The dimeric gallium-phosphorus compound [(Me 3 Si-CH 2 ) 2 GaP(SiMe 3 ) 2 ] 2 (1) was prepared from the 1:1 mole ratio lithium-halide elimination reaction of (Me 3 SiCH 2 ) 2 GaP(SiMe 3 ) 2 Ga(CH 2 SiMe 3 ) 2 Cl with LiP-(SiMe 3 ) 2 in benzene solution and has been characterized through multinuclear
Isolation and characterization of a novel tetrahydro-[2,2′]bipyrrolyl dimer as an impurity from a knorr reaction
✍ Scribed by Alison Thompson; Yousef Alattar; Cory S. Beshara; Rodney K. Burley; T. Stanley Cameron; Katherine N. Robertson
- Publisher
- Journal of Heterocyclic Chemistry
- Year
- 2004
- Tongue
- English
- Weight
- 225 KB
- Volume
- 41
- Category
- Article
- ISSN
- 0022-152X
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✦ Synopsis
Abstract
A novel dimer, tetraethyl 2,2′,3,3′‐tetramethyl‐1,1′,2,2′‐tetrahydro‐4__H__,4′H‐2,2′‐bipyrrolyl‐5,5,5′,5′‐tetracarboxylate, has been isolated as an impurity (0.4% yield) from a Knorr reaction for the synthesis of ethyl 3,5‐dimethylpyrrole‐2‐carboxylate from 2,4‐pentanedione and diethyl oximinomalonate in a dissolving zinc reduction. The solid‐state structure of this novel dimer was determined by X‐ray crystallography. Knorr reactions typically rely upon the requisite pyrrole being the only water‐insoluble crystalline material present in the reaction mixture, and so work‐up and purification procedures for Knorr reactions should be monitored carefully given the water‐insolubility of this dimer. Investigations regarding mechanistic implications and reductive dimerization are underway.
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