Claims
- 1. In a process for the preparation of a loweralkyl 1,4-diloweralkyl-3-loweralkoxycarbonyl-pyrrole-2-acetate of the formula: ##STR4## by reacting a mixture of a chloromethyl loweralkyl ketone of the formula: Cl--CH.sub.2 --CO--R.sub.4, with a diloweralkyl acetone dicarboxylate of the formula: ##STR5## and a loweralkylamine of the formula: R.sub.3 NH.sub.2, wherein the foregoing formulas said R.sub.3 and said R.sub.4 represent loweralkyl, the improvement consisting essentially of said reaction being carried out in a two-stage procedure according to the steps of
- (a) adding said chloromethylloweralkyl ketone to a pre-mixed cooled solution of said loweralkylamine and said dicarboxylate in a suitable solvent with reaction at below 60.degree. C., and
- (b) heating the resultant reaction mixture to from about 70.degree. to about 100.degree. C. for a period sufficient to dehydrate the dihydroxy pyrrolidine intermediate in said resultant reaction mixture and produce the desired loweralkyl 1,4-diloweralkyl-3-loweralkoxycarbonyl-pyrrole-2-acetate.
- 2. The improved process of claim 1 wherein said dicarboxylate is diethyl acetone dicarboxylate.
- 3. The improved process of claim 1 wherein said dicarboxylate is diethyl acetone dicarboxylate and said loweralkylamine is methylamine.
- 4. The improved process of claim 1 wherein said dicarboxylate is diethyl acetone dicarboxylate, said loweramine is methylamine and said ketone is chloroacetone.
- 5. The improved process of claim 1 wherein said solvent is chloroform.
- 6. The improved process of claim 1 wherein said solvent is water.
- 7. The improved process of claim 1 wherein said solvent is toluene.
- 8. The improved process of claim 1 wherein said solvent is selected from the group consisting of chloroform, toluene, water and aqueous mixtures of toluene and chloroform.
- 9. The improved process of claim 1 wherein said Step (b) the heating is carried out at a temperature greater than 90.degree. C.
- 10. The improved process of claim 1 wherein the heating of said Step (b) is carried out at a temperature from 80.degree. to about 100.degree. C.
- 11. The improved process of claim 1 wherein the loweralkyl 1,4-diloweralkyl-3-loweralkoxycarbonyl-pyrrole-2-acetate produced is further reacted by contacting with a suitable alkali metal hydroxide for a suitable period to convert the ester groups to acid producing a 1,4-diloweralkyl-3-hydroxycarbonyl-pyrrole-2-acetic acid.
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part-of pending application Ser. No. 137,511 filed: Apr. 4, 1980, abandoned.
US Referenced Citations (2)
Non-Patent Literature Citations (1)
Entry |
Elderfield, Heterocyclic Compounds, vol. 1, (New York, 1950), pp. 132-134. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
137511 |
Apr 1980 |
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