Benzaldehyde, o-Hydroxy

The stereoselective synthesis of c/.v-fused pyrano and furanobenzopyran can be achieved through the one-pot three-component reaction of o-hydroxy benzaldehyde, aromatic amines, and cyclic enolethers in the presence of catalytic amounts of Bi(OTf)3 (10 mol%) in air and the moisture-stable ionic liquid [bmim]PF6 [116]. The reaction of salicilaldehyde, aniline and 2,3-dihydrofuran furnishes the c/.v-fused furanochroman. In a similar fashion, various substituted salicilaldehydes and... 

The plausible mechanism of the reaction is shown in Fig. 25. The reaction probably proceeds through the activation of imine (formed in situ from the o-hydroxy benzaldehyde and the aromatic amine) by the catalyst followed by the addition and subsequent cyclization of the enol ether, resulting in the formation of the fused acetal. Ionic liquids are stable enough with amines and water and also effectively activate the imines to undergo cyclization. The recovered ionic liquid can be re-used with gradual decrease in the efficiency of the method. The hydro-phobic nature of the ionic liquid also helps in recovery of the catalyst. 

Slightly greater effects are observed for the B-bands of m-hydroxy-benzaldehyde and ra-nitrophenol (D, H-bond +68 and +96 A), although the nitro and formyl groups may not be terminal. Greater displacements should have been expected for the B-bands of o-hydroxy benzaldehyde and o-nitrophenol, but, owing to the formation of intramolecular hydrogen bonds by these derivatives (cf. below), an experimental confirmation is, unfortunately, not possible. 

Another important industrial process for manufacture of o-anisic aldehyde is based on methylation of o-hydroxy benzaldehyde or salicylaldehyde based on phenol. 

It was heartening to see that for many end products, individual cresols proved to be very effective alternative feedstocks to more conventional and traditional ones such as phenol. For instance, p-hydroxy benzaldehyde was hitherto obtained as a by-product during production of salicyl aldehyde from phenol based on Reimer-Tiemann reaction. In fact, phenol-based p-hydroxy benzaldehyde is only 15% of the mixed aldehydes, and 85% of the product is o-hydroxy benzaldehyde or salicylaldehyde. Direct oxidation of 79-cresol to 187... 

The 2-alkylbenzoselenazolium salt 48 reacted with substituted o-hydroxy-benzaldehydes (49) to give the spiro compound 50. [Eq. (16)]. 

To a glass test tube containing 376 mg finely powdered urea-hydrogen peroxide (UHP) adduct (4 mmol) was added 2 mmol o-hydroxy-benzaldehyde, and the reaction mixture was placed in an oil bath at 55°C for 1.5 h. After completion of the reaction, as monitored by TLC (8 2 v/v, hexane/EtOAc), the reaction mixture was extracted into EtOAc, and the combined extracts were washed with water and dried over anhydrous sodium sulfate. The solvent was removed under reduced pressure to afford the crude product, which was purified by chromatography to give 85% catechol. 

Similar Henry-type condensations were utilised in syntheses of heterocyclic derivatives from o-hydroxy-benzaldehydes. Condensations with bromonitromethane afforded 2-nitrobenzoC ]furans after dehydration of intermediate nitroaldols in refluxing acetic anhydride,whilst Michael additions to nitroalkenes prior to... 

Nanoparticulate ZnO was used as an efficient catalyst for the synthesis of cou-marins (84) by the reaction of o-hydroxy benzaldehydes (82) and 1,3-dicarbonyl compounds (83) via Knoevenagel condensation under microwaves and thermal conditions (Scheme 9.24) in moderate to excellent yields (Kumar et al. 2011). This protocol differs from the previous methods for the synthesis of coumarins (84) in terms of simplicity and effectiveness. The application of ZnO/MgO in ionic liquid [bmim] [BF4] was carried out successfully for the synthesis of 4//-pyrans (85) and coumarins (88) at ambient temperature via Knoevenagel condensation reaction of aldehydes (8) or 2-hydroxybenzaldehyde derivatives (86) with active methylene compounds (16, 43, 87) (Schemes 9.25 and 9.26) (Valizadeha and Azimib 2011). The method has several advantages in terms of mild reaction conditions, reusability of the catalyst, high yields of the products, and short reaction times. In comparison with methods mentioned in the literature for the synthesis of 4F(-pyrans (85) and coumarins (88), this protocol has better yield and eco-friendly advantages. 

