Claims
- 1. A process for the manufacture of chelidonic acid comprising the steps of:
- (i) mixing metal alkoxide, dialkyl oxalate and an alcohol together in a reaction vessel;
- (ii) stirring the mixture of (i) while adding acetone at a rate such that the concentration of unreacted acetone in the reaction mixture is not greater than 30% of the dialkyl oxalate and metal alkoxide together;
- (iii) neutralizing the product of (ii) with acid;
- (iv) refluxing to form chelidonic acid.
- 2. A process as claimed in claim 1 wherein in step (ii) the mixture is heated towards the end of the acetone addition.
- 3. A process as claimed in claim 1 wherein an excess of alcohol is present during step (ii).
- 4. A process as claimed in claim 1 with the provision that the neutralized acetone dialkyloxalate is not isolated prior to reflux.
- 5. A process as claimed in claim 1 wherein the metal alkoxide and dialkyl oxalate are in a molar ratio of 1:1 and alcohol is in excess.
- 6. A process as claimed in claim 1 wherein the sodium alkoxide, dialkyl oxalate and acetone are in a molar ratio of 2.1:2.1:1.
- 7. A process as claimed in claim 1 wherein acetone is added at a rate such that the concentration of acetone in the reaction mixture is between 1 and 15% of the total dialkyl oxalate and metal alkoxide together.
- 8. A process as claimed in claim 1 wherein acetone is added at a rate such that the concentration of acetone in the reaction mixture is between 5 and 10% of the total dialkyl oxalate and metal alkoxide together.
Parent Case Info
This is a continuation application of Ser. No. 07/986,224 filed Dec. 7, 1992, now abandoned.
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
3759833 |
Easton et al. |
Sep 1973 |
|
4537971 |
Rebhahn et al. |
Aug 1985 |
|
Non-Patent Literature Citations (2)
Entry |
Riegel, Zwilgmeyer, Organic Syntheses Coll., vol. II, (1943) pp. 126-128. |
Huang et al. CA 98(3):16549v (1983). |
Continuations (1)
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Number |
Date |
Country |
Parent |
986224 |
Dec 1992 |
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