyl compounds lie markedly lower (104-110 kJ moF ). Thus, the A-t-butyloxaziridine derived from adamantanone loses half of its chirality within 2.3 days at 20 C (73JCS(P2)1575). 

The derivative of glycine, prepared from benzophenone (cat. BF3 Et20, xylene, reflux, 82% yield), has found considerable use in the preparation of amino acids. It can also be prepared by an exchange reaction with benzophenoneimine (Ph2C=NH, CH2CI2, rt). ... 

Although a practical grade of benzophenone can be used in this preparation, it is better to use material that has been recrystallized from alcohol. 

Benzopinacol has been prepared by the action of phenylmag-nesium bromide on benzil 1 or methyl benzilate. Usually it has been obtained by reduction of benzophenone, the reducing agents being zinc and sulfuric acid or acetic acid, aluminum amalgam, and magnesium and magnesium iodide. The present... 

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. ... 

Quinazoline 3-oxides were first prepared by Awers and von Meyen-burg in 1891 by the dehydration of o-acylamino benzophenone oximes with acetic acid-acetic anhydride and were assigned the in-dazole structure (33). This was then modified by Bischler to the... 

An ingenious synthesis of 1-arylisoindolcs has been developed by Vebor and Lwowski, based upon the reaction of an o-phthalimido-methylbenzophenone (41, R = aryl) with hydrazine (Table IV). The benzophenone is prepared by a Friedel-Crafts reaction with o-phthalimidomethylbenzoyl chloride (40). The mechanism of isoindole formation can be represented sehematically by a sequence involving attack by hydrazine at the imide to give the ring-opened hj drazide (42), followed by cyclization to phthalazine-l,4-dione (44) with displacement of the o-aminomethylbenzophenone (43). Intramolecular condensation of the latter can lead, via the isoindolenine... 

Fluproquazone (97) contains a 2-quinazolinone nucleus and is found to be an analgetic agent useful in mild to moderate pain. One of the preparations involves reaetion of 2-isopropylamino-4-methyl-4 -fluoro-benzophenone (96) with potassium cyanate in hot acetic acid [27],... 

Preparation of 2-Cyc/opropy/methy/amino-5-Ch/orobenzophenone To a solution of 315 g (1.09 mols) of 2-cyclopropylmethylamino-5-chloroDenzhydrol in 4 liters of benzene is added 453.6 g (5.22 mols) of manganese dioxide, freshly prepared according to the method of Attenburrow et al, J.C.S. 1952, 1104. The mixture is then refluxed for VA hours, filtered, and the filtrate evaporated under vacuum. The reddish residue is recrystallized from 510 ml of 90% acetone-10% water, giving 181 g of pure 2-cyclopropylmethylamino-5-chloro-benzophenone, MP 79° to 80°C (58% yield). Upon concentration of the mother liquor a second crop of 2-cyclopropylmethylamino-5-chlorobenzophenone weighing 34.1 g and melting at 76.5°-78°C are obtained. 

Benzophenone has been prepared by the distillation of calcium benzoate,1 by the action of benzoyl chloride on benzene in the presence of aluminium chloride,2 by the action of phosgene on benzene in the presence of aluminium chloride,3 by the action of carbon tetrachloride on benzene in the presence of aluminium chloride followed by hydrolysis.4... 

Benzophenone (Coll. Vol. x, 89) In 57 per cent yield from benzoyl chloride and diphenylcadmium or phenylcadmium halides, prepared by adding cadmium chloride to 2 moles of phenylmagnesium bromide. Gilman and Nelson, Rec. trav. chim. 55i Sig (1936). 

Intramolecular arylations can also be carried out photochemically. Huisgen and Zahler (1963 a) prepared fluoren-9-one by irradiation of benzophenone-diazonium salts in dilute sulfuric acid. The classical Pschorr synthesis of phenanthrene-9-carb-... 

Two polymers have been prepared with the benzophenone tetracarboxylic dianhydride (BTDA) and either bis-l,3-(4-aminophenoxy)-benzene or bis-l,3-(4-aminophenoxy)-2-cyano-benzene (Fig. 5.6). Both polymers are soluble in NMP and their Tg values are respectively 191 and 243°C.59... 

The Ullman reaction has long been known as a method for the synthesis of aromatic ethers by the reaction of a phenol with an aromatic halide in the presence of a copper compound as a catalyst. It is a variation on the nucleophilic substitution reaction since a phenolic salt reacts with the halide. Nonactivated aromatic halides can be used in the synthesis of poly(arylene edier)s, dius providing a way of obtaining structures not available by the conventional nucleophilic route. The ease of halogen displacement was found to be the reverse of that observed for activated nucleophilic substitution reaction, that is, I > Br > Cl F. The polymerizations are conducted in benzophenone with a cuprous chloride-pyridine complex as a catalyst. Bromine compounds are the favored reactants.53,124 127 Poly(arylene ether)s have been prepared by Ullman coupling of bisphenols and... 

Intermolecular photocycloadditions of alkenes can be carried out by photosensitization with mercury or directly with short-wavelength light.179 Relatively little preparative use has been made of this reaction for simple alkenes. Dienes can be photosensitized using benzophenone, butane-2,3-dione, and acetophenone.180 The photodimerization of derivatives of cinnamic acid was among the earliest photochemical reactions to be studied.181 Good yields of dimers are obtained when irradiation is carried out in the crystalline state. In solution, cis-trans isomerization is the dominant reaction. 

The first compounds of this class46 have been obtained via Route A. The initial condensation of phthalic anhydride with dimethylaniline requires a Friedel-Crafts catalyst, while condensation of the resulting benzophenone with the indole requires acetic anhydride. For Route B preparation of the intermediate l,2-dimethyl-3-(2-carboxybenzoyl)indole has also been described47 by condensation of the two components in the presence of aluminum chloride. However, in our experience, aluminum chloride is, in this case, unnecessary, thus rendering this route the method of choice. 

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