Decarboxylation of 5-amino-orotic acid and a Schiff base derivative by rhenium(V)

• Decarboxylation of 5-amino-orotic acid and salicylimine-orotic acid
• Novel Re(V) and Re(III) complexes
• X-ray crystal structures

The reaction of 5-amino-orotic acid (H2aor) with trans-[ReOBr3(PPh3)2] in 2-propanol produced the complex [ReV(apd)Br(aor)(PPh3)2] (1, apd2 − = 5-imidopyrimidine-2,4-dione). The ligand apd2 − was formed by the decarboxylation of H2aor, and it is coordinated via the dinegative imido nitrogen only. The Schiff base derivative of H2aor, salicylimine-orotic acid {5-(2-hydroxy-benzylideneamino)-1,2,3,6-tetrahydro-2,6-dioxopyrimidine-4-carboxylic acid; H2sor}, was also decarboxylated in the reaction with trans-[ReOI2(OEt)(PPh3)2] in ethanol to form [ReIII(cor)I(PPh3)2]I (2, Hcor = 5-(2-hydroxybenzylideneamino)-pyrimidine-2,4(1H,3H)-dione). Decarboxylation of H2sor was not observed in its reaction with trans-[ReOCl3(PPh3)2], which led to the isolation of [ReOCl(sor)(PPh3)] (3), in which sor2 − is coordinated as a tridentate ligand as expected. Spectroscopic results and the X-ray crystal structures of compounds 1–3 are also presented.

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