Benzophenone dimethyl acetal

At platinum anodes and under aprotic conditions (CH3CN-LiC104), benzophenone hydrazones afford exclusively benzophenone azines (Scheme 6, a), while in MeOH/NaOMe benzophenone dimethyl acetals are formed (Scheme 6, b). At graphite anodes (MeOH/ NaOMe), diphenyldiazomethane is formed as an intermediate [122] (Scheme 6, c). 

Benzophenone dimethyl acetal crystallizes directly in good yield, but in most cases the reaction mixture is fractionated, if necessary in a vacuum. The acetals thus obtained are, however, not quite free from silicon compounds to destroy the latter, the distillate is boiled with potassium hydroxide and a little alcohol or the undistilled liquid is treated as follows The liquid is poured (if necessary with cooling) into ca. 30% potassium hydroxide solution (500 ml per mole of orthoester) and shaken for about 10 min at room temperature or boiled (for, e.g., higher alcohols) for some time under reflux the alcoholic layer, now containing no silicon compounds is separated, dried over potassium carbonate, and fractionated (yield 70-90%). 

A related [l,2]-rearrangement was described by Schlenk and Bergman in 1928. As shown below, reduction of benzophenone dimethyl acetal (6) with metallic sodium led to the formation of diphenyl methyl carbinol (8), presumably via intermediate organosodium species 7. ... 

Benzaldehyde, 43, 73, 123 Benzaldehyde diethyl acetal, 108, 110,122—3 Benzaldehyde dimethyl acetal, 34, 111 Benzenesulphonylhydrazonc, 13 Benzophenone, 137 Benzophenone cyanohydrin, 137 p-Benzoquinone, 137... 

Unlike coumarin, chromone (206) undergoes efficient unsensitized photoaddition to tetramethylethylene, cyclopentene, ketene dimethyl acetal, and but-2-yne.180 The major product of such an addition to tetramethylene is the cis-fused cyclobutane derivative (207) the formation of the two minor products (208 and 209) is easily rationalized. Added benzophenone has no visible effect on this cycloaddition, which is therefore believed to involve the attack of triplet chromone on the ground-state alkene. Photoaddition to furo-chromones has also been studied,179 and the photosensitized cyclo-... 

Benzaldehyde dimethyl acetal Benzaldehyde glyceryl acetal Benzaldehyde propylene glycol acetal Benzoin Benzophenone Benzothiazole Benzyl acetate Benzyl acetoacetate Benzyl alcohol Benzyl benzoate... 

Materials. 4-vinylbenzyl chloride, 4-(dimethylamino)pyridine (DMAP), 2,2-bis(hydroxymethyl) prpionic acid (bisMPA), benzaldehyde dimethyl acetal, p-toluene sulfonic acid-monohydride ( TSAOH), and n-butyl lithium (2.5M) were purchased from Sigma-Aldrich. Benzylidene-2,2-bis(oxymethyl)propionic acid and its anhydride were prepared following a literature procedure (2SJ. Dichloromethane (DCM) was distilled under nitrogen from calcium hydride immediately prior to use. Tetrahydrofuran (THF) was distilled under nitrogen from sodium/benzophenone immediately prior to use. All other reagents were commercially obtained and used without further purification. 

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. 

Trinitrodimethylbenzophenone, Ci gH 11N3O7, mw 345.26, N 12.17%. Two isomers are known 3,5,3 -Trinitro-2,4 dimethylbenzophenone, (H3C)2(02N)2CgH.C0.CgH4.N02 pltlts (from ale, glac acet ac or benz), mp 139-40° mod sol in glac acet ac, benz acetone si sol in hot ale v si sol in eth, petr eth CS2 insol in w can be prepd by nitrating 2,4-dimethyl-benzophenone 3 -nitro-2,4-dimethyl- or 3,5-dinitro-2,4-dimethylbenzophenone with mixed acid (Refs 1 3)... 

The reactions of 1,1-dimethyl-2,2-bis(trimethylsilyl)silene (54) with carbonyl compounds such as acetone and ethyl acetate, and particularly with benzophenone imine, are very much faster than its ene reactions with hydrocarbons such as isobutene244,246,266, pointing to the involvement of the nucleophilic lone pairs in the former case. 

Printing plates have been prepared which depend on the photopolymerization of allyl esters to generate an image [81]. As an etch resist for printed circuits, a solution of a prepolymer of allyl methacrylate, benzil, and 4,4 -bis(dimethyl-amino)benzophenone in methyl isobutyl ketone-cellosolve acetate was coated on a substrate. After exposure to UV, the image was developed with methyl ethyl ketone [81]. 

HI = hot-injection method, HU = heating-up method, RT = room temperature, CdMe = dimethyl cadmium, ZnEt = diethylzinc, TMS = trimethlsilyl, (BDMSj Te = his tert-butyldimethylsilyljteUuride, TDPA = tetradecylphosphonic acid, ODPA = octadecy-Iphosphonic acid, SA = stearic acid, LA = lauric acid, MA = myristic acid, OA = oleic acid, ac = acetate, acac = acetylacetonate, st = stearate, hdx = hexadecylxanthate, ex = ethylxanthate, dx = decylxanthate, TOPO = trioctylphosphine, HDA = hexadecylamine, DDA = dodecylamine, ODA = octadecylamine, TOP = trioctylphosphine, TBP = tribu-tylphosphine, ODE = 1-octadecene, HH = hexadecylhexadecanoate, BP = benzophenone, TOA = trioctylamine, OAm = oleylamine, DPE = diphenylether, TAA = thioacetamide TEA = triethanolamine, DDT = dodecanethiol, dedc= diethyldithiocarbamate. 

The identification of the photodegradation products of fexofenadine obtained in UV was performed based on molecular ions [M4-H]+. The mass spectrum of DP-1 show the molecular ion at m/z = 457 amu, and the product was identified as the 4-[4-(hydroxydiphenyl-methyl)-l-piperidinyl]-l-(4-phenylisopropyl)butanol. The second product DP-2 (m/z = 499 amu) was identified as a,a,-dimethyl-4-[l-hydroxy-4-[4-(benzophenone)l-piperidinyl]buthyl]-benzene acetic acid. 

Also obtained by degradation of 6,7-dimethyl-3-(4-methylphenyl)-2-phenylb enzofuran with chromium trioxide in boiling acetic acid, followed by saponification of the keto ester so obtained (2-benzoyloxy-3,4-dimethyl-4 -methyl benzophenone) [44,46]. m.p. 84° [44,46,518,718] JR [44]. 

OH Preparation by hydrogenolysis of 2,2, 4,4 -tetrakis-(benzyloxy)-6,6 -dimethyl-benzophenone (SM) in the presence of 10% Pd/C in ethyl acetate (90%) [1376], SM was obtained by condensation of orcinol dibenzyl ether with orsellinic acid dibenzyl ether in methylene chloride in the presence of trifluoroacetic anhydride for 5 min (75%). 

---