Benzaldehyde diacetate

Neutral alumina (3.6 g) is added to a solution of benzaldehyde diacetate la (0.054 g, 0.284 mmol) dissolved in a minimum amount of dichloromethane (1-2 mL) at room temperature and the reaction mixture was thoroughly mixed using a vortex mixer. The adsorbed material is dried in air (beaker) and placed in an alumina bath inside the microwave oven. Upon completion of the reaction as followed by TLC examination (40 s), the product is extracted into dichloromethane (4x5 mL). Removal of the solvent, under reduced pressure afforded essentially quantitative yield of benzaldehyde 2a. 

Keywords benzaldehyde diacetate, deacetylation, zeolite HSZ-360, microwave irradiation, benzaldehyde... 

The nitration of acetophenone has been extensively studied. It is carried out at a low temperature (5° to -20°) by the action of nitric and sulfuric acids and gives m-nitroacetophenone (55 83%) and smaller amounts of o-nitroacetophenone. Under similar conditions, benzalde-hyde is converted to m-nitrohenzaldehyde (84%). If nitration is performed on benzaldehyde diacetate, C(HsCH(CXZCXZH3)2, with subsequent hydrolysis, p-nitrobenzaldehyde (73%) is obtained furthermore, a slight modification of this procedure causes the formation of mainly the ortho isomer (43%). ... 

If benzaldehyde diacetate is the starting material, the amount of ortho- and para-nitration increases 198 nevertheless o- and />-nitrobenzaldehyde are pre-... 

Benzodioxins.—A synthesis of 5- and 8-hydroxy-l,3-benzodioxin-4-ones from 2,6- and 2,3-dihydroxybenzoic acid, dibromomethane, and benzaldehyde diacetate has been described. AA -Carbonyldi-imidazole reacts with 2-hydroxybenzamide to give the 1,3-benzodioxin in 72% yield (Scheme 9). Amides which lack intramolecular hydrogen-bonding react differently. ... 

In 212 cc of water are mixed 21.2 grams (0.112 mol) of N-(benzylidene)-3-amino-2-oxa-zolidone, 8.93 grams of concentrated sulfuric acid, and 30.1 grams (0.124 mol) of 5-ni-tro-2-furaldehyde diacetate. This mixture is heated to effect the hydrolysis of N-(benzy-lidene)-3-amino-2-oxazolidone, steam distillation of the benzaldehyde and hydrolysis of 5-nitro-2-furaldehyde diacetate. Approximately IV2 hours are required for this reaction to take place. When the bulk of the benzaldehyde has been removed, 50 cc of 99% isopropanol are added, the reaction mixture is refluxed a short time, and the crystals of N-(5-nitro-2-furfurylidene)-3-amino-2-oxazolidone are filtered from the hot suspension. The product is washed with water and isopropanol and dried a yield of 23.3 grams, 92.8% based on N-(benzylidene)-3-amino-2-oxazolidone of MP 254° to 256°C is obtained, according to U.S. Patent 2,759,931. 

Alternatively, when 21 was treated with benzaldehyde diethyl acetal-hydrochloric acid, ethyl 3,5 4,6-di-0-benzylidene-L-gulonate (76) was formed in >90% yield. Diacetal 76 was efficiently oxidized to 77 (>90% yield) with dimethyl sulfoxide-trifluoroacetic anhydride, or by way of the nitrate of 76 and triethylamine. Hydrolysis of 77 then afforded ethyl L-xy(o-2-hexulosonate in 86% yield.383... 

Iodosobenzene diacetate [IBD, PhI(OAc)2] is able to oxidize benzylic alcohols to benzaldehydes when a solid mixture of iodosobenzene diacetate and the alcohol is irradiated with microwaves. Best results are obtained when iodosobenzene diacetate is supported on alumina.118 The use of polymer supported iodosobenzene diacetate (PSDIB) simplifies the work-up in the oxidation of benzylic alcohols to benzaldehydes.119 PSDIB can be employed in the presence of KBr and using water as solvent, resulting in the transformation of secondary alcohols into ketones and primary alcohols into carboxylic acids.117... 

The direct conversion of 2-phenylthiochroman-4-ones to thiochromones (thioflavones) 525 can be achieved with DDQ, iodobenzene diacetate (IBDA) or iodine (Equation 185) <1999SC1857>. Thioflavanones afford 3-substituted thioflavones 526 by isomerization of the initially formed aldol product from reaction with a substituted benzaldehyde (Equation 186) <1991BSF976>. 

