Water (1 ?30 mL), NaOH (two M option, 1 ?two mL), and brine (1 ?10 mL). The combined water extracts were left at area temp. until there was full precipitation of the solid impurities (generally overnight). The mixture was then filtered through slow-filtering paper (e.g., Whatman Grade 50) and acidified to pH = two by the slow addition of hydrochloric acid (four M aqueous remedy) to give a lemon yellow slurry. Right after 5 h, the solid was collected on a filter, washed with HCl (0.1 M aqueous remedy, five ?20 mL) and water (50 mL), and dried in vacuo. The dry residue was heated at reflux in acetonitrile (25 mL) for 20 min. Right after standing at five for 2 h, the solid was collected on a filter, washed with cold acetonitrile (five ?three mL), and dried in vacuo to provide 6 (4.479 g, 62 ) as a lemon yellow strong [product may have contained residual acetonitrile (30?0 mol- , 1.5? wt.- )]; m.p. 280 (steadily turned black, decomposition). HPLC purity 95 . C40H40O7S12 (1017.47): calcd. C 47.21, H 3.96, S 37.82; identified C 46.91, H four.12, S 37.36. MS (ESI): calcd. for C40H39O7S12 [M ?H]- 1014.935; identified 1014.946. IR (KBr): = 2963 (m), 2918 (m), 2860 (m), 1688 (s), 1508 (m), 1453 (m), 1431 (m), 1367 (m), 1317 (m), 1261 (m), 1223 (s), 1167 (m), 727 (w) cm-1. 1H NMR (400 MHz, [D6]DMSO): = 1.59 (s, 9 H, CH3), 1.62 (s, 9 H, CH3), 1.69 (s, 9 H, CH3), 1.72 (s, 9 H, CH3), two.07 (s, 0.eight?.2 H, acetonitrile), six.79 (s, 1 H, OH) ppm.1414958-33-0 web 13C NMR (100 MHz, [D6]-DMSO): = 27.52 (CH3), 28.56 (CH3), 31.35 (CH3), 33.92 (CH3), 60.72 (SCS), 60.80 (SCS), 83.59 (COH), 122.11 (C), 133.40 (C), 138.33 (C), 139.87 (C), 140.60 (C), 140.94 (C), 167.06 (CO2H) ppm. Tris(8-carboxy-2,2,six,6-tetramethylbenzo[1,2-d;4,5-d]bis[1,3]dithiol-4-yl)methyl (five) and Quinone Methide 7 A suspension of six (0.375 g, 0.37 mmol) in freshly distilled TFA (four mL) was stirred for 16 h at area temp. under argon.1175052-07-9 manufacturer [24] The deep colored greenish-brown answer was concentrated in vacuo to provide a black cake. The cake was dissolved in NaOH (two M remedy, 5 mL, 10 mmol), and also the resulting remedy was diluted with water (ten mL) to afford a reddish-brown answer.PMID:25959043 [25] The addition of brine (10 mL) resulted inside the formation of an abundant quantity of a fine precipitate. The mixture was left beneath argon for 4 h after which filtered by means of slow-filtering paper. The deep green clear filtrate was acidified to pH = 3 by the addition of HCl (2 M resolution) to give five (0.206 g, 56 ), which was isolated as reported above. The solid material collected on the filter and was washed with water/brine (1:1 v/v, three ?five mL). The strong was then dissolved in acidified methanol [concentrated HCl (25 ) in methanol (50 mL)]. The resulting deep purple solution was concentrated in vacuo, along with the crude solution was purified by column chromatography on silica gel (dichloromethane/methanol, from 20:1 to three:1 v/v) to afford quinoide 7 (0.078 g, 22 ) as a reddish-black powder; m.p. 280 (decomposition). Information for 7: MS (ESI): calcd. for C39H37O5S12 [M ?H+]- 968.929; discovered 968.935. IR (KBr): = 2957 (m), 2920 (s), 2851 (m), 1686 (m), 1659 (m), 1603 (s), 1585 (s), 1495 (m), 1452 (s), 1385 (s), 1366 (s), 1231 (s), 1150 (s), 1105 (m), 733 (m) cm-1. UV/Vis (methanol): max (, Lmol-1cm-1) = 276 (38100), 369 (11700), 477 (9600), 529 (10800) nm. 1H NMR (400 MHz, [D6]DMSO): = 1.57 (s, six H, CH3), 1.63 (s, 6 H, CH3), 1.69 (s, six H, CH3), 1.71 (s, six H, CH3), 1.72 (s, six H, CH3), 1.76 (s, 6 H, CH3) ppm. 1H NMR (600 MHz, CD3OD): = 1.64 (s, 6 H, CH3), 1.72 (s, 6 H, CH3), 1.74 (s, six H,.