- AuIII binding to C5 of the model nucleobase 1,3-dimethyluracil (1,3-DimeU): Preparation and X-ray crystal structures of trans-K[Au(CN)2Cl(1,3-DimeU-)] and of two derivatives
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The reaction of trans-K[Au(CN)2Cl2] with 1,3-dimethyluracil (1,3-DimeU) gives trans-K[Au(CN)2Cl(1,3-DimeU--C5)] (1) which contains the 1,3-dimethyluracil-5-yl entity (1,3-DimeU--C5) bound to AuIII. Complex 1 represents the first example of an X-ray structurally characterized organogold(III) complex of a nucleobase. Further reaction with purine model nucleobases (nb) such as 9-ethylguanine (9-EtGH), 9-methyladenine (9-MeA), and 1-methylcytosine (1-MeC) leads to mixed nucleobase complexes of type trans-[Au(CN)2(1,3-DimeU--C5)(nb)] (nb=9-MeA, 2a; nb=9-EtGH, 3a; nb=1-MeC, 4a) or to compounds containing the protonated purine base Hnb+ and [Au(CN)2X(1,3-DimeU--C5)]- as a counter ion (X=Cl or CN), e.g. [9-MeAH][Au(CN)2Cl(1,3-DimeU--C 5)]·H2O (2b) and [9-EtGH2][Au(CN)3(1,3-DimeU--C5)] (3b). The crystal structures of 1, 2b, and 3b were determined. The C-bound nucleobase exerts a distinct trans-influence, as evident from long Au-Cl bonds in 1 and 2b (2.340(3) A and 2.358(6) A) and a long bond (2.082(7) A) between Au and the cyano ligand trans to 1,3-DimeU- in 3b.
- Zamora, Felix,Zangrando, Ennio,Furlan, Michela,Randaccio, Lucio,Lippert, Bernhard
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- Chemical models and their mechanistic implications for the transformation of 6-cyanouridine 5′-monophosphate catalyzed by orotidine 5′-monophosphate decarboxylase
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The reactions of 6-cyano-1,3-dimethyluracil have been studied as chemical models to illustrate the mechanism for the transformation of 6-cyanouridine 5′-monophosphate (6-CN-UMP) to barbiturate ribonucleoside 5′-monophosphate (BMP) catalyzed by orotidine 5′-monophosphate decarboxylase (ODCase). The results suggest that the Asp residue in the ODCase active site plays the role of a general base in the transformation.
- Wu, Yuen-Jen,Liao, Chen-Chieh,Jen, Cheng-Hung,Shih, Yu-Chiao,Chien, Tun-Cheng
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scheme or table
p. 4821 - 4823
(2010/08/22)
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