The formation and intramolecular dipolar cycloaddition of azomethine ylides formed by carbenoid reaction with C=N bonds has recently been studied by the authors group.84 Treatment of 2-(diazoace-tyl)benzaldehyde O-methyl oxime (176) with rhodium(II) octanoate in the presence of dimethyl acetylenedicarboxylate or N-phenylmaleimide produced cycloadducts 178 and 179, respectively. The cycloaddition was also carried out using p-quinone as the dipolarophile. The major product isolated corresponded to cycloadduct 180. The subsequent reaction of this material with excess acetic anhydride in pyridine afforded diacetate 181 in 67% overall yield from 176. The latter compound incorporates the basic dibenzofa, d -cyclohepten-5,10-imine skeleton found in MK-801,85 which is a selective ligand for brain cyclidine (PCP) receptors that has attracted considerable attention as a potent anticonvulsive and neuro-protective agent.86,87... 

Diphenyl-16S6 (1,3,6,9,11,14 = diacetal) Thiacalix[4]arene ( 16S8 ) 17S2 3-Thiapentane-l,5-dithiol + benzaldehyde Thiophene + SC12 Dihalogenid 1 (CH2)10 Dihalogenid 2 (CH2)5... 

The reaction of isonicotinic acid hydrazide and corresponding benzaldehyde under microwave conditions gave the heterocyclyl acylhydrazones (xxi). The oxidation of xxi with iodobenzene diacetate (IBD) gave the heterocyclyl-1,3,4-oxadiazoles (xxii) in a solid state [29]. 

Benzaldehyde is prepared by the hydrolysis of (dichloromethyl)benzene (benzal chloride) in either aqueous acid or aqueous alkali and by the oxidation of toluene with chromium trioxide in acetic anhydride (Scheme 6.3). In the latter synthesis, as the benzaldehyde is formed, it is converted into its diacetate by the acetic anhydride, so preventing further oxidation subsequent hydrolysis generates the aldehyde group. The benzaldehyde has thus been protected from oxidation. Benzyl alcohol can... 

Ten grams (0.094 mole) of benzaldehyde (free of benzoic acid) is added to a mixture of 10.6 g. (10% excess) of acetic anhydride and 0.1 g. of concentrated sulfuric acid. The mixture is agitated and cooled so the temperature does not rise above 70°. The mixture is allowed to stand 24 hours at room temperature. It is then dissolved in ether, and the resulting solution is extracted with water, dilute sodium carbonate solution, and again with water. After being dried over sodium sulfate the ethereal solution is distilled. There is obtained 16 g. (81%) of the diacetate, b.p. 154 /20 mm., m.p. 46°. 

Triarylbismuthine A -tosylimides react with benzaldehyde, benzoyl chloride and phenyl isocyanate to give A -tosylimine, A-tosylamide and A -tosylurea derivatives, respectively [91CL105] (Section 5.5.2.3). The imides oxidize secondary and benzylic alcohols to carbonyl compounds, sometimes accompanied by the concurrent formation of a diaryl(A -tosylamino)bismuthine [96JCR(S)24] (Section 5.2.4). When treated with acetic acid, the imides are converted to the corresponding triarylbismuth diacetates and sulfonamides (Scheme 3.9). 

Benzylic oxidation of toluenes. Toluene is oxidized by palladium acetate (equimolar) in acetic acid at 90° (13 hrs.) to benzyl acetate (80% yield), benzaldehyde (4%) and benzylidene diacetate (6%) with formation of palladium (O).4 This oxidation is sensitive to electronic factors. Thus p-methoxytoluene is converted in 96% yield into p-methoxybenzyl acetate whereas p-nitrotoluene is essentially inactive. 

The products of aldol/dehydration reactions of active methylene compounds with unsaturated aldehydes undergo in situ hetero-IMDA reaction. Reaction of 2-phenyl-5-methyl-2.4-di-hydro-3//-pyrazol-3-one with 2-(3-methyl-2-butenyloxy)benzaldehyde in acetonitrile containing catalytic 1,2-ethanediammonium diacetate gave the products of a highly stereoselective IMDA reaction82. 

Brigl and Schinle condensed D-fructose with benzaldehyde containing zinc chloride, and obtained a crystalline di-O-benzylidene-D-fructose. The structure of this diacetal was established when Brigl and Widmaieri methylated the compound, hydrolyzed the benzylidene acetal groups, and converted the resulting amorphous mono-O-methyl-D-fructose into 2,3 4,6-di-0-isopropylidene-l-0-... 

In 212 cc of water are mixed 21.2 grams (0.112 mol) of N-(benzylidene)-3-amino-2-oxa-zolidone, 8.93 grams of concentrated sulfuric acid, and 30.1 grams (0.124 mol) of 5-ni-tro-2-furaldehyde diacetate. This mixture is heated to effect the hydrolysis of N-(benzy-lidene)-3-amino-2-oxazolidone, steam distillation of the benzaldehyde and hydrolysis of... 

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