Benzyl Acetals

Simple benzylidene acetals of carbohydrates are photochemically cleaved in a way similar to the well-used AT-bromosuccinimide process regioselective ring opening process into bromodeoxysugars. 

This light-initiated NBS reaction is similar to the photolysis of o-nitrobenzylidene acetals but is a one-step process instead of the following two-step procedure. 

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Mix 31 g. (29-5 ml.) of benzyl alcohol (Section IV, 123 and Section IV,200) and 45 g. (43 ml.) of glacial acetic acid in a 500 ml. round-bottomed flask introduce 1 ml. of concentrated sulphuric acid and a few fragments of porous pot. Attach a reflux condenser to the flask and boil the mixture gently for 9 hours. Pour the reaction mixture into about 200 ml. of water contained in a separatory funnel, add 10 ml. of carbon tetrachloride (to eliminate emulsion formation owing to the slight difference in density of the ester and water, compare Methyl Benzoate, Section IV,176) and shake. Separate the lower layer (solution of benzyl acetate in carbon tetrachloride) and discard the upper aqueous layer. Return the lower layer to the funnel, and wash it successively with water, concentrated sodium bicarbonate solution (until effervescence ceases) and water. Dry over 5 g. of anhydrous magnesium sulphate, and distil under normal pressure (Fig. II, 13, 2) with the aid of an air bath (Fig. II, 5, 3). Collect the benzyl acetate a (colourless liquid) at 213-215°. The yield is 16 g. 

Cm OROCARBONS ANDCm OROHYDROCARBONS - BENZYL Cm ORIDE, BENZAL Cm ORIDE AND BENZOTRICm ORIDE] (Vol 6) Benzyl acetate [140-11-4]... 

Of the 11 compounds which constitute approximately 86% of jasmin volatiles, only benzyl acetate, i7t-jasmone (18), and methyl jasmonate possess the characteristic odor of jasmin. Trace components including i7t-j asrnin lactone [34686-71-0] (20) (0.9%) andmethyl ( /-jasmonate (6) (0.1%) are the key contributors to the jasmin odor. 

Jasmine. Jasmine is one of the most precious florals used ia perfumery. The concrete of jasmine is produced by hydrocarbon extraction of flowers from Jasminum officinale (var. GrandijJorum). The concrete is then converted to absolute by alcohoHc extraction. It is produced ia many countries, the most important of which is India, followed by Egypt. Jasmine products are rather expensive and are produced ia relatively small amounts compared with other materials. However, jasmine is particularly important ia perfume creation for its great power and aesthetic quaUties. Eour of the principal odor contributors to jasmine are OT-jasmone [488-10-8] (14), methyl jasmonate [91905-974-] (15), benzyl acetate [140-11 ], and iudole [120-72-9] (16). 

In detergent perfumes, the stabiUty of vanillin is not always certain. It depends on the association made with other raw materials, eg, with patchouli, frankincense, cloves, most of the animal notes, and such chemicals as amyl saUcylate, methyl ionones, heflotropin, gamma undecalactone, linalool, methyl anthrarulate, benzyl acetate, phenyl ethyl alcohol, cedar wood derivatives, oak mosses, coumarin, benzoin. Pern balsam, and cistus derivatives. In some cases, these mixtures can cause discoloration effects. 

Nearly all uses and appHcations of benzyl chloride are related to reactions of the active haUde substituent. More than two-thirds of benzyl chloride produced is used in the manufacture of benzyl butyl-phthalate, a plasticizer used extensively in vinyl flooring and other flexible poly(vinyl chloride) uses such as food packaging. Other significant uses are the manufacture of benzyl alcohol [100-51-6] and of benzyl chloride-derived quaternary ammonium compounds, each of which consumes more than 10% of the benzyl chloride produced. Smaller volume uses include the manufacture of benzyl cyanide [140-29-4], benzyl esters such as benzyl acetate [140-11-4], butyrate, cinnamate, and saUcylate, benzylamine [100-46-9], and benzyl dimethyl amine [103-83-8], and -benzylphenol [101-53-1]. In the dye industry benzyl chloride is used as an intermediate in the manufacture of triphenylmethane dyes (qv). First generation derivatives of benzyl chloride are processed further to pharmaceutical, perfume, and flavor products. 

Ethyl malonate or n-butylamine Benzyl acetate or diethylcarbitol -160° Isopentane... 

Isoamyl acetate (banana Vinyl acetate Methyl vinyl acetate Benzyl acetate Cyclohexyl acetate... 

The authors repeated the experiment with two, more strongly retained, solutes m-dimethoxy benzene and benzyl acetate. These solutes were found to elute at (k ) values of 10.5 and 27.0 respectively on a silica column operated with the same mobile phase. The results obtained are shown as similar curves in Figure 13. The m dimethoxy benzene, which eluted at a (k ) of 10.5, also failed to displace any ethyl acetate from the silica gel even when more than 0.5 g of solute resided on the silica surface. Consequently, the m-dimethoxy benzene must have also interacted with the surface by a sorption process. 

Taking a value of 2.5 x 10" for Dm i -g the diffusivity of benzyl acetate in n-heptane), equation (8) can be employed to calculate the curve relating (H) and (u) for an uncoated capillary tube. The results are shown in Figure 3. 

C. In their first series of experiments, six data sets were obtained for (H) and (u), employing six solvent mixtures, each exhibiting different diffusivities for the two solutes. This served two purposes as not only were there six different data sets with which the dispersion equations could be tested, but the coefficients in those equations supported by the data sets could be subsequently correlated with solute diffusivity. The solvents employed were approximately 5%v/v ethyl acetate in n-pentane, n-hexane, n-heptane, -octane, -nonane and n-decane. The solutes used were benzyl acetate and hexamethylbenzene. The diffusivity of each solute in each solvent mixture was determined in the manner of Katz et al. [3] and the values obtained are included... 

Solvent Et. Acetate in n-Alkane Benzyl Acetate Dm Hexamethyl- benzene Dm lO cm s l... 

The results obtained were probably as accurate and precise as any available and, consequently, were unique at the time of publication and probably unique even today. Data were reported for different columns, different mobile phases, packings of different particle size and for different solutes. Consequently, such data can be used in many ways to evaluate existing equations and also any developed in the future. For this reason, the full data are reproduced in Tables 1 and 2 in Appendix 1. It should be noted that in the curve fitting procedure, the true linear velocity calculated using the retention time of the totally excluded solute was employed. An example of an HETP curve obtained for benzyl acetate using 4.86%v/v ethyl acetate in hexane as the mobile phase and fitted to the Van Deemter equation is shown in Figure 1. 

Figure 1. The (H) versus (u) Curve for Benzyl Acetate Using 4.86 %v/v Ethyl Acetate in n-Hexane as the Mobile Phase...

Figure 2. Graph of Multi-path Variance against Solute Diffusivity for Benzyl Acetate...

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