Synthetic perfumes

The first step in this sequence of reactions is the oxidation of piperonyl alcohol to obtain piperonal, an aromatic aldehyde. The reaction is selective and only the aldehyde is obtained no oxidation to the carboxylic acid is observed  

Treatment of the oxime intermediate with alcoholic KOH causes an elimination reaction that yields the target nitrile product, piperonylonitrile  

The present synthetic sequence offers an alternative approach to the preparation of aromatic nitriles. The classic route to this class of compounds is to use the Sandmeyer reaction. The key steps in this latter pathway involve the diazotization of an aromatic amine followed by reaction of the diazonium salt, which is not isolated (it is explosive ), with CuCN to give the aromatic nitrile directly. Aromatic halides (Br or Cl) may also be prepared in this manner using the corresponding copper(l) halides, as shown here  

Common names piperonal, 3,4-(methylenedioxy)benzaldehyde CA number [120-57-0] 

Purpose. The selective oxidation of a primary (1°) alcohol to an aldehyde is investigated. The use of polymer-bound chromium trioxide as an oxidizing agent is explored. You will prepare the intermediate aldehyde, piperonal, as the first step in the sequence to synthesize piperonylonitrile. 

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Bodies of an alcholic nature play a very important part in both natural and synthetic perfumery. They are found to a very large extent in essential oils, both in the free state and also in the form of esters. Some that have not so far been recognised as constituents of essential oils, have been found to be so highly odorous, and so useful as perfume materials, that they are prepared artificially, and enter largely into the composition of the synthetic perfumes which to-day are indispensable to the manufacturer of perfumes. It is obvious that those alcohols which are soluble in water, such as methyl and ethyl alcohols, although they may be original constituents of some essential oils, are removed by the ordinary distillation processes, so that they do not, in fact, appear in the essential oil as found in commerce. 

It is prepared artificially, for use as a synthetic perfume, by several methods, for example, by heating benzyl chloride with oxide of lead to 100", or by heating benzyl chloride with potassium acetate and saponifying the benzyl acetate so formed, with caustic potash. 

Phenylacetic aldehyde, CgHgO, is one of the most important of modern synthetic perfumes. It has not been found naturally in essential oUs. It possesses a powerful odour of hyacinths, and is extremely useful for the reproduction of all odours of this and the narcissus type. 

Vanillin, CgHgOj, is one of the most important synthetic perfumes. It is the active odorous ingredient of the vanilla pod, in which it occurs to the extent of about 2 per cent., appearing on the surface of the bean as a fine white crystalline efflorescence. It occurs naturally also in Sumatra benzoin (about 1 per cent.), Siam benzoin (15 per cent.), and the balsams of Tolu and Peru (traces). Numerous other bodies have been recorded as containing it, such as asafoetida, beetroot and asparagus, the seeds of Lupinus albus, the seeds of Sosa canina, etc. 

The ketone, ionone, is one of the most important of all the synthetic perfumes, and one most valued by perfumers as being indispensable for the preparation of violet odours. 

CONSTITUENTS OF ESSENTIAL OILS, SYNTHETIC PERFUMES AND ISOLATED AROMATICS... 

Benzaldehyde has limited uses as a chemical intermediate. It is used as a solvent for oils, resins, cellulose esters, and ethers. It is also used in flavoring compounds and in synthetic perfumes. 

As the chemical industry expanded, Perkin continued his own scientific research in the peace of his private laboratory. He had not lost his touch. Among the synthetic methods he discovered is one now called the Perkin reaction. He used it to make a synthetic substitute for a vegetable substance called coumarin, which has a pleasant, vanillalike odor. Coumarin spawned the synthetic perfume business and made luxurious scents available to all. Once again, a Perkin chemical started a new industry, albeit a modest one in comparison with dyes and pharmaceuticals. Despite the worldwide impact of Perkins discoveries, he was not knighted by the British monarchy until 1906, the fiftieth anniversary of his discovery of mauve. The world chemistry community feted him lavishly that year, and he traveled to the United States collecting further honors. A year later, at the age of 69, he died peacefully, at home. 

PERKIN, SIR WILLIAM HENRY (1838-1907). An English chemist who was the first to make a synthetic dyestuff (1856). He studied under Hofman at the Royal College of London. Perkin s first dye was called mauveine, but he proceeded to synthesize alizarin and coumarin, the first synthetic perfume. In 1907 he was awarded the first Perkin Medal, which has ever since been awarded by the American Division of the Society of Chemical Industry for distinguished work in chemistry. Not withstanding the fact that Perkin patented and manufactured mauve dye in England, the center of the synthetic dye industry shifted to Germany, where it remained until 1914. 

