DARK BLUE LOW MELTING CRYSTALLINE SOLID
Guaiazulene can be used as a starting material for the synthesis of:
- Azulene-based dye molecules such as 3-(7-isopropyl-1,4-dimethylazulen-3-yl)-2-cyanoacrylic acid and 5-(7-isopropyl-1,4-dimethylazulen-3-yl)-2-cyanopenta-2,4-dienoic acid.
- Stilbazulenyl nitrone, a second-generation azulenyl nitrone which can be used as a chain-breaking antioxidant.
- Bis-azulenyl based near-infrared fluorescence quencher.
antioxidant, inhibits lipid peroxidation inhibitor, antiinflammatory, hepatoprotectant; LD50(rat) 1550 mg/kg po
ChEBI: Guaiazulene is a sesquiterpene. It derives from a hydride of a guaiane.
10 kg a gum of Guacum officinale was heated with 3-4 kg of sulfur to 130°C.
The heating was slowly continued for 220°C under the nitrogen. The formed
water steam was removed with the nitrogen current. The temperature should
be higher 100°C in order to the water didnt fall into reaction mixture. H2S was
obtained simultaneously the dehydrogenation and removed with water steam.
Hydrogen sulfide was connected in an alkaline trap.
When a H2S discharge stopped, the temperature was decreased to 120°C and
the reaction mixture was distilled in vacuum 1-20 mm. The distillate had deep
blue color and contained 6-7 kg oil with 20% of 7-isopropyl-1,4-
dimethylazulene. It was dissolved in the 5-10 volumes of light petroleum,
shook with sodium hydroxide for removing the sulfur containing substaneces,
washed to neutral. Then petrolem layer was mixed with 10-15 L 62% H2SO4
for removing the by-products, the petroleum layer lost the blue color and the
desired substance was in sulphuric acid layer. The last one was shook with ice
and NaOH. As a result about 7% NaSO4 solution in sulfuric acid was obtained.
It was diluted and azulene gave an emulsion, which was extracted with 10 L
of petrolem and distilled. The 7-isopropyl-1,4-dimethylazulene is distilled at
167°-168°C/12 mm. Yield 10-15%.
This substance is a primary reference substance with assigned absolute purity (considering chromatographic purity, water, residual solvents, inorganic impurities). The exact value can be found on the certificate. Produced by PhytoLab GmbH & Co. KG
It forms blue-violet plates from EtOH. Also redistil it in vacuo until distillate solidifies. UV has max at 284nm (log 4.6, heptane). The picrate has m 122o(EtOH). [Beilstein 5 III 1677, 5 IV 1751.]
