• 10.1021/ic026240s
  • Inorganic Chemistry
  • Volume 42
  • August 2003
  • pp 4930-4937

Toward Optimized High-Relaxivity MRI Agents:  The Effect of Ligand Basicity on the Thermodynamic Stability of Hexadentate Hydroxypyridonate/Catecholate Gadolinium(III) Complexes

Tweaks Necessary to Improve Yield



This paper describes the synthesis of a new hydroxypyridinone applicable for MRI technology. The basicity was measured and related to the thermodynamic stability with Gd.

Reaction of interest:

Our interest was the formation of the ring 6- methyl 3,-2-hydroxypyridinone: this step was previously described by an older paper written in German[1].  In the more recent article it was indicated that the synthesis was reproduced like previously reported.


The procedure described allowed the production of the desired compound, but in a very low yield.

Change and improvement:

The first improvement that allowed recovery of 20 % of the desired product was to centrifuge instead of filtering the orange reaction mixture.

We also found out the yield improves with an increase in the dryness of THF. It was realized that drying the ammonia gas allowed a large improvement that wasn’t specified in the procedure. We also tried different solvents, but none of them improved the yield.

[1] Feist, D. Chem. Ber. 1902, 35, 1540.

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