.06 g, 0.ten mmol, 76 , Rf = 0.36 (60:40 hexanes:EtOAc)). 1H NMR (CDCl3, 500 MHz): 8.20 (br s, 1H, NH), 7.56 (d, J = eight.7 Hz, 1H, ArH), 7.26 (d, J = 9.0 Hz, 2H, ArH) six.96 (s, 2H, ArH), 6.94 (d, J = eight.7 Hz, 1H, ArH), six.78 (d, J = 8.6 Hz, 2H, ArH), three.88 (s, 3H, OCH3), 3.80 (s, 3H, OCH3), three.76 (s, 3H, OCH3), three.70 (s, 6H, OCH3), 1.09 (s, 9H, C(CH3)3), 0.26 (s, 6H, Si(CH3)2). 13C NMR (CDCl3, 125 MHz): 192.0, 160.two, 152.six, 146.0, 142.eight, 141.three, 134.9, 130.3, 129.99, 129.95, 125.0, 124.eight, 114.4, 114.two, 113.4, 109.9, 107.five, 61.0, 56.7, 56.two, 55.five, 26.3, 18.eight, -4.1. HPLC: 20.21 min., purity at 254 nm 99 . HRMS (ESI+): m/z calculated for C32H39NNaO7Si [M +Na]+ 600.2388, located 600.2383. 4.1.20. 2-(3-tert-Butyldimethylsiloxy-4-methoxyphenyl)-3-(3,four,5trimethoxybenzoyl)-6,7-dimethoxyindole (24)–To a remedy of compound 11 (0.25 g, 0.60 mmol) in o-dichlorobenzene (10 mL) was added three,4,5-trimethoxybenzoyl chloride (0.15 g, 0.66 mmol). The reaction mixture was heated to reflux at 160 for 12 h. The odichlorobenzene was removed by easy distillation, along with the resulting dark green colored solid was subjected to flash chromatography working with a prepacked 50 g silica column [solvent A: EtOAc; solvent B: hexanes; gradient: 7 A / 93 B (four CV), 7 A / 93 B 60 A / 40 B (10 CV), 60 A / 40 B (five.Minocycline hydrochloride 2 CV); flow rate: 50 mL/min; monitored at 254 and 280 nm] resulting in TBS-indole 24 as a yellow powder (0.08 g, 0.14 mmol, 23 , Rf = 0.17 (70:30 hexanes:EtOAc)). 1H NMR (CDCl3, 500 MHz): 8.53 (br s, 1H, NH), 7.71 (d, J = eight.5 Hz, 1H, ArH), 6.98 (m, 4H, ArH) 6.77 (d, J = 2.0 Hz, 1H, ArH), 6.73 (d, J = 8.five Hz, 1H, ArH), 4.06 (s, 3H, OCH3) 3.96 (s, 3H, OCH3), three.79 (s, 3H, OCH3), 3.76 (s, 3H, OCH3), three.69 (s, 6H, OCH3), 0.94 (s, 9H, C(CH3)3), 0.03 (s, 6H, Si(CH3)2). 13C NMR (CDCl3, 125 MHz): 191.eight, 152.six, 151.eight, 148.0, 145.two, 142.eight, 141.3, 134.6, 134.0, 130.two, 125.2, 125.1, 122.3, 122.2, 116.8, 113.1, 111.8, 110.four, 107.four, 61.three, 60.9, 57.3, 56.1, 55.five, 25.8, 18.five, -4.7. HPLC: 19.24 min., purity at 254 nm 99 . HRMS (ESI+): m/z calculated for C33H41NNaO8Si [M+Na]+ 630.2494, found 630.2491. 4.1.21. 2-(3-Hydroxy-4-methoxyphenyl)-3-(three,5-dinitrobenzoyl)-6methoxyindole (25)–To a well-stirred remedy of compound 13 (0.40 g, 0.69 mmol) in THF (ten mL) at 0 was added tetrabutylammonium fluoride (TBAF) (1.Cyproheptadine 03 mL, 1.PMID:36014399 03 mmol, 1 M in THF) dropwise. The reaction mixture was stirred for 30 min though warming to space temperature. The reaction mixture was quenched with water (ten mL) and extracted with EtOAc (three ten mL). The combined organic extract was dried more than Na2SO4 and concentrated beneath lowered stress. Purification by flash column chromatography applying aNIH-PA Author Manuscript NIH-PA Author Manuscript NIH-PA Author ManuscriptBioorg Med Chem. Author manuscript; offered in PMC 2014 November 01.MacDonough et al.Pageprepacked 50 g silica column [solvent A: EtOAc; solvent B: hexanes; gradient: 7 A / 93 B (four CV), 7 A / 93 B 60 A / 40 B (10 CV), 60 A / 40 B (two CV); flow rate: 40 mL/min; monitored at 254 and 280 nm] afforded the preferred indole totally free phenol ligand 25 (0.15 g, 0.33 mmol, 47 , Rf = 0.12 (70:30 hexanes:EtOAc)) as a yellow powder. 1H NMR ((CD3)2SO, 500 MHz): 12.21 (br s, 1H, NH), 9.06 (br s, 1H, OH), 8.68 (t, J = 2.0 Hz, 1H, ArH), eight.41 (d, J = two.0 Hz, 2H, ArH) eight.05 (d, J = 8.5 Hz, 1H, ArH), 6.97 (dd, J = 2.0 Hz, 1H, ArH), six.92 (dd, J = 8.5 Hz, two.0 Hz, 1H, ArH), 6.71 (dd, J = eight.0 Hz, 2.0 Hz, 1H, ArH), 6.68 (d, J = eight.five Hz, 1H, ArH), 6.54 (d, J = two.0 Hz, 1H, ArH), 3.83 (s, 3H, OCH3), three.
