trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid
CAS: 705-16-8
Molecular Formula: C10H16O2
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid - Names and Identifiers
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid - Physico-chemical Properties
| Molecular Formula | C10H16O2 |
| Molar Mass | 168.23 |
| Density | 1.077±0.06 g/cm3(Predicted) |
| Melting Point | 54° |
| Boling Point | 85-90 °C(Press: 0.3 Torr) |
| pKa | 4.90±0.33(Predicted) |
| Storage Condition | Room Temprature |
| Physical and Chemical Properties | Chemical properties (±) trans-chrysanthemum acid is white crystal, m.p.52 ~ 53 ℃, soluble in alcohol, n-hexane, benzene, toluene, ether and other organic solvents, difficult to dissolve in water. |
| Use | Use (+) Trans chrysanthemum acid is an important intermediate for the preparation of pyrethroids for health use. |
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid - Upstream Downstream Industry
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid - Production method
Chrysanthemum acid generally has greater biological activity with trans-chrysanthemum acid, and the cis-trans isomers of chrysanthemum acid are usually separated. There are many separation methods, mainly using their differences in physical and chemical properties, such as fractional crystallization, distillation, chromatography, etc. Due to the difference in the acidic strength of cis-trans acid, the distribution coefficient of its salt in the oil-water system is different. Continuous extraction method can be used, or the aqueous solution of its salt can be partially acidified, the pH value can be adjusted, and its solubility in water can be used for separation. It can also be separated by partial hydrolysis method using the different saponification speed of cis-trans acid ester.
(±) Trans-chrysanthemum acid is further resolved to obtain 1R-trans-chrysanthemum acid (or D-trans-chrysanthemum acid), which can prepare highly active pyrethroids such as Es-bio-allenthrin (EBT), Bio-allenthrin, S-bio-allenthrin, etc. It has the following structural formula:
The preparation method is to put ethyl chrysanthemum acid with inverse ratio of 35: 65 in a reaction kettle equipped with a stirred reflux condenser and a thermometer, raise the temperature to 120 ℃, add sodium methoxide as an indexing catalyst, and after the heat preservation reaction for 2 hours, add a proper amount of ethanol and 30% liquid alkali into the reactor, raise the temperature for reflux reaction for 3 hours, remove the ethanol generated by the reaction, add water for dilution, add hydrochloric acid, the toluene layer was washed to neutral with water, distilled and desoluted to obtain trans-chrysanthemum-rich acid with a cis-inverse ratio of about 10 ∶ 90, with 90% content and 90% yield.
The above-mentioned trans-chrysanthemum acid and an appropriate amount of organic solvent are put into the reaction kettle, stirred and cooled to about -5 ℃, frozen and crystallized, and crystallized and filtered to obtain high trans-chrysanthemum acid with a reverse-cis ratio of 98: 2 and a content of> 95%.
You can also put (±) cis-trans chrysanthemum acid salt into the reaction kettle, add sodium hydroxide solution to adjust pH = 10, and then introduce carbon dioxide into the solution, crystallize, filter, and dry to obtain (±) cis chrysanthemum acid. The remaining solution contains more trans-chrysanthemum acid salts, which can be recycled by adjusting the pH value.
In addition,(±) cis-trans chrysanthemum acid reacts with boron tribromide in the presence of organic peroxides to generate (±) trans chrysanthemum acid.
Dissolve chrysanthemum acid with cis-inverse ratio of 70: 30 in toluene, protect it by nitrogen in its reaction kettle, add boron tribromide and toluene solution dropwise under the condition of stirring at 20 ℃, stir for 2.5h at the same temperature after adding, add 1% HCl to the reaction solution, stir, and then layer, the organic layer is washed and layered with 10% NaOH solution, the water layer is acidified with dilute H2SO4, the toluene layer was washed with water, concentrated and distilled, and the fraction of 110~119 ℃/333Pa was collected as chrysanthemum acid, with the inverse ratio of 7: 93.
In addition, (±) trans chrysanthemum acid can also be prepared by Martel method.
Last Update：2024-04-10 22:29:15
trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid - Nature
| EPA chemical information | Cyclopropanecarboxylic acid, 2,2-dimethyl-3-(2-methyl-1-propenyl)-, (1R,3R)-rel- (705-16-8) |
Last Update：2024-04-09 21:04:16
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Raw Materials for trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid
Downstream Products for trans-(±)-2,2-dimethyl-3-(2-methylprop-1-enyl)cyclopropanecarboxylic acid
(1R-cis)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane carboxylic acid
1R,3R-chrysanthemic acid
1R-trans-methyl caronaldehydate
1R,3R-chrysanthemic acid
1R-trans-methyl caronaldehydate