Ultraviolet spectra uridine

The nuclear magnetic resonance spectrum of pseudouridine is in agreement with this formulation, in that it shows that there is no proton attached to C-5 in the pyrimidine ring. Moreover, the signal from the C-1 proton occurs at a S value lower than that given by the C-1 proton in uridine, as would be expected for a C—CH proton as against an N—CH proton. The ultraviolet spectrum shows that neither nitrogen atom is substituted, and methylation with diazomethane yields two mono-A -methyl derivatives and one di-iV-methyl derivative. 

Fig. 6.—Ultraviolet Absorption Spectrum of Uridine at pH Values Indicated. (Adapted from Fox and Shugar.87)...

A suspension of 4.00g (6.75 mmol) of 3, 5 -bis-0-(p-nitrobenzoyl)-2 -deoxy-5-(trifluoromethyl)uridine in 250 ml of methanol was treated with 10 ml of diisopropylamine and refluxed until it had dissolved (about 18 minutes), and the solution was concentrated. The dry residue was partitioned between 50 ml of chloroform and 50 ml of water. The chloroform layer was washed with 20 ml of water, and the combined aqueous layers were concentrated. A low ultraviolet extinction (e 7200 and 262 pm pH 1) and the presence of isopropyl signals in the NMR spectrum (two singlets aty8.73 and 8.85) indicated the dry residue contained diisopropylamine, probably as a salt with the relatively acidic heterocyclic N-H in 14. 

The ultraviolet absorption spectrum of the coenzyme corresponds to that of uridine. Bromine destroys the uracil moiety of the coenzyme and effects the destruction of biological activity. 

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