Table 2. Summary of All Nucleobase Labels As Outlined in Schemes 1–11.
| nucleobase label | time (days)a | chemical stepsb | yield (%) | ref |
|---|---|---|---|---|
| [8-13C]-adenine | 1 | 1 | 64 | (75), (85) |
| [8-13C]-guanine | 1 | 1 | 94 | (75), (85) |
| [2-13C]-adeninec | 2.5 | 7 (1) | 18 | (104) |
| [1-15N]-adenine | 2.5 | 2 (1) | 60 | (101) |
| [3-15N]-adenine | 11 | 6 (2) | 47 | (108) |
| [7-15N]-adeninec | 2.5 | 7 (1) | 18 | (104) |
| [7-15N]-guanined | 1.5 | 3 | 65 | |
| [9-15N]-adenine | 5.5 | 3 (3) | 79 | (117) |
| [6-13C, 5-2H]-uracil | 7 | 4 | 63 | (82), (85) |
| [5-13C, 5-19F, 6-2H]-uracil | 8 | 5 | 38 | (18), (57), (82), (85), (86) |
| [6-13C]-thymine | 2.5 | 3 | 45 | (89) |
a
Total reaction time was based on the time required for all chemical steps. In addition, 16 h were added for any explicit mention of overnight procedures, and 24 h were added for any chromatographic purifications.
b
Number in parentheses represents the number of chromatographic purification steps.
c
All data for [2-13C]-adenine and [7-15N]-adenine labeling came from the same doubly labeled [2-13C, 7-15N]-adenine labeling scheme.104
d
This synthetic procedure is from Dayie and co-workers.500