1-[[2,4,6-Tris(1-methylethyl)phenyl]sulfonyl]-1H-imidazole

To a stirred suspension of NaH (60percent in oil dispersion) (2.9 g, 72 mmol) in dry THF (200 mL) at 0C was added in portions 16 (2.5 g, 15.8 mmol), followed by 2, 4, 6-triisopropyl-benzenesulfonylimidazole (13 g, 39.6 mmol), and the whole mixture was then stirred for 3 h. Cold H2O (80 mL) was added, and the resulting mixture was extracted with EtOAc (3 × 50 mL). The combined extracts were washed with brine (50 mL) and then dried (anhydrous Na2SO4). Evaporation of the solvent gave the crude product, which was purified by flash chromatography on silica gel (hexane/EtOAc, 50:1) to afford 17 (2.5 g, 42percent yield) as colorless oil. [alpha]D20 -2.0 (c = 1.00, CH2Cl2); 96percent ee; 1H NMR (300 MHz, CDCl3): delta 1.04 (t, J = 7.5 Hz, 3 H), 1.22-1.28 (m, 18 H), 2.02-2.07 (m, 2 H), 2.62-2.68 (m, 2 H), 2.81 (dd, J = 2.5, 4.8 Hz, 1 H), 2.90-2.93 (m, 2 H), 3.22-3.25 (m, 1 H), 4.12-4.16 (m, 2 H), 4.50-4.55 (m, 1 H), 7.18 (s, 2 H); 13C NMR (75 MHz, CDCl3): delta 12.4, 13.9, 22.9, 23.6, 24.7, 24.8, 29.8, 34.3, 45.5, 52.5, 72.9, 79.4, 85.2, 123.8, 130.7, 150.6, 153.7; HRMS (ESI): m/z [M+Na]+ calcd for C23H34O4SNa: 429.2070; found: 429.2073.To a stirred suspension of NaH (60percent in oil dispersion) (2.9 g, 72 mmol) in dry THF (240 mL) at 0C was added in portions 7 (3.8 g, 24 mmol), followed by 2, 4, 6-triisopropyl-benzenesulfonylimidazole (20 g, 60 mmol), and the whole mixture was then stirred for 3 h. Cold H2O (100 mL) was added, and the resulting mixture was extracted with EtOAc (3 × 40 mL). The combined extracts were washed with brine (50 mL) and then dried (anhydrous Na2SO4). Evaporation of the solvent gave the crude product, which contains 12 and its regioisomer 13 with a ratio of 3:1. The mixture was purified by flash chromatography on silica gel (hexane/EtOAc, 50:1) to afford 12 and 13. For 12 (4.1g, 41percent yield; colorless oil): [alpha]D20 +2.0 (c = 1.00, CH2Cl2); 94.6percent ee; 1H NMR (300 MHz, CDCl3): delta 1.04 (t, J = 7.5 Hz, 3 H), 1.22-1.29 (m, 18 H), 2.01-2.08 (m, 2 H), 2.60-2.70 (m, 2 H), 2.81 (dd, J = 2.55, 4.81 Hz, 1 H), 2.90-2.93 (m, 2 H), 3.20-3.28 (m, 1 H), 4.12-4.16 (m, 2 H), 4.50-4.54 (m, 1 H), 7.18 (s, 2 H); 13C NMR (75 MHz, CDCl3): delta 12.3, 14.0, 23.0, 23.6, 24.7, 24.8, 29.8, 34.3, 45.5, 52.4, 72.8, 79.4, 85.2, 123.8, 130.7, 150.6, 153.7; HRMS (ESI): m/z [M+Na]+ calcd for C23H34O4SNa: 429.2070; found: 429.2073. For 13 (1.3g, 14percent yield; colorless oil): 1H NMR (400 MHz, CDCl3): delta 1.08 (t, J =7.5 Hz, 3H), 1.25-1.28 (m, 18H), 2.07-2.26 (m, 3H), 2.52-2.61 (m, 1H), 2.85-2.99 (m, 1H), 3.18-3.28 (m, 2H), 4.03-4.22 (m, 3H), 4.39 (dd, J = 3.81, 11.42 Hz, 1H), 7.20 (s, 2H); 13C NMR (100 MHz, CDCl3): delta 12.4, 14.0, 19.1, 23.7, 24.8, 24.8, 29.8, 34.4, 53.5, 54.7, 67.1, 73.1, 84.9, 124.0, 129.1, 151.0, 154.1; HRMS (ESI): m/z [M+Na]+ calcd for C23H34O4SNa: 429.2070; found: 429.2073. The enantiomeric excess of 12 was determined by chiral HPLC analysis (column, Chiralpak AD-H, 4.6 mm × 250mm, n-hexane / i-PrOH = 97:3; flow rate: 0.5 mL/min, lambda = 230nm). The retention times corresponding to 12 and its enantiomer are 12.8 min and 10.2 min, respectively.

Coupling or condensation reagents used in oligonucleotide synthesis.

Molecular Weight:334.5
XLogP3:4.6
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:5
Exact Mass:334.17149925
Monoisotopic Mass:334.17149925
Topological Polar Surface Area:60.3
Heavy Atom Count:23
Complexity:464
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes