Hydrocinnamaldehyde

Support for initial N alkylation is provided by the reaction of N-isobutenyl-N-methylbenzylamine (26) with methyl iodide, which gave a,a-dimethyb hydrocinnamaldehyde (27) on hydrolysis (ii). 

Note CP-l/HDC and CP-l/HEC denote highly dispersed and highly edge-coated Pt respectively on CP-1. CAOL, HCAL and 3-PPOL denote cinnamyl alcohol, hydrocinnamaldehyde and 3-phenyl propanol respectively. 

Derivatization of the optically active aldehydes to imines has been used for determination of their enantiomeric excess. Chi et al.3 have examined a series of chiral primary amines as a derivatizing agent in determination of the enantiomeric purity of the a-substituted 8-keto-aldehydes obtained from catalysed Michael additions. The imine proton signals were well resolved even if the reaction was not completed. The best results were obtained when chiral amines with —OMe or —COOMe groups were used [2], The differences in chemical shifts of diastereo-meric imine proton were ca. 0.02-0.08 ppm depending on amine. This method has been also used for identification of isomers of self-aldol condensation of hydrocinnamaldehyde. 

A more general reaction between kojic acid and aldehydes is a trimolecu-lar condensation discovered by Barham and Reed." By a process of elimination, they arrived at the conclusion that C6 of kojic acid was most probably the point of attack two molecules of kojic acid reacted with one molecule of the aldehyde, with the elimination of one molecule of water, giving a product of structure LXXV. Such compounds were prepared from kojic acid and the following aldehydes the normal alkanals from formaldehyde to heptanal, benzaldehyde, cinnamaldehyde, hydrocinnamaldehyde, 2-furaldehyde, and acrolein. The compound derived from kojic acid and benzaldehyde (LXXV, R = phenyl) was also obtained by treating LXXII (R = phenyl) with hot, aqueous sodium carbonate.92... 

Tessonnier, J.-P., et al., Pd nanoparticles introduced inside multi-walled carbon nanotubes for selective hydrogenation of cinnamatdehyde into hydrocinnamaldehyde. Applied Catalysis A General, 2005. 288(1-2) p. 203-210. 

A typical probe reaction for estimating catalytic properties in selective hydrogenations is the hydrogenation of cinnamaldehyde. This molecule contains both a C=C and a C=0 double bond, thus the formation of hydrocinnamaldehyde and/or cinnamyl alcohol by reduction of the one or the other, or the formation of phenyl propanol in the case of complete reduction may indicate the potential of the catalyst for other fine chemical transformations. Indeed, this reaction was one of the first to be tested by CNT-supported catalysts [120]. Noble metals show a high activity in this reaction and... 

Another process mechanistically related to imine exchange is the dynamic production of pyrazolotriazinones reported in 2005 by Wipf and coworkers [29]. After first verifying that reaction of either 16 or 17 with equimolar quantifies of isobutyraldehyde and hydrocinnamaldehyde at 40°C in water (pH 4.0) resulted in the same 3 7 mixture of 16 and 17 at equilibrium (Fig. 1.6, Eq. 1), the authors demonstrated that a library could be generated by reaction of pyrazolotriazinone 16 with a series of aldehydes (Fig. 1.6, Eq. 2). Direct metathesis of pyrazolotriazinones was also demonstrated, as was reaction with ketones. Importantly, equilibration was halted by raising the pH to 7. 

Reduction of the double bond only was achieved by catalytic hydrogenation over palladium prepared by reduction with sodium borohydride. This catalyst does not catalyze hydrogenation of the aldehyde group [31]. Also sodium borohydride-reduced nickel was used for conversion of cinnamaldehyde to hydrocinnamaldehyde [31]. Homogeneous hydrogenation over tris(triphenylphosphine)rhodium chloride gave 60% of hydrocinnamaldehyde and 40% of ethylbenzene [5(5]. Raney nickel, by contrast, catalyzes total reduction to hydrocinnamyl alcohol [4S. Total reduction of both the double... 

Shibasaki has examined catalysis of a complex, prepared in situ from PdCl2, AgOTf, (R)-or (S)-BINAP, 4 A molecular sieves, and H20, in the aldol addition reaction of enolsilanes by (Eq. 8B2.5) [13]. Under these conditions, aryl methyl ketone-derived trimethylsilyl enolates add to benzaldehyde and hydrocinnamaldehyde, affording adducts with up to 73% ee. 

Yamamoto has recently described a novel catalytic, asymmetric aldol addition reaction of enol stannanes 19 and 21 with aldehydes (Eqs. 8B2.6 and 8B2.7) [14]. The stannyl ketones are prepared solvent-free by treatment of the corresponding enol acetates with tributyltin methoxide. Although, in general, these enolates are known to exist as mixtures of C- and 0-bound tautomers, it is reported that the mixture may be utilized in the catalytic process. The complexes Yamamoto utilized in this unprecedented process are noteworthy in their novelty as catalysts for catalytic C-C bond-forming reactions. The active complex is generated upon treatment of Ag(OTf) with (R)-BINAP in THF. Under optimal conditions, 10 mol % catalyst 20 effects the addition of enol stannanes with benzaldehyde, hydrocinnamaldehyde, or cinnamaldehyde to give the adducts of acetone, rerf-butyl methyl ketone (pinacolone), and acetophenone in good yields and 41-95% ee (Table 8B2.3). 

Recently, Castle and coworkers introduced C3-alkyny]-substituted chiral quaternary ammonium salt of type 41, and evaluated its ability as a chiral phase-transfer catalyst in the aldol reaction between 1 and hydrocinnamaldehyde using BTTP as a base, in which a high level of enantioselectivity (91% ee) was observed for syn-22 (Scheme 2.19) [41],... 

As shown in Scheme 7, treatment of hydrocinnamaldehyde with a catalytic amount of Pd/C in 0.1 m NaOH at 250 °C for 4—5 h gave the coupling product 1,5-diphenylpentane in 90% yield [18]. The reaction pathway is supposed to be as follows. Aldol, which was formed by the aldol reaction under basic condition, was converted into enal. The enal was transformed into the product via reduction [19] and decarbonylation [18]. As shown in Scheme8, this reaction can be used for preparation of the fully deuterated compound. 

Figure 33. Three-component coupling reaction using hydrocinnamaldehyde (2) as an electrophile.

Hydrocinnamaldehyde strong, pungent, floral, 97°-98° (12 mm Hg) remains clear... 

Methyl-3-phenylpropanal Hydrocinnamaldehyde, a-methyl- (8) Ben-zenepropanal, a-methyl- (9) (5445-77-2)... 

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