Motoyoshi, K., Toyoshima, Y., Sata, M., and Yoshimura, M., Comparative studies on the irritancy of oils and synthetic perfumes to the skin of rabbit, guinea pig, rat, miniature swine and man, Cosmet. Toiletries, 94, 41, 1979. 

In many cases marketers would also like to claim "free from synthetic perfume," but this desire is usually frustrated by the fact that for most popular odor types it simply is not possible to compose allnatural fragrances of good consumer acceptability at a reasonable price. What is possible is to create good perfumes of a wide range of odor types that contain a high level of natural components, say, more... 

A) The result of gas chromatography of a genuine frankincense. (B) This is the GC chart of a completely fake mix. It contains the common adulterant DEP (diethyl phthalate), which is represented by the very large peak at 47 minutes, and DEP amounts to up to 90°/o of this sample. The rest of the sample is a synthetic perfume and shows a completely different fingerprint of peaks from the genuine oil. Oils adulterated with DEP are often totally synthetic and contain no genuine essential oil. The technique of GC analysis is explained in Chapter 5. The analysis was carried out by Jenny Warden of Traceability. 

Lewinsohn, A. Modern Technical Methods for the Manufacture of Synthetic Perfumes The Perfumery and Essential Oil Record. (1923) 14 398-399... 

Use Mordant for dyeing, pigments, manufacturing of alizarin, chrome alum, oil purification, pickling, manufacture of catalysts, leather tanning, synthetic perfumes, photography, process engraving and li-... 

Use Chemical intermediate for dyes, flavoring materials, perfumes, and aromatic alcohols solvent for oils, resins, some cellulose ethers, cellulose acetate and nitrate flavoring compounds synthetic perfumes manufacturing of cinnamic acid, benzoic acid pharmaceuticals photographic chemicals. 

Use Dyes, phenolphthalein, phthalimide, anthranilic acid, synthetic perfumes, laboratory reagent. 

Vanillin and veratraldehyde are two fine examples of flavor and fragrance chemicals which have been successfully synthesized from p-cresol. A number of low volume synthetic perfume materials based on p-cresol esters and ethers have also been introduced. Following are some of the important products. 

This is a synthetic perfume having a definite penetrating odor of narcissus and is used in many perfumes of the lily, lilac, and honey suckle type. 

Some of the esters and ethers of 79-cresol and its derivatives have become very popular in the manufacture of synthetic perfumes. Prominent among them are 79-cresyl methyl ether, p-cresyl acetate, p-cresyl phenyl acetate, etc. Some of them are very popular in the manufacture of Indian agarbattis (incense sticks). Thymol and menthol which were traditionally obtained from the natural sources are now synthetically made from m-cresol and are much cheaper as flavor and fragrance chemical than the natural ones. BAYER AG of Germany is the largest manufacturer of synthetic thymol and menthol. 

R. W. James, Fragrance Technology, Natural and Synthetic Perfumes, Noyes Data Corporation, 1975. 

Givaudan-Roure, The Givaudan-Roure Index, Givaudan-Roure, 2004. R.W. James, Fragrance Technology, Natural and Synthetic Perfumes, Noyes Data Corporation, Park Ridge, NJ, 1975. 

Cross-metathesis reactions are useful for the production of fine chemicals such as synthetic perfumes, prostaglandin intermediates, and insect pheromones. An example of the last is the cross-metathesis of ethyl oleate with 5-decene in the presence of a MoCl5/Si02/Me4Sn catalyst at 90 °C [14], or a Mo03/Si02/cyclopropane catalyst at 50 °C [16], resulting in a cisitrans mixture of ethyl 9-tetradecenoate, an insect pheromone precursor (Eq. 12). 

The authors observed that an exhaustive list of all the chemicals present in coffee flavor had not yet been compiled, but they believed they had identified the components that are present at the higher ratio of weight, and those which principally control the odor note. Most of the substances identified were well-known compounds present in other roasted products as well, for instance in caramel sugar, cocoa, baked bread and—partially—even in wood tar. However, some of the chemicals detected were new and, obviously, characteristic of roasted coffee. Traces of methyl mercaptan, which was already known at that time and which smells even worse, were also detected in coffee aroma. Commenting on this observation, Reichstein and Staudinger note that it is generally known that many popular raw materials and synthetic perfume compounds owe their characteristic note, which is extremely pleasant to the olfactory sense, to their content of small quantities in additives which carry a rather unpleasant odor in themselves but prove very attractive in thinned solutions and in admixture with other oils. The authors tried to reconstitute coffee aroma, and only by combining over 40 of the substances extracted from coffee... 

The most important characteristic of effective poison gases (using the term with reservation) is that they must penetrate and distribute themselves quickly toward their objective. In this respect, they resemble perfumes. The reservoir of knowledge on which any nation mnst draw in the event of war is its industries of synthetic perfume. Few poison gases are actually lethal poisons. [Ibid., p. 237]... 

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