Nts of rising polarity (from petroleum ether to MeOH) to yield 9 fractions (Fr.1 r.9). Fr.1 was subjected to Sephadex LH-20 (acetone) and preparative-TLC to afford 2 (4.five mg). Fr.3 was separated by column chromatography (CC) on Lobar LiChroprep C18 eluting with MeOH 2O gradient to offer 5 sub-fractions (Fr.3.1 r.3.five). Fr.three.3 was then chromatographed on silica gel eluting with CHCl3 eOH gradient (60:1) and additional purified by Sephadex LH-20 (MeOH) to afford 3 (9.4 mg), 5 (7.1 mg), and eight (five.1 mg). Fr.four was also further separated by CC on silica gel to give five subfractions (Fr.four.1 r.four.five). Fr.4.2 was purified by CC on Sephadex LH-20 (MeOH) and by semi-preparative HPLC using MeOH 2O gradient (50:50) to yield 1 (4.1 mg, tR 25.6 min), 7 (7.0 mg, tR 18.1 min), and six (28.7 mg, tR 20.8 min). Fr.four.4 was subjected to CC on silica gel making use of CHCl3 eOH gradient (50:1) and purified by Sephadex LH-20 (acetone) to obtain 9 (10.two mg), ten (5.four mg), and 4 (14.6 mg). Compound 1: yellowish oil; []D27 -224 (c 0.25, MeOH); UV (MeOH) max (log ) 200 (4.31), 291 (4.09) nm; CD max () 195 (-4.36), 203 (-16.79), 252 (-1.56), 288 (-11.82) nm; 1H and 13C NMR data, see Table 1; HRESIMS m/z 275.1398 [M + H]+ (calcd for C15H19N2O3, 275.1390), 297.1216 [M + Na]+ (calcd for C15H18N2O3Na, 297.1215). Compound 2: white amorphous powder; []D27 -8.3 (c 0.12, CHCl3); UV (MeOH) max (log ) 215 (4.54), 237 (4.05), 331 (four.01) nm; 1H and 13C NMR information, see Table two; HRESIMS m/z 211.0597 [M + H]+ (calcd for C10H11O5, 211.0607). Compound 3: white amorphous powder; UV (MeOH) max (log ) 200 (three.69), 217 (three.58), 255 (three.75), 288 (3.27), 300 (three.26), 333 (3.29) nm; 1H NMR data (at 500 MHz in DMSO-d6): H 6.4-Bromo-3-hydroxypyridine Purity 69 (s, H-3), 7.24 (s, H-5), 6.65 (s, H-9), six.53 (s, H-11), 10.25 (s, OH-10), 2.73 (s, H-14), 3.89 (s, H-15), three.94 (s, H-16); 13 C NMR information (at 125 MHz in DMSO-d6): C 102.0 (C, C-1), 163.five (C, C-2), 97.3 (CH, C-3), 164.5 (C, C-4), 102.1 (CH, C-5), 139.8 (C, C-6), 116.six (C, C-7), 137.7 (C, C-8), 116.six (CH, C-9), 158.4 (C, C-10), 100.7 (CH, C-11), 153.five (C, C-12), 156.1 (C, C-13), 24.eight (CH3, C-14), 56.5-Bromobenzene-1,3-diamine In stock 1 (CH3, C-15), 55.PMID:23399686 six (CH3, C-16). HRESIMS m/z 287.0918 [M + H]+ (calcd for C16H15O5, 287.0920). three.5. Computational Facts Conformational searches for 1a and 1b were performed by way of the Dreiding force field in MarvinSketch irrespective of rotations of methyl and hydroxyl groups [24], the geometries of which have been additional optimized in the B3LYP/6-31G (d) level in methanol to provide the conformers (3 for 1a and two for 1b, see Figures five and six, respectively) within a 3 kcal/mol power threshold in the global minimum with no vibrational imaginary frequencies. The optimized conformers were then subjected for the calculations of ECD spectra applying the time-dependent density functional theory (TD-DFT) method at theMar. Drugs 2013,B3LYP/6-31G(d) level, which have been drawn by means of SpecDic application with sigma = 0.25 and UV shift = -20 nm (magnified by 0.five times) and weighted by Boltzmann distribution (Figure three), respectively [25]. All of the above calculations had been performed using the integral equation formalism variant polarizable continuum model (IEF-PCM) as implemented in Gaussian 09 [26]. Figure five. Conformers with populations of 1a (in MeOH).24.537.438.1Figure six. Conformers with populations of 1b (in MeOH).39.760.33.six. Antibacterial Assays The experiments have been performed working with the disk diffusion method [27]. Chloromycetin was applied as good control. three.7. Brine Shrimp (Artemia salina) Lethality Assay The assay was c.
