Benzaldehyde esterification

Benzaldehyde esterification is catalyzed by CaO. The variations of the activity and basicity of CaO catalysts parallel each other as the pretreatment temperature of catalyst changes, indicating that the base sites are the active sites. The reaction is of the Cannizzaro type as shown below, and the slow step involves H transfer from (I) to (II). 

The 3-arylglutaric esters 3 required as substrates were obtained by condensation of 2 equiv. of ethyl acetylacetate with respective benzaldehydes, followed by hydrolysis and decarboxylation of the resulting product under basic conditions. After esterification, ester 3 was obtained in 75% overall yield (R = Cl, = Me) [10]. 

Izumi and Urabe [105] found first that POM compounds could be entrapped strongly on active carbons. The supported POMs catalyzed etherization of ferf-butanol and n-butanol, esterification of acetic acid with ethanol, alkylation of benzene, and dehydration of 2-propanol [105], In 1991, Neumann and Levin [108] reported the oxidation of benzylic alcohols and amines catalyzed by the neutral salt of Na5[PV2Mo10O40] impregnated on active carbon. Benzyl alcohols were oxidized efficiently to the corresponding benzaldehydes without overoxidation ... 

The simple cleavage of lactones 1 or 2 with alcohol and acid has not been reported. However, when 1 is treated with benzaldehyde diethyl acetal and hydrochloric acid, ethyl 3,5 4,6-di-0-benzylidene-L-gulonate (47) is formed in >90% yield.77,78 No other isomers were observed, and other acetals of benzaldehyde, as well as aliphatic aldehydes, afford similar products in good yield.77 D Addieco prepared36 similarly protected derivatives of L-gulonic acid by oxidation of l,3 2,4-di-0-ethylidene-D-glucitol (15), followed by esterification of the resulting acid with diazomethane. 

Isocarboxazid Isocarboxazid, 2-benzylhydrazid-5-methyl-3-isoxazolecarboxylate (7.2.6), can be synthesized from acetylacetone, which on nitrosation with nitrous acid gives 5-methyl-isoxazol-3-carboxyhc acid (7.2.2). Esterification of this product gives the ethyl ester of 5-methyl-isoxazol-3-carboxyhc acid (7.2.3). The synthesized ester (7.2.3) is further reacted with benzylhydrazine, to give isocarboxazide (7.2.6), or with hydrazine, which forms 5-methyl-isoxazol-3-carboxylic acid hydrazide (7.2.4). Reacting the latter with benzaldehyde gives hydrazone (7.2.5), which is further reduced to the isocarboxazide (7.2.6) [46,47]. 

Methyl cinnamate is a colorless crystalline solid mp 36.5 °C) with a fruity, sweet-balsamic odor. In addition to the common esterification methods, it can be prepared by Claisen condensation of benzaldehyde and methyl acetate in the presence of sodium. Methyl cinnamate is used in soap perfumes, as well as in blossom and oriental perfumes, and is sometimes added to aromas. 

Benzyl alcohol readily undergoes the reactions characteristic of a primary alcohol, such as esterification and etherification, as well as halide formation. In addition, it undergoes ring substitution. In the presence of acid, polymerization is observed, and the alcohol can be thermally dehydrated to toluene [108-88-3], Catalytic oxidation over copper oxide yields benzaldehyde benzoic acid is obtained by oxidation with chromic acid or potassium permanganate. Catalytic hydrogenation of the ring gives cyclohexylmethanol [100-49-2]. 

Ethyl benzalmalonate has been prepared by the esterification of benzalmalonic acid in the presence of concentrated sulfuric acid 4 by the action of benzal chloride on sodiomalonic ester 6 by the condensation of benzaldehyde and malonic ester in the pres-... 

Monodirectional 12 membered ring zeolites (offretite, L, mordenite and 0) are very inefficient as catalysts for formaldehyde benzene condensation to give diphenylmethane, esterification of phenylacetio acid with equimolar amounts of ethanol, Friedel-Crafts acylation of 3-phenylpropanoyl chloride with anisole and Claisen-Schmidt condensation of acetophenone with benzaldehyde. This fact has been attributed to diffusional constraints of organic compounds inside the channels. By contrast, the behaviour of the tridireotional f zeolite is very similar to that of dealuminated HY zeolites, inoreasing the turnover of the acid sites with the framework Si-to-Al ratio. 

In the present paper we have studied four acid catalyzed reaotions involving carbonyl compounds alkylation of benzene with formaldehyde, esterification of phenylacetic acid, Friedel-Crafts acylation by phenylpropanoyl chloride, and the cross aldolic condensation of acetophenone with benzaldehyde in the presence of three Hp zeolites with different framework Si-to-Al... 

Carbonyl)chlorohydridotris(triphenylphosphine)ruthenium(II) was used as a catalyst in the transfer hydrogenation of benzaldehyde with formic acid as a hydrogen source. Under these conditions, the reduction ofbenzaldehyde to benzyl alcohol is accompanied by esterification of the alcohol with the excess of formic acid to provide benzyl formate (Scheme 4.16). In this microwave-assisted reaction, the catalyst displayed improved turnover rates compared to the thermal reaction (280 vs. 6700 turnovers/h), thus leading to shorter reaction times36. 

