Rose ketones

Essential oils are organic compounds derived from flowers, seeds, leaves, roots, resins, and citrus fruits. The structures of many fragrant compounds have been studied, and processes for making these valuable compounds in a laboratory have been developed. There are now approximately 5000 synthetically produced chemicals that are available to a perfumer. These chemicals include vanillin, rose oxides, and the damascenes, or rose ketones. 

The rose ketones provide the sweet smell of a rose. 

The rose ketones 11, first discovered ini970 [gl] in Bulgarian rose oil, and named damas-cones, show unique organoleptic properties. Because of this they have elicited great interest, also as target molecules for new synthetic methods. a-Damascone 12 possesses a quite unique fruity odor, and its utilization aliows the creation of perfumistic notes otherwise difficult to achieve. 

C13H20O, Mr 192.30, isomers of ionone which differ only in the position of the ring double bond (a-, /3-, Y-, S-, and c-damascone). The name damascones or rose ketones is derived from their occurrence in the essential oil of damask rose (Rosa damascena). a-D. bp. 77-80°C (0.13 Pa), [alg +487° (CHCI3) /5-D. bp. 52 °C (0.13 Pa). D. possess the common olfactory feature of a narcotic-herby odor of exotic flowers with an undertone resembling black currents. Although a- and /3-D. in rose oil have a combined content of merely ca. 0.15%, they determine the basic odor of the oil (olfactory threshold 0.009 ppb). D. occur in other flower oils as well as in tea, certain tobacco, and fruit aromas, e.g., apples and raspberries, a- and /3-D. are in-... 

Damascenes have a heavy, narcotically spicy scent, with undertones reminiscent of blackcurrants and prunes. The two enantiomers together amount at most to 0.15% by weight in rose oil, but they contribute decisively to its base note. Interesting is damascene s very low scent threshold of 0.009 ppb. Rose oxide and the rose ketones have subsequently been discovered in a whole range of aromas, for example in the bouquet of several wine varieties. 

The increasing demand for rose ketones led in the 1980s to the development of industrial syntheses of these scented compounds by Firmenich. The starting... 

Methyl-heptylene carbinol, CjHjgO, has been obtained by the reduction of methyl-heptylene ketone by means of sodium and alcohol. It is-an oil with an odour recalling those of rose and linaloe, and has the following characters —... 

This ketone has been isolated from oil of rose, and in traces, from oil of cloves. It has the following constitution —... 

The interaction of biguanides and ketones was studied thoroughly by Curd, Rose and their co-workers [58), and independently by Modest and Levene [443). It has become a widely used synthetic route to certain dihydrotriazines [27. 43, U, 56, 136, 156, 185, 200, 226, 417, 471, 493, 534), the chemistry of which has been reviewed recently [442). 

Benzopbenone or Diphenyl ketone (also called a -Oxodiphenylmethane or BenzoylbenZene)(called a-Oxo-diphenylmethan, Diphenylketon, Benzo-phenon, a -Oxo-ditan or Benzoylbenzol in Ger), C6H5.CO.C6Hs mw 182.12, O 8.78% wh rhmb crysts with rose-like odor mp a-form 49°, (3... 

Ketones were found to be the major volatile components in boiled crayfish tail meats. A total of seven saturated ketones (C6 - Cll), one unsaturated ketone, one cyclic ketone, one aromatic ketone and two alkanediones were identified in the boiled crayfish tail meat. The two alkanediones, 2,3-butanedione and 2,3-pentanedione, gave an intense buttery and desirable aroma. Acetophenone imparted sweet rose floral odor. Four methyl ketones (C7 - Cll) and 2,3-pentanedione were identified in boiled crayfish hepatopancreas. Pour methyl ketones (C5 - C8) were identified in pasteurized crahmeat. These methyl ketones were usually associated with green, fruity aromas and gave more floral aromas as chain length increased. Several ketones (C4 - C8) also have been reported as volatile flavors of shrimp (13). The diketones might be important aroma components for crayfish tail meat and hepatopancreas products in providing desirable balance of the meaty and buttery notes. 

Otherwise, in general construction the perfume follows closely that of a classical oriental, with citrus oils (making up some 25%), lavender, sandalwood, patchouli, vanillin, coumarin, castoreum, and rose. The general sweetness of the perfume is further enhanced by the choice of musk materials, Galaxolide (5%), Tonalid, ethylene brassylate, and musk ketone, as well as by the use of Cashmeran, an intensely sweet fruity musk material associated with the synthesis of Galaxolide. 

Apart from the materials already mentioned the top note contains a simple mixture of bergamot and orange. The middle note is dominated by a traditional jasmin base, with muguet (hydroxycitronellal 10%), and rose. At the heart of the perfume is the classical chypre accord between vetiveryl acetate (10%), methyl ionone, oakmoss, aldehyde C14, coumarin, sandalwood, patchouli, musk ketone, and amber. The amber note can be reproduced by the simple but effective combination of labdanum, olibanum, and vanilla. Small amounts of other animalic notes such as civet may also be used. 

Oxyberberine (49), when further oxidized by pyridine chlorochromate and then treated with methanol, gives the methoxy-ketone (50 R = Me) the tetra-methoxy-analogue of (49) behaves similarly.132 The carbinolamine (50 R = H) is obtainable, together with the keto-acid (53), by the photolysis of oxidoberberine (51), in the presence of oxygen and rose bengal, to produce the peroxide (52), followed by treatment with pyridine hydrochloride a tetramethoxy-analogue of oxidoberberine, prepared by the reduction of norcoralyne with zinc and acetic acid, followed by oxidation with a peracid, behaves in the same way.133... 

A variety of benzene-derivatives are found in many grape varieties, including vinyl phenols, benzyl alcohol, 2-phenyl ethanol and raspberry ketone. Vinyl phenols are characterised by spice and dove-like, 2-phenyl ethanol by rose and lilac, and raspberry ketone by a raspberry attribute (Francis and Newton 2005). It should be noted that, although a portion of 2-phenyl ethanol can derive from glycoside hydrolysis, a greater proportion of this compound is formed in the metabolism of the amino acid phenylalanine (Ugliano et al. 2006). 

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