| Abstrakt: |
A novel dimer, tetraethyl 2,2′,3,3′tetramethyl1,1′,2,2′tetrahydro4H,4′H2,2′bipyrrolyl5,5,5′,5′tetracarboxylate, has been isolated as an impurity 0.4 yield from a Knorr reaction for the synthesis of ethyl 3,5dimethylpyrrole2carboxylate from 2,4pentanedione and diethyl oximinomalonate in a dissolving zinc reduction. The solidstate structure of this novel dimer was determined by Xray crystallography. Knorr reactions typically rely upon the requisite pyrrole being the only waterinsoluble crystalline material present in the reaction mixture, and so workup and purification procedures for Knorr reactions should be monitored carefully given the waterinsolubility of this dimer. Investigations regarding mechanistic implications and reductive dimerization are underway. |
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