Table 2 Yields & MALDI-FTMS and ESI-QToF analysis of C8–H alkylation of oligonucleotides a

From: Late-stage guanine C8–H alkylation of nucleosides, nucleotides, and oligonucleotides via photo-mediated Minisci reaction

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Entry

Oligonucleotides & sequence

Yield [%]b

Free radical precursors

Calcd. exact mass

Exptl. m/z (MALDI-FTMS)

1

Guanosine

G

99c

Et-B(OH)2

311.1230

[M-H]− = 312.1309d

2

GpA

5′-GA-3′

71c

Et-B(OH)2

640.1755

[M+Na]− = 663.1656d

3

GpG

5′-GG-3′

59c

Et-B(OH)2

684.2017

[M-H]− = 683.1948d

4

GpC

5′-GC-3′

66c

Et-B(OH)2

616.1643

[M-H]− = 615.1554d

5

ON 1

5′-GUUUCC-3′

78

Et-B(OH)2

1839.2814

[M + H]+ = 1840.31214

6

ON 2

5′-UUUGCC-3′

71

Et-B(OH)2

1839.2814

[M + H]+ = 1840.28383

7

ON 3

5′-UUUCCG-3′

80

Et-B(OH)2

1839.2814

[M + H]+ = 1840.29030

8

ON 4

5′-GUUACC-3′

78

Et-B(OH)2

1862.3087

[M + H]+ = 1863.31278

9

ON 5

5′-AUUGCC-3′

69

Et-B(OH)2

1862.3087

[M + H]+ = 1863.31867

10

ON 6

5′-GCUAUCU-3′

63

Et-B(OH)2

2168.3340

[M + H]+ = 2169.36146

11

ON 7

5′-GUUACCUU-3′

73

Et-B(OH)2

2474.3593

[M + H]+ = 2475.35981

12

ON 8

5′-GUUACCUCU-3′

74

Et-B(OH)2

2779.4006

[M + H]+ = 2780.42431

13 e

ON 5

5′-AUUGCC-3′

59

nPr-B(OH)2

1876.3243

[M + H]+ = 1877.31866

14f

ON 5

5′-AUUGCC-3′

31

N3(CH2)3-Bpin

1917.3257

[M + H]+ = 1918.30266

15g

ON 5

5′-AUUGCC-3′

57

Cyclobutyl-B(OH)2

1888.3243

[M + H]+ = 1889.30149

16h

ON 5

5′-AUUGCC-3′

63i

Cyclopentyl-B(OH)2

1902.3400

[M + H]+ = 1903.33673

  1. aGeneral condition: Oligonucleotide (100 nmol), ethylboronic acid (400.0 equiv.), MesAcr (50 mol%), (NH4)2S2O8 (200.0 equiv.), TFA (50.0 equiv.), and catechol (100.0 equiv.) in MeCN (0.25 mL), H2O (0.25 mL), irradiated by 85 W white light at r.t. for 16 h.
  2. bYields were determined by LC-MS and used the analytical method B.
  3. cYields were determined by LC-MS and used the analytical method A.
  4. dThe mass data was collected by using HRMS.
  5. eN-butylboronic acid (400.0 equiv.) was used, and reaction time was extended to 24 hours.
  6. falkylpinacolyl boronate esters (400.0 equiv.) was used, and methylboronic acid (400.0 equiv.) was additionally added.
  7. gCyclobutylboronic acid (200.0 equiv.) was used, equivalent of catechol has been reduced to 200, and irradiated by 10 W white LED at 10 °C.
  8. hCyclopentylboronic acid (400.0 equiv.) was used, and irradiated by 10 W white LED at 10 °C.
  9. iYields were determined by LC-MS and used the analytical method C.
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