Claims
- 1. A process for producing tetramethyl pyrazine comprising:
- a. extracting ground roots and stems of a plant selected from the group consisting of Ligusticum chuanxiong Hort and Ligusticum wallichii Franch with 95% ethanol and refluxing the ethanol for about 2 hours;
- b. distilling the ethanol extract under reduced pressure to yield a residue;
- c. dissolving the resulting residue in warm water;
- d. extracting the resulting aqueous solution of step c twice, when cooled, with an equal volume of petroleum ether;
- e. extracting the resulting ether phase with an equal volume of 0.1N HCl;
- f. separating and adjusting the aqueous phase to pH 9-10 with sodium carbonate;
- g. extracting the aqueous phase of step f with chloroform;
- h. collecting the chlorofom extract and distilling the same under reduced pressure to recover chloroform and yield a residue gel;
- i. dissolving the resulting residue gel in petroleum ether;
- j. distilling the petroleum ether under reduced pressure to yield a second residue;
- k. dissolving the second residue of step j in a mixture of 8:2 petroleum ether and chloroform;
- l. distilling the mixture of step k under reduced pressure to yield a solid residue;
- m. dissolving the solid residue in warm water, cooling the resulting aqueous solution and adjusting the same to pH 8-9; and
- n. distilling the aqueous solution, cooling and crystallizing needle tetramethyl pyrazine.
Parent Case Info
This application is a division of application Ser. No. 910,240, filed 09/22/86, now U.S. Pat. No. 4,906,470.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
4708949 |
Liu |
Nov 1987 |
|
4865599 |
Chiou et al. |
Sep 1989 |
|
Divisions (1)
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Number |
Date |
Country |
Parent |
910240 |
Sep 1986 |
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