This reaction is based on the formation of a color in a mixture of an aqueous sodium nitroprusside solution with carbonyl compounds in an alkaline medium. A positive test is obtained with aliphatic and certain aromatic aldehydes and aromatic and aliphatic ketones. The literature data on this reaction are conflicting and no general rule can be expressed about which carbonyl compounds give the reaction and which do not. For example, the color is not produced with formaldehyde, glyoxal, benzaldehyde, o-hydroxy-benzaldehyde, chloral, vanillin, benzophenone, naphthyl phenyl ketone, trihydroxybenzophenone, benzil, acetophenones substituted on the aromatic nucleus with hydroxyl, etc. The reaction can therefore be used for the differentiation of certain types of aldehydes and ketones, as, for example, acetaldehyde from formaldehyde, and acetophenone from benzophenone or hydroxyacetophenone, etc. Further, various colors formed in alkaline media or after the subsequent acidification of the reaction mixture can also be used for differentiation. Sodium hydroxide can be replaced by ammonia, piperidine... 

Chloro-l,3-dithian, obtained by the reaction of 1,3-dithian and A-chloro-succinimide, undergoes dissociation to chloride and dithianium ions in liquid SO2, as judged by the peak at 8 = 10.65 in the n.m.r. spectrum due to the 2-methine hydrogen. Reaction with phenol and iVA-dimethylaniline produced 2-(p-hydroxyphenyl)- and 2-(p-dimethylaminophenyl)-l,3-dithian, in 75 and 30% yield, respectively. The dithian derivatives of the o-hydroxy-benzaldehydes... 

Benzaldehyde, 4-methoxy-, lithiation of amine adducts, 56, 261 Benzamidoxime, o-hydroxy-, reaction with acetaldehyde, 56, 71... 

Oxidation of the carbinol (4) with periodate does not give the expected iro-epoxy compound but the benzaldehyde acetal of 3,5-di-t-butylcatechol (5). This oxidative rearrangement is apparently limited to o-hydroxy-substituted diaiyl- and triaryl-carbinols. ... 

Dimethoxy-benzaldehyd 2,4-Dimethyl-5-hydroxy-benzaldehyd 60-65% 77% Hexanal 40-50°/o... 

Beilstein Handbook Reference) AI3-02174 Benzaldehyde, 2-hydroxy- Benzaldehyde, o-hydroxy- BRN 0471388 CCRIS 7451 EINECS 201-961-0 FEMA No. 3004 HSDB 721 NSC 49178 o-Formylphenol o-Hydroxybenzaldehyde SAH Salicylal Salicylaldehyde Salicylic aldehyde. Used in analytical chemistry, perfumery, synthesis of coumarin, as an auxiliary fumigant and in flavoring. Oil mp = -7° bp = 197° d ° = 1.1674 km = 259, 328 nm (cyclohexane) very soluble in EtOH, Et20, MezCO, CeHe, less soluble in CHQ3, H2O MLD (rat sc) 900 -1000 mg/kg. Janssen Chimica Penta Mfg. Seimi Chem. 

In which of the following compounds would you expect intramolecular hydrogen bonding to occur o-nitroaniline, o-cresol, o-hydroxybenzoic acid (salicylic acid), o-hydro-benzaldehyde (salicylaldehyde), o-fluorophenol, o-hydroxy-benzonitrile-... 

Formylplienol (4-Hydroxy benzaldehyde) 4-(Metbylsulfonyl)phenal o-Vanillin(2-Formyl-6-methoxyphenol,... 

Hydrazinocarbonylmethyl-4-phenyl-l(2//)-phthalazinone (78) wifli p-bromo-benzaldehyde gave 2-[(p-bromobenzyIidenehydrazinocarbonyl)methyl]-4-phenyl-l(277)-phthalazinone (79) (reactants, trace AcOH, EtOH, reflux, 2h 70%) or with o-hydroxyacetophenone gave 2-[(o-hydroxy-a-methylbenzyli-denehydrazinocarbonyl)methyl] -4-phenyl-1 (277)-phthalazinone (80) (likewise 80%) other aldehydes or ketones produced analogous products. 

The BFs-promoted reaction of benzaldehyde with silylketene dithioacetal results in the deoxygenative formation of an allylic cation. This S-stabilised intermediate can be captured by an o-hydroxy substituent leading to the chroman 17 (Scheme 17) <01JOC3924>. 

Within the last two decades, a number of chemical structures have been proposed as metal deactivators for polyolefins. These include carboxylic acid amides of aromatic mono- and di-carboxylic acids and N-substituted derivatives such as N,N -diphenyloxamide, cyclic amides such as barbituric acid, hydrazones and bishydrazones of aromatic aldehydes such as benzaldehyde and salicylaldehyde or of o-hydroxy-arylketones, hydrazides of aliphatic and aromatic mono- and di-carboxylic acids as well as N-acylated derivatives thereof, bisacylated hydrazine derivatives, polyhydrazides, and phosphorus acid ester of a thiobisphenol. An index of trade names and suppliers of a few commercial metal deactivators is given in Appendix A4. 

Di their work the authors describe a method for introducing alkyl radicals into the position X. Using allq l-substituted o- and p-hydroxy-benzaldehyde in this synthesis, rather pure final products can apparently be produced. 

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