Cinnamaldehyde—continued

In continuation of a previous work (1), catalytic hydrogenation of cinnamaldehyde has been studied in slurry phase using a high-pressure autoclave. A series of carbon powder (CP)-supported Pt catalysts with widely varying Pt dispersion and Pt location on the support has been used in the study. The purpose has been to find out how the location of the metal on the support and its dispersion affect the two parallel reaction paths, namely the hydrogenation of the C=0 and C=C bonds. 

Fortier and Fritz [13] separated water by lEC and devised a unique equilibrium system for in-line spectrophotometric detection. This method has been refined and its capabilities expanded by continuing research by Chen and Fritz [14-17]. Water is separated chro-matographically from the other sample components on a short column packed with cation-exchange resin in the form using dry methanol as the eluent. Detection of the water peak is made possible by addition of a low concentration of cinnamaldehyde to the methanol eluent. In the presence of an acid catalyst, such as a -cation exchanger, cinnamaldehyde reacts with methanol to form the dimethylacetal. 

All the catalytic hydrogenations (2-pentyl-2-nonenal or cinnamaldehyde) were carried out in a 200-ml static reactor under atmospheric pressure with a continuous flow of hydrogen and at temperatures ranging from 50°C to 120°C (23). Activity and selectivity values were obtained by gas phase chromatography analysis of the liquid mbdure on a Cp SIL5 capillary column. 

No safety concerns about the use of cinnamaldehyde as an herbal remedy, food additive, or pesticide has been expressed. The U.S. Food and Drug Administration (FDA) has classified the compound as a generally-recognized as safe (GRAS) food additive, permitting its continued use as a food additive in the United States. 

As presented in some detail by Gingrich and Baum (see their Table 4.31 and Scheme 4.51) azlactones react with ot,p-unsaturated imines to give ot-pyridones. Sandhu and co-workers continued the studies in this area, and they now view this reaction as involving initial electrophilic attack on the azlactone (munchnone) followed by cyclization to an ot-pyridone, rather than prior ring-opening to the corresponding ketene tautomer, as was originally proposed (Table 4.1). With azlactone 52 and A-aryl cinnamaldehyde anils 53, in the presence of acetic anhydride, the 4-substituted azlactones 54 are isolated (Fig. 4.15). Dalla Croce... 

Improved procedure. The hazardous prepn. of the Cr03-2C5H5N complex can be avoided by generating it in situ. - E 6 moles CrOg added, with ice-cooling if necessary, to a soln. of 12 moles pyridine in methylene chloride with stirring, which is continued 15 min. at room temp, under anhydrous conditions, then a soln. of cinnamyl alcohol in a small volume of methylene chloride added in one portion, and stirring continued 15 min. at room temp. cinnamaldehyde. Y 96%. F. e. s. R. Ratcliffe and R. Rodehorst, J. Org. Chem. 55, 4000 (1970) in acetic acid cf. K.-E. Stensio, Acta Chem. Scand. 25, 1125 (1971). 

There has been a continuing interest in syntheses of 3-amino-2,3,6-trideoxy-hexoses such as daunosamine (9), acosamine (10), etc. In an interesting paper by Fronza et the two sugars have been synthesized from the non-carbohydrate compound (11), which was obtained in 25-30% yield from the incubation of cinnamaldehyde v th acetaldehyde in the presence of bakers yeast (Scheme 2). The crucial amino-lactone (12) was also synthesized from L-threonine. The same authors have also completed their synthesis of A-benzoyl-L-ristosamine (3-benzamido-2,3,6-trideoxy-L /6o-hexose) from 3-benzamido-2,3,6-trideoxy-L-xy/o-hexono-1,5-lactone (Vol. 13, p. 79). An alternative synthesis of methyl A-acetyl-a-L-acosaminide (13) has been described by reduction of the appropriate acetylated oxime by diborane. The thioglycoside (14) was also prepared. ... 

Pb-tetraacetate added portionwise with ice-cooling during 0.5 hr. to a soln. of frans-cinnamaldehyde in dry benzene through which a stream of NHg-gas is passed, and stirring continued 3 hrs. fran -cinnamonitrile. Y 89%.—This simple and convenient method can be used for the prepn. of a great variety of nitriles. F. e. s. K. N. Parameswaran and O. M. Friedman, Ghem. Ind. 1965, 988. 

In this section, you will prepare N-cinnamyl-m-nitroaniline (9) by a sequence beginning with the condensation of cinnamaldehyde (5) with nx-nitroaniline (6), followed by reduction of the intermediate imine 7 with sodium borohydride, as shown in Equations 17.12-17.14. The formation of the imine is reversible, but the reaction is driven to completion by azeotropic distillation. Because cyclohexane and water form a minimum-boiling azeotrope (Sec. 4.4), the water generated by the condensation of 5 and 6 is continuously removed by distilling the cyclohexane-water azeotrope throughout the course of the reaction. 

Isolation of Cinnamaldehyde. Remove the milky dnnamaldehyde-water (two-phase) distillate that collects in the collar of the stiU using a 9-in. Pasteur pipet (or 6-in. in the case of sidearm stills). Transfer this material to a 12- or 15-mL centrifuge tube. Continue the distillation for approximately 1 h or until about 5-6 mL of distillate is collected in the centrifuge tube. 

---