We have previously reported the use of a 13C tag at the C2 of 15N-multilabeled purine nucleosides to distinguish the adjacent-labeled 15N atoms from those in an untagged nucleoside. We now introduce the use of an indirect tag at the C8 of 15N7-labeled purine nucleosides. This tag allows unambiguous differentiation between a pair of 15N7-labeled purines in which only one is 13C8 labeled. Although the very small C8-N7 coupling (<1 Hz) precludes its direct detection in 1D 15N spectra, 2D 1H-15N NMR experiments display the large C8-H8 coupling (>200 Hz) because H8 is coupled to both N7 and C8. The 13C8 atom is introduced by means of a ring closure of the exocyclic amino groups of a pyrimidinone using [ 13C]sodium ethyl xanthate. Here, we present methods for the syntheses of [8-13C-1,7,NH2-15N 3]adenosine, -guanosine, and their deoxy analogues.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Organic Chemistry|
|State||Published - Oct 31 2003|
All Science Journal Classification (ASJC) codes
- Organic Chemistry