3-damascone

The a- and /3-damascones are used in perfume compositions, especially rose perfumes, and in flavor compositions, to which they impart naturalness and body. 

Rose (Morocco) Rose (Bulgaria, Turkey) Rosa centiofolia Rosa damascena (S)-Citronellol, geraniol, nerol (23), 2-phenylethanol, (4R)-rose oxide (24), /3-damascone (25), /3-damascenone (26) 95,96... 

Damascone (norisoprenoid) Camellia sinensis (Japanese green tea, Sen-cha) (Theaceae) OD-R (honey-like)... 

The theory of electrocyclic reactions predicts a disrotatory closure of 4ir-systems in the excited state. This prediction was verified in fact by Lehr using the same biscyclohexenyl ketone (equation 14). The cyclization proceeded at various wavelengths in pentane as well as in benzene. The reaction could not be inhibited by luqrhthalene or piperylene. Sensitization with acetophenone did not accelerate the reaction. Fituilly, no deuterium was incorporated when ds-benzene was used as solvent. 3-Damascone undergoes an sqrparent disrotatory closure with ctqrture of the zwitterionic intermediate by solvent (equation 15). ... 

Diels-Alder catalyst (4, 10-11). Details for the synthesis of 3-damascone and -damascenone by the Diels-Alder reaction are now available. ... 

The synthetic chemistry of damascones and damascenones has been reviewed. New syntheses have been reported of /8-damascenone (141) from dimedone, of 3-hydroxy-/3-damascone (142) and 3-hydroxydihydro-/3-damas-cone (143),and of various damascones and their demethyl analogues. ... 

Recently, rhodium(II) acetate-catalyzed decompositions of a-diazo-3-dihydroxyesters (or a-diazo- 3-hydroxyketones) have been applied to an elegant synthesis of 3-damascone (fragrance). 

One of the most important discoveries recently made in the field of carotenoid aroma compounds relates to the class of damascones. Seven naturally occurring members (266) to (272) of this class are known today. The discovery of these new compounds started with the isolation of damascenone (268) from Bulgarian rose oil in 1970 120). Later, the same compound was detected in various tobacco brands 5, 110, 306), tea 491), raspberry oil 708), cooked apples 442), various grape and wine varieties 546, 549), beer 598), coffee oil 179), buchu leaf oil 283) and Roman camomile 638). 3-Hydroxy-(3-damascone (269) was shown to be an important aroma component of tobacco 108, 169, 285) in which it develops a green, rose-floral and sweet Burley-like note (556). (3-Damascone (267) was found in Burley tobacco 110) and rose oil 108), whereas a-damascone (266), accompanied by (3-compound (267) and damascenone (268), was exclusively observed in tea oil 491). Among the known cyclization products (270) to (272), the last two compounds were found in tobacco (779), while ketone (270) was detected in tea 491). 

Damascone 85, an isomer of -ionone, is also majorily transformed (70-95%) into its 4-hydroxylated product by several strains of Botrytis cinerea. However, small amounts of 2- and 3-hydroxylated products (2-25%) were observed in these bioconversions [117]. a-Damascone 86 is more extensively metabolized, giving rise to various 3-oxidized metabolites in low yields [118]. 

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