Macrocyclic Musk Compounds

The development of the macrocyclic musk compounds began in 1926 with the structural characterization of muscone and civetone by Ruzicka and others [15, 22,24-26]. They demonstrated the compounds to be cyclic macromolecules, the existence of which had been considered impossible according to the so-called "Baeyer's strain theory" [3,15,56].

After this breakthrough additional macrocyclic compounds exhibiting musklike odors were isolated from natural materials, their structures were elucidated, and syntheses were developed [15,16,26]. The natural macrocyclic musk compounds turned out to be ketones (animal sources) and lactones (plant materials) [5,15]. They are 15- or 17-membered ring systems. The type of odor is influenced by the ring size. Starting from 14 ring atoms, a weak musk scent is perceived. Compounds with 15-16 ring atoms exhibit strong musk odor [26].

Owing to their outstanding properties (stability to light and alkaline conditions, fixation, and high quality odors), macrocyclic musk compounds are of high value for the fragrance industry. Accordingly, there have been many attempts to improve syntheses of naturally occurring macrocyclic musks for industrial application and to develop new, more easily accessible members of this class [3,15, 26]. The synthesized macrocyclic compounds can be divided into ketones, dike-tones, lactones, oxalactones (ether lactones), dilactones, ketolactones, and esters. Some of the most prominent examples are listed in Table 5.

In addition to the naturally occurring representatives, a wide array of other substances not being found in nature has been synthesized [26,57-59]. One of the most important compounds of this group (production of about 300 tonnes per year) is the dilactone ethylene brassylate [59].Ethylene brassylate is an inexpensive musk compound because of its easy synthesis and the low costs of the starting materials [5,60]. Another inexpensive macrocyclic musk compound is Ha-banolide, the unsaturated version of Exaltolide [61].

Table 4 Industrial use of polycyclic musks in Europe (in tonnes) [50]

Year HHCB AHTN ADBI AHDI ATII

1992 2400 885

1995 1482 585 34 50 40

1998 1473 385 18 19 2

Table 5 Commercially important macrocyclic musks

CAS name CAS no.

Trade name(s) Chemical name

Molecular formula

Chemical structure

9-Cyclohepta-

decen-1-one

542-46-1

Civettone Civetone cfs-9-Cyclohepta-decenone, 10-Ketocyclo-heptadecene

Decen Olide

3-Methyl-cyclopenta-decanone 541-91-3

Muscone

3-Methylcyclo-pentadecanone

Photo Reseau Anneau Techno

Oxacyclo-heptadec-8-en-2-one 123-69-3

Ambrettolide

7-Hexadecen-

16-olide,

16-Hydroxy-

7-hexadecenoic-

acidlactone,

Cyclohexade-

cenolide

C16H28O2

Oxacyclohexa- Exaltolide, decan-2-one Muskalactone, 106-02-5 Pentalide,

Thibetolide

15-Pentade-canolide

C15H28O2

C17H30O

C16h30O

Table 5 (continued)

CAS name CAS no.

Trade name(s) Chemical name

Molecular Chemical formula structure

Cyclopenta-

decanone

502-72-7

Exaltone, Cyclop enta-

Normuscone decanone

Cyclohepta-

decanone

Dihydro-civettone, Dihydro-civetone

Cyclohepta-decanone

Oxacyclohexa-

decen-2-one a4902-57-a

Habanolide, Globalide

Oxacyclohexa-decen-2-one

1,4-Dioxa-

cyclohepta-

decane-

5,17-dione

105-95-a

Musk T, Musk NN, Astratone, Musk MC-5

Ethylene brassylate,

Ethylene-1,

B-tride-

canedioate

C15H26O4

Nitro Macro Compounds

1,4-Dioxacy- Musk MC-4, clohexadecane- Musk C14 5,16-dione 54982^-1

Ethylenedode-candioate

1,6-Dioxacy- Musk 781, cloheptadecan- Cervolide 7-one 6707-60-4

12-Oxahexa-decanolide, 12-Oxa-1,16-hexadecanolide

C15H28O3

Polycyclic Musk

C15H28O

C17H32O

C15H26O2

C14H24O4

The synthesis of macrocyclic musk compounds is difficult and in many cases a multi-step procedure. Due to the relatively high production costs, their economical importance is still limited. In 1996 they comprised about 5% of the total amount (8000 tonnes) of musk compounds [5].In contrast to the nitro musks and the polycyclic musk compounds which are offered for 10-30 DM kg1 and 20-60 DM kg-1,respectively, the price for the macrocyclic representatives ranges from 50 to 5000 DM kg-1. Macrocyclic musks are expected to be of increasing importance in the future, especially because many of them are naturally occurring and even the artificial representatives (e.g., ethylene brassylate) closely resemble the natural counterparts [5].In addition, the progress in synthetic chemistry contributes to declining prices and will stimulate increased use of this type of musks [60].

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Responses

  • michael massawa
    What are macrocycli musk names?
    3 years ago
  • Eliano
    Are macrocylic musks toxic?
    2 years ago
  • stefan
    What are polycyclic musks?
    3 months ago

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