Price and Hammett s rule has found confirmation in the reaction of benzaldehyde with acetone and ethyl methyl ketone (Gettler and Hammett, 1943), in the acid-catalyzed hydration of olefins (Taft, 1956a), in the hydrolysis of esters catalyzed by ion-exchange resins (Samelson and Hammett, 1956), in acid-catalyzed deoxymercuration (Kreevoy et al., 1962), and in the esterification of carboxylic acids in methanol (Smith, 1939). Taft (1956b) has noted that the rule seems to require the following modifications. The entropy-bearing substituent... 

The common intermediate in two published biomimetic routes to Lythraceae alkaloids was substituted 4-phenylquinolizid-2-one. In one approach based on a biogenetic hypothesis of Ferris et al. (62), Wrobel and Gol biewski condensed pelletierine (126) with isovanillin (128) and obtained a transfused quinolizidine derivative (130, jS H-5) (64) in 75% yield. A model condensation of pelletierine (126) with benzaldehyde which resulted in a mixture of quinolizidones was reported earlier by Matsunaga et al. (65). In another approach Rosazza et al. (52) condensed A -pjperideine (132) with /J-ketoester 133 to get 134. The next stage in both approaches was reduction of the ketone and esterification or transesterification with derivatives of p-hydroxycinna-mic acid (135 or 136). Investigations into the oxidative coupling of 137 were unsuccessful. 

An acetal of benzaldehyde may become a protective group of polyhydroxy compounds. The hydroxyl groups in the 1 and 3 positions of glycerol may form a cyclic acetal with benzaldehyde. The secondary hydroxyl group left intact is available for esterification. Hydrogenolytic removal of the benzal group allows the synthesis of the P-monoglyceride (eq. 13.21).46... 

Benzyl benzoate is a constituent of Peru balsam and occurs naturally in certain plant species. Commercially, benzyl benzoate is produced synthetically by the dry esterification of sodium benzoate and benzoyl chloride in the presence of triethylamine or by the reaction of sodium benzylate with benzaldehyde. 

Addition of chloroform to benzaldehyde followed by esterification with acetic anhydride gives the trichloro derivative known as rose crystals or, more commonly by the misnomer, rose acetone. Such misnomers are not uncommon with older fragrance materials. Some... 

As expected, we found that the oxidation of 4-methylphenol in acetic acid medium in the presence of Pd-Sn / C catalyst leads to 4-hydroxybenzylic acetate with a good selectivity (Table 2, entry 2). The study of the reactionnal intermediates in such a medium shows the difficulty to oxidize the acetate into 4-hydroxy-benzaldehyde under these conditions (Table 2, entry 5) while the esterification of alcohol by acetic acid is complete (Table 2, entry 3). 

Chlorination of toluene under radical conditions (either through the use of an initiator or by photolysis) gives a mixture of mono-, di- and trichlorotoluene. In practice in the perfumery industry, the reaction is run with an excess of toluene present, which means that benzyl chloride is the major product. A little benzal chloride is produced and can be separated and hydrolysed to give benzaldehyde. The major use of benzyl chloride is in the production of benzyl alcohol and its esters. The alcohol is produced by hydrolysis of the chloride. The esters can be prepared by esterification of the alcohol, but it is better economically to prepare... 

Thus, chalcone (26), available via aldol condensation between the appropriate benzaldehyde and acetophenone, was transformed into the 1,3-diarylpropene (27) via a two-step sequence involving ethyl chloroformate and NaBH4, followed by protection of the phenolic hydroxy group as the TBDMS ether. Asymmetric dihydroxylation of olefin (2 7) with AD-mix-a gave an intermediate diol, which was converted into ortho-ester (28) with triethyl orthoformate in the presence of catalytic pyridinium -toluenesulfonate (PPTS), followed by deprotection of the TBDMS ether with TBAF in THE. Treatment of ortho-ester (28) with triethyl orthoformate and PPTS gave an intermediate (27( ,35)- w j -flavan-3-ol formate ester. De-esterification with K2CO3 in THF/methanol and oxidation of the... 

The same authors have also reported 1,3-dipolar cycloadditions using 2-hydroxy and 3-hydroxybenzaldehydes grafted on a soluble ionic liquid support [62]. New benzaldehyde-supported ionic liquids were prepared via two different routes. In the first approach the synthesis started from an N-alkylimidazole and 2-chloroethanol, thermolysis of which, followed by anion exchange to form the BF4 or PF ionic liquid, gave the desired supports. After esterification with an acid-functionalized 2-hydroxybenzaldehyde, excellent yields of the benzaldehyde-supported ionic liquids were obtained. The synthetic approach is shown in Scheme 7.13. 

Procedures for determining the C-terminal residue of proteins involve hydrazenol-ysis and reduction with hydrides (directly or after esterification), though they are not widely used. The C-tenninal residue is identified as either the anuno acid or its alcohol after hydrolysis. In the hydrazenolysis, the peptidic hydrazide can be ronoved by extracting with benzaldehyde, which forms hydrazone with hydrazide. 

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