5- Guaiazulene

The generic term azulene was first applied to the blue oils obtained by distillation, oxidation, or acid-treatment of many essential oils. These blue colours are usually due to the presence of either guaiazulene or velivazulene. The parent hydrocarbon is synthesized by dehydrogenation of a cyclopentanocycloheptanol or the condensation of cyclopentadiene with glutacondialdehyde anil. 

C, obtained from the wool oil of Bulnesia sarmienti, Lorenz. On heating with sulphur it gives guaiazulene. 

Guaiol is valuable as a raw material for preparing guaiazulene (109), an antiinflammatory ia pharmaceutical preparations for skin cosmetics. Guaiol is also used as alow cost fixative ia perfumery. The acetate, guaiyl acetate [134-28-1/, is also useful ia perfumery. Bulnesol is not used as such but contributes to the fixative properties of guaicwood oil. The price of the oil ia 1995 was 9.90/kg (69). 

The azuleno[l, 8-rc/]azepine 35 is formed as a byproduct from the reaction of excess benzonitrile with 7-isopropyl-l,4-dimethylazulene (guaiazulene, 34) in the presence of a strong base.111 The mode of formation of this unexpected fully conjugated 14jt system has been discussed. 

Thomas and Long487 measured second-order rate coefficients for detritiation of [l-3H]-azulene and [3-3H]-guaiazulene in a range of acids at 25 °C (Table... 

The reductive coupling of guaiazulene, a fulvalene analog, with activated calcium in THF affords a 60 40 mixture of two isomers, 8,8 -147 (Figure 75) and 8,6 -(diguaiazulenide)bis(tetrahydrofuran)calcium, respectively. Thermolyses of each isomer revealed that the 8,8 -isomer is the thermodynamically preferred isomer, and it forms preferentially when the coupling is performed at 67 °C.342... 

The transformation has been employed extensively in the preparation of precursors to a number of natural products including dihydrojasmone, rosaprostol, valeranone, and hirsutene [20]. Its use en route to guaiazulene (23) is illustrated in Scheme 5. 

Scheme 5 Reductive cyclization of ketonitriles an route to guaiazulene.

Electroreduction of y- and 5-cyano ketones in isoPrOH with a Sn cathode gave a-hydroxyketones with good diastereo-selectivities as cyclization products. The reaction has been used as a key step for the synthesis of, for example, guaiazulene, triquinanes, and dihydrojasmone. Similarly, the corresponding intermolecular couplings were realized [315]. 

The main constituents of the oil are the sesquiterpene alcohols guaiol [489-86-1] and bulnesol [22451-73-6] [542]. The oil may be used as a starting material for the synthesis of guaiazulene, which has anti-inflammatory properties. 

Gurjun balsam oil and gurjun balsams are used for their good fixative properties, e.g., in soap perfumes and serve also as a starting material for the production of guaiazulene. FCT 1976 (14) p.789, p. 791 [50J0-55-5]. 

Artemisia lactiflora Wallich Tian Cai (whole plant) Flavonoid glycoside, coumarin, lactiflorenol, spathulenol, s-guaiazulene, beta-guaienen, trans-(3-farnesene, frans-caryophyllene, limonene, elemene, copaene, myrcene.57 Diuretic, regulate menstruation, treat headache, high blood pressure. 

Guaiazulene - [COLORANTS FORFOOD, DRUGS, COSMETICS AND MEDICALDEVICES] (Vol 6)... 

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