We report a high-yield route to the following specifically 15N- and 13C-multilabeled nucleosides: [1,3,NH2-15N3]- and [2-13C-1,3,NH2- 15N3]-adenosine; [1,3,NH2-15N3]- and [2-13C-1,3,NH2-15N3]- guanosine; [1,3,NH2-15N3]- and [2-13C-1,3,NH2-15N3]-2'- deoxyadenosine; [1,3,NH2-15N3]- and [2-13C-1,3,-NH2-15N3]-2'- deoxyguanosine. In each set, the 13C2 atom functions as a 'tag' that allows the 15N1 and 15N3 atoms to be unambiguously differentiated from the untagged versions in 15N NMR of RNA or DNA fragments. The key intermediate of this synthetic strategy for both the adenine and guanine nucleosides is [NH2,CONH2-15N2]-5-amino-4-imidazolecarboxamide. The [2-13C]-label is added through a ring closure using [13C]-sodium ethyl xanthate (NaS13CSOEt). Enzymatic transglycosylation of either multilabeled 6- chloropurine or multilabeled 2-mercaptohypoxanthine and a final reaction with 15NH3 give the adenine and guanine nucleosides. This is the first report of a [3-15N]-labeled guanine nucleoside.
ASJC Scopus subject areas
- Organic Chemistry