Method for preparing 1-(2, 6, 6-trimethyl-3-cyclohexenyl)-1, 3-butanedione
A technology of cyclohexenyl and trimethyl, applied in the field of preparation of 1--1,3-butanedione, can solve problems such as low yield
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[0022] The invention provides a preparation method of 1-(2,6,6-trimethyl-3-cyclohexenyl)-1,3-butanedione, comprising the following steps:
[0023] React 1-(2,6,6-trimethylcyclohex-3-enyl)ethanone with an acetylating reagent in a solvent to obtain 1-(2,6,6-trimethylcyclohex-3-enyl) Hexenyl)-1,3-butanedione.
[0024] The present invention uses 1-(2,6,6-trimethylcyclohex-3-enyl)ethanone as raw material, and its structural formula is shown in formula II:
[0025]
[0026] The present invention has no special restrictions on the source of the (2,6,6-trimethylcyclohex-3-enyl)ethanone, using 1-(2,6,6-trimethyl Cyclohex-3-enyl)ethanone can be used. In a specific embodiment of the present invention, the preparation method disclosed in the patent application number 200710071156.9 is preferably used for preparation.
[0027] In the present invention, the acetylation reagent preferably includes one or more of acetyl chloride, acetic anhydride and glacial acetic acid. In the present ...
Embodiment 1
[0041] Add 300mL xylene and 46.8g (1.2mol) sodium amide to the reaction flask, adjust the temperature to 50°C, and add 166g (1.0mol) 1-(2,6,6-trimethylcyclohexyl-3- Alkenyl) ethyl ketone, the temperature is controlled at 50°C, and the drop is completed in about 2 hours. After the dropwise addition, continue to react at a constant temperature of 50°C for 0.5 hours, the reaction solution is cooled to 30°C, and 184g (1.8mol) of acetic anhydride is slowly added dropwise, and the reaction The temperature is controlled at 30°C, the dropwise addition is completed in about 2 hours, and the constant temperature reaction is continued for 1 hour;
[0042]Slowly add 500mL of water to the obtained reaction solution, stir completely and then separate into layers, then add 300mL of 10% sulfuric acid, stir completely and then separate into layers, neutralize the oil layer with 3% sodium hydroxide solution to neutrality, then add 300mL of water to wash; The solvent was recovered, rectified und...
Embodiment 2
[0050] Add 200mL toluene and 24g (1.0mol) sodium hydride to the reaction flask, adjust the temperature to 30°C, and add 166g (1.0mol) 1-(2,6,6-trimethylcyclohex-3-enyl) dropwise under stirring ) ethyl ketone, the temperature is controlled at 30°C, and the drop is completed in about 3 hours. After the dropwise addition, continue to react at a constant temperature of 30°C for 1 hour. At 20°C, the dropwise addition is completed in about 3 hours, and the constant temperature reaction is continued for 2 hours;
[0051] Slowly add 500mL of water to the obtained reaction solution, stir completely and separate layers, then add 300mL of 2% phosphoric acid, stir completely and separate layers, the oil layer is neutralized to neutral with 3% potassium hydroxide solution, and then washed with 300mL of water. Recover the solvent, rectify under reduced pressure, collect the fraction at 95-96°C / 2mmHg, and obtain 172.3g of light yellow transparent oily liquid; the light yellow transparent oil...
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