99523-90-7Relevant academic research and scientific papers
The Differentiation of ?- and τ- Derivatised Histidines
Colombo, Roberto,Colombo, Fabio,Derome, Adrew E.,Jones, John H.,Rathbone, Daniel L.,Thomas, David W.
, p. 1811 - 1816 (2007/10/02)
Two simple methods of differentiating ?- and τ-derivatised histidines unambiguously are described.The first involves conversion into the two known im-methyl-L-histidines, which, to avoid all possible confusion arising from ambiguous nomenclature and previous work, have been correlated with N(α)-t-butyloxycarbonyl-N(?)-benzyloxymethyl-L-histidine, whose structure has been established by X-ray crystallography.The second method, which is appropriate for im-substituents of type RCH2-, involves the measurement of nuclear Overhauser effects.If the substituent is at the ?-position, the CH2 signal is enhanced if the low-field adjacent proton between the heterocyclic nitrogens is irradiated, but not if the high-field, more distant, ring proton is irradiated.If the substituent is at the τ-position, the CH2 signal is enhanced whichewer of the equidistant ring protons is irradiated.
