15N Double-Labeled Guanosine from Inosine through Ring-Opening−Ring-Closing and One-Pot Pd-Catalyzed C−O and C−N Cross-Coupling Reactions
摘要:
[N,1-N-15(2)]-Guanosine, or [1,NH2-N-15(2)]-guanosine, and derivatives were prepared from tri-O-acetylinosine, via N-nitration and reaction with (NH2OH)-N-15, followed by conversion of the N-15-labeled 1-hydroxyinosine to the corresponding 2,6-dichloropurine riboside. The sequential one-pot C-O and C-N key couplings of this dichloro derivative with PhCH2OH and (PhCONH2)-N-15 or (PrCONH2)-Pr-i-N-15 was achieved in good overall yields, with Pd(0)-Xantphos as the best choice of five different catalytic systems examined.
Use of a <sup>13</sup>C Atom To Differentiate Two <sup>15</sup>N-Labeled Nucleosides. Syntheses of [<sup>15</sup>NH<sub>2</sub>]-Adenosine, [1,NH<sub>2</sub>-<sup>15</sup>N<sub>2</sub>]- and [2-<sup>13</sup>C-1,NH<sub>2</sub>-<sup>15</sup>N<sub>2</sub>]-Guanosine, and [1,7,NH<sub>2</sub>-<sup>15</sup>N<sub>3</sub>]- and [2-<sup>13</sup>C-1,7,NH<sub>2</sub>-<sup>15</sup>N<sub>3</sub>]-2‘-Deoxyguanosine
作者:Hong Zhao、Alex R. Pagano、Weimin Wang、Anthony Shallop、Barbara L. Gaffney、Roger A. Jones
DOI:10.1021/jo971206u
日期:1997.10.1
We report the first examples of the specifically N-15 and C-13 multilabeled nucleosides: [1,NH2-N-15(2)]- and [2-C-13-1,NH2-N-15(2)-]-guanosine; [1,7,NH2-N-15(3)]- and [2-C-13-1,7,NH2-N-15(3)]-2'-deoxyguanosine. In each set, the [C-13] atom functions as a ''tag'' that allows the N1 and N2 N-15 atoms of two N-15-labeled guanines to be unambiguously differentiated in RNA and DNA fragments. The syntheses employ high-yield reactions in which protecting groups are not required and use relatively low cost sources of isotopes: [N-15]-ammonium chloride and [N-15]- Or [C-13,N-15]-potassium cyanide.