Of guaiazulene

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 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]. 

Comparison of the H-NMR spectrum of 190 with that of guaiazulene itself and consideration of the derived chemical shift increments indicated partial delocalization of... 

A solution of tetrachlorocyclopropene (1.78 g, 10 mmol) in CH2CI2 (5 mL) was added dropwise to a stirred suspension of AICI3 (1.47 g, 11 mmol) in CHjClj (80 mL). The mixture was gradually heated to 20 C, and left at that temperature for 15 min, which resulted in 1,2,3-trichlorocyclopropenylium tetrachloroaluminate (1). This suspension was cooled to — 70 C, then a solution of guaiazulene (5.58 g, 28.2 mmol) in CHjClj (50 mL) was added dropwise with stirring during 50 min. The mixture was kept at — 70 C for... 

I FIGURE 11.6.sfrof The structure of guaiazulene (with numbering). 

FIGURE 11.6./)S9C The2-D H- C HSQC NMR spectrum of guaiazulene in CDCL... 

I FIGURE A.ghmbc The 2-D gHMB C NMR spectrum of guaiazulene in CDCI3,... 

There is an example of electrophilic substitution occurring in a side-chain as well as in the azulene ring. Sulphenylation of guaiazulene with trifluoromethylsulphonyl chloride leads to substitution in the 4-methyl and 7-isopropyl groups as well as at the 3-position [138]. 

Analogous alkylation of guaiazulene 106 with MA has been reported by Ogura et On refluxing a benzene solution, blue crystalline needles of 107 were obtained. The latter was reported to decompose to the starting... 

Azulene (LV), and several of its alkyl derivatives, give complexes of the form azulene Fe2(CO)s when treated with Fe(CO)s (52, 73). In the case of guaiazulene (l,4-dimethyl-7-isopropylazulene) two isomeric complexes of this type have been isolated. Evidence for a similar isomeric pair has been found for 4-methylazulene (73). Once again the structure of these interesting complexes is not known with certainty. Physical data indicates that the two... 

Bowden, B.F., J.C. Coll, and D.M. Tapiolas Studies of Australian Soft Corals. XXX. A Novel Tris orsesquiterpene from a Cespitularia Species and the Isolation of Guaiazulene from a Small Blue Alcyonium Species. Aust. J. Chem. 36, 211 (1983). 

Fusetani, N., S. Matsunaga, and S. Konosu Bioactive Marine Metabolites. I. Isolation of Guaiazulene from the Gorgonian Euplexaura erecta. Experientia 37, 680 (1981). 

Bowden, B.F., Coll, J.C., and Tapiolas, D.M. (1983a) Studies of Australian soft corals. XXX A novel trisnorsesquiterpene from a Cespitularia species and the isolation of guaiazulene from a small blue Alcyonium sp. Aust. ]. Chem., 36,211-214. 

Nozone, T, Ishikawa, S., and Shrndo, K. (1989) Facile shifts of bromine atom on C-3 position of guaiazulene and synthesis of variously functionalized azulenes using these reactions. Chem. Lett., 18, 353-356. 

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