Description
1, 2-Dimethoxybenzene, commonly known as veratrole, is an organic compound with the formula C6H4(OCH3)2. It is a colorless liquid with a pleasant odor and slight solubility in water.
It is the dimethyl ether derived from pyrocatechol, too.
1, 2-Dimethoxybenzene is naturally occurring. Its biosynthesis entails the methylation of guaiacol by guaiacol O-methyltransferase.1, 2-Dimethoxybenzene is an insect attractant.
Guaiacol O-methyltransferase gene is first scent gene discovered so far in any plant species.
Uses
1, 2-Dimethoxybenzene is a building block for the organic synthesis of other aromatic compounds. Veratrole is relatively electron-rich and thus readily undergoes electrophilic substitution. An example of the use of veratrole is in the synthesis of Domipizone.
Veratrole can easily be brominated with NBS to give 4-bromoveratrole.
References
1.https://en.wikipedia.org/wiki/1,2-Dimethoxybenzene
2.https://pubchem.ncbi.nlm.nih.gov/compound/1_2-Dimethoxybenzene#section=Chemical-and-Physical-Properties
Chemical Properties
Colorless crystals or liquid. Soluble in alcohol
and ether; slightly soluble in water.
Occurrence
Reported present in asparagus (raw and cooked), bonito (dried), broccoli (cooked), cauliflower (cooked),
cognac, endive, grape, Gruyere de Comte cheese, guava, leek (raw and heated), olive, peas, rhubarb, rice bran and vanilla extract.
Uses
1,2-Dimethoxybenzene was used to investigate the electroantennogram response of vine weevil,
Otiorhynchus sulcatus to plant volatiles.
Uses
Veratrole is common reagent in organic synthesis such as the synthesis of arizonins B1 and C1. Also used in the synthesis of pharmacophores of salmeterol and roflumilast as dual β2-adrenoreceptor agonists-PDE4 inhibitors.
Definition
ChEBI: A dimethoxybenzene with the methoxy groups at ortho-positions.
Preparation
Prepared by methylation of pyrocatechol.
1,2-Dimethoxybenzene can also be prepared from Catechol. The specific synthesis steps are as follows:
Aqueous sodium hydroxide(40%,175 ml)is added dropwise during 3 hr at 18-22 to a well stirred mixture of catechol (50 g,0.45 mole),sodium hydrosulphite (20 g,0.115 mole),dimethyl sulphate (110 ml,146.63 g, 1.16 mole)and alcohol (150 ml).Ice (1 kg)is added to the reaction mixture and left overnight at room temperature.It is extracted with ether (2x 200 ml).The ether extract is washed with water,dried (anhydrous sodium sulphtate)and distilled.Veratrole is obtained as oil.Yield 52.75 g (84.1%).B.p.207°(1it.3b.p.207).
Taste threshold values
Intolerable at 40 ppm.
General Description
1,2-Dimethoxybenzene reacts with Li{N(SO
2CF
3)
2} to yield molecular crystal [Li{N(SO
2CF
3)
2}{C
6H
4(OCH
3)
2}
2] having solid-state lithium ion conductivity. It is a potential pollinator attractant of the nocturnal moth
Hadena bicruris.
Toxicology
Data from 1,2-dimethoxybenzene and read-across analog 1,4-dimethoxybenzene (CAS # 150-78-7) show that 1,2-dimethoxybenzene is not expected to be genotoxic. Data show that there are no safety concerns for 1,2-dimethoxybenzene for skin sensitization under the current declared levels of use. The repeated dose, reproductive, and local respiratory toxicity endpoints were evaluated using the TTC for a Cramer Class I material, and the exposure to 1,2-dimethoxybenzene is below the TTC (0.03 mg/kg/day, 0.03 mg/kg/day, and 1.4 mg/day, respectively). The phototoxicity/photoallergenicity endpoints were evaluated based on UV spectra; 1,2-dimethoxybenzene is not expected to be phototoxic/photoallergenic. For the environmental endpoints, 1,2-dimethoxybenzene is not a PBT as per the IFRA Environmental Standards, and its risk quotients (i.e., PEC/PNEC) for the aquatic environment, based on its current volume of use in Europe and North America, are < 1
Purification Methods
Steam distil veratrole, then fractionally distil it from BaO, CaH2 or Na. Crystallise it from *benzene or low-boiling pet ether at 0o. Fractionally crystallise it from its melt. Store it over anhydrous Na2SO4. [Beilstein 6 IV 5564.]
