Stannous Chloride → 6-amino-1-[2-(trimethyl-silanyl)-ethoxymethyl]-3-{1-[2-(trimethyl-silanyl)ethoxymethyl]-1-H-benzoimidazol-2-yl}-1-H-indazole

Participants

Reaction Conditions

Reaction Steps

Tin(II) chloride (12.0 g, 63.3 mmol) was added to a solution of 6-nitro-1-[2-(trimethyl-silanyl)-ethoxymethyl]-3-{1-[2-(trimethyl-silanyl)-ethoxymethyl]-1-H-benzoimidazol-2-yl}-1-H-indazole (7.18 g, 13.3 mmol) in DMF/H2O (160 mL/10 mL), and the reaction stirred at 50° C. for 2.5 h. The reaction was cooled to 0° C., and saturated sodium bicarbonate was added slowly, with mixing, until all frothing from quenching had subsided. The material was concentrated in vacuo and taken up in ether (100 mL). Insoluble material was removed by filtration and rinsed with ether (50 mL). The filtrate was washed with brine (50 mL), dried (Na2SO4), and concentrated in vacuo. Purification by silica gel chromatography (25% ethyl acetate/hexane) gave 6.05 g (89%) of 6-amino-1-[2-(trimethyl-silanyl)-ethoxymethyl]-3-{1-[2-(trimethyl-silanyl)-ethoxymethyl]-1-H-benzoimidazol-2-yl}-1-H-indazole as a faintly yellow waxy solid. 1H NMR (300 MHz, CDCl3) δ 8.40 (d, 1 H, J=9.0 Hz), 7.89–7.86 (m, 1 H), 7.63–7.60 (m, 1 H), 7.35–7.31 (m, 2 H), 6.78 (dd, 1 H, J=8.7, 1.8 Hz), 6.75 (s, 1 H), 6.25 (s, 2 H), 5.69 (s, 2 H), 3.93 (br s, 2 H), 3.65–3.55 (m, 4 H), 0.93 (t, 2 H, J=8.1 Hz), 0.85 (t, 2 H, J=8.1 Hz), −0.04 (s, 9 H), −0.15 (s, 9 H). Anal. (C26H39N5O2Si2) C, H, N. Calculated: C, 61.26; H, 7.71; N, 13.74. Found: C, 61.18; H, 7.65; N, 13.82.

Provenance & Evidence