Benzaldehyde yield

Unlike aliphatic aldehydes (with the exception of formaldehyde which 3delds hexamethylenetetramine. Section 111,67) benzaldehyde yields hydrobenzamide (and not an aldehyde ammonia) with ammonia ... 

Diamino-4-phenylthiazole condenses with benzaldehyde, yielding 2-amino-4-pheny]-5-benzalaminothiazole (241). 

On reduction, benzaldehyde yields, in addition to benz 1 alcohol, a pinacone known as Itydrobenzoin,... 

Tryptophan (15) and its substituted derivatives also react with aldehydes to give l,2,3,4-tetrahydro-jS-carboline-3-carboxylic acids (17), Acetaldehyde and benzaldehyde yield the expected products with the amino acid and its A -methyl derivative (abrine). ... 

Under the same conditions, benzaldehyde yielded 80 per cent of benzyl alcohol and piperonal 86 per cent of piperonyl alcohol. 

Figure 4.38 Increase in benzaldehyde yield with increase in reaction temperature by performing benzal chloride hydrolysis in a slit-shaped interdigital micro mixer [46].

Recently, much attention has been devoted to the use of car-banions derived from optically active a-substituted sulfoxides in asymmetric synthesis. Thus, the condensation of the lithium salt of the optically active dithioacetal mono-5-oxide 51 with benzaldehyde yields a mixture of diastereomeric adducts 307, which were converted in high chemical yield into the corresponding optically active a-methoxyaldehyde 308, having 70% optical purity (316). 

The condensation of 2-hydroxyacetophenone with benzaldehyde yielded exclusively 2 -hydroxy-chalcone, and the cyclization to flavanone was not observed. An investigation of the species adsorbed on the catalyst (289) suggested that CS condensation on the Ba(OH)2 surface occurs via a very rigid transition state, whereby the OH group of 2-hydroxyacetophenone is bonded to the catalyst surface and placed at great distance from the carbonyl carbon atom of the aldehyde, making the cyclization of 2 -hydroxy-chalcone to flavanone difficult. Deactivation of the catalyst was not observed in the presence of moderate amounts of organic acids, such as benzoic, acrylic, or trichloroacetic acid. 

Erba et al. (102) observed a novel formation of pyrrole imines 181 from the 1,3-dipolar cycloaddition of mtinchnones 179 and 5-amino-l-aryl-4,5-dihydro-4-methylene-1,2,3-triazoles 180 (Table 10.4). Treatment with benzaldehyde yielded 3-formylpyrroles (182). The reaction presumably involves loss of carbon dioxide, nitrogen, and morpholine from the initial cycloadduct. Unsymmetrical mtinchnones behave regioselectively and furnish products derived from bonding between C(2) of... 

Hydrogenation of benzaldehyde yields benzyl alcohol, condensation with aliphatic aldehydes leads to additional fragrance substances or their unsaturated intermediates. Unsaturated araliphatic acids are obtained through the Perkin reaction, for example, the reaction with acetic anhydride to give cinnamic acid. 

A few years ago, Blagonev and Ivanov described the bis-deprotonation of aryl acetic acids by Grignard reagents. These magnesinm dianions, known as Ivanov reagents, react with aldehydes and ketones. Reaction between dianions of phenylacetic acid and benzaldehyde yields the anti S-hydroxy acid as the major diastereomer anti/syn 69/22) (equation 113). This result is in agreement with the formation of a cyclic chair-like transition state according to the model of Zimmerman-Traxler . 

By using condensing agents which are not at the same time dehydrating agents, the intermediate aldol compound can be isolated (see p. 101). A mixture of acetaldehyde and benzaldehyde yields cinnamic aldehyde by the action of hydrogen chloride, sodium hydrate, or sodium ethylate. (B., 17, 2117 20, 657.)... 

Substituted aldehydes and substituted amines also react for example, the sodium salt of a-naphthylamine 4-sulphonic acid when dissolved in water and shaken with an alcoholic solution of benzaldehyde yields sodium benzylidine naphthionate. 

As a complement to the stable metallacyclobutane catalysts, a series of stable alkylidene catalysts have been prepared and shown to be active living polymerization catalysts. The complex W(CHt-Bu)(NAr)(Ot-Bu)2 [47,48] (Ar = 2,6-diisopro-pylphenyl) (35) was reacted with 50-200 equivalents of norbornene in toluene at 25 °C, followed by end-capping with benzaldehyde, yielding polymers in which the major component has a molecular weight proportional to the number of equivalents of norbornene consumed, with dispersities of approximately 1.05,... 

A stereoselective synthesis of ( )-ephedrine and ( )-methylephedrine has been described (318). The method utilizes a carbanion, in which the negative charge is located a to the nitrogen, formed by deprotonation of 1. Subsequent reaction with benzaldehyde yields the 2-oxazolidone 2, and thermal removal of the diphenylphosphinyl group gives the 2-oxazolone 3. Hydrogenation of 3 proceeds with perfect stereoselectivity to yield the erythro isomer 4, which is easily converted to ( )-ephedrine or ( )-W-methylephedrine. 

Benzaldehyde yielded no dibenzyl ditellurium. In the reation with 3-phenylprop-2-enal the double bond was hydrogenated and bis[3-phenylpropyl ditellurium was isolated in 48% yield. Ketones reacted only sluggishly under these conditions. Cyclohexanone gave dicyclohexyl ditellurium in a yield of only 11%. 

Catalyst (atomic ratio) Contact time (s) Conversion (%) Benzaldehyde selectivity (%) Benzaldehyde yield (mol%)... 

From Cinnamyl Alcohol. The dried phenylhydrazone mixture was extracted several times with hot chloroform and the chloroform-soluble portion chromatographed on a silica gel-Celite (2 to 1) column. The band which was eluted with 5% ethyl ether in petroleum ether proved to be the 2,4-dinitrophenylhydrazone of benzaldehyde yield, 83.7% melting point, 235-7° C. 

Gosh has independently reported a second and-selective aldol addition process (Eq. (8.4)) [6]. Amino indanol derived esters such as 11 are enolized with excess TiCl4 (2 equiv) and Hiinig s base to furnish a brown solution consisting exclusively of the Z-enolate as determined by H NMR spectroscopy. Addition of aldehyde (2 equiv) at -78 °C affords the corresponding aldol adducts 12/13 in 44-97% yield and up to 99 1 antitsyn diastereoselectivity. The optimal substrates in the addition reaction include aliphatic and unsaturated aldehydes. It is interesting to note that the only aromatic aldehyde examined, benzaldehyde, yielded products as a 1 1.l mixture of antv.syn diastereomers. 

Woerpel has recently reported a tandem double asymmetric aldol/C=0 reduction sequence that diastereoselectively affords propionate stereo-triads and -pentads commonly found in polyketide-derived natural products (Scheme 8-2) [14], When the lithium enolate of propiophenone is treated with excess aldehyde, the expected aldolates 30/31 are formed however, following warming to ambient temperature a mono-protected diol 34 can be isolated. In a powerful demonstration of the method, treatment of 3-pentanone with 1.3 equiv of LDA and excess benzaldehyde yielded product in corporating five new stereocenters in 81% as an 86 5 5 3 mixture of diastereomers (Eq. (8.8)). A series of elegant experiments have shown that under the condition that the reaction is conducted, the aldol addition reaction is rapidly reversible with an irreversible intramolecular Tischenko reduction serving as the stereochemically determining step (32 34, Scheme 8-2). 

If the reaction of thiosemicarbazide with chloroacetone is carried out in a warm dilute solution of hydrochloric acid, the thiosemicarbazone of chloroacetone (242) is formed in 85% yield. Heating 242 in ethanol cyclizes it to thiadiazine 243, whereas heating in anhydrous ethanolic benzaldehyde yields the benzylidene derivative of 4-methyl-2-hydrazinothiazole (244). At the same time, refluxing 242 in concentrated hydrochloric acid gives rise to 4-methyl-3-aminothiazoline-2-imine (245) in 95% yield. The latter compound can be also obtained by the action of concentrated HCl on thiadiazine 243. On using various a-halogenoketones and thiosemicarba-